East Greenland 72-74° N Inland to Coast Thermo-tectonic Evolution

Jensen, Peter K.; Hansen, Kirsten

Publication date: 2018

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Citation for published version (APA): Jensen, P. K., & Hansen, K. (2018). East Greenland 72-74° N Inland to Coast Thermo-tectonic Evolution. 130.

Download date: 27. sep.. 2021 1. Igneous rocks and processes 1.1 Hotspots and intraplate signatures close to those of lithospheric wallrock materials. We suggest that, with the possible magmas: mantle sources, exception of very strongly enriched magma types, magmatic processes and the continental lithosphere has in many cases metasomatism. acted as a ‘pepper mill’, only spicing up CFB magmas otherwise predominantly generated in

the sublithospheric mantle. ORAL

The role of sublithospheric mantle ORAL sources in continental flood basalt magmatism: lessons learned from the Magmatism associated with Karoo LIP Gondwanaland rifting: Evidence from Iraq Zagros Suture Zone Jussi S. Heinonen1, Arto V. Luttinen2, Teal R. Riley3 and Sanni Turunen2 Sabah Ismail1 and Shaleer Burhan2 1Department of Geosciences and Geography, University 1Education college for pure sciences/Kirkuk of Helsinki, 2Finnish Museum of Natural History, University/Iraq, 2Applied Geology Department/Kirkuk University of Helsinki, 3British Antarctic Survey University/Iraq

The role of sublithospheric mantle sources is The opening of the southern basin of the Neo- elusive in continental flood basalt (CFB) Tethys as a result of the breakup of Gondwana provinces. This is because on their way to the during Late Triassic was accompanied by the surface of the Earth, the parental magmas of CFBs eruption of flood basalts. This process led to the interact with thick continental lithosphere and fragmentation of continental lithosphere and may lose their primary geochemical rifting of these fragments from the northern characteristics. Several studies have also margin of Gondwana and created deep trench suggested that the predominant mantle sources grabens which were subsequently filled by of continental flood basalts are within the radiolarite deposits. Such events are well continental lithosphere. Our studies in the documented in southern Turkey, northwestern Antarctic and, more recently, African parts of the Syria and southwestern Cyprus. Fragments Early Jurassic Karoo LIP over the past 25 years related to these activities also exist as thrust have revealed the existence of several nappes in the Iraqi Zagros Suture Zone(Avroman sublithospheric mantle-derived magma types. platform limestone and Qulqula radiolarite)Such Their sources range from depleted upper mantle nappes also occur systematically beneath the (DM) to different kinds of enriched mantle (EM), obducted ophiolites from Greece to Oman. In the and possibly even to ancient primordial plume Iraqi Zagros Suture Zone the Late Triassic sources originating from the core-mantle Avroman nappe was thrusted over the Early boundary. Whereas the recognized EM sources Cretaceous Qulqula radiolarite and both were seem to be anomalous and had minor thrusted over the Late Cretaceous ophiolites. The contributions to Karoo magmatism, the DM and Avroman volcanics are lava flows consisting of primordial-like sources may have been very olivine-basalts, diabases, trachytes and tuffs. important in the generation of voluminous Karoo Previous K-Ar dating of a diabase rock gave an magmas. Energy-constrained assimilation‒ age of 220 Ma ± 20. Geochemical analysis of these fractional crystallization modeling has revealed rocks indicates that the alkali olivine basalts are that only a few percent of assimilation can shift strongly enriched in light rare earth elements the CFB trace element and radiogenic isotope without Eu anomalies. Trace element data for the

1 most primitive mafic igneous rock samples end-members: Two have Nb-depleted suggest that the tholeiitic basalts are derived compositions relative to primitive mantle, but from an enriched mantle source with OIB markedly different depleted and enriched signature formed within plate activity. This isotopic compositions. The third end-member is alkaline magmatism may have taken place as Nb-undepleted and shows isotopic affinity to continental flood basalts erupted during rifting of bulk silicate Earth. Three Karoo picrite suites can Gondwana at Norian with evidences of mantle be associated with these end-members, whereas plume interaction in the early rifting phase other picrites probably represent subordinate related to the opening of the Neo-Tethys. mantle components.

In the Karoo province, the delta-Nb tracers pave the way for: (1) provincial scale mapping of ORAL mantle heterogeneity using variably contaminated flood basalts and (2) identification Tracing of mantle heterogeneity in of picrites best suited for geochemical Karoo flood basalts using Nb-Zr-Ti-Y characterisation of the major mantle ratios components.

Arto Luttinen1, Sanni Turunen1 and Jussi Heinonen2 1Finnish Museum of Natural History, P.O. Box 44, 00014 ORAL University of Helsinki, Finland, 2Department of Geosciences and Geography, P.O. Box 64, 00014 Assessing primary vs. secondary University of Helsinki, Finland geochemical fingerprints of Icelandic basalts using high-Fo# olivine The study of mantle sources of continental flood crystals basalt provinces is often compromised by crustal Maja B. Rasmussen1, Sæmundur A. Halldórsson1, contamination overprinting of the incompatible Martin J. Whitehouse2, Sally A. Gibson3 and David element and isotopic ratios of the predominant R. Hilton4 rock types. Geochemical tracers which are 1Nordic Volcanological Center, University of Iceland, unaffected by contamination help to: (1) identify Reykjavik, Iceland, 2Swedish Museum of Natural co-genetic types of flood basalts, (2) establish History, Stockholm, Sweden, 3University of Cambridge, parent-daughter relationships between flood Cambridge, UK, 4Scripps Institution of Oceanography, basalt types and rare uncontaminated picrites, UCSD, La Jolla, USA and (3) constrain mantle source heterogeneity even when picrite types are unknown. Identification of such tracers has turned out to be Oxygen isotope ratios (d18O) of Icelandic basalts difficult, however. are notably distinct from MORB-sourced basalts. Two prevailing hypotheses have been put We have examined variations of Nb/Y, Nb/Zr, and forward to account for this: interaction with low- Nb/Ti at given Zr/Y (quantified d18O crust or mantle heterogeneity [1]. High-Fo# using ΔNbY, ΔNbZr and ΔNbTi) in geochemically olivine crystals are widely used as a proxy for diverse Karoo flood basalts. Importantly, the primary melt composition prior to crustal delta-Nb values are only mildly affected by modification [2]. Therefore, their geochemical melting, crystallisation, and contamination characteristics can be useful to determine the processes and can be used as tracers of mantle source of low-d18O in Icelandic basalts. We couple source heterogeneity. in-situ d18O of high-Fo# (>80) olivine crystals from the neovolcanic rift- and flank zones as well In the Karoo province, the variations as older Tertiary units with major and trace in ΔNb , ΔNb , and ΔNb and initial Nd and Sr Y Zr Ti elements using SIMS, EMPA and LA ICPMS as isotopic ratios call for at least three mantle source tools to identify primary vs. secondary controls

2 on some notable geochemical characteristics of lavas in the Luenha river area, Central Icelandic basalts. Mozambique, reveal a third significant mantle source for Karoo basalts. The olivine crystals show limited intra-grain variability but, collectively, they display a The Luenha picrites differ from other Karoo 18 variation in d O(Ol) of >3 ‰ across Iceland, with picrites based on their high positive ΔNb values most values falling below the expected depleted (+0.5 to +0.6), low Ti contents, and low Zr/Y. mantle-value (~5.1 ±0.2‰ [3]). The lowest Variable initial 87Sr/86Sr and incompatible trace 18 d O(Ol) (+2.77 ‰), is measured in crystals from element ratios likely result from mild crustal central Iceland, close to the inferred plume head contamination. A single picrite sample lacks [4]. Trace element ratios of these olivine crystals indications of contamination and indicates a (e.g., Mn/Fe) suggest a peridotitic mantle source, mantle source with 87Sr/86Sr of 0.7041 and εNd of implying a shallow (likely crustal) origin of the +2 and an overall geochemical affinity to a 18 low d O(Ol). In contrast, crystals from the South primitive or mildly depleted mantle. We maintain Iceland Volcanic Zone display trace element that this magma source may represent the ratios indicative of greater amount of pyroxenite previously unknown mantle component which is 18 in their source region while their d O(Ol) vary required to explain the high abundance of Karoo significantly (from +3.45 to +4.98 ‰). These low-Ti basalts with positive ΔNb. Bearing in mind results, together with previously published that several large igneous provinces (e.g. Ontong 3He/4He values for these same samples [4], imply Java) have been recently associated with melting a regional shift in the dominating mantle of geochemically primitive mantle type plume lithology and plumbing conditions beneath heads, the Luenha picrites may provide a unique Iceland. geochemical insight into a major plume source previously inferred from geophysical studies of the Karoo province.

ORAL

Luenha picrites reveal a primitive ORAL mantle type plume source in the Karoo large igneous province? The important distinction between ancient HIMU and young HIMU-like Sanni Turunen1, Arto Luttinen1 and Jussi sources in intraplate magmatism Heinonen2 1Finnish Museum of Natural History, P.O. Box 44, 00014 Quinten van der Meer1, Tod Waight2, James Scott3 University of Helsinki, Finland, 2Department of and Carsten Münker4 Geosciences and Geography, P.O. Box 64, 00014 1Natural History Museum, University of Copenhagen, University of Helsinki, Finland 2Department of Geosciences and Natural Resource Management (Geology Section), Copenhagen University, 3Department of Geology, University of Otago, 4Institut Two distinctive picrite suites have been für geologie und Mineralogie, Universität zu Köln previously considered to represent important parental magma types in the Karoo large igneous province: (1) the Mwenezi picrites indicate an Continental intraplate magmas with isotopic enriched mantle source (initial εNd ca. -10) of affinities similar to HIMU are identified lithospheric origin for enriched high-Ti basalts, worldwide. Involvement of an asthenospheric whereas (2) the Vestfjella ferropicrites reveal a HIMU or HIMU-like source is contested because depleted convective upper mantle source the characteristic radiogenic Pb compositions at (εNd +8) for low-Ti basalts. Both picrite suites are unradiogenic Sr and moderate Nd and Hf characterised by negative ΔNb values (-0.9 to - compositions can also result from in-situ 0.1) indicative of relative Nb-depletion. Our ingrowth in metasomatised lithospheric mantle. geochemical data on recently discovered picritic Sr-Nd-Pb-Hf isotopic composition of late

3 Cretaceous lamprophyre dikes from Westland, similar to the global array. The second group has New Zealand provide new insight into the high Ni* of 1060 to 1820 and high Mn* of 150 to formation of a HIMU-like alkaline intraplate 175(n=3 of 17 samples), elevated in Ni* and magmatic province under the Zealandia Mn*with respect to the global array. The olivine microcontinent and former contiguous regions of mineral chemistry is independent of whole rock Gondwana. The oldest (102-100 Ma) calc-alkaline trace element and isotope geochemistry that lamprophyres are compositionally similar to the reflects mixing between the mantle source preceding arc-magmatism and represent melts components. originating from subduction-modified lithosphere. From ~98 Ma, alkaline intraplate Olivine crystals from Heard Island that plot along magmatism emerged throughout Zealandia that the global array are consistent with derivation would remain active up to the present day. We from a pyroxenite rich source (60 to 90%). break with the classical grouping of this Furthermore, a pyroxenite rich source lithology is magmatism into a single suite and show that attributed to all geochemical end members. distinct ancient and young enriched sources However, the wide range implies incomplete controlled melt isotopic compositions. The hybridisation or heterogeneous supply of eclogite distribution of these sources in the Cretaceous in the mantle below Heard Island. was strongly coupled to lithosphere terrane The olivine crystals that display elevated Ni* and structure and emphasizes the influence of Mn* potentially reflect melting of the oceanic enriched metasomes in the lithospheric mantle as lithospheric mantle, which has previously been a melt source. metasomatised by melts generated by the mantle plume.

POSTER

Tracing pyroxenite in the mantle POSTER source at Heard Island in the Indian Hydrothermal alteration of the Ocean ultramafic rocks at the Kemi

Abigail K Barker1, Inês G Nobre Silva2, Jane intrusion Barling3 and Naomi J Saunders3 Fabian Mauricio Botello1, Holger Paulick1, Timo 1Mineralogy, Petrology, Tectonics, Uppsala University, Huhtelin2 and Sari Grönholm3 2Memorial University of Newfoundland, 3Department of 1Oulu Mining School, University of Oulu, Finland, Earth Sciences, University of Oxford 2Outokumpu Chrome Oy, Kemi Mine, 3Geological Survey

of Finland-GTK Heard Island hosts the largest active volcano of the Kerguelen Oceanic Plateau, where whole rock The Kemi chromite deposit is located close to the geochemistry suggests an important contribution town of Tornio (northern Finland). The from recycled ocean crust. We present minor mineralization is hosted within the mafic- element compositions for olivine from Heard ultramafic Kemi intrusion that is part of the Island, as a tracer of the initial magma, in order to Tornio – Näränkäväärä belt. This belt consist of investigate the connection between source about 20 individual intrusive igneous complexes lithology and mantle source components. within the Fennoscandian Shield that have been Olivine crystals in the lavas from Heard Island emplaced at 2.4 to 2.5 Ga. The Kemi intrusion has have 72.5 to 87.5 Fo mol% and form two groups a lenticular shape and is about 15 km long and 2 distinguished by Ni and Mn compositions. The km wide in the middle section (Alapieti et al., main group of olivine crystals contain Ni* of 540 1989). The main chromite units are located in the to 870 (Ni*=Ni x FeO/MgO; n = 14 of 17 samples) basal part of the intrusion and have an average and Mn* of 90 to 110 (Mn* = Mn/FeO), which are thickness of 40 m, but vary from a few meters to

4 160m. The chromitite units are enveloped and carried out mineral-melt thermobarometric intercalated with variably altered peridotite and modelling on dykes of the Miocene-Pliocene bronzites. Northeast Rift Zone (NERZ) on Tenerife, which is a superbly exposed example of a feeder system to Hydrothermal alteration has pervasively affected a major ocean island volcanic rift. Our initial the ultramafic sequence mainly in the lower and results point to sub-MOHO level crystallization of upper segments, leaving the middle partly feldspar and pyroxene, in stark contrast to the unaltered (Alapieti et al., 1989). These lithologies latest rift eruption on El Hierro. Our preliminary can still be identified due to the preservation of data thus support a model of rift growth on their primary textures. Bronzites and peridotites Tenerife through injection of mantle-derived hot surrounding the chromitite layers have been fingers. This conclusion is in line with anisotropy altered to serpentine, talc, tremolite, chlorite and of magnetic susceptibility (AMS) data, which carbonates (Gronhölm, 1994). Alteration has also indicate non-unidirectional emplacement of affected chromite grain composition and texture, magma along the rift. Moreover, the mantle finger finding some grains with inclusions of altered model is consistent with plume-like (HIMU) silicate minerals. The occurrence of the radiogenic isotope ratios preserved in many of mentioned alteration assemblages requires the the NERZ dykes. Ocean island rift formation thus influx of fluids rich in SiO2aq (Paulick et al., 2006). appears to differ between islands in the Canary The study of the hydrothermal alteration permits archipelago, which must be taken into interpretation of its origin and makes it possible consideration when assessing mantle versus to establish spatial distribution of the altered crustal geochemical indices. assemblage as well as associations with the ore and possible exploration vectors.

POSTER

POSTER Geochemical characteristics of an enriched Icelandic tholeiitic magma Birthing an ocean island rift: mantle suite: the case of the Kverkfjöll fingers or lateral flow? volcanic system Frances Deegan1, Valentin Troll1, Harri Geiger1, 1 1 Lina Barke1, Juan Carlos Carracedo2 and Eemu Ranta , Sæmundur A. Halldórsson , 1 1 Francisco José Perez-Torrado2 Gu∂mundur H. Gu∂finsson , Enikö Bali , Vesa 2 1 3 1Uppsala University, Uppsala, Sweden, 2Universidad de Nykänen , Karl Grönvold and Riina Kaikkonen Las Palmas de Gran Canaria, Gran Canaria, Spain 1Nordic Volcanological Center, University of Iceland, 2 Reykjavik, ICELAND, Geological Survey of Finland, Rovaniemi, FINLAND, 3Oulu Mining School, University Rift zones play a key role in modulating the of Oulu, FINLAND growth and destruction of ocean islands. However, it is not always clear whether magma The active Kverkfjöll central volcano and its feeds into rifts from the mantle or from beneath associated fissure swarm are situated at the the island’s central complex before being northern margin of the Vatnajökull glacier, diverted into rift zones. Seismic monitoring of the Iceland. The volcanic system is characterized by 2011- 2012 eruption on El Hierro showed that it subglacial pillow basalt ridges and post-glacial was fed by magma that underwent lateral lava flows, erupted on c. 35 km thick crust at the transport at the base of the ocean crust before flank of the Northern Rift Zone (NRZ). Published final ascent. If this is generally true for Canary petrochemical data from Kverkfjöll are very Island rifts, then there may be large implications limited, in contrast to its neighboring volcanoes for rift zone magma evolution and the Bárdarbunga, Grímsvötn and Askja. We present preservation (or crustal modification) of mantle preliminary geochemical and Hf-Pb isotope data isotope signatures. To test this concept, we

5 largely acquired from subglacial pillow rim temperatures of MORBs confirming that the glasses, focusing further on their dissolved melts are derived from the asthenosphere. volatile contents (EPMA, FTIR) as well as trace Applying correction along the olivine-liquidus elements (LA-ICP-MS). slope to sub-lithospheric pressures suggests a mantle segregation temperature of max. ~1300- The Kverkfjöll basalts are noticeably enriched in 1350°C which overlaps the range estimated for FeO (12-16 wt.%), with relatively uniform MORB. Therefore the high Fe/Mn and compositions (MgO = 4-8 wt.%) compared to Ni*FeO/MgO cannot have been caused by melting other tholeiitic magma suites in Iceland. They are of very high temperature peridotitic mantle at anomalously enriched in incompatible elements, large depths as has been suggested for some closely resembling transitional and alkali basalts plume basalts by various authors. Results for from flank zone areas in Iceland. Such trace element modeling in the OBS1 pyroxenite enrichments are also evident in the dissolved melting simulator (Kimura & Kawabata, 2015) on volatile contents of the Kverkfjöll glasses, which primitive samples from Gough Island reproduce are some of the highest in Icelandic basalts (e.g. Cl expected pressures and temperatures of melting = 350 ppm, H2O = 0.9 wt.%). Moreover, the Pb-Pb and suggest 8-13% pyroxenite in the mantle and Pb-Hf isotopic signatures of Kverkfjöll falls in source and ~80% pyroxenite melt in the magmas between the well-defined trend of the NRZ in agreement with the olivine compositions. For basalts and the EM1-like compositions of the comparison, olivine compositions from two Cape flank volcano Öræfajökull, unique among Verde Islands indicate a plume melt end-member Icelandic basalts [1]. derived by peridotite melting at temperatures comparable to those for Gough Island despite The aim of this in-progress study is to address if very similar pressures and extents of melting as the Kverkfjöll basalts sample a distinct, indicated by the La/Sm and Dy/Yb of the basalts. previously unrecognized component of the This shows that the Sobolev et al. (2007) olivine Iceland mantle, or if their volatile enrichment and model is still viable for moderate temperature atypical isotopic signatures can be explained by OIBs. other means.

POSTER

Alkaline OIBs derived by pyroxenite- melting of low-T mantle

Nina Søager1, Maxim Portnyagin2, Paul Martin Holm1 and Dieter Garbe-Schönberg3 1Department of Geosciences and Natural Resource Management, University of Copenhagen, 2Geomar, Helmholtz Centre for Ocean Research, Kiel, Germany, 3Christian-Albrechts-Universität zu Kiel, Kiel, Germany

High precision microprobe and laser ablation analyses of forsteritic olivine phenocrysts from the alkaline EM1-type ocean islands of Gough and Tristan have high ratios of Fe/Mn, Zn/Fe, Ga/Sc and Ni*FeO/MgO suggesting a large pyroxenite melt component in the magmas. Crystallization temperatures calculated for the magmas range between 1140 and 1227°C and overlap the

6 1.2. Volcanism in the North and important to the tectono-volcanic evolution during the transition from pre- to syn-breakup Atlantic, from breakup to magmatism. current time

ORAL ORAL Anatomy of the Sørvágsfjörd volcanic complex: Late Palaeocene explosive Structural links between the Jan basaltic volcanism on the Faroe Mayen Microcontinent and the Islands central East Greenland coast prior to, during, and after breakup. Uni Árting1, Morten S. Riishuus2, Hans Amundsen3, Turid Madsen2 and Nicole Schmitz Anett Blischke1, Ögmundur Erlendsson2, Pierpaolo 1Jarðfeingi & University of the Faroe Islands, 2Jarðfeingi, Guarnieri3, Bryndís Brandsdóttir4 and Carmen 3Vestfonna Geophysical Gaina5 1Iceland GeoSurvey, Branch at Akureyri, Rangárvöllum, 603 Akureyri, Iceland, 2Iceland GeoSurvey, Grensásvegi We report on the basaltic Sørvágsfjörd volcanic 9, 108 Reykjavík, Iceland, 3Geological Survey of complex (SVC) at the base of the Malinstindur Fm Denmark and Greenland (GEUS), Øster Voldgade 10, in the Faroe Islands Basalt Group. This ~1.5 km DK1350 Copenhagen K, Denmark, 4Institute of Earth wide and ~90 m high structure is exposed in a sea Science, Science Institute, University of Iceland, Askja, cliff on Vágar Island. The structure rests on fluvio- Sturlugata 7, Reykjavik, 5Dynamics (CEED), University lacustrine sediments of the Prestfjall Fm and it of Oslo, Sem Sælands vei 24, P.O. Box 1048, Blindern, represents a positive paleo-relief onlapped by Oslo, Norway flood basalts. The SVC composite stratigraphic sequence includes from base to top: i) A detailed tectonostratigraphic framework volcaniclastic sandstone grading into bedded model of the Jan Mayen microcontinent area has tuffs, ii) agglomerates, iii) two ignimbrite units, been correlated with its western conjugate iv) erosion surface, v) paleosol bed, in places margin of central East Greenland, spanning from replaced by lahar/debris flow, vi) ignimbrite unit, the primary North Atlantic breakup (~56-55 Ma) vii) agglomerate, viii) two ignimbrite units, ix) to secondary local breakup processes (~49-21 erosion surface. The complex is faulted and Ma). The reconstructions of the Jan Mayen intruded by stacked sills, dykes and irregular microcontinent and surrounding oceanic crustal plugs. On nearby Tindhólmur islet (1.5 km SSW) evolution demonstrate a clear correlation to a paleo-valley incises the Prestfjall Fm, is filled central East Greenland, with respect to major with lava flows and overlain by lahars and structural boundaries and unconformities within ignimbrites. Another younger and deeper paleo- the stratigraphic record. Igneous stratigraphy valley incises the lahar/ignimbrite sequence and was compared specifically for the plateau basalts, is subsequently filled by lavas, mega-breccia, and the alignment to the Iceland Plateau rift lahars (and re-incised). Both valleys are buried by segments, and to the Igtertivâ Formation of Kap the Malinstindur Fm. The SVC records a Dalton within the Blosseville Kyst area. significant explosive volcanic period characterized by two phases that both include The Jan Mayen microcontinent represents the near-vent agglomerates and pyroclastic density next adjacent graben system besides the currents. The explosive volcanism was preceded Liverpool Land high domain and appears to by regional uplift, faulting, erosion and valley follow the northeast-southwest trending half- incision, followed by construction of positive graben symmetry of the Mesozoic period of the volcanic relief, erosion and continued uplift due Jameson Land Basin. These observations are to intrusion activity, erosion and valley incision based on structural segmentation and trends prior to burial. The SVC is unique within the NAIP visible in Paleozoic-Mesozoic stratigraphic

7 thickness map series for both conjugate areas. Reykjanes ridge AVR are observed at regular The Blosseville Kyst adjacent area of the southern interval. These ridges are formed in multiple extension of the microcontinent indicate a rapid eruptions and occupy the rift valley. However, thinning of the pre-break-up section but increase towards the north rift valleys are absent ore in break-up and post break-up volcanic strata. shallow. In between the rift valleys we observe monogenetic eruptive vents. Reorganization of For the first time we demonstrate that the the plate boundary is observed in magnetic fabric western flank of the Jan Mayen microcontinent of the seafloor and numerous oceanic core was also a volcanic margin, and we reconstruct complexes seem to be related to such the newly mapped Late Eocene to Early Oligocene reorganization. Off rift monogenetic eruptive sub-crop and volcano-facies maps of the Jan vents are also more frequent as we go further Mayen microcontinent aligned to a newly away from Iceland. mapped volcano-facies and structural elements map of the Blosseville Kyst – Scoresby Sund – Liverpool Land basin margin. ORAL

Coast-parallel dolerite dykes along SE ORAL Greenland: Southernmost onshore From Iceland to the Bight Transform evidence of the Tertiary North Fault. Evolution of 1000 km of Atlantic Igneous Province?

Volcanic Rifting Plate Boundary Martin Klausen1, Dominic Loreti1, Christian Tegner2, Charles Lesher2, Thomas Ulrich2 and Armann Hoskuldsson1, Richard N Hey2, Fernando Thomas Kokfelt3 Martinez3, Asdis Benediktsdottir1 and Sigvaldi 1Department of Earth Sciences, Stellenbosch University, 4 Thordarson Private Bag X1, Matieland 7602, South Africa, 1 2 3 University of Iceland, University of Hawaii, University 2Department of Geoscience, Aarhus University, Hoegh- 4 of Hawaii - SOEST/HIGP, Iceland Geosurvey Guldbergs Gade 2, DK-8000 Aarhus C, Denmark, 3Geological Survey of Denmark and Greenland, GEUS, Oester Voldgade 10, DK-1350 Copenhagen K, Denmark Iceland is a part of the NAIP and as such forms a large island in the middle of the north Atlantic. With its continental shelf, Iceland covers about Pristine dolerite dykes of presumed Tertiary age 780 kkm3. The MAR plate boundary crosses have previously been mapped on the SE coast of through Iceland from south to north. In this Greenland, south of where the coast-parallel presentation, we present results from two Tertiary East Greenland dyke swarm (EGDS) missions that cover the southern and northern extends into the Atlantic Ocean (Klausen & part of the Reykjanes ridge. We shall show how Larsen, 2002). Between 64˚15’ and 65˚45’N, the Reykjanes ridge plunges into the abyss from a total of six dykes constituting a more northerly Iceland and follow its extent some 1000 km to the located and E-W trending segment are all south, until it hits the Bight Transform fault. This compositionally similar to the older tholeiites of part of the MAR system is slow spreading with an EGDS (Hanghøj et al., 2003); whereas, twelve average separation of 2 cm per year. Due to dykes constituting a more curved SW-NE unprecedented detailed multibeam mapping in trending southern segment resemble younger the area finest details in volcanic structures can transitional-alkaline EGDS dolerites. Together be observed. However, the active plate boundary with their distinct OIB-like bulk rock geochemical shows remarkable diversity in overall forms and signatures, these two southerly located swarm individual landforms as we extend away from segments most likely formed at the same time as Iceland. Close to Iceland shallow magma storage the main EGDS and were primarily sourced from in the crust is evident, with calderas and evolved a ~600 km southward displaced proto-Icelandic magma composition. At the termination of the hot spot enriched mantle source. Compared to

8 the Icelandic Mantle array by Fitton et al. (1997) Greenland's southern tip and the Laptev and a petrogenetic REE-grid by Tegner et al. Sea. Opening of this c. 6000 km long segment

(1998), relatively high Zr/Y, Nb/Y and (La/Sm)N occurred around a pole in the Laptev Sea, with suggest that the southern segment’s transitional- higher extension rates at the southern distal alkaline primary melts formed through ~ 5% end. SDRs of the magma-rich NEA margins partial mantle melting and segregated at ~30 km diminish northward and are absent in the Eurasia depth. Based on these results – albeit without Basin. This architecture is well known and has supporting absolute ages or cross cutting typically been attributed to the radius of a plume. relationships – we tentatively propose that (1) However, given that plates are approximately early tholeiitic melts formed through rigid, there is another option – that magmatism decompression melting along a proto-Atlantic rift reflects the rate of extension (and associated that lines up with the EGDS, but injected obliquely decompressional melting). The NEA break-up into the E-W trending northern dyke swarm magmatism may therefore be rooted in plate segment; and (2) a dextrally offset off-axis rift tectonics. system allowed for the generation of more alkaline melts to feed more westerly located A relationship between extension rate and melt coast-parallel dykes within the southern swarm generation is further supported by evidence from segment. the margins along the Aegir-Kolbeinsey Ridge pair, located on either side of Jan Mayen.

ORAL ORAL NE Atlantic break-up and magmatism The evolution of Hekla volcano in the Erik Lundin1, A.G. Doré2 and R. Kyrkjebø 20th century: Integrating remote 1 Statoil ASA, Research Center, Arkitekt Ebbels vei 10, sensing data from the past 70 years 7053 Trondheim, NORWAY, 2Statoil (UK) Ltd, One Kingdom Street, London W2 6BD, UK Gro B. M. Pedersen1, Joaquin M. C. Belart1, Fadi

Kizel2, Eyjolfur Magnusson1, Olga K. 3 3 Northeast Atlantic (NEA) break-up in the Early Vilmundardóttir , Friðþór S. Sigurmundsson , 3 2 Eocene has generally been viewed as the Guðrun Gisladóttir and Jón Atli Benidiktsson 1 culmination of a series of episodic rifts events, Institute of Earth Sciences, University of Iceland, Sturlugata 7, 101 Reykjavík, Iceland,, 2Faculty of spanning from Carboniferous through Electrical and Computer Engineering, University of Paleocene. However, Paleocene rifting is Iceland, 3Institute of Life and Environmental sciences, conspicuously minor or absent. We propose University of Iceland development of a dextral Paleocene proto-NEA Transform system that allowed opening without further rifting. Several observations support this Hekla volcano is one of the most active volcanic proposal: the linear, although segmented, line of systems in Iceland and has erupted ~23 times break-up cutting obliquely across the Cretaceous since the settlement of Iceland in AD 874. The hyperextended basin; a steeply terminated outer historical Hekla eruptions have been studied margin; shallowing basement and thickening from written records and tephra chronology. continental crust toward the margin; coeval These eruption records indicate a very constant compression at Greenland's northern leading magma production, which over the last edge, and sinistral motion along its western side. millennium have produced a total of at least 7 km3 (DRE) of eruptive material. The proto-NEA Transform linked with the De Geer Transform and further with a transform In the 20th century Hekla mountain erupted five along the northern Barents and Kara Sea, times (1947-1948; 1970, 1980-1981, 1991, effectively yielding a broken plate between 2000). These eruptions were well documented

9 and it has been estimated that ~80% of the total composition than the upper mantle. However, erupted volume was lava. However, the lava flow since the GIFR initiated just where the embryonic thicknesses used in the volume calculations are North Atlantic rift crossed older Caledonian uncertain due to coarse sampling at selected lava sutures, alternative “top-down” models have thickness profiles or at flow fronts. Accurate lava been proposed, opposing a “bottom-up” model in volume estimates are therefore crucial in order to which an emerging deep mantle plume would asses the volume of eruptive material in the 20th exactly coincide with the location of lithospheric century. weaknesses. Here, we present a new top-down physical model where lithospheric extension led In the Hekla area, repeated aerial stereo- to delamination of a dense quasi-stable mantle photography surveys have been conducted since lithosphere and lower crust. The delaminated 1945 allowing creation of Digital Elevation material sank into the lower mantle and caused a Models (DEMs) and ortho-photographs using plume-like return flow of hot and primordial digital photogrammetric techniques. We selected material that reached the North Atlantic rift seven photogrammetric surveys (1945, 1946, system and caused enhanced melt productivity. 1960, 1979, 1984, 1987, 1992) to construct Our model predicts melt volumes that are of historical DEMs (5m/pixel) and ortho-photos similar magnitude as those observed in the North (0.5-1m/pixel). Together with modern radar- Atlantic, and explains why Iceland remains based DEMs (1998 and 2012-2013) and a lidar- magmatically active at present. based DEM (2015) these data sets provide pre- and post-eruption topography of Hekla for each of the five eruptions in the 20th century. These DEMs allow creation of thickness maps and ORAL thereby unprecedented estimation of lava flow thickness and lava flow volume. Geometry and temporal development of the Faroe Islands Basalt Group in the Faroe-Shetland Basin: Seismic

ORAL mapping and well correlations by chemo/lithostratigraphy A hot, top-down model for the formation of the North Atlantic Morten S. Riishuus1, Uni Árting1, Heri Ziska1 and Jim á Horni1 Igneous Province and the Iceland hot 1Faroese Geological Survey spot

Kenni Dinesen Petersen1, Christian Schiffer2 and The offshore distribution of the Faroe Islands Thorsten Nagel1 Basalt Group (FIBG) has received much debate 1Aarhus University, 2Durham University since the early 1980’s. We present new observations and interpretations on the late Palaeocene-early Eocene volcanic history of the The Greenland-Iceland-Faroe Ridge (GIFR) is an Faroe-Shetland Basin (FSB). These efforts are area that has been magmatically hyperactive based on novel integration of i) seismic mapping since the formation of the North Atlantic Igneous of the geometry of the pre- and syn-breakup Province at ~55 Ma. The magmatic crustal volcanic piles and volcanic facies with ii) thickness and its compositions is different from chemo/litho-stratigraphy of the volcanic the average oceanic crust in a way that possibly sequences in the nine exploration wells in requires elevated temperature and enriched Faroese sector of FSB and iii) the known onshore composition of the mantle melt source. A popular petro-chemistry of the FIBG. Contour maps of the explanation for this involves the convective rise depth to i) the base of the volcanic pile, ii) the A’- of hot plumes, often postulated to originate at the horizon, and iii) the top of the Palaeogene lower mantle with a different temperature and volcanics are presented along with isopach maps

10 of the thickness distribution of the respective the intrusive units originally classified as basaltic pre- and syn-breakup volcanics and associated sills are predominantly pre-breakup extrusive volcanic foresets. We illustrate the offshore basalts and hyaloclastites. This enabled mapping geometry of the FIBG with generalized of discrete volcanic packages within the geoseismic sections and its temporal dominantly non-volcanic sedimentary section in development with sequence stratigraphic charts. the greater Judd Basin area. Comparative analysis of volcanic thickness distributions and kinematic indicators reveal a Mapping of pre- and syn-breakup volcanic units number of aspects concerning the emplacement around the greater Judd Basin area, demonstrates of flood volcanism into FSB; including seemingly a large variation in the interaction between the persistent lava transport systems, south- and volcanic and non-volcanic systems. Towards the eastward progradational lava deltas, sub-basins south volcanics were fed into the Judd basin at times acting as depocentres for volcanics while during mid-Palaeocene. Following a volcanic volcanically starved at other times. A greater regression, basinal accommodation space was volume of volcanics was delivered to FSB during filled by siliciclastic sediments primarily sourced the pre-breakup volcanism in comparison to the from the southeast. In the early Eocene volcanics syn-breakup phase. The syn-breakup volcanic again transgressed far into the Judd basin before deposits are predominantly present in the volcanism eventually was restricted to the northern part of FSB and along Fugloy ridge, location of the incipient Northeast Atlantic likely reflecting eastward migration of volcanic further north-northwest. systems and proximity of the emerging Aegir One implication of mapping the event horizon of ridge. an igneous province using seismic data is that we can now achieve a more detailed understanding

of the temporal and spatial evolution of volcanic ORAL and sedimentary depositional processes in basin- hosted volcanic provinces. Interaction between volcanic and sedimentary transport systems in the greater Judd Basin on the North East Atlantic Margin

Heri Ziska1, Uni Árting1 and Morten S. Riishuus1 1Jarðfeingi (Faroese Geological Survey)

Understanding the transition from the volcanic units of the North Atlantic Igneous Province to the non-volcanic units in the Faroe Shetland Basin, has proven to be a challenge, partly due to inability of seismic data to resolve the difference in seismic response between volcanic and non- volcanic units, and partly due to lack of well control.

Published interpretation of well 6005/15-1 on Sjúrður High suggested a thin extrusive basalt section in the early Eocene and intrusive units in the mid-Palaeocene section. A new integrated interpretation of reprocessed seismic data and re-evaluation of well-cuttings demonstrates that

11 1.3. Understanding Large asthenosphere and dyke-intusion of the continental crust and sediments of the margin. Igneous Provinces and We suggest that the pre-Caledonian margin of the associated rapid environmental Iapetus preserved in the Scandes comprise most changes: from the North of the elements of passive continental margins, Atlantic Igneous Province and and that it probably represents one of the best exposed field analogue for the deeper and least beyond. known parts of passive margins. ORAL

The Pre-Caledonian Margin of Baltica: ORAL overview and research in progress Comparing the geophysical Torgeir B. Andersen1, Johannes Jakob1, Hans expression of the Seiland Igneous Jørgen Kjøll1, Fernando Corfu1, Sverre Planke1, Christian Tegner2, Loic Labrousse3, Geoffroy Province with the SW Barents Sea Mohn4 and Trond H. Torsvik1 crust – indications for a LIP during 1CEED, IG-UiO, Norway, 2Geosciences, Univ. Århus, opening of the Iapetus ocean? Denmark, 3UPMC Paris6, France, 4Univ-Cergy-Pontoise, France Christine Fichler1, Zeudia Pastore1 and Suzanne A. McEnroe1 1Norwegian University of Science and Technology The Caledonian margin of Baltica formed by continental break-up of Rodinia in the Late Proterozoic to Ediacaran. With exception of the The Seiland Igneous Province (SIP) in northern dike-swarm near Egersund in SW Norway, the Norway is expressed by large outcrops of mafic Fennoscandian basement including the and ultramafic rocks of Neo-Proterozoic autochthonous basement windows along the axis (Ediacaran) age and is hosted by the Caledonian of the mountain belt were little affected by the Kalak nappe. The SIP has been suggested to be the magmatism associated with the break-up. The plumbing system of a large igneous province. distal parts, however, were strongly attenuated, Unaltered ultramafic rocks in crustal settings are hyper-extended and a 1000 km long segment, characterized by low magnetization and intensively intruded by a Large Igneous Province exceptional high crustal densities, the latter (LIP), the Pre-Caledonian LIP (PC-LIP). Here, we forming a contrast to common crustal rocks. Such provide glimpses of our work in progress from rock attributes have also been detected by the vestiges of the margin. More details on several integrated interpretation of gravity, magnetic and aspects of the margin evolution are presented by seismic data on the continental shelf in the co-authors. Here we present a regional model for southwestern (SW) Barents Sea at Senja Ridge the pre-Caledonian margin suggesting it was and Veslemøy High. Furthermore, a highly dense highly complex and included micro-continental rock unit of large lateral extension, has been sliver(s) and both a hyperextended, magma-poor found below large parts of the SW Barents Sea, domain with transition(s) to attenuated either, at a lower crustal level, or in the embryonic oceanic and magma-rich margin uppermost mantle. We investigate a possible link domains. The break-up related PC-LIP between the rock units with high density in the magmatism lasted from approximately 615 to SW Barents Sea and the SIP. If both belong to the 570 Ma, but the most intense activity appears to same magmatic event, they may be characterized have been at ~600 Ma. Our ongoing work as relicts of a LIP which developed at the time of suggests that the impingement of a mantle plume the opening of the Iapetus Ocean. An alternative on the Ediacaran continental lithosphere was scenario for the origin of the offshore ultramafic associated with a temperature anomaly of rocks at the Veslemøy High has been published ~100oC, causing widespread melting of the suggesting exhumed mantle developed by

12 hyperextension during the ultraslow opening of ORAL the Cretaceous Bjørnøy Basin. Finally, obducted ophiolitic crust containing mantle rocks is Large-scale sill emplacement in another possibility which will be discussed. Brazil as a trigger for the end-Triassic crisis

Thea Hatlen Heimdal1, Henrik Hovland Svensen1, ORAL Jahandar Ramezani2, Karthik Iyer3, Egberto Karoo LIP thermogenic degassing less Pereira4, René Rodrigues4, Morgan Thomas Jones1 and Sara Callegaro1 important than previously estimated 1Centre for Earth Evolution and Dynamics (CEED), UiO, — new evidence from thermo-hydro- 2Massachusetts Institute of Technology (MIT), mechanical numerical simulations 3GeoModelling Solutions GmbH; GEOMAR, 4Rio de Janeiro State University Christophe Galerne1 and Jörg Hasenclever2 1GEOMAR Helmholtz Centre for Ocean Research Kiel, Germany, 2Institute for Geophysics, University of It has long been postulated that the Central Hamburg, Germany Atlantic Magmatic Province (CAMP) was involved in the end-Triassic extinction (ETE), one of the largest mass extinctions of the Phanerozoic. Thermogenic discharge into the atmosphere Previous studies have mainly focused on the associated with the Karoo LIP event (183 Ma) is extrusive section of the province, however currently estimated to as much as 12,600 Gt of several lines of evidence point toward sill methane. In order to precise the degassing rates emplacement in Brazil being a key factor at the basin floor, we investigate the influence of regarding the extinction. These sills have the Karoo Basin stratigraphic physical properties, intruded the Amazonas and Solimões basins, including a realistic initial TOC profile. Using which include major deposits of evaporite, state-of-the-art numerical models of carbonate and organic-rich shale, and it has been hydrothermal fluid flow through porous rocks we suspected that contact metamorphism of these investigate the formation and evolution of lithologies generated thermogenic gases that hydrothermal systems powered by sill intrusions. were released to the end-Triassic atmosphere. We take into account the energy consumption of Until now, detailed studies regarding the extent the dehydration reaction and the thermogenic of the sill complex and estimates of sediment- cracking in the sediments as well as the derived volatiles have been absent, likely because increasing pore space upon sediment outcrops and samples are extremely limited. Here dehydration. Permeability depends on porosity we have access to samples and logs from seven and, in addition, a simple Mohr-Coulomb deep boreholes drilled in the Amazonas and rheology is used to simulate hydrofracturing. Our Solimões basins. The sills comprise up to 24% of results indicate that fluid flow caused by a single the stratigraphy, and the majority have intruded sill intrusion emplaced in the deep organic-rich evaporite-and carbonate dominated deposits. formation is insufficient to rapidly transport Thermal modeling demonstrates that large scale thermogenic methane to the basin floor. Instead carbon generation followed sill emplacement, the mobilized methane accumulates in shallower including as much as 116 000 Gt CO2. We also parts of the basin, where it may be later provide new constraints on the timing of sill remobilized by shallower intrusions. Our new emplacement by high precision U-Pb zircon estimates suggest a reduction of one to two geochronology. Our findings demonstrate orders of magnitude in the amount of synchronicity between the sills and the ETE, and thermogenic gas emitted during the Karoo LIP we suggest that venting of sediment-derived event. volatiles such as C, S and Cl played a major role in the end-Triassic crisis.

13 ORAL

ORAL The lithostratigraphy of a hyperextended domain in the Evidence from Denmark for NE magma-rich to magma-poor Atlantic pre-PETM volcanism transition zone in the southern Pre- Claus Heilmann-Clausen1, Bo Pagh Schultz2, Claus Caledonian LIP, Scandinavian Beyer3, Henrik Friis1, Petra L. Schoon4, Christian Caledonides, Norway Tegner1 and Ole Bjørslev Nielsen1 1Department of Geoscience, Aarhus University, Høegh- Johannes Jakob1, Geoffroy Mohn2, Pierre Closset3 Guldbergs Gade 2, 8000 Aarhus C, Denmark, 2Muserum, and Torgeir B. Andersen1 Division of Natural History, Havnevej 14, 7800 Skive, 1The Centre for Earth Evolutions and Dynamics, Denmark, 3CB-Magneto, Nørregade 27, 8670 Låsby, Department of Geosciences, University of Oslo, Norway, Denmark, 4Department of Geology, Lund University, 2Department of Geosciences and Environmental Sölvegatan 12, 22362 Lund, Sweden Sciences, Université de Cergy-Pontoise, France, 3Institut de Physique du Globe de Strasbourg, UMR 7516 CNRS, Université de Strasbourg, France A new section on the Fur island in Denmark includes two quadruple volcanic ash layers which are older than the Paleocene-Eocene Thermal Remnants of the ancient rifted margin of Baltica Maximum (PETM). The ash layers occur are preserved in the allochthons of the immediately below sediments dated to the PETM Scandinavian Caledonides. The Baltica margin interval. The ash layers are of a normal basaltic nappes comprise a magma-rich segment, i.e. the type and older than hitherto recognized volcanic pre-Caledonian LIP (Tegner et al. 2016), and a ash layers from the Paleocene-Eocene transition magma-poor. (Andersen et al. 2012; Jakob et al. in Denmark (i.e., the negative and positive 2017). The transition zone between the magma- numbered ash series of Bøggild, 1918). Three rich and magma-poor domains corresponds other Danish PETM sections (Ny Klitgård, Ølst- approximately to the northern termination of the Hinge, Harre-1) show 1-3 volcanic ash layers Jotun Nappe Complex. Metaperidotites and closely associated with the base of the PETM metamorphosed mafic rocks abound in the interval. The ash layers point to a significant metasediments of this transition zone. volcanic episode and their stratigraphic position supports previous evidence for NE Atlantic North of Lesja, an original lithostratigraphic volcanism as a trigger of the PETM (e.g. Svensen succession of the ancient Baltica hyperextended et al., 2004). All sections show a shift from oxic margin may be preserved. At its base is a sheet of sea-floor conditions (indicated by bioturbation) metaperidotite that is locally characterized by a below the PETM interval, to anoxic conditions pegmatitic texture, containing pseudomorphs (indicated by finely laminated sediment) within after decimetre-sized, metamorphic olivine. Few the PETM interval. The basal layer of the PETM mafic dykes cutting the metaperidotite are also interval at Fur is a 5 cm thick density flow deposit observed. occurring immediately above the ash layers. The The top of the metaperidotite sheet is in contact density flow deposit is not recognized in other with metamorphosed mafic rocks or in a Danish sections and points to local sea-floor stratigraphic contact with a monomictic instability. metaperidotite conglomerate. The latter grades upwards into a polymictic conglomerate. The

metamorphic mafic rocks and the conglomerates above the metaperidotites, but locally also the ultramafic rocks, are overlain by a metasedimentary unit that comprises a large number of mafic intrusives (and volcanics?) and

14 locally contains ultramafic clasts. Similar as well as a full range from basic to silicic successions have been described from fossil compositions. It can be shown that over the PETM ocean-continent transition zones elsewhere (e.g. times, the volcanism was particularly Manatschal and Müntener 2009). widespread, with significant ash beds as well as a plumbing system that significantly intruded into We suggest that the lithostratigraphic succession the surrounding sedimentary basins at this time north of Lesja represents a hyperextended causing a multitude of gas escaped venting domain in the magma-rich to magma-poor structures. The changes in style from early transition zone of the pre-Caledonian margin of eruptions to the second phase volcanism in the Baltica that received abundant mafic magmas NAIP need to be considered to help our during and after the mantle was exhumed at the understanding of the PETM crisis. seafloor.

ORAL ORAL Fur Island in Denmark: A window Types and styles of volcanism in the into Paleocene-Eocene North Atlantic Igneous Province: hyperthermals and North Atlantic Implications towards understanding volcanism their potential climatic impact. Morgan Jones1, Ella Stokke1, Bo Schultz2, Lars 1 2 Dougal A. Jerram , Henrik H. Svensen , Sverre Augland1, Sverre Planke1, Christian Tegner3, 3 4 2 Planke , John M. Millett , Morgan T. Jones , Lars Tamsin Mather4, Lawrence Percival5 and Henrik 2 5 Augland and Mansour M. Abdelmalak Svensen1 1 CEED, University of Oslo, Norway/DougalEARTH LTD, 1Centre for Earth Evolution and Dynamics, University of 2 3 UK, CEED, University of Oslo, Norway, VBPR, Oslo, Oslo, Norway, 2Museum Salling – Fur Museum, 4 Norway/CEED, University of Oslo, Norway, VBPR, Oslo, Denmark, 3Department of Geoscience, Aarhus 5 Norway/University of Aberdeen, Scotland, VBPR, Oslo, University, Denmark, 4Department of Earth Sciences, Norway University of Oxford, UK, 5Université de Lausanne, Switzerland

The North Atlantic Igneous Province (NAIP) is arguably the best studied of the Large Igneous The Paleocene and Eocene epochs were typified Provinces (LIPs), but it is somewhat unusual in by ice-free greenhouse conditions, punctuated by that its volcanism is somewhat protracted and even warmer hyperthermal events driven by pulsed. Two main phases are recognised with one rapid release of carbon to the atmosphere. The occurring some 5 million years before the largest of these, the Paleocene-Eocene Thermal Paleocene-Eocene thermal maximum (PETM) Maximum (PETM), was an extreme (5-6 °C) and and another which occurs at the PETM. The rapid (<20 kyr) global warming event at ~56 Ma different styles and types of volcanism that are that persisted for ~170 kyr. The PETM coincided found during the onset, main phases and the with a major pulse of magmatism from the North waning parts of the NAIP, as well as the intrusive Atlantic Igneous Province (NAIP), suggesting that plumbing systems that go to feed them, all play a the emplacement of the NAIP could be potential role into how the LIP may have responsible for the climate perturbations. An contributed to the changing climate at this time. excellent locality to explore this relationship is Flood volcanism is rarely restricted to simple lava the island of Fur in Denmark, where over 180 flows, and here we review the relative timings tephra layers originating from the NAIP are and locations of the key types of eruption that preserved in a diatomitic clay sequence. Here we occurred in the NAIP. Lava flows, hyaloclastites, present the initial results of the project major volcanic centres, and thick ash “Ashlantic”, which drilled a 73 m borehole accumulations bears testament to the volcanism through the Fur Formation in August 2017. We

15 use a variety of detailed geochemical and for detailed studies of deep to intermediate stratigraphic analyses to assess the extent and processes at magma-rich rifted margins. We duration of volcanism across the PETM. In propose that the architecture of the magma-rich particular, we use volcanic proxies such as Hg margin of Iapetus and magma-rich rifted margins, deposition to assess the influence of volcanism in general, can be studied in the Caledonides. The and thermogenic degassing on the surface carbon well-preserved parts of the margin comprise: 1) cycle. We will combine this with high precision U- Parts of a lower crustal magmatic complex Pb dating of magmatic zircons found in tephra w/gabbros and mafic dykes intruding stretched layers and high-resolution cyclostratigraphy to crystalline basement; 2) Strongly stretched and place the PETM and later hyperthermals within attenuated crystalline basement intruded by an improved absolute timeframe. Expanded shelf mafic dikes; 3) Highly intruded pre- to syn-rift sections such as the Fur Formation are sediments and 4) Extrusive mafic lavas, including fundamentally important for understanding pillow basalts, interlayered with metasediments. hyperthermal events and volcano-climate Together these levels represent a nearly interactions due to the possibility of measuring continuous section through a magma-rich rifted variations on a sub-millennial timescale. margin, with some never-before described levels, such as the lower crustal magmatic complex.

ORAL ORAL A fossil magma-rich rifted margin revealed in the Scandinavian Environmental and ecosystem Caledonides responses to massive volcanism during the end-Triassic mass 1 1 Hans Jørgen Kjøll , Torgeir Andersen , Christian extinction Tegner2, Loic Labrousse3, Fernando Corfu1 and Sverre Planke1 Sofie Lindström1, Bas van de Schootbrugge2, 1Centre for Earth Evolution and Dynamics (CEED), Gunver K. Pedersen1, Andrea Marzoli3, Joshua University of Oslo, Norway, 2Centre of Earth System H.F.L. Davies4, Sara Callegaro5, Christian Tegner6 Petrology, Department of Geoscience, Aarhus and Hamed Sanei6 University, Denmark, 3Universite Pierre et Marie Curie, 1GEUS, 2Utrecht University, 3University of Padova, Paris, France 4University of Geneva, 5University of Oslo, 6University of

Aarhus The Iapetus opened ~610 Ma ago possibly due to the interaction with a mantle plume at the base of The end-Triassic mass extinction (201.56 Ma; the lithosphere. Stretching of the conjoined Wotzlaw et al. 2014) is generally explained by crystalline crust started prior to break-up and massive input of CO2 and/or methane to the provided accommodation for continental and atmosphere from the Central Atlantic magmatic shallow marine syn-rift sediments. An early non- province (CAMP). High precision U/Pb dating of magmatic phase with discrete and localized CAMP intrusives and extrusives have shown that deformation was followed by pervasive mafic the magmatic activity commenced c. 100.000 magmatism where dyke-emplacement accounted years prior to the ETE (Davies et al. 2017), and for the bulk of the stretching. During the occurred in at least four pulses over Caledonian orogeny, the Iapetan margin approximately 600.000 years (Blackburn et al. was thrusted onto Baltica as the Iapetus closed. 2013). Indeed, both calcareous and organic δ13C- Now, vestiges of the magma-rich margin reside records across the Triassic-Jurassic boundary within nappes from central Sweden to northern (TJB) show that large scale emissions of Norway. Although overprinted by Caledonian isotopically light carbon to the atmosphere took fabrics, there are localities where pre-Caledonian place at that time. Physiological responses in structures are well-preserved, thereby allowing

16 terrestrial plant fossils indicate that this lead to pathways, and larger vents, because more rock is intense global warming across the TJB (McElwain mobilized near the seabed. Four datasets from et al. 1999), while in the marine realm, ocean the Vøring and Møre basins (Mid-Norway), acidification from the increased pCO2 is indicated consisting of 718, 213, 106 and 13 Paleogene by the loss of calcifying organisms (van de hydrothermal vent complexes, are used to Schootbrugge et al. 2007). Recently, a new determine the relationship between vent correlation of TJB successions, based on a diameters and conduit heights. The vent combination of biotic (palynology and complexes and associated sills were mapped 13 ammonites), geochemical (δ Corg) and radio- using regional 2D seismic data (first dataset) and isotopic (U/Pb ages of ash beds) constraints, was 3D seismic data (three datasets). Generally sills proposed (Lindström et al. 2017). This new have pipe-like vent complexes located above correlation has an impact on the causality and their margins or above sill steps or local highs, temporal development during the end-Triassic however, one shallow sill has >110 hydrothermal event, as it indicates that the bulk of the hitherto vent complexes distributed over its top surface. dated CAMP rocks preceded or was The upper part of the vent complexes display contemporaneous to the onset of the mass mound, crater, or eye-shaped geometries. extinction. Here, we investigate the temporal Observed vent diameters range from ~100 m to chain of events across the ETE as constrained by ~11 km, with a sizable majority <2.5 km wide. the new correlation in combination with new The vertical conduit heights range from ~100 m high-resolution CAMP ages extrusives to ~4 km with a sizable majority <2.5 km. There (Blackburn et al. 2013; Davies et al. 2017). are weak positive correlations between the upper vent complex diameters and conduit heights in all four datasets. The weak correlations suggest the quantity of energy transferred from the sill ORAL aureoles, via fluid transport, to the hydrothermal The Relationship Between Paleogene vents is partially dependent on the heights of the conduits. Hydrothermal Vent Complex Diameters and Conduit Heights in the Vøring and Møre Basins Offshore ORAL Mid-Norway Release of volatiles during North Ben Manton1, Sverre Planke1, Hugo Thould2, Sigurd Kjoberg3, Henrik Svensen4 and Øyvind Atlantic flood basalt volcanism and Hammer5 correlation to the Paleocene-Eocene 1VBPR, Oslo Science Park, Oslo, Norway, 2Department of Thermal Maximum (PETM) Earth Sciences, Oxford University, Oxford, UK, 3CEED, Oslo University, Oslo, Norway, 4Department of Jonas Møller Pedersen1, Thomas Ulrich1, Adam Geosciences, Oslo University, Oslo, Norway, 5Natural Kent2, Charles Lesher1 and Christian Tegner1 History Museum, Oslo University, Oslo, Norway 1Centre of Earth System Petrology, Department of Geoscience. Aarhus University., 2College of Earth, Ocean, and Atmospheric Sciences, Oregon State University. Large Igneous Provinces (LIPs) emplaced within basins are frequently associated with many hydrothermal vent complexes sourced from Significant environmental changes and global thermal aureoles around sill intrusions. These warming during the PETM have been attributed piercement structures consist of cylindrical to the release of CO2 or methane gas due either to conduits that connect the sill aureoles with vents extensive melting of hydrates at the ocean floor at the paleosurface. More energy is considered to or to interaction of mantle-derived magmas with be required to create both longer conduits, as carbon-rich sediments. Although it is well they require higher fluid pressure to fracture long established that flood basalt volcanism

17 associated with the opening of the North Atlantic Norway Ocean broadly coincides with the PETM, further detailed timing constraints from stratigraphic The NE and NW Atlantic continental margins are correlations, magnetostratigraphy, and the characterized by massive Paleogene igneous duration of flood basalt volcanism suggest that it constructions, associated with continental is also possible that the main flood basalt breakup and early seafloor spreading. We have sequence in East Greenland postdates PETM. recently completed a comprehensive Estimates suggest that a minimum of 1.8x106km3 interpretation of the nature and distribution of of basaltic lava erupted during North Atlantic the extrusive and intrusive mafic rocks on flood basalt volcanism. Based on measurements regional 2D and selected high-quality 3D seismic of melt inclusions from the East Greenland flood data in both regions. Interpretations have been basalts our calculations show that approximately augmented by scientific and industry borehole

2300Gt of SO2 and 600Gt HCl were released into data and on-shore field work. On the Vøring the atmosphere. Yearly fluxes are estimated to be Marginal High, 3D mapping reveals a highly

8-23 Mt/y SO2 and 2-6 Mt/y HCl if all the North variable crustal structure, with large-scale pre- Atlantic flood basalts erupted in 100.000- breakup structural highs and sedimentary basins. 300.000 years. This is equivalent to ≈18600 Laki- These structures where infilled and covered by like events, one happening every 5-16 years. The flood basalts and volcanogenic sediments during

SO2 released into to the atmosphere during flood the early stages of continental breakup in the basalt volcanism can form acid aerosols that earliest Eocene. Subsequently, rift basins absorb and reflect solar radiation, causing an developed along the continent-ocean boundary effective cooling effect. and were infilled by up to 6 km thick basalt sequences, imaged as SDRs. Intrusive sill The climatic changes due to the release of complexes and associated hydrothermal vent volatiles in these amounts, and for periods complexes in the Vøring Basin have dominantly a extending for hundred thousand of years are Paleocene-Eocene boundary age based on a few likely to be significant. One consequence of the high-quality U/Pb ages and seismic mapping. North Atlantic flood basalt volcanism may Similar igneous complexes, including SDRs, lava therefore have been the initiation of global deltas, lava fields, sills, and hydrothermal vent cooling to end the PETM. complexes, were also mapped in the NW Atlantic and on the NE Greenland margin. The dominant

hypothesis is that the massive magmatism was ORAL caused by a mantle plume originating from the core-mantle boundary, and that intense and NE and NW Atlantic Paleogene short-lived (<100,000 years) intrusive and Voluminous Magmatism and Global extrusive magmatism triggered global warming during the Paleocene-Eocene thermal maximum Crises: Seismic Observations and the (PETM). However, we argue that new scientific Need for Future Scientific Drilling drilling in the NE and NW Atlantic is required to substantiate these hypotheses. Sverre Planke1, Christian Berndt2, Christian Tegner3, Ritske Huismans4, Henrik H. Svensen5, Jan Inge Faleide5, Dougal A. Jerram5, John Millett6, Mansour M. Abdelmalak6, Charles E. Lesher3 and Reidun Myklebust7 1Centre for Earth Evolution and Dynamics (CEED), University of Oslo, Norway, and VBPR, Oslo, Norway,

2GEOMAR, Kiel, Germany, 3Aarhus University, Denmark, 4University of Bergen, Norway, 5CEED, University of

Oslo, Norway, 6VBPR, Oslo, Norway, 7TGS, Asker,

18 ORAL

Improving seismic interpretation of ORAL igneous sill complexes via seismic U-Pb baddeleyite dating of multiple modelling mafic dyke swarms in the Dharwar Ole Rabbel1, Olivier Galland1, Karen Mair1, Isabelle craton, India – evidence for a 30° Lecomte2 and Juan Bautista Spacapan3 internal block rotation during the 1Physics of Geological Processes, Department of Paleoproterozoic Geoscience, University of Oslo, Norway, 2Department of Geoscience, University of Bergen, Norway, 3Universidad Ulf Söderlund1, Wouter Bleeker2, Kursad Demirer1, Nacional de La Plata, Argentina Rajesh K. Srivastava3, Michael Hamilton4, Mimmi

Nilsson1, Lauri J. Pesonen5, Richard E. Ernst6 and Seismic interpretation has been playing a key role Amiya K. Samal3 in establishing the role of igneous sill complexes 1Department of Geology, Lund University, Sölvegatan emplaced in organic-rich sediments on global 12, SE-223 62 Lund, Sweden, 2Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario, K1A 0E8, climate change throughout geological history Canada, 3Centre of Advanced Study in Geology, Institute (e.g., Svensen et al. 2004, Aarnes et al. 2015): the of Science, Banaras Hindu University, Varanasi 22100, heat brought by the sills to their organic-rich host 4Jack Satterly Geochronology Laboratory, Dept. of Earth leads to massive thermogenic generation of Sciences, University of Toronto, Toronto, ON, greenhouse gases (e.g., CO2, CH4), eventually 5Laboratory for Paleomagnetism, Geological Survey of catastrophically released to the atmosphere. Finland, P.O. Box 96, 02151 Espoo, Finland, Robust volume estimates of these greenhouse 6Department of Earth Sciences, Carleton University, gases rely on robust estimates of magma volumes Ottawa, ON K1S5B6, Canada of the sill complexes, which require confident mapping of subsurface sill intrusions. A significant portion of large igneous provinces Large sills are easy to map in seismic data, (LIPs), especially those thought to be associated because they create strong property contrasts, with mantle plumes, have been linked with which cause high amplitude reflections. However, breakup of continents and, therefore, provide a igneous sills vary strongly in thickness and up to critical source of information in reconstructions 88 percent of the sills may be missing in the of ancient crustal blocks. First-order crustal interpretation, since their thickness is below the connections to a plume include radiating mafic seismic resolution limit (Schofield et al. 2015). dyke patterns, inferred to reflect lateral magma transport away from a plume centre located at In this presentation, we present seismic the focal point of the swarm1,2. The 2.37 Ga giant modelling study designed to characterize typical Bangalore-Karimnagar dyke swarm of the seismic signatures (splitting, stepping, braided Dharwar craton, southern India, displays a reflections) of thin intrusions, and to indicate distinct radial pattern (of at least 30º) from which potential ways to infer the shapes of thin a western source of magma has been intrusions in the seismic interpretation. Due to inferred3,4. However, on the basis of their anomalously high vp/vs ratio, intrusions paleomagnetic data and an arcuate trend to cause a characteristic amplitude-vs-offset (AVO) structures in the Archaean basement, an response with high AVO intercept and gradient. alternative interpretation of the fanning pattern Thus, we will highlight the great potential of of the Bangalore-Karimnagar swarm has been using seismic pre-stack and offset data for the raised5,6,7. Here we present 17 U-Pb baddeleyite interpretation of thin intrusions. Our results ages, which comprise seven generations of indicate how seismic interpretation and thereby Paleoproterozoic dykes swarms within the 2.37- volume estimates of sill complexes can be 1.79 Ga age interval. significantly improved using data of relevant quality.

19 By restoring a 30° counter-clockwise rotation of channels during the end-Permian, the Toarcian, the northern Dharwar block relative to the and the PETM, and present a classification and southern block, we show that pre-2.08 Ga arcuate detailed overview of the key parameters and fanning dyke swarms consistently become governing their formation. We show that the approximately linear, as do ancient curvilinear potential for degassing of greenhouse gases, trending geological features, such as regional aerosols, and ozone destructive gases in Dharwar greenstone belts and the late Archean sedimentary basins affected by volcanism is (ca. 2.5 Ga) Closepet batholith. This finding substantial, and can explain the triggering of both reinforces previous suggestions that the radial transient climatic events and mass extinctions. pattern is apparent, and not a primary featuree.g. 7. Our findings call for reassessment of previous paleoreconstructions involving the Dharwar ORAL craton based on tectonic/geologic piercing points, paleomagnetism and inferred plume The pre-Caledonian Scandinavian centre locations. Dyke Complex and 600 Ma plate reconstructions of Baltica

ORAL Christian Tegner1, Torgeir B. Andersen2, Hans Jørgen Kjøll2, Eric L. Brown1, Graham Hagen- Volcanic causes for the PETM and Peter1, Fernando Corfu2, Sverre Planke2 and Trond other past hothouse climates H. Torsvik2 1Centre of Earth System Petrology (ESP), Department of Henrik H. Svensen1, Dougal A. Jerram2, Alexander Geoscience, Aarhus University, Denmark, 2Centre for G. Polozov3, Morgan T. Jones4, Lars E. Augland4 Earth Evolution and Dynamics (CEED), University of and Sverre Planke5 Oslo, Norway 1CEED, Univ. Oslo, 2CEED and DougalEarth, 3CEED and Institute of Geology of Ore Dep., Petr., Min., and Geochem., RAS, Moscow, 4CEED, 5CEED and VBPR A spectacular dyke complex is surprisingly well preserved along c. 1000 km in the Caledonian nappes of central and northern Scandinavia. This Mass extinctions and transient climate events dyke complex was originally emplaced into commonly coincide in time with the formation of continental sedimentary basins along the rifted Large igneous provinces (LIPs). Classic examples margin of Baltica, it is part of the Central Iapetus include the end-Permian event which coincides Magmatic Province (CIMP), and it has U-Pb ages with the Siberian Traps, the end-Triassic with the of 615-590 Ma. Central Atlantic Magmatic Event (CAMP), the Toarcian with the Karoo LIP, and the Palaeocene- To constrain its origin and to potentially guide Eocene Thermal Maximum (PETM) with the plate reconstructions of Baltica we: (1) re-visited North Atlantic Igneous Province. The the dyke complexes of the Ottfjället, Sarek, emplacement of igneous sills into sedimentary Kebnekaise, Tornetrask and Indre Troms basins, and the associated contact mountains of Sweden and Norway; (2) produced metamorphism of the host sedimentary rocks, new and compiled published geochemical data; has emerged as a major player in the (3) modeled mantle sources and melting understanding of the link between LIPs and past dynamics; and (4) extended reconstructions of climatic change. We stress that for these the paleo-position of Baltica back to 600 Ma. The processes to have an environment impact, the compiled dataset includes c. 600 analyses that gases need to be transferred to the surface and forms a coherent suite dominated by tholeiitic atmosphere on a very short timescale, which is ferrobasalt, but including alkali basalts in the borne out by dating of the sill complexes in central portion. question. We have identified a range of different pipe structures that acted as gas transport

20 The tholeiitic dykes display lateral variations in clinopyroxene) and combining it with an geochemical enrichment (e.g. delta-Nb, La/Sm(N) experimentally determined partition coefficient and Sr isotopes) in the southern and central (KD), the volatile load of basaltic equilibrium portions, grading to more depleted compositions melts can be calculated. We measured a in the north. Our petrological modeling suggests clinopyroxene/melt sulfur KD of 0.001±0.0003 melting of asthenospheric mantle involving at for basaltic experiments performed at conditions least two source compositions at temperatures typical of LIP basalts (FMQ-2; 800-1000 MPa; elevated about 100 °C above ambient mantle, 1000°-1350°C), through ion microprobe consistent with melting of a zoned mantle plume (Nordsim). Experiments were also originating from a plume generation zone at the simultaneously analyzed for Cl and F. For these core-mantle boundary. If the position of the elements the measured KDs were 0.0106±0.0089 present plume generation zone in the Pacific can and 0.1837±0.0795, respectively. Compatibility be viewed as stationary back to 600 Ma, we of sulfur, chlorine and fluorine in clinopyroxene entertain the idea that the Scandinavian Dyke from basaltic systems is markedly different Complex may be used to guide plate (F>Cl>S), in agreement with what observed by reconstructions. previous studies. Application of the newly measured sulfur KD to samples from thoroughly- dated lava piles from the Deccan Traps and from the Siberian Traps sills reveal that most of the POSTER basalts were at or near sulfide saturation (ca. Pyroxenes used as probes for 2000 ppm for low fO2 melts). assessing gas loads from LIP magmas: a crystal/melt partitioning study for sulfur and halogens POSTER

Sara Callegaro1, Don R Baker2, Andrea Marzoli3, Glendonite in an early Eocene Martin Whitehouse4, Paul R Renne5 and Henrik Konservat-Lagerstätte (Fur Svensen1 Formation of Northern Denmark) and 1CEED - University of Oslo, 2McGill University, Palaeocene / Eocene formations on 3University of Padova, 4Nordsim - NRM Stockholm, 5Berkeley Geochronology Center Svalbard are good climate and biosphere interpretive indicators.

Magmatism from Large Igneous Provinces (LIPs) Bo Pagh Schultz1, Johan Lindgren2, Barbara has in several cases been causally linked to mass Teichert3, Morgan T Jones4, Christian Tegner5, extinctions, with at least five conspicuous Rene Sylvestersen6, Jan Audun Rasmussen7 and examples in the Phanerozoic. LIPs likely Henrik Madsen8 generated changes on the global environment by 1Museum curator, Museum Salling - Fur Museum, degassing of volatile species such as S, C and Nederby 28, 7884 Fur, Dk, 2Senior lecturer, Department halogen compounds, from both melts and of Geology, Lund University, Sölvegatan 12, 223 62 Lund, Sweden, 3Senior researcher Ph.d., Institut für thermal metamorphism of volatile-rich intruded Geologie und Paläontologie, Universität Münster, D- sediments. However, quantitative estimates of 48149 Münst, 4Ph.D. Centre for Earth Evolution and the degassed volatiles are hard to obtain for Dynamics (CEED) University of Oslo P.O. Box 1028 , ancient magmatic systems, particularly in the Norway, 5Professor, Department of Geoscience, Aarhus absence of melt inclusions. We propose to fill the University, DK-8000 Aarhus C, Denmark, gap of knowledge on sulfur partitioning between 6Museumcurator, Museum Salling - Fur Museum, minerals and melts, at the aim of using Nederby 28, 7884 Fur, Dk, 7Senior researcher Ph.d. phenocrysts as probes of volatile contents in the Fossil og Molermuseet, Museum Mors, Skarrahagevej 9, melts from which they crystallized. Measuring a 7900 Mors., 8Head of department, Fossil og Molermuseet, Museum Mors, Skarrahagevej 9, 7900 volatile concentration in natural minerals (chiefly

21 Mors POSTER

Lithological and geochemical The early Eocene Fur Formation of Denmark variations during the PETM and later comprises a 60 meters thick diatomite holding over 200 volcanic ash layers related to the North Eocene hyperthermals: details from a Atlantic Igneous Province (NAIP) (Larsen 2003). new drill core from Fur, Denmark. The Fur Formation overlays the Ølst Formation Ella Wulfsberg Stokke1, Morgan T. Jones1, Øyvind (Stolleklint Clay) which includes both the Hammer2 and Henrik Svensen1 Palaeocene-Eocene boundary and Palaeocene- 1Centre for Earth Evolution and Dynamics (CEED), Eocene Thermal Maximum (Schoon 2013, 2015). University of Oslo, 2Natural History Museum, University Intriguing is therefor outcrops in parts of the Fur of Oslo, PO Box 1172, 0318 Oslo, Norway Formation of ikaite pseudomorph termed glendonite, CaCO3 . Sediment legit shows that the cold environment mineral ikaite, CaCO3 • 6H2O, One of the most extreme episodes of global formed shortly after deposition in relation to warming in Earth’s history is the Paleocene- thick volcanic ash layers. (Hugget et al. 2005; Eocene thermal maximum (PETM), which lasted Schultz 2009, 2014). The occurrence of ~170 000 years from ~55.8 Ma, and was followed glendonites indicates a period of cooling after the by several smaller hyperthermal events during Palaeocene-Eocene Thermal Maximum possibly the Eocene. The period was initiated by due to heavy volcanism (Brooks 2006). In the substantial carbon release to the ocean- NAIP Palaeocene/Eocene Glendonites are also atmosphere system, causing a global temperature seen on Svalbard ( Spielhagen 2009). The increase of ~5-8°C. This global warming event interpretive powers are immense as Mo clay area coincided with the second pulse from the North Fossil Lagerstätte is unparalleled worldwide in Atlantic Igneous Province (NAIP), suggesting a terms of representing the initial diversification of possibly causal relationship. One of the best the modern fish in the marine, offshore realm exposures covering the PETM interval is the Fur (Pedersen et al. 2011). It contains the first major Formation and Stolleklint Clay, found on the post-K/T boundary diversification of marine fish island of Fur in northwest Denmark. Over 180 in association with terrestrial organisms such as interbedded tephra layers of NAIP origin are birds, insects and plants, all of which are found within this diatomite and clay rich extremely well-preserved, as has been sequence. The diatomite clays were deposited demonstrated in pioneering works in the field of during the late Paleocene and early Eocene in a molecular palaeontology (Vinter 2008; Lindgren restricted, shallow marine basin with et al. 2012, 2014, 2017). The rich and diverse interchanging well laminated and structureless fossil content comprising both marine and (strongly bioturbated) subsections reflecting terrestrial organisms makes the Mo clay area an alternating redox bottom conditions. During a outstanding window into the early Eocene recent fieldtrip as part of the Ashlantic project, a biosphere, where fossil indicate high latitude ~70m long core was drilled through this migrations of particular faunal elements. sedimentary succession in order to investigate the role of volcanism in the prolonged global warming and observed climatic changes during the PETM. In this contribution, we will present a

new and detailed overview of the lithological and chemical variations through the Fur Formation, including data from high-resolution XRF-core logging. Our data give an improved insight to the PETM and post-PETM climatic perturbations, and

help us understand the climatic response to ash deposition.

22 1.4. Tephra markers in the extends as far back as 50.000 years, with eruption frequency peaks between 1-2000, 5-7000, 9- circum North Atlantic area 10.000, 12-14.000, ~16-18.000, ~22-23.000, ~32-33.000, 36-~37.000, ~45-46.000 and ~49- 50.000 years. ORAL

Explosive volcanic activity in Iceland during the Weichelian – Different ORAL from the Holocene? Proximal tephras from São Miguel, Esther Ruth Guðmundsdóttir1, Guðrún Larsen2, Azores Islands, and their links with Jón Eiríksson3 and Ólafur Ingólfsson4 distal sites in Europe 1Nordic Volcanological Center, Faculty and Institute of Earth Sciences, University of Iceland, 2Nordic Hans Johansson1 and Stefan Wastegård1 Volcanological Center, Institute of Earth Sciences, 1Stockholm University University of Iceland, 3Institute of Earth Sciences, University of Iceland, 4Faculty and Institute of Earth Sciences, University of Iceland The Azores archipelago is one of the most active volcanic areas in the North Atlantic region, with approximately 30 eruptions during the last 600 years. The geochemical composition of associated Eruption frequency is high in Iceland and has tephra-derived glass is, however, not well been estimated to exceed 20 eruptions per characterized. It has recently been suggested that century on average during the Holocene. The trachytic tephras found in distal areas such as majority of the eruptions are mafic (~ 90%) and North Africa, the British Isles and Greenland may predominantly explosive (~70%). derive from eruptions on the Azores, but For the past 10.000 years the explosive activity in proximal data from the Azores are scarce and the Iceland is relatively well known based on correlations have been tentative at best. These numerous soil profiles and lake sediment tephras lie clearly outside the geochemical archives across the country. What about during Icelandic province and have a potential to the Weichselian? How was the explosive volcanic improve the European tephro- activity in Iceland during this last glaciation? Was stratigraphy/tephrochronology framework, it similar to the Holocene? Which volcanoes were especially in sites in south and central Europe active and what was the level of their tephra where tephras from more than one European producing activity? volcanic system have been found (e.g. Lane et al., 2015). Analyses of tephra glass from five mid and To answer these questions, tephra in high- late Holocene eruptions on the Azores Islands resolution lake sediments spanning 10.000 years were presented by Johansson et al. (2017) and and marine sediments extending 50.000 years there is a striking geochemical similarity between have been investigated. Lake sediments in East trachytic tephras from volcanoes on the São Iceland (Lake Lögurinn), records 170 explosive Miguel island and cryptotephras found on Ireland eruptions during the Holocene. The marine (e.g. Chambers et al., 2004). The dominant wind sediments (core MD99 2272) from the North direction over the Azores is favourable for tephra Icelandic shelf records about 200 tephra layers dispersal to western Europe and we suggest that back to the middle Weichelian. at least three tephras found in Ireland were erupted from the Furnas volcano, and that There are strong indications that volcanism in trachytic tephras erupted from São Miguel have a Iceland during the Holocene has been periodic at potential to contribute to the construction of a several timescales with apparent periods of 140, European-wide tephrostratigraphic framework. 500, and 4-5000 years. Preliminary results from this study reveal that the 4-5000 year periodicity

23 ORAL

ORAL Tephra stratigraphy in Iceland during the Holocene Linking late Quaternary palaeoclimate records in the North Thor Thordarson1 and Áslaug Geirsdóttir1 Atlantic area: cryptotephras at 1Faculty of Earth Sciences, University of Iceland

Körslättamossen, S Sweden Tephrochronology plays a conspicuous role in Simon Larsson1 and Stefan Wastegård1 paleoclimate studies across the North Atlantic 1Department of Physical Geography, Stockholm because tephra horizons are excellent University stratigraphic markers and correlation tools in

Holocene sedimentary archives. Comprehensive The spatial and temporal development of rapid knowledge of the tephra stratigraphy in Iceland is climate shifts during the last deglaciation in the essential for understanding of the far-field North Atlantic area is still uncertain (e.g. Davies chronologies and for tephra detection and et al. 2012). The method of tephrochronology has discrimination. Over the last two decades we the potential to precisely link different have seen momentous improvements in the palaeoclimate archives from sites separated by Holocene tephra record in Iceland, especially vast distances (e.g. Lane et al. 2017), which is because of the expansion of the traditional soil- particularly useful to assess the issue of the based tephra studies to include glacial, lacustrine timing and spatial development of these climate and marine sediment archives along with events (e.g. Lowe 2001, Lane et al. 2011, Davies et heightened awareness of the importance of al. 2012). tephra studies for volcanological and petrological research. This has been achieved via collective, The Körslättamossen fen in Scania, southern inter-disciplinary effort involving several Sweden—previously studied by Hammarlund & dedicated research groups and the key outcomes Lemdahl (1994)—was analysed for include: (a) a near complete high-resolution cryptotephras. Preliminary results indicate the Holocene tephra stratigraphy, dating back to 8-12 presence of at least five separate cryptotephra ka for West, Central, South and Southeast Iceland, layers (concentrations >500 shards/cm3), two of including the circumference of the Vatnajökull which have been geochemically analysed and glacier, (b) a near-complete Holocene record of identified as the Hässeldalen Tephra (HDT) and magma compositions produced by individual the Laacher See Tephra (LST). This is the first volcanoes, including detailed geochemical geochemically confirmed find of the LST on characterization of all major silicic tephra Swedish mainland, extending its dispersal area deposits, (c) a much improved, high precision further northwest than in previous analytical procedure for major and volatile reconstructions and providing new insights to element concentrations in volcanic glass, suitable the dispersals of its several eruptive stages. The for grains down to the size range of 3-10 mm, (d) Körslättamossen fen appears to be a promising a comprehensive geochemical procedure for site for the usage of tephrochronology to link tephra identification, (e) that some of the key far- palaeoclimate archives in the circum North field tephra marker horizons previously Atlantic area. conceived to be the product of one eruption, are in fact comprised of several tephra layers

produced over periods of few hundred year. I intend to present a comprehensive review these

research endeavors and their outcomes.

24 ORAL Earth Sciences, University of Iceland, 2Department of Geosciences, UiT The Arctic University of Norway, Tephrochronology of North Europe: A Tromsø; 3Centre for GeoGenetics, Nat, 3Icelandic look back and prospects for the Institute of Natural History, Akureyri, Iceland, 4Faculty and Institute of Earth Sciences, University of future Iceland, 5Department of Geoscience, Aarhus University, Denmark; 3Centre for GeoGenetics, 1 Stefan Wastegård Natural History Museum 1Institut för naturgeografi, Stockholm

In recent years the terrestrial tephra stratigraphy Chronological control and the resultant ability to in Iceland has been vastly improved through examine the degree of synchrony among records detailed investigations of soil and lake sediment of different origin are critical for the archives revealing hundreds of tephra layers. understanding of climate and environmental These studies have focused on areas in south, variability. There is an increasing demand for north, east and central parts of Iceland. Fewer exact time markers in the palaeoclimate studies have been carried out in west Iceland. The aim of this study was to significantly improve the community as more investigations now aim at knowledge of tephra stratigraphy and high temporal resolutions. Tephrochronology, tephrochronology in western Iceland by which is an age-equivalent dating method, investigating the sedimentary records from eight exploits these time-synchronous markers and lakes in the northernmost part of the Vestfirðir offers a unique possibility to test hypotheses peninsula. In these eight lake sediment records regarding synchronous or non-synchronous spanning the Holocene, 39 tephra layers have responses to climate forcing. Few, if any been identified, thought to represent 34 eruptive geochronological methods can match the events originating from five volcanic systems; precision it offers both temporally and spatially. Hekla, Katla, Snæfellsjökull, Grímsvötn and A new generation of tephrochronologists has Veiðivötn-Bárðarbunga. Of these 39 tephra been undertaking novel research into layers, 34 have not been reported before in the cryptotephras (layers of nonvisible volcanic ash Vestfirðir peninsula. Six have recently been encompassed within sediments) in ice-cores, the reported in the area; the Hekla 1693 tephra North Atlantic, the Mediterranean and several (Brynjólfsson et al., 2015) Snæfellsjökull Sn-1 adjacent areas. The range of tephrochronology tephra, Hekla 3 tephra, Hekla 4 tephra, Brattihjalli has radically been extended into geographic tephra (Schomacker et al., 2016) and areas not previously considered suitable for this Saksunarvatn tephra (Schomacker et al., 2016; approach and many more records can now be Harning et al., 2016). Here we propose that the integrated in a 'tephra lattice' for precise linking Brattihjalli tephra is in fact the 6060 year old of sequence. In this talk, I will give a Hekla Ö tephra marker layer, demonstrating that comprehensive overview of the state-of-art of the Hekla Ö tephra extended much further to the tephrochronology of North Europe and also west than previously reported, covering about present some prospects for the future. 2/3 of the country. Thus, the Hekla Ö tephra covers an as large area in Iceland as the Hekla 5, Hekla 4, Hekla 3 and Hekla 1104 tephras, POSTER emphasizing the importance of Hekla Ö as a chronological marker. Holocene tephra stratigraphy in the Vestfirðir peninsula, NW Iceland

Esther Ruth Guðmundsdóttir1, Anders Schomacker2, Skafti Brynjólfsson3, Ólafur

Ingólfsson4 and Nicolaj K Larsen5 1Nordic Volcanological Center, Faculty and Institute of

25 POSTER 1.5. New trends in the study of Timing of early Holocene explosive the crystallisation and evolution eruptions in Iceland – improved of layered mafic complexes tephrochronology ORAL

Maarit Kalliokoski1, Esther Ruth Strontium isotopes in plagioclase 2 1 Guðmundsdóttir , Bergrún Arna Óladóttir , record magma chamber dynamics of Hreggviður Norðdahl3 and Ívar Örn Benediktsson3 the Skaergaard intrusion 1Nordic Volcanological Center, Institute of Earth Sciences, University of Iceland, Iceland, 2NordVulk, Graham Hagen-Peter1, Christian Tegner1, Peter Faculty of Earth Sciences, Institute of Earth Sciences, 2 1 University of Iceland, Iceland, 3Institute of Earth Thy and Charles Lesher 1 Sciences, University of Iceland, Iceland Centre of Earth System Petrology, Aarhus University, 2 Denmark, Department of Earth and Planetary Sciences, University of California, Davis, U.S.A. The Icelandic tephrochronology is an important tool for dating and correlating sedimentary We report Sr isotope data obtained by laser- archives, landforms and archaeological sites both ablation multi-collector ICPMS for individual in Iceland and overseas. A robust plagioclase crystals from the Skaergaard tephrochronology is also essential for deriving intrusion. Guided by micro-XRF petrography, we information on eruption frequency patterns. targeted cores and rims of primocrysts, as well as However, the early Holocene part of the Icelandic interstitial plagioclase from all major zones and tephrochronology lacks securely dated tephra subzones of the Layered Series (LS), Upper marker horizons. Ages of the tephra layers Border Series (UBS), and from the Sandwich between the Hekla 5 and Saksunarvatn tephras in Horizon (SH) and transgressive soil profiles and peatlands have previously been granophyre. Current analytical protocol enables dated only indirectly by interpolating soil or 87Sr/86Sr determination with precision of 1 part sediment accumulation rates between tephra in 104 using a Nu Plasma II mass spectrometer layers of known age. As this period represents and RESOultion 193 nm excimer laser with a about one third of the Holocene, it is critically ~150-um-diameter beam. Initial 87Sr/86Sr ratios important to establish new tephra markers (weighted means for individual samples) range within this part of the tephrochronology. The from ~0.7041 to 0.7045 for plagioclase ranging detailed tephra stratigraphy from Lake Lögurinn, from 25–70 An%. There are correlations between East Iceland (Gudmundsdóttir et al. 2016) was 87Sr/86Sr and An%, with the largest variation in used as an aid in selecting potential tephra 87Sr/86Sr among An-rich plagioclase. markers in soil sections, lake sediments and Stratigraphic relations show a progressive peatlands in East, Northeast and North Iceland. increase in 87Sr/86Sr from ~0.7041 at the base of To qualify as a tephra marker, a tephra needs to Lower Zone A to ~0.7044 at the top of Lower have at least regionally significant dispersal area, Zone B, a value that is essentially uniform up it must be securely dated and harbour stratigraphy through the SH. The UBS mirrors the characteristics which distinguish it from other LS, but also contains radiogenic An-rich tephras close in age (Larsen and Eiríksson plagioclase (87Sr/86Sr up to ~0.7045) near the 2008). Thus, new marker tephras for the early roof of the intrusion in contact with Tertiary Holocene are established by electron probe volcanic rocks. In the field these samples are microanalysis of tephra geochemistry, careful associated with rafts of partially assimilated comparison of tephra stratigraphy between sites Precambrian gneiss. The plagioclase Sr isotopic and radiocarbon dating of selected tephra layers. record suggests an important role for in situ AFC processes during early stages of Skaergaard evolution that diminished with inward solidification and insulation of the magma

26 reservoir from country rocks and, in particular, crystallisation of the remaining liquid fraction. the roof zone of the UBS containing rafts of The model is in line with the in the situ basement material. crystallisation of Langmuir (1989), and also, with variations, apply to some other KSC intrusive units.

ORAL

Magmatic fractionation by cumulate ORAL rock formation with expulsion of residual melts: a case from the Differential migration of interstitial Tertiary Kærven Syenite Complex, immiscible liquids in the Skaergaard East Greenland Layered Series Marian Holness1, Gautier Nicoli1 and Victoria Paul Martin Holm1 and Niels-Ole Prægel2 Honour1 1University of Copenhagen, 2Copenhagen University 1 Library Dept. Earth Sciences, University of Cambridge

The evolution of silicate melts by crystal The liquid line of descent of the Skaergaard fractionation processes in magma chambers is magma intersects a binodal creating an relatively well understood from experimental immiscible conjugate pair comprising a dense Fe- petrology, thermodynamic modelling, and suites rich liquid and a buoyant Si-rich liquid. These two of volcanic rock. However, from studies of liquids have different wetting properties: the Si- plutonic complexes it is evident that our rich liquid wets plagioclase, whereas the Fe-rich understanding of the physical processes acting in liquid wets oxides, pyroxene and olivine. The two magma chambers during the crystallisation of liquids may therefore undergo differential magmas, and which are believed responsible for migration within a gabbroic crystal mush: the Fe- the evolution of silicate melts, needs further rich liquid sinks and accumulates in mafic layers, clarification, even with respect to quite while the Si-rich liquid rises and accumulates in fundamental issues. We present new major and plagioclase-rich regions. Microstructural trace element data from an intrusive unit of the evidence demonstrates that differential Tertiary Kærven Syenite Complex, East migration occurred in rapidly deposited modally Greenland. The geochemistry of the syenitic graded layers from LZc upwards in the Layered rocks of the WK-2 unit displays ambiguous Series. The melanocratic bases of modally graded indications for their formation. On one hand layers in UZa develop finely-spaced internal accumulation of a gabbroic mineral assemblage is layering, consistent with patterning driven by indicated from linear correlation of several different wetting properties of the immiscible elements, and on the other hand an alkali feldspar interstitial liquid. dominated assemblage significantly affects the Evidence for differential migration is also rock compositions as shown by high Eu/Eu*, Ba recorded by mafic and felsic rims developed on and K/Rb. A simple liquid line of descent by the top and bottom margins of anorthositic roof fractional crystallisation executed by crystal blocks in LZc. Highly tabular blocks have an upper settling or open system wall rock crystallisation mm-thick mafic rim and a lower leucocratic rim. cannot explain the geochemical variation. As the block aspect ratio decreases, the rims Instead, we present a crystallisation model for disappear, with the mafic rim retained at lower the WK-2 unit consisting of a) partial aspect ratios than the leucocratic rim. These rims crystallisation of an isolated mush during which are formed as the Fe-rich interstitial liquid sinks the liquidus assemblage changes from gabbroic through the mush until it reaches the relatively to alkali feldspar syenitic, b) expulsion of a impermeable blocks, whereas the Si-rich liquid fraction of the residual liquid, and c) final

27 rises and ponds beneath them. Tabular blocks are morphological evidence for deposition of most effective at trapping these liquids. individual euhedral grains. Evidence from consideration of dihedral angle variation and the These observations demonstrate the complexity morphology of late-stage gabbroic pegmatites of behaviour in a crystal mush containing two- suggests that the floor mush near the wall at UZa phase interstitial liquid. Simple cumulate times was anomalously thick. We argue that paradigms do not apply in such a system. trough bands are a normal component of sedimentation on the floor of the chamber, and

that the unusually extensive stacks of trough ORAL bands in UZa are a consequence of temporary overthickening and steepening of the floor. Sedimentary layering in mafic intrusions: the Skaergaard trough bands ORAL

Marian Holness1, Zoja Vukmanovic1, Jens Late-stage melt migration in the Andersen2, Gautier Nicoli1, Sam Weatherley3, Skaergaard Intrusion Brendan Dyck4 and Victoria Honour1 1University of Cambridge, 2Camborne School of Mines, Victoria Honour1, Marian Holness1, Samuel University of Exeter, 3Geological Survey of Denmark and Weatherley2, Gautier Nicoli1, Brendan Dyck3 and Greenland, 4Simon Fraser University, Vancouver Jens Andersen4

1University of Cambridge, 2Geological Survey of Denmark and Greenland, 3Simon Fraser University, The trough bands of UZa of the Skaergaard 4University of Exeter Intrusion comprise individual stacks of upwardly concave, crescentic, modally graded layers, forming elongate structures pointing towards the The Skaergaard Intrusion preserves a variety of intrusion centre from the nearby vertical wall on late-stage melt structures such as gabbroic the western part of the chamber floor. Their pegmatites, paired felsic and mafic lenses origin is contentious, with some advocating a (interpreted to be solidified coarsened sedimentary origin while others argue for post- immiscible emulsions), dendritic anorthosites, accumulation formation via recrystallization and and melanogranophyres. Previous work on such metasomatism primarily triggered by localised structures has focused on particular localities in gravitationally-driven compaction. the intrusion, treating each structure in isolation.

Crescentic modally graded layers are present We have established relationships between the throughout the Layered Series below UZa. different melt migration structures, linking Although they do not commonly form extensive morphological and compositional variation to the stacks, their bases are clearly erosional surfaces, physical properties of the crystal mush and the attesting to their sedimentary origin. Similar progressive evolution of the bulk magma. erosional surfaces are commonly preserved in Gabbroic pegmatite morphology varies through the UZa trough bands, associated with changes in the floor cumulates due to changes in mush axial positon or width of the trough. The UZa rheology (Larsen & Brooks, 1994), consistent trough bands occur within a ~300m thick with newly developed constraints on mush stratigraphic interval containing abundant highly thickness. Pegmatites are podiform in thick mush elongate prismatic plagioclase grains that we but planar in thin mush. They are spatially argue were derived from collapse of the wall associated with paired felsic and mafic lenses, mushy layer. Detailed microstructural analysis of which occur 5-10 metres stratigraphically above the modally graded layers in the trough bands pegmatites in LZ, but at the same stratigraphic demonstrates a locally developed strong mineral horizon in UZ. The paired lenses form irregular, lineation parallel to the trough axis, together with approximately layer-parallel clusters in thick

28 mush, but thin concordant dendritic structures crystallisation of 60% of its mass and a within strongly foliated modally graded layers. convective loss of ~15 wt % Si-rich melt. The modal mineralogy of the paired lenses evolves upward consistent with evolution down In bulk MR rocks, FeO and P2O5 are negatively the binodal: below LZc the mafic component correlated. Gabbros rich in P2 are poor in P2O5, comprises olivine pyroxenite, but is dominated except for the main Au mineralisation and by oxides above LZb. In UZb pegmatites are samples with granophyric veins. Using a SOM melanogranophyric, and paired lenses are (self-organizing map) analysis, Au Ce, Y, Nb and confined to localised horizons recording Pb are shown to follow P2O5, and Au is added significant syn-magmatic disruption, consistent along grain boundaries to layers already enriched with the inferred evolution of the bulk magma in precious metal bearing droplets of sulphide towards the Si-rich side of the binodal. melt.

Our observations demonstrate that mush The present-day gabbros represent the sum of physical properties control the movement of processes acting between the liquidus and interstitial liquids, with wide-ranging subsolidus in semi-closed, proto-MR layers. Mush implications for our understanding of sub- melts fractionated until their evolved residuals volcanic processes. were re-mixed into and drove the evolution ofremaining bulk liquid.

ORAL ORAL Skaergaard gabbros: Fractionation Untangling the formation of and dissolution in crystal mush adcumulate rocks in layered intrusions: a microstructural study of

Troels Nielsen1 the Skaergaard and Bushveld 1Geological Survey of Denmark and Greenland intrusions

Zoja Vukmanovic1 and Marian Holness1 Recent work on the macro-rhythmic (MR) 1Department of Earth Sciences, University of Cambridge layered gabbros in the Skaergaard Intrusion that host the PGE-Au mineralisation shows that their Despite decades of study, the formation of evolution involved dissolution of early-formed adcumulates remains a topic of discussion in the liquidus phases and the convective loss of layered intrusion community. Models for the interstitial liquid (mush melt). An early formed formation of adcumulates broadly fall into two liquidus paragenesis (P1) was replaced by a groups: 1) those based on a primary origin by the gabbroic paragenesis (P2) that crystallised from growth of primocrysts in chemical mush melt and was out of equilibrium with the communication with the overlying bulk magma contemporary bulk liquid. P2 constitutes up to 50 (Wager et al., 1960); and 2) those based on two- vol. % of the sampled gabbro and hosts droplets phase flow, whereby the evolved melt is expelled of immiscible sulphide melt. from the crystal mush by gravitationally-driven Melts on the liquid line of descent reach the two- compaction (McKenzie, 2011, Meurer & Meurer, liquid field and unmixed in Fe- and Si-rich silicate 2006; Sparks et al., 1985; Tegner et al., 2009). melts when the intrusion was 90 % solidified. The To resolve this issue, we performed a detailed mineralization formed after 75% crystallisation microstructural examination of two different and MR layers of the mineralisation would retain examples: the Layered Series of the Skaergaard ~25 wt. % dense and Fe-rich melt after Intrusion, and anorthosites from Upper Zone of the Bushveld intrusion. We analysed grain

29 orientation by electron backscatter diffraction, ilmenite) and top-of-interval concentrations of and compared this with mineral chemistry. plagioclase. The layering style develops from Plagioclase in the Skaergaard shows almost no being wispy and laterally discontinuous close to evidence for crystal plasticity, and no evidence the margin, to strongly defined and laterally for dissolution-reprecipitation. We argue that continuous at the centre. On-lapping, layer- Skaergaard gabbros underwent negligible truncation and channel-like features are compaction and therefore that the adcumulates commonly observed. The oxide-rich horizons are are primary. In contrast, Bushveld anorthosites commonly associated with stoped wall and roof show ample evidence for dislocation creep such blocks, up to 400 m long, which are oriented with as low angle boundaries, and neoblasts formed long-axes parallel to the floor. In the size range during dynamic recrystallisation. However, the 10-1–101 m, the tops of high aspect ratio blocks extent of deformation is the same for exhibit cm-thick oxide rims; the undersides anorthosites both immediately below and above exhibit cm-thick rims of leucocratic (felsic) metre-scale magnetitite layers, suggesting that material. These paired rims are absent from low- the deformation is likely to be due to regional aspect ratio blocks. Oxide-rich seeps, discordant slumping, rather than internally-generated to layering, are also commonly observed. buoyancy forces. On the basis of these observations we Our results suggest that compaction is not the propose a combined ‘sedimentary’ and in-situ main mechanism that drives the formation of magmatic origin for Fe-Ti-V deposits whereby (1) adcumulates but, when present, can result in a newly-crystallised, gravitationally unstable minor medication of the primary igneous fabric. material, was removed from the wall and deposited on the floor; the deposition process resulted in density-sorted modal layers, and (2) liquid immiscibility in the mush produced ORAL conjugate Fe-rich silicate and felsic liquids that Combined ‘sedimentary’ and in-situ enhanced the primary modal layering, and led to the oxide-rich seeps and paired rims on origin for magmatic Fe-Ti-V deposits: blocks. This model is compatible with the new insights from the Skaergaard absence of LZc on Skaergaard's western margin. intrusion, East Greenland

Samuel Weatherley1, Jens C. Ø. Andersen2, Marian B. Holness3, Brendan J. Dyck4, Gautier Nicoli3 and Victoria C. Honour3 1GEUS, Øster Voldgade 10, 1350 Copenhagen K. Denmark, 2Camborne School of Mines, University of Exeter, Penryn Campus, Penryn, Cornwall, TR10 9FE. UK, 3Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge C2 3EQ. UK, 4Department of Earth Sciences, Simon Fraser University, Burnaby, V5A 1S6, Canada

New field observations from Skaergaard, East Greenland reveal five 0.5–2m thick, oxide-rich intervals within a ~30 m thick sequence near the top of LZc. Individual intervals are continuous along strike from the centre of the intrusion to the margin. This sequence exhibits density-sorted modal layering defined by basal concentrations of Fe-Mg rich phases (including magnetite and

30 1.6. Alkaline magmatism, Field observations, petrography and clinopyroxene-melt equilibrium calculations carbonatites and associated reveal open- and closed-system magma chamber mineral resources. processes that played a role in the magmatic ORAL evolution: magma recharge and mingling, pyroxene recycling, fractional crystallisation and Clinopyroxene as a petrogenetic accumulation. Repeated recharge events of the indicator: using integrated trace two principal magmas resulted in multiple interactions between more primitive and more element and zoning profiles to reveal fractionated co-existing magma batches. magma chamber processes in the Ditrău alkaline magmatic system Investigation of complex zoning characteristics and equilibrium melt calculations show that Anikó Batki1, Elemér Pál-Molnár2, M. Éva antecryst recycling is a significant process during Jankovics3, Andrew C. Kerr4, Balázs Kiss1 and magma recharge and demonstrate that Gregor Markl5 incorporated crystals can significantly affect the 1MTA-ELTE Volcanology Research Group, 1/C Pázmány host magma composition and so whole-rock Péter Street, H-1117 Budapest, Hungary, 2Department geochemical data should be interpreted with of Mineralogy, Geochemistry and Petrology, University great care. of Szeged, Hungary, 3MTA-ELTE Volcanology Research Group,1/C Pázmány Péter Street, H-1117 Budapest, Hungary, 4School of Earth and Ocean Sciences, Cardiff University, Main Building, Cardiff CF10 3AT, UK, ORAL 5Fachbereich Geowissenschaften, Universität Tübingen, Wilhelmstrasse 56, D-72074 Tübingen, Germany Probing the structural state of Y and Nd in eudialyte using X-ray Clinopyroxene is considered as a significant absorption spectroscopy petrogenetic indicator that can be used to unravel 1 2 the evolution of magmatic systems. EMPA and Anouk M. Borst , Platon N. Gamaletsos , Adrian A. 1 1 3 LA-ICP-MS have been used to analyse major and Finch , Nicola J. Horsburgh , Henrik Friis , Takeshi 2 4 4 trace element compositions of diverse Kasama , Joerg Goettlicher , Ralph Steiniger and 5 clinopyroxene crystals in seven related rock Kalotina Geraki 1School of Earth and Environmental Sciences, types of the alkaline igneous suite of the Ditrău University of St Andrews, United Kingdom, 2Center for Alkaline Massif, Romania. Electron Nanoscopy, Technical University of Denmark, Kongens Lyngby, Denmark, 3Natural History Museum, Phenocryst and antecryst populations from high- University of Oslo, Oslo, Norway, 4ANKA Synchrotron Cr Fe-diopside to high-Zr aegirine-augite have Radiation Facility, Karlsruhe Institute of Technology, been distinguished based on mineral zoning Eggenstein-Leopoldshafen, Ge, 5Science Division, patterns and geochemical characteristics. Diamond Light Source, Harwell Science and Innovation Clinopyroxenes record two major magma Campus, Didcot, United Kingdo sources as well as distinct magma evolution trends. The diopside population is derived from an early camptonitic magma related to basanitic Eudialyte group minerals (EGM) are important parental melts, whilst a group of diopside- rare earth-bearing alkali-zirconosilicates in hedenbergite crystals represents a newly agpaitic syenites. Alongside c.12 wt.% ZrO2 and 1- identified Na-, Nb- and Zr-rich magma source for 2 wt.% Nb2O5, EGM host c.1-10 wt.% total rare the the Ditrău magmatic system. This magma earth oxides with relatively high proportions of fractionated towards ijolitic and later phonolitic valuable heavy REE (c.35%). The EGM structure compositions with pronounced HREE, Nb, Zr and accommodates REE in various sites, mostly Hf enrichment along with increasing Na/Ca ratio. inferred to occupy the 6-fold coordinated Ca- dominated M1-site, or the low symmetry 8-9-10-

31 fold coordinated Na-site. However, XRD Østfjordsdal, Narsarsuk, Nunarsuit, Paatusoq) refinement is relatively insensitive to REE site Gardar magmatism and the geographical extent allocation, and HREE and LREE may occupy of the Province from Ivigtut in the West to different sites due to their varying ionic radii. Paatusoq in the East. Gardar magmas intruded How REE are distributed on the micro- Archaean crust (Ivigtut), Ketilidian /nanoscale, particularly following fluid metasediments (Paatusoq) and Ketilidian interaction, is poorly known. We use synchrotron granitoids (the others). radiation X-ray absorption spectroscopy to study the structural state and distribution of LREE and Age-corrected Hf isotopes show low Hf values HREE in EGM and their alteration products. We inconsistent with sourcing from depleted mantle in Gardar times. Early Gardar zircons have collected Y K-edge and Nd LIII-edge µ-XANES and μ-EXAFS to quantify coordination numbers and significantly lower age-corrected Hf than those of bond distances, with Y and Nd as proxies for the Late Gardar. Hf signatures in Early Gardar HREE and LREE respectively. Micro-XRF element zircons project back to Ketilidian or older mantle mapping combined with SEM and TEM provide extraction ages (> 1.8 Ma). One might interpret insights in the micro-/nanoscale REE distribution such data to indicate that Hf in the Early Gardar in EGM and its alteration products. Crystalline zircons was scavenged from Ketilidian basement. (XRD-confirmed) EGM from Ilímaussaq, However, primary Gardar melts are unlikely to Narssârssuk, Norra Kärr, Kipawa and Lovozero have contained negligible Hf and an unrealistic yield near-identical µ-XANES for Nd and Y, proportion of assimilated Ketilidian Hf is indicating similar LREE/HREE site occupations in required. However the data are consistent with a EGM of varying compositions. Preliminary Y model whereby subduction of Archaean crust (i.e. 176 177 EXAFS processing of the Narssârssuk EGM yield very low Hf/ Hf) during the Ketilidian optimal fits in 6-fold coordination and Y-O bond enriched the subcontinental lithospheric mantle distances of c. 2.26-2.32 Å, consistent with Y with Archaean Hf. In Gardar times, mantle substitution for Ca on the octahedral M1-site. melting preferentially accessed this subducted (Archaean) mantle component, providing Cerium absorption in the Nd LIII pre-edge region demonstrates minor variations in Ce-oxidation magmas with anomalously low Hf isotopic ratios. state across the localities. As rifting continued, proportionately more contemporary Hf was present in the melts. The model suggests recycling of Archaean crust via the mantle in Gardar times. ORAL

The Spatio-Temporal Evolution of Hf isotopes in the Gardar: Evidence for ORAL Mid-Proterozoic Crustal Recycling? Geochemical constraints on the

Adrian A Finch1, Anouk M Borst1, William formation of the Archean Siilinjärvi Hutchison1, Nicola J Horsburgh1, Tom Andersen2 carbonatite-glimmerite complex, and Siri L Simonsen2 Fennoscandian shield 1University of St Andrews, 2University of Oslo Esa Heilimo1, Hugh O'Brien1 and Pasi Heino2 1Geologica Survey of Finland, 2Yara Suomi Oy, Siilinjärvi The Gardar Province of Greenland refers to mine alkaline magmatism from intraplate rifting in the Mesoproterozoic. To understand further the sources of heavy REE and HFSE in the Gardar, we With an age of 2610 ± 4 Ma the Siilinjärvi analysed the Lu-Hf isotopes of several Gardar carbonatite-glimmerite complex in Finland is one centres, representing early (Motzfeldt, North of the oldest known carbonatites and the oldest Motzfeldt, Ivigtut) and late (Ilímaussaq, being currently mined for phosphorous. It was

32 emplaced in the Karelia Province following ORAL cratonic stabilization. The Siilinjärvi complex consists of carbonatite, calcio-carbonatite, Fluid-rock reactions in the carbonatite-glimmerite, and glimmerite carbonatites of the 1.3 Ga Grønnedal- surrounded by a fenite, forming a tabular body 16 Íka alkaline complex, Southwest km long and 1.5 km wide. The complex is affected Greenland by north-south Palaeoproterozoic steep shearing. Carbonatite occurs as thin (several cm) roughly Eemu Ranta1, Gabrielle Stockmann2, Thomas vertical lenses in glimmerite that forms thicker Wagner3, Tobias Fusswinkel3, Erik Sturkell4, Elin (10 cms) vertical veins. Despite the large Tollefsen2 and Alasdair Skelton2 carbonate-phlogopite modal variablity, 1Nordic Volcanological Center, University of Iceland, compositions of the phases calcite, dolomite, Reykjavik, ICELAND., 2Department of Geological tetraferriphlogopite, apatite and richterite do not Sciences, Stockholm University, Stockholm, SWEDEN, vary significantly across the complex. The 3Institute of Applied Mineralogy and Economic Geology, distribution of apatite is rather uniform, with RWTH Aachen University, GERMANY, 4Department of average glimmerite and carbonatite containing Earth Sciences, University of Gothenburg, SWEDEN

10.4 and 9.9 modal % apatite, respectively. Compositionally the carbonatite veins are calcio- Petrogenetic studies of carbonatites – carbonate- carbonatites, whereas the glimmerites are dominated igneous rocks – are challenging potassic ultramafic rocks with Mg# over 0.8. All because carbonatite mineral assemblages and are cumulates, but are geochemically linked, mineral chemistry typically reflect variable showing similar trace element trends. Average C- pressure-temperature conditions during 13 O isotopic compositions are δ C=3.7‰ and crystallization, and fluid-rock interaction caused 13 δ O=7.4‰. The geochemical data indicate that by magmatic-hydrothermal fluids. However, this the carbonatite and glimmerite are cogenetic complexity results in recognizable alteration with fractionation processes possibly playing a textures and trace element signatures in the significant role in their genesis. Isotopic mineral archive that can be used to reconstruct compositions show relatively uniform patterns the magmatic evolution and fluid-rock and, we propose that the carbonatite and related interaction history of carbonatites. lithologies are evolved from primitive carbonatite liquids produced by low degree Our study focuses on the 1.3 Ga Grønnedal-Íka melting of a carbonated mantle source. We carbonatite-syenite complex in Southwest propose that the complex has represents a Greenland. The alkaline complex marks the onset relatively deep well mixed magma chamber with of the Gardar continental rifting event, during consequent accumulation and crystallization, which it was subsequently intruded by basaltic feeding magmatic activity at higher levels. dikes and underwent extensive faulting. We present LA-ICP-MS trace element data for magnetite, calcite, siderite and ankerite-dolomite from the iron-rich carbonatites of Grønnedal-Íka,

and use this data, in combination with detailed cathodoluminescence imaging, for identifying magmatic and secondary geochemical fingerprints preserved in these minerals.

The chemical and textural gradients point toward a 55 m wide basaltic dike as the focal point of a

fossil hydrothermal fluid flow system, providing heat for F and CO2 rich fluids that mobilized LREEs, Nb, Ta, Ba, Sr, Mn and P. These fluids reacted with and altered the composition of the surrounding carbonatites up to a distance of 40 m

33 from the dike contact, where a high-grade as a complex intergrowth of several rock types, magnetite mineralization was formed through which pinch and swell and include eudialyte-rich oxidation of siderite. Our results can be used for and naujaite-like rock. These layers are not a discriminating between primary magmatic simple modal enrichment of eudialyte, but are minerals and later alteration related assemblages interpreted by us as a reaction between naujaite in carbonatites in general, which can lead to a slabs and kakortokite magma. The remaining better understanding of how these rare rocks are layers (E-I) occur as faint layers in grey formed. kakortokite and represent a local modal enrichment of eudialyte. Therefore, we suggest the kakortokite stratigraphy to be described as LLK (≥ 200 m) overlain by SLK (≈ 75 m).

ORAL ORAL A review of the Transitional Layered Kakortokite (TLK), IlÍmaussaq Alkaline pegmatites of the Larvik Complex, South Greenland Plutonic Complex – what are they?

Hans Kristian Schønwandt1, Gregory B. Barnes1 Øyvind Sunde1, Henrik Friis1 and Tom Andersen2 and Thomas Ulrich2 1Natural History Museum, University of Oslo, P.O. Box 1G.B. Barnes & Associates, 47 Labouchere Road, South 1172, Blindern, 0318 Oslo, Norway, 2Department of Perth, W.A. 6151, Australia, 2Department of Geoscience, Geosciences, University of Oslo, P.O. Box 1047, Blindern, Aarhus University, Denmark 0316 Oslo, Norway

Kakortokite represents the lowest member of the The Larvik Plutonic Complex is a differentiated peralkaline magmatic stratigraphy of the alkaline complex situated in the Permian Oslo Mesoproterozoic IlÍmaussaq Complex, South Region and consists of a series of semi concentric Greenland. Kakortokite is an agpaitic nepheline ring intrusions of monzonitic rocks (Petersen syenite of which the lowest part shows 1978; Neumann 1980). The monzonitic rocks are spectacular layering. Kakortokite is originally collectively known as larvikite and extensively subdivided into three parts: (1) A lower layered quarried as a dimension stone. Within the host kakortokite (LLK) about 200 m thick, (2) slightly plutons numerous nepheline syenite and syenite layered kakortokite (SLK) about 35 thick, which pegmatites, as well as minor nepheline syenite is overlain by (3) transitional layered dykes occur with an ambiguous relationship and kakortokite(TLK) with a thickness of about 40 m. contrasting mode of emplacement. Although The LLK consists of three-layered units many of these pegmatites have been extensively composed of black, red, and white layers formed studied for their mineral content and provided by modal enrichment of arfvedsonite, eudialyte first descriptions of 30 mineral species, the and feldspar-nepheline respectively. SLK is petrological evolution of the pegmatites is still almost unlayered and appears as a grey poorly understood. Different classification kakortokite, locally with faint black layers. TLK schemes have been devised to relate and represents a return to the black-red-white- compare contrasting pegmatite features such as layered units. morphology, mineralogical zonation, and rock textures (e.g., Brogger 1890; Piilonen et al. 2012). TLK is best exposed north-west of the proposed However, such differences are not directly fault along Lakseelv where it gradually grades related to petrogenetic similarities between into the overlaying lujavrite. In this section, nine these pegmatites. Wöhlerite, ideally eudialyte-enriched layers occur named A to I in NaCa2(Zr,Nb)(Si2O7)(O,OH,F)2, occurs abundantly descending order from the contact to the among the early liquidus mineral assemblages of lujavrite. The uppermost four layers (A-D) occur the nepheline syenite pegmatites. The flexible

34 crystal structure of wöhlerite is able to Trace element data show catapleiite-alteration incorporate cations of different size and valence, caused a 15-25% decrease in REE, Ta, Nb, Zr, Sr and thus record contrasting pegmatite-forming and Y (relative to precursor eudialyte) and up to magmas. four-fold increase in Rb and Th ([Th]pmo = 27-100 ppm), while gittinsite- and zircon-alteration This contribution provides a regional comparison caused stronger heavy REE (HREE) depletion of wöhlerite major- and trace-element (≤50%). REE fractionation is evidenced by composition coupled with detailed field mapping lowered Sm/Nd ratios in all but one of selected pegmatites to reveal a close pseudomorph-sample, indicating that altering petrogenetic relationship between pegmatites fluids were capable of remobilizing and and heterogeneities of the host larvikite. fractionating HFSE and REE.

143 144 Nd/ Ndt=1160 ratios of fresh eudialyte (µeud = 0.511090, s.d. = 5) are indistinguishable from ORAL those of pseudomorphs (µpmo = 0.511097, s.d. = 7) Trace element and Nd-isotope data of at the 90% confidence level, suggesting that fluids were (late-)magmatic in origin. However, zircon- eudialyte from the Kakortokite type pseudomorphs yield higher 143 144 sequence of the Ilímaussaq complex Nd/ Ndt=1160 (0.511166±7), which, combined suggest subsolidus remobilization of with stronger HREE depletion and enrichment in rare earth elements by magmatic Sr (130%) and Ba (79%) hints at a different fluids origin for the zircon-forming fluid.

Mathijs van de Ven1, Anouk Borst2, Gareth Davies1 POSTER and Adrian Finch2 1Vrije Universiteit Amsterdam, 2St. Andrews University Mineralogy and petrology of mafic

dikes from the Siilinjärvi carbonatite The kakortokites, agpaitic floor cumulates of the complex, Finland peralkaline Ilímaussaq Complex, South Greenland (1160 Ma1), constitute a world-class Matias Carlsson1, Hannes B. Mattsson2, Karin deposit of rare earth elements (REE), largely Högdahl3, Alireza Malehmir2 and Pasi Heino4 1 hosted in the alkali-zirconosilicate eudialyte. Geology and Mineralogy, Åbo Akademi University, Akatemiankatu 1, 20500 Turku, Finland, 2Dept. of Earth Autometasomatic and/or hydrothermal Sciences, Uppsala University, Villavägen 16, 752 36 alteration of eudialyte has caused formation of Uppsala, Sweden, 3Dept. of Earth Sciences, Uppsala pseudomorphs exhibiting a variety of secondary University and Geology and Mineralogy, Åbo Akademi 2 REE-/Zr-phases. Previous work identified three University, 4Yara Suomi Oy, Siilinjärvi, Finland alteration types, characterized by the secondary zirconosilicates catapleiite, gittinsite and zircon. The 2.6 Ga Siilinjärvi carbonatite complex in Here we present ICP-MS trace element and TIMS central Finland is transected by a large number of Sm/Nd isotope data of micro-drilled eudialyte- mafic dykes. Here we combine field-relations, pseudomorph pairs from four samples spanning with mineralogical and petrological analysis to the kakortokite stratigraphy (three catapleiite- infer dike emplaced in three distinct stages. The type, one gittinsite-type) and one zircon-type older two generations (Gen I and II) are intesely pseudomorph sample from the ‘hybrid’ units that deformed in constrast to the composite dike of cross-cut them, to study the nature of altering Gen III. fluids and their high field strength element (HFSE-)mobilizing capacity. Mineralogically the dykes are comparable, containing plagioclase, amphibole, quartz, calcite

35 as major phases, with accessory chlorite, apatite, cancrinite nepheline syenite (särnaite) and epidote, titanite and opaques. Gen I dykes have crosscutting tinguaite dikes. While different characteristically allanite and near-euhedral whole-rock särnaite samples did not form an chamosite crystals (chlorite), surrounded by fine- isochron, mineral separates derived from grained titanomagnetite/ilmenite. These särnaite have yielded a Rb–Sr age of 287±14 Ma chamosites are likely pseudomorphs replacing (2σ) (Bylund and Patchett, 1977), broadly coeval original phlogopite crystals. with the Permian Oslo Rift magmatism (ca. 308– 245 Ma: Larsen et al., 2008), but not precise The alkaline composition of Gen I dykes enough to draw confident parallels. (predominantly K-rich foidites, with up to 13 wt.% Na2O+K2O) suggests that they are related To further constrain the timing of magmatic to different degrees of mantle melting. It is simply activity at Särna, we are studying the Rb–Sr not possible to produce the observed systematics of these alkaline igneous rocks by a compositions by fractionation of any potential newly developed technique for in situ Rb–Sr phenocryst phase. The two younger dyke dating by LA-ICP-MS/MS (Zack and Hogmalm, generations can be reproduced by a relatively 2016). Detailed characterization of mineral “normal” basaltic fractionation series (spanning textures and chemistry by SEM in combination from basalts, via K-rich alkali-basalts to trachytic with micro-analytical dating can give reliable Rb– compositions). Sr ages of alkaline rocks, which are notorious for pervasive alteration and open-system behaviour. The Gen I dykes seem to be directly associated Preliminary results include the first radiometric with a mantle source similar to that which age of a Särna tinguaite, which was dated at produced the apatite-bearing carbonatites. The 296±7 Ma (2σ) in biotite phenocrysts and later dyke generations have bulk-rock confirms that the särnaite and tinguaite are compositions that are not normally found in coeval. Deriving more precise ages from a variety direct relation to carbonatites, indicating a of rock types will also allow us to make more significant time gap between the Gen I dykes and robust connections with the phases of formation subsequent generations in which time the mantle of the Oslo Rift. source had changed significantly to produce these chemically contrasting magma suites.

This is an ERA-MIN StartGeoDelineation POSTER contribution sponsored by Vinnova, SGU, Tekes, NIO and Yara. Thorium in eudialyte ore deposits from Greenland studied by

synchrotron radiation (μ-XRF/-XAFS) POSTER and electron microscopic techniques (SEM, TEM) Geochronology of the Särna alkaline complex, Dalarna, Sweden Platon N. Gamaletsos1, Anouk M. Borst2, Takeshi Kasama1, Adrian A. Finch2, Joerg Goettlicher3, John A. Eliasson1, Thomas Zack1 and Axel SL Ralph Steininger3, Berit Wenzell1, Zoltan I. Sjöqvist1 Balogh1 and Athanasios Godelitsas4 1Department of Earth Sciences, University of 1Center for Electron Nanoscopy, Technical University of Gothenburg Denmark, Kongens Lyngby, Denmark, 2School of Earth and Environmental Sciences, University of St. Andrews, St Andrews, UK, 3ANKA Synchrotron Radiation Facility, The Särna alkaline complex is a well-known yet Karlsruhe Institute of Technology, Eggenstein- poorly studied locality of highly peralkaline Leopoldshafen, Ge, 4Department of Geology and igneous rocks in middle Sweden. It mainly Geoenvironment, National & Kapodistrian University of consists of two rock types: varieties of intrusive Athens, Athens, Greece

36 The Nordic region holds some of the world’s (metabasalts), biotite-quartz-plagioclase largest eudialyte deposits, which contain gneisses (metapsammites and porphyry promising rare earths concentrations. Due to low metadacite and metaandesite) of Orosirian content of actinides (including thorium / Th) in period. Each lithology is predominant in such rocks, eudialyte would avoid many of the alternating bands extended NNE-SSW. issues of potential radioactive contamination in Supracrustals are metamorphosed on the level of tailings that bedevil e.g., monazite and xenotime amphibolite facies and migmatized. Intrusive extraction. Here, we study the nature of Th rocks are represented by coeval rare bodies of associated with rare earth elements (REE) in gabbro, peridotite and widespread Calymmian eudialyte ore deposits from Greenland in micro- granitic plutons (Motuza 2005; Linnemann et al. /nano-scale using the technical advance of 2008). combining synchrotron radiation (SR μ-XRF/- XAFS) and electron microscopic (SEM, TEM) Varena suite comprises olivine, enstatite, techniques. Preliminary synchrotron radiation & diopside, olivine-magnetite, magnetite, apatite- electron microscopic observations of altered bearing, and presumably also dolomite rocks. eudialyte reveal the presence of Th-bearing They form integrated bodies few sq. km large, 2 phases at the micro-/nano-scale. Similar concentrated in the ~300 km area extended in N- heterogeneity is observed for the REE in S direction(Motuza et al. 2016). eudialyte replacement products. We collected Th Rocks of Varena suite and the country rocks L -edge extended x-ray absorption fine structure III (amphibolites, metaporphyres) are affected by (μ-EXAFS) spectral data of Th-enriched strong metasomatic alteration. The microareas, identified by SR μ-XRF mapping that mineralization of REE (up to 2759-3100ppm confirmed the heterogeneous distribution of Th, of La and Ce respectively), Th, U, P hosted by which provide information on the local structural monazite, apatite(?), allanite is spatially related environment of Th within altered eudialyte. Th- to the Varena suite and some metasomatized bearing phases were detected along altered supracrustals. margins of eudialyte, in secondary phases, and interstitial to primary phases such as feldspar, The views on the genesis of Varena suite are amphibole and eudialyte. Concerning fresh contradicting. By various authors they are eudialyte, Th is undetectable by SR μ-XRF. regarded as skarns, presuming metasomatic However, further research is needed to clarify origin, as layered intrusions or products of these phenomena. alkaline and carbonatitic magmatism(Motuza et al, 2016).

In this presentation the genetic model is POSTER reviewed based on reinterpretation of structural, geochemical, petrographical data, and new Varena suite in the crystalline crust isotopic studies of O, C, Sr in the rocks of Varena of the Southern Lithuania: suite. It is also an attempt to raise methodological implication to the genesis and questions such as Lu-Hf dating of apatite and find mineralization. opportunities for cooperation in further studies.

Vaida Kirkliauskaite1, Gediminas Motuza2 and Raminta Skipityte1 1PhD student, 2Prof.dr.

Crystalline crust in Southern Lithuania is covered by 200-500 m thick sedimentary cover and is investigated by potential field mapping and drilling. It is composed by amphibolites

37 POSTER Blaxland et al. (1978) with the newly revisioned Rb-Sr decay constant (Villa et al., 2015) yields an New Rb-Sr and Zircon U-Pb dating of age of 1311±26 Ma. the Grønnedal-Íka igenous complex, This confirms the Grønnedal-ìka complex as the SW Greenland oldest of the Gardar intrusions and most likely Gabrielle Stockmann1, Andreas Karlsson2, marks the onset of the Gardar continental rifting Alexander Lewerentz1, Tonny B. Thomsen3, of South Greenland. Thomas F. Kokfelt3, Elin Tollefsen1, Erik Sturkell4 and Lena Lundqvist5 1Department of Geological Sciences, Stockholm POSTER University, SWEDEN, 2Department of Geosciences, Swedish Museum of Natural History, Stockholm, Experimental simulation and SWEDEN, 3Geological Survey of Denmark and Greenland (GEUS), Copenhagen, DENMARK, predictive modelling of rare earth 4Department of Earth Sciences, University of element enrichment in carbonatites Gothenburg, SWEDEN, 5Swedish Geological Survey and alkaline magmas (SGU), Gothenburg, SWEDEN Johann Tuduri1, Zineb Nabyl1, Fabrice Gaillard1, Malcom Massuyeau2, Giada Iacono-Marziano1, Dating of the Grønnedal-Íka igneous complex in Jérémie Melleton1 and Laurent Bailly1 Southwest Greenland is important to understand 1BRGM, UMR7327, 3 avenue Claude Guillemin, 45100 the continental rifting event – the Gardar episode. Orléans, France and also University of Orléans, ISTO, In this study, three different methods have been 2University of Johannesburg, PO Box 524, Auckland applied to rock specimens and previously Park 2006, South Africa published data to better constrain the age of the complex: a) U-Pb dating of zircons extracted from hand specimens of Upper Series nepheline Carbonatites and alkaline magmas are key pieces syenites and from drillcore samples of a central of the deep carbon cycle and constitute one of the carbonatite plug collected by Kryolitselskabet principal resources of rare metals including REE. Øresund A/S, b) new in-situ Rb-Sr analysis on Several experimental studies have tackled the Lower Series granular syenite, and c) re- rare metal partitioning between immiscible calculation of whole rock Rb/Sr data by Blaxland carbonate and silicate liquids (Martin et al. 2013; et al. (1978). Veskler et al. 1998, 2012). They show negative to massive enrichments in the carbonate liquid. Prismatic zircons, 100-200 µm in size, light However, no prevailing cause has been clearly brown in colour, showing magmatically zoned isolated as such enrichments can be ruled by cores and irregularly shaped alteration rims with experimental conditions (P, T, ƒO2), melt overgrowths of U and Th oxides were analysed compositions (water and alkali contents), or with ThermoFinnigan Element 2 Inductively technical issues such as unequilibrated Coupled Plasma Sector Field Mass Spectrometer experiments. instrument at GEUS. This gave an U-Pb age of 1325±6 Ma after having selected suitable data The aim of this study is to simulate, by HP-HT points from CL. experiments in the nephelinite-carbonatite system, crystal fractionation and immiscibility In-situ Rb-Sr dating using an Agilent 8800 ICP between carbonate and silicate liquids, in order MS/MS on selected minerals from granular to assess the factors ruling REE enrichment syenite gave an isochron age of 1314±14 Ma on during the differentiation of alkaline magmas. the basis of 20 spots in biotite and k-feldspar using the technique outlined in Zack and Thirty experimental charges were synthetized Hogmalm (2016). Re-evaluation and re- using piston-cylinder and internally heated calculation of the whole-rock dataset from pressure vessel. The partitioning of REE between

38 carbonate liquids, silicate liquids and crystals oxides in variable proportion and forms of (pyroxene, calcite, nephelinite, perovskite, monomineral aggregates of 3-100 µm, interstitial titanite) has been characterized. REE partition veins or schlieren of 30-250 µm dimensions. coefficients between carbonate and silicate liquid Pyrrhotite makes up nearly 75% of sulphides increase while Ca partition coefficient increases, bulk. Pyrrhotite, chalcopyrite and pentlandite suggesting that both have the same behavior. have magmatic origins confirmed by sulfur

Also, the more the silicate liquid is polymerized, isotopes of δ34SCDT of about 0 ‰. (Wiszniewska the more REE are concentrated into carbonate J. et al.) Sulfides contain often nanoforms of REE liquids. The Ca partition coefficient has been thus (La, Ce and Nd) and precious elements (gold, calibrated by an empirical model based on the platinum) mineral admixtures of 10-100 µm or silicate melt composition. even up to 300 µm in sulfides. Untypical zircon grains of blown candle flame structure and rims This study reveals the optimum conditions for around ore minerals were observed and which carbonatite melts get enriched by >10 prepared for age determinations. times with respect to the residual silicate melts. This predictive approach may serve as guide for New results of polymetallic and precious metal prospection of REE-enriched carbonatites. sulfides together with REE dispersed mineralization may increase an economic value of Fe-Ti-V documented deposits in SAM.

POSTER Polymetallic, REE and precious elements new results within Suwalki Anorthosite Massif, NE Poland

Janina Wiszniewska1 and Michal Ruszkowski2 1Polish Geological Institute -National Research Institute, 2Department of Geology, University of Warsaw

The Suwalki Anorthosite Massif (SAM) is located in NE part of Poland, within Mezoproterozoic, beltiform magmatic AMCG [anorthosite - mangerite - charnokite - granite rapakivi] suite known as a Mazury Complex. This complex associate with tectonic deep rift crustal structure. The SAM occupies an area of 250 km2 of the oval shape diapiric structure. Its central part is made up of anorthosites surrounded by rings of norites, gabronorites and diorites. Fe-Ti-V ore minerals concentrations with subordinate Fe-Cu-Co-Ni sulphides that represent 1 to 4% of the rock volume (Wiszniewska J., 2002, Wiszniewska J. et al. 2002) locally even more to a maximum content of 8%.

Chalcopyrite, pyrrhotite, cubanite, pentlandite, cobaltite, bornite, chalcocite, millerite and sphalerite are most common magmatic sulfide minerals. These minerals coexist with Fe-Ti

39 1.7. Magmatic Plumbing the extensional rift setting, the dyke emplacement generated exclusively double- Systems. couple earthquakes with solely strike-slip ORAL faulting mechanisms.

A seismic study of the 2014-15 Bárðarbunga-Holuhraun rifting event ORAL Thorbjörg Ágústsdóttir1, Robert S. White1, Jennifer Dyke tip processes and large-scale Woods1, Tim Greenfield2, Tom Hudson1 and Bryndís Brandsóttir3 deformation: implications for 1University of Cambridge, 2University of Southampton, geodetic modelling 3Institute of Earth Sciences, Science Institute, University of Iceland Håvard Svanes Bertelsen1, Frank Guldstrand1, Olivier Galland1 and Karen Mair1 1Physics of Geological Processes, University of Oslo, On 16 August 2014 an unusual sequence of Norway earthquakes began near the southeastern rim of the ice-covered Bárðarbunga caldera in central Iceland. Over the course of two weeks a dyke Geodetic modelling of dykes using the Okada propagated 48 km beneath the glacier dislocation model has become a standard northeastwards and into the Holuhraun lava approach when interpreting geodetic data field, where it erupted for six months, becoming monitored over active volcanoes. The Okada the largest eruption in Iceland for over 200 years. model assumes that (1) dykes are tensile During this time, a gradual, incremental caldera fractures and (2) the host is purely elastic. collapse took place in the Bárðarbunga central However, recent field observations and volcano. This study analyses the seismic response laboratory results suggest an alternate dyke to the event, both due to the dyke propagation, propagation mechanism; the viscous indenter, i.e. and the associated caldera collapse. the dyke tip propagates by pushing its host rock Approximately 35,0000 earthquakes were ahead, failing in shear. To which extent different recorded during the pre-intrusive, intrusive, dyke propagation mechanisms affect the eruptive and post-eruptive periods, associated surface deformation is currently whereof ~4,000 earthquakes were associated unknown. To address this, we compare two series with the caldera collapse, delineating faults of laboratory models of dyke emplacement, accommodating the subsidence and showing during which we monitored surface deformation good correlation with geodetic data. Detailed at high resolution and precision. In the first analysis of the earthquake source mechanisms series, the model crust was elastic gelatine and shows that ~90% can be explained by a double- the dyke propagated as tensile fracture; the couple solution. The dominant failure mechanism resulting surface deformation was comparable during the collapse is steep normal faulting, with with the predictions of the elastic Okada model, sub-vertical P-axes, striking sub-parallel to the i.e. an elongated topographic trough above the caldera rim. The northern and southern sides of dyke apex, surrounded by two uplifted zones. the caldera, however experienced very different Conversely, in the second series, the model crust seismicity rates, highlighted by the order of was a cohesive Coulomb silica flour and the dyke magnitude difference in the cumulative seismic propagated as a viscous indenter; the resulting moments. We present evidence of a complex surface deformation was only uplift. The first- asymmetric caldera collapse, not controlled by a order differences between the two series of single caldera ring fault. The ~31,000 models show that local tip processes indeed earthquakes delineating the segmented, lateral control large-scale deformation induced by dyke intrusion fractured a pathway through the propagating dykes, and so the surface crust, utilizing pre-existing weaknesses. Despite deformation patterns. Our results question the

40 systematic use of tensile elastic fracture models occurrence and geometry of sill intrusions and to interpret geodetic measurements associated including these in velocity models. with dyke emplacement. Finally, our results show that relevant interpretation of geodetic measurements requires a proper physical ORAL understanding of dyke propagation mechanisms. Fracture networks in and around

igneous intrusions on Svalbard: ORAL implications for fluid flow

Seismic Interpretation of Sill- Marte Festøy1, Kim Senger2 and Sten-Andreas Complexes in Sedimentary Basins: Grundvåg3 The ‘Sub-Sill Imaging Problem’ 1Master graduate, 2Primary supervisor, 3Co-supervisor

Christian Haug Eide1, Nick Schofield2, Isabelle Igneous intrusions exert a strong influence on Lecomte1, Simon J. Buckley3 and John A. Howell2 1University of Bergen, 2University of Aberdeen, 3Uni petroleum systems, groundwater aquifers and Research CIPR CO2 storage reservoirs. This is especially true for migration pathways, as any given intrusion may act as a barrier to, or a carrier for fluid flow, Application of 3D-seismic reflection-data to potentially compartmentalizing a reservoir or igneous systems in sedimentary basins has led to creating seal by-pass structures. The fracture a revolution in the understanding of mafic sill- network in the intrusion and its surroundings complexes. However, there is considerable will control the permeability along and across a uncertainty on how geometries and architecture single intrusion. However, the various fracturing of sill-complexes within the subsurface relates to processes are relatively poorly constrained, those imaged in seismic reflection-data. To being controlled by magma emplacement, magma provide constraints on how sill-complexes in cooling and tectonic events, and field data are seismic data should be interpreted, we present required to better understand this interplay. In synthetic seismograms generated from a seismic- this study we investigate 15 outcrops from scale (22x0.25 km) outcrop in East Greenland central Spitsbergen, Arctic Norway, in order to constrained by abundant field-data. This study constrain the impact of Early Cretaceous igneous highlights how overlying igneous rocks adversely intrusions on subsurface fluid flow. We combine affect imaging of underlying intrusions and rocks traditional field mapping with photogrammetry by decreasing seismic amplitude, frequency and to construct high-resolution 3D virtual outcrop making steeply dipping features near-impossible models, providing 330 m of scanlines, 928 to image. Furthermore, seismic modelling in this fracture measurements using a geological study shows that, because of the high impedance compass and an iPhone and 7993 fracture contrast between siliciclastic host-rock and measurements from virtual outcrop models. dolerites, very thin (1-5 m) intrusions should in Fracture sets, both within the dolerites and the principle be imaged in reflection-seismic data at nearby host rocks, are predominantly oriented 3 km depth. However, comparison with actual either parallel or perpendicular to the intrusion seismic data with well-data shows significant contact. At one of the study sites, the fracture amounts of un-imaged sill intrusions, and this is frequency in the intrusion-proximal host rocks likely due to limited seismic resolution, increases toward the intrusion contact, from 6 overburden complexity, inadequate velocity- fractures/m (f/m) in the background to 10 f/m models, and interference between reflections approximately 1 m from the intrusion contact. from closely spaced sills and sill-splays. Calcite cemented fractures are frequently Significant improvements to sill imaging and observed in within intrusions, but also within interpretation could be made by better predicting intrusion-proximal host rocks. A conceptual

41 model for rock evolution and fracture climate changes and mass extinctions during development in and around igneous intrusions is Earth's history. presented. In this presentation, I will develop the main points of our understanding of sill formation, i.e. the feeders of sills, the factors controlling their ORAL initiation, their propagation mechanisms and subsequent evolutions to saucer-shaped The relevance of sills and related flat- intrusions or laccoliths. lying intrusions in volcanic plumbing systems

Olivier Galland1, Håvard S. Bertelsen1, Christian H. ORAL Eide2, Frank Guldstrand1, Øystein T. Haug1, Héctor Deep and shallow magma storage on A. Leanza3, Karen Mair1, Octavio Palma4, Sverre Planke5, Ole Rabbel1, Benjamin Rogers1, Tobias Bali Schmiedel1, Alban Souche1 and Juan B. Spacapan6 Harri Geiger1, Valentin R. Troll1, Ester M. Jolis1, 1Physics of Geological Processes, Department of Frances M. Deegan1, Chris Harris2, Martin J. Geosciences, University of Oslo, Norway, 2University of 3 4 5 Bergen, Norway, 3Museo Argentino de Ciencias Whitehouse , David R. Hilton and Carmela Freda Naturales-CONICET, Argentina, 4Y-TEC-CONICET, 1Department of Earth Sciences, Uppsala University, Argentina, 5VBPR, CEED, University of Oslo, Norway, Uppsala, Sweden, 2Department of Geological Sciences, 6YPF-CONICET, Argentina University of Cape Town, South Africa, 3Department of Geosciences, Swedish Museum of Natural History, Stockholm, Sweden, 4Geosciences Research Division, Although dykes are considered to be the main Scripps Institution of Oceanography, La Jolla, CA 92093- upward magma pathways through the Earth’s 0244, USA, 5Istituto Nazionale di Geofisica e Vulcanologia, Rome, Italy crust, the last two decades of research showed that significant parts of volcano plumbing systems consist of flat-lying igneous intrusions, The architecture of sub-volcanic magma supply namely sills. The aim of this contribution is to systems exerts a fundamental control on eruptive provide a didactic overview of our current behaviour and thus on volcanic hazards. The understanding of the formation of sills and of island of Bali in the Sunda arc, Indonesia, is their scientific and economic relevance (Galland densely populated and home to two active et al., accepted). stratovolcanoes, Agung and Batur, but relatively little is known of their underlying magma Sills form mainly in the layered parts of the crust, plumbing systems. Here we reconstruct magma principally in volcanic deposits and sedimentary storage and evolution under Bali by employing basins where lateral magma flow through sill clinopyroxene and plagioclase mineral-melt complexes and networks can reach several equilibrium thermobarometry, oxygen isotope hundreds kilometers. Sill exhibits various shapes, crystal stratigraphy, and He isotopes in pyroxene. from strata-concordant, transgressive sheets to Clinopyroxene records magma storage at the saucer shapes. Furthermore, sills represent crust-mantle boundary, consistent with mantle- intermediate feeder structures for volcanic like He isotope pyroxene values and mildly eruptions and, therefore, a better understanding submantle δ18O values. Plagioclase, in turn, of sill emplacement and evolution is essential for reveals upper crustal magma storage and mantle- assessing volcanic hazards. Sills emplaced in like δ18O values, indicating differentiation of sedimentary basins also deeply affect petroleum ascending primary magma in upper crustal systems and are essential components in reservoirs. Indeed, recent arc-wide InSAR data exploring hydrocarbons. Finally, the massive and for the Sunda arc revealed frequent shallow-level fast emplacement of sills resulting from LIPS in magma storage along the arc, which contrasts sedimentary basins triggered catastrophic

42 traditional petrogenetic models for arcs. Multi- To further interpret our experimental dataset we level magma storage likely favours prolonged attempt a numerical comparison using a static differentiation of Sunda arc magmas, which could elastoplastic 2D code to investigate the expected promote future hazardous eruptions on Bali. elastic and plastic deformation using the imposed experimental intrusion geometry and host rock properties.

ORAL

Dyke induced quasi-2D deformation ORAL in a Coulomb britte host — the influence of host strength on Ground deformation in the propagation and emplacement Bárðarbunga Volcanic System, Iceland, Following the 2014-2015 Frank Guldstrand1, Olivier Galland1, Alban Lateral Dyke, Caldera Collapse and 1 1 Souche , Håvard Svanes Bertelsen and Alain Major Effusive Eruption Zanella2 1Physics of Geological Processes, University of Oslo, Siqi Li1, Freysteinn Sigmundsson1, Vincent 2L.P.G-Le Mans, Le Mans Université Drouin1, Benedikt G. Ófeigsson2 and Michelle

Parks2 1Nordic Volcanological Center, Institute of Earth The emplacement of magmatic dykes within the Sciences, University of Iceland,101 Reykjavik, 2Icelandic Earth's crust represents a fundamental process of Meteorological Office, 150 Reykjavik, Iceland. magma transport and feeding of volcanic eruptions. Understanding the dyke emplacement mechanism requires an understanding of how the The largest instrumentally recorded ground host deforms to accommodate the dyke deformation event in Iceland occurred during propagation and growth. Most established dyke 2014-2015 within the Bárðarbunga volcanic emplacement models solely account for tensile system. A 48-km-long lateral dyke propagated opening of an elastic host, whereas the Earth's away from the caldera, followed by six-month- crust also exhibits prominent inelastic Coulomb long effusive eruption at the far end of the dyke, brittle behavior. In this study, we aim to while the Bárðarbunga caldera gradually encompass how brittle deformation affects dyke collapsed by 65 meters (Sigmundsson et al. 2015, emplacement in cohesive Mohr-Coulomb Gudmundsson et al. 2016). We study ground material. deformation in the volcanic system after these events, in order to provide an improved We present quantitative experimental results understanding of the deformation that follows obtained from a quasi-2D experimental setup the events, and distinguish signals induced by (Hele-Shaw cell type), which consists of two visco-elastic responses from those related to vertical glass plates (3 cm gap) containing fine- renewed melt supply. grained dry Coulomb mixes of silica flour and glass beads with varying cohesions. Golden syrup We observe ground deformation using is slowly injected into the silica flour via a bottom Interferometric analysis of Synthetic Aperture inlet at a constant flow rate for ~1 hour. While the Radar (InSAR) and GPS geodesy. Two year quasi-2D setup restricts the injected syrup to a interferograms (2015-2017) from Sentinel-1 "sheet-like" intrusion, it allows direct satellites are created to observe the overall observation of the host deformation such that we deformation field. Interferogram stacking is can measure displacement maps, shear strains, implemented to reduce atmospheric noise. and surface deformations accommodating dyke Observed deformation is a superpostion of emplacement from strong to weak host rocks. several sources, including glacial isostatic adjustment and steady plate movements. These

43 effects are subtracted from the observations contact-parallel magma flow during the initial (Drouin et al., 2017) to reveal excessive stages of intrusion emplacement. The magma displacement rates we attribute to post-rifting flow fabric is overprinted by strain-localisation relaxation in the dyke area. The movements are bands, which indicate that the magma attributed to visco-elastic response of the Earth, subsequently became viscously stalled and was which results in gradual recovery of the area and deformed by consecutively intruding magma. higher displacement rate after eruption events. This change in magma rheology can be attributed The post-rifting relaxation is modelled by a two- to the interaction between the strain-localisation layer model with elastic crust and visco-elastic bands and the flow bands, which caused upper mantle. extensive fracture-rich layers in the magma and led to decompression degassing, crystallization, In the caldera area, a similar study will help to and rapid solidification of half of the magmatic understand if present inflation and earthquake body. Our observations indicate that syn- activity at Bárðarbunga is induced by magma emplacement rheology change, and associated inflow or is a visoelastic response to the large fracturing of intruding magma not only occur in deflation in 2014-2015. volcanic conduits, but also play a major role in the emplacement of shallow viscous magma

intrusions. ORAL

Syn-emplacement fracturing in the ORAL Sandfell laccolith, eastern Iceland How do sills become laccoliths? An Tobias Mattsson1, Steffi Burchardt1, Bjarne S. G. answer from integrated laboratory Almqvist1 and Erika Ronchin1 1Department of Earth Sciences, Uppsala University, and numerical modelling Villavägen 16, SE 752 36, Uppsala, Sweden 1 1 Tobias Schmiedel , Olivier Galland , Øystein T. Haug1 and Christoph Breitkreuz2 Felsic magma commonly pools within 1Physics of Geological Processes (PGP), Department of mushroom-shaped magma chambers, so-called Geosciences, University of Oslo, Norway, 2Geological laccoliths or cryptodomes at shallow crustal Institute, Technical University Bergakademie Freiberg, Germany levels, which can cause collapse of the volcanic edifice. While deformation of magma in volcanic conduits is an important process for regulating Igneous intrusions in the upper brittle crust eruptive behaviour (Pistone et al., 2016), the bulk exhibit diverse shapes ranging from thin sheets of the deformation associated with laccolith (dykes, sills, cone sheets), to thick, massive emplacement is considered to occur in the host- intrusions (laccoliths, plutons, plugs). Presently, rock (Pollard & Johnson, 1973), and the effects of none of the established models of magma magma deformation on the intrusion emplacement have the capability to simulate this emplacement is largely unexplored. Here we diversity because they account for end member describe the deformation associated with the rheology of the host rocks (elastic, viscous or 3 emplacement of the 0.5 km rhyolitic Sandfell plastic), whereas natural rocks are complex laccolith in eastern Iceland, which formed in a elasto-plastic materials. We investigated the single intrusive event. By combining field effects of host rock rheology on magma measurements, 3D modelling, anisotropy of emplacement using scaled laboratory models. magnetic susceptibility, and microstructural The model rocks were dry Coulomb granular analysis, we quantify deformation that occurred materials of variable strength (cohesion). We in both the host-rock and the magma to show that strong (high-cohesion) host rock, investigate its effect on intrusion emplacement. results in the emplacement of thin, sheet Magmatic and magnetic fabric analyses reveal intrusions (sills, cone sheets). Conversely, weak

44 (low-cohesion) host rock results in the It may be of variable size and shape, containing emplacement of massive intrusions (laccoliths, variable amounts of magma, melts and crystals plugs). We integrate our laboratory results with and comprising magma bodies with variable numerical simulations to constrain the host rock connectivity. At Krafla caldera, multiple deformation mechanism that accommodates constraints can be applied, including direct magma emplacement in the experiments. Our constraints from accidental drilling into rhyolitic results show how both sills and laccoliths result magma at 2.1 km depth. We interpret the data in from initial thin sills that spread horizontally terms of at least two magma bodies at shallow until triggering shear failure of the overburden at depth: (i) a basaltic magma body with a pressure a critical radius. Two scenarios can then happen: center near the center of the Krafla caldera in the (1) the overburden is cohesive enough and allows 3-5 km depth range, contributing to S-wave space opening in the sub-surface to accommodate shadows and influencing seismic propagation, as viscous magma inflow along the failure planes, so well as being responsible for an sills evolve as sheets (saucer shape or cone inflation/deflation pattern during the 1975-1984 sheets), or (2) the overburden is not cohesive Krafla rifting episode, and (ii) a shallower body of enough and does not allow sub-surface space rhyolitic magma with an upper surface at 2.1 km opening to accommodate viscous magma inflow depth underlying a high-temperature geothermal along the failure planes, so the sill inflates and area. This rhyolitic body was inactive during lifts up the overburden along shear zones to form 1975-1984, but also contributes to S-wave a massive laccolith. shadows. It has been drilled close to or into multiple times and is responsible for superheated steam near the bottom of several geothermal wells. Future advance in our understanding ORAL volcano interiors is expected from the Krafla Structure and dynamics of the Krafla Magma Testbed initiative (http://kmt.is); an international effort to establish an in-situ magma magma domain and its associated laboratory at Krafla, including drilling again to geothermal area: Ground magma and coring of the magma-geothermal deformation and magma plumbing at interface. the Krafla Magma Testbed, Iceland

Freysteinn Sigmundsson1, Vincent Drouin1, Pall ORAL Einarsson1, Knutur Arnason2, Gylfi Pall Hersir2, 3 4 5 Léa Levy , Elías Rafn Heimisson , Erik Sturkell , Impact of host rock heterogeneity on Anette K. Mortensen6 and John Eichelberger7 1Nordic Volcanological Center (Nordvulk), Institute of failure mechanism around magmatic Earth Sciences, University of Iceland, Iceland, 2ÍSOR – intrusions Iceland GeoSurvey, Reykjavík, Iceland, 3Nordvulk, ÍSOR and Ecole Normale Supérieure, Paris, 4Stanford Alban Souche1, Olivier Galland1 and Øystein T. University, California, USA, 5University of Gothenburg, Haug1 Gothenburg, Sweden, 6Landsvirkjun, Reykjavík, Iceland, 1Physics of Geological Processes, Geosciences 7University of Alaska Fairbanks, USA Department, University of Oslo, Norway

We interpret extensive volcano geodesy results at Rock failure mechanism accommodating the Krafla volcano, Iceland, together with results emplacement of magmatic intrusions is from various other observations, including dominantly controlled by the local stress regime geophysical surveying and drilling. The combined within the host rock. Most of the mechanical data is interpreted in terms of a magma domain models addressing rock failure conditions (e.g., model, which we consider to represent the for a given tectonic regime or magma crustal volume hosting magma at a shallow level. overpressure) simplify the stress calculation by

45 assuming the homogeneity of the host rock generally around 100kJ/m^2 for competent rock, properties. whereas lab measurements on similar rocks yield estimates Gc which are significantly lower. In this study, we highlight the importance of local heterogeneity in controlling the failure In order to understand the discrepancy between mechanism ahead of a magmatic intrusion. The in-situ and lab measurements of Gc, we test host- heterogeneity is introduced by mean of a rock rheologies that are more realistic than the stochastic perturbation with given wave-length commonly used linear elastic theory. These and amplitude on the host rock cohesion. We rheologies take additional processes into account numerically model and quantify the elasto-plastic which affect the Griffith energy balance of a deformation of the system in response to the growing crack, such as: (1) pressure dependent overpressurization of an intrusion. Depending on elasticity with reduced moduli in regions of low- the characteristics of the heterogeneity, we pressure, (2) plastic failure where shear stresses observe the development of plastic zones exceed a critical yield stress, and (3) viscous flow representative of either tensile or shear failure. affecting the host rock during the cooling phase of We show that shear failure is the dominant the magmatic intrusion.To test these hypotheses, mechanism as soon as heterogeneities are we construct three numerical models, each introduced, even for relatively large dilatancy testing one of the host-rock rheologies described property of the host rock (up to the limit of above. associative plasticity). We conclude that heterogeneities within the host rock may locally Our results show that the most significant "seed" shear faults ahead of the magmatic changes to the Griffith energy balance are intrusion in the propagating direction. We further obtained from the elasto-plastic model where G illustrate the implications of these results by values are almost 100 time lower than results considering the emplacement of a dyke in an from the linear elastic solution. We thus find that extensional setting (Icelandic case) and show that large-scale fracturing, which we model as shear failure may be a dominant mechanism in plasticity, can resolve the long-standing problem pre-eruptive seismic activity consequent to dyke of disparate critical energy release rate Gc emplacement, in good agreement with seismic obtained by different means. data monitored during recent magmatic events.

POSTER ORAL A new model for saucer-shaped The effect of the host-rock rheology intrusions: shear failure versus on dyke propagation energy balance: tensile opening at sill tips a numerical modelling study. Øystein Haug1, Olivier Galland1, Pauline 2 1 1 Rémi Vachon1 and Christoph Hieronymus1 Souloumiac , Alban Souche , Frank Guldstrand 1 1Uppsala University and Tobias Schmiedel 1PGP, University of Oslo, 2Géosciences et Environnement Cergy (GEC), Université de Cergy-Pontoise, France Propagation of magmatic intrusions such as dykes and sills is an essential factor that controls Sills with a characteristic saucer shape are volcano dynamics. It has been shown that an common features in many sedimentary basins intrusion, or a fracture in general, will propagate worldwide. Previous models of sill emplacement when G, the energy released due to crack usually assume that pure elastic bending of the extension, exceeds a critical energy release rate overburden of growing sills control their value Gc, which is considered a material property evolution to saucer shape. However, field of the host-rock. Estimates of Gc from observations show that significant shear damage observations of dyke length and aperture are

46 also accommodate sill emplacement. To which gravity anomaly. A model for the subsurface extent such damage plays an active role on sill structure of the SIP has been constructed by emplacement or not is not understood. To forward modelling of 3D gravity and magnetic address this, we study the condition for shear data using density and magnetic attributes from failure and the distribution of damage in the the outcrops. overburden of sills using the limit analysis software Optum G2. Through a parameter study, There are multiple roots, two of which reach a we investigate the effect of the length-to-depth depth of 9 km. The annular distribution of the ratio (L/D) of the sill, the cohesion of the host roots suggests that this is close to the original rock and the emplacement depth on the over- geometry, which, despite the complex pressure within the sill at failure. The results geodynamic history, has been preserved. show that the characteristic saucer shape is Therefore, the Kalak nappe unit hosting the SIP, ubiquitously reproduced using this approach may not have experienced a strong tectonic (Haug et al, 2017). The over-pressure required reworking. for shear failure scales linearly with the host Forward magnetic modelling of the SIP allowed cohesion and as a power-law of L/D. From these for estimating the geometry and the observations, we propose a scaling law for a new magnetization of the magnetic sources. This shear failure criterion in the overburden of a sill. indicates that most of the sources of the magnetic We compare our scaling law to an analytical anomalies are related to gabbroic bodies, and to a solution of hydrofractures, and show that tensile lesser extent to the contacts of the ultramafic tip propagation is favored for small sills, but intrusions with the country rock, possibly overburden shear failure may become favorable indicating these contacts have some degree of for large sills. From these results, we suggest that serpentinization, or mineralization. Based on the sills initially grow laterally by tensile propagation combined results of 3D gravity and magnetic until reaching a critical L*, when the overburden modelling we suggest that the SIP is weakly fails in shear, leading to the emplacement of magnetic at depth. Furthermore, the depths of the saucer-shaped sill’s inclined sheets. numerous mafic and ultramafic complexes vary geographically within the SIP. A low angle

detachment fault dipping towards the north POSTER truncating the deeper part of the SIP would explain these observations. THE SEILAND IGNEOUS PROVINCE: IMAGING A WELL PRESERVED EDIACARAN DEEP SEATED POSTER MAGMATIC SYSTEM BY 3D GRAVITY AND MAGNETIC MODELLING Rock magnetic properties and magnetic carriers of a deep crustal Zeudia Pastore1, Christine Fichler1 and Suzanne magmatic system, the Reinfjord 1 McEnroe Ultramafic Complex, Seiland Igneous 1Department of Geoscience and Petroleum at the Norwegian University of Science and Technology Province, Northern Norway (NTNU) 1 1 Geertje W. ter Maat , Suzanne McEnroe , Nathan Church1, Zeudia Pastore1, Alexander Michels1, The Ediacaran Seiland Igneous Province (SIP) is Hirokuni Oda2 and Rune Larsen1 the largest complex of mafic and ultramafic 1Norwegian University of Science and Technology, intrusions in northern Fennoscandia, and one of 2Geol. Surv. Japan, AIST, Tsukuba, Japan the few examples in the world of a well preserved deep-seated magmatic plumbing system. The The Reinfjord Ultramafic Complex (RUC) is part intrusive rocks of the SIP cause a prominent of the 5000km2 Seiland Igneous Province (SIP) in

47 northern Norway. The SIP is considered to be a 1.8. Building Baltica deep-seated conduit system of a large igneous province. The SIP was emplaced into continental crust at 25-30 km depth at 570-560 Ma. The RUC ORAL intruded into gabbros and meta-sedimentary gneisses resulting in three formations. 1) Central Fennoscandia, Sarmatia and Volgo- Series consisting of dunites; 2) Upper Layered Uralia: the building stones of the East Series consisting of dunites and wehrlites, and 3) Lower Layered Series containing the most European Craton/Baltica pyroxene-rich rocks, with an associated but Svetlana Bogdanova1 mineralogically distinct marginal zone resulting 1Department of Geology, Lund University, Sweden from contact metamorphism of the melts and host rocks. Exposures of deep ultramafic systems are rare, and RUC gives a unique opportunity to The three lithosphere segments Fennoscandia, study the magnetic properties of the roots of a Sarmatia and Volgo-Uralia (Fig.), which deep seated magmatic system. constitute the East European Craton (Baltica), have each specific crustal architecture and The rock magnetic properties of the different evolution (Bogdanova, 1993; Gorbatschev & formations give insight in the magnetic carriers, Bogdanova, 1993; Bogdanova et al. 2008). While and can be associated to primary (spinel, and Volgo-Uralia is nearly all Archean, but exsolution in pyroxene), or secondary processes, complicated by thorough Paleoproterozoic such as serpentinization. Scanning SQUID reworking, Fennoscandia is Archean in the north- microscopy of thin sections combined with east but Proterozoic in the south-west, while optical and electron microscopy indicate which Sarmatia features several separate Archean minerals carry the magnetization, that then can blocks cemented by Archean and be linked to the rock magnetic properties. Paleoproterozoic collisional belts. The segments Characterizing the primary, and secondary, are separated by the major ca. 2.1 Ga Volga-Don magnetic carriers, allows for assessing the and ca. 1.8 Ga Central Russian Paleoproterozoic contribution of bodies such as the RUC to collisional belts followed by Meso- to magnetic signals from deep crustal rocks. Neoproterozoic aulacogens. Understanding the nature of the magnetic properties of deep ultramafic rocks now exposed Baltica was built up during numerous collisional at the Earth’s surface will aid in the interpretation and accretionary orogenies, and also breakups ( of ground-, aeromagnetic, and satellite surveys in Ga): and paleomagnetism. • 2.8-2.7: most Archean blocks amalgamated forming the protocratons of Fennoscandia and Volgo-Uralia but still separated by

oceans in Sarmatia

• 2.5-2.4: first records of protocraton breakup (Fennoscandia and Volgo-Uralia) • 2.4-2.0: continuing breakup of Archean Fennoscandia when several small oceans were opened

• 2.1-2.0: the Sarmatian and Volgo-Uralian Archean blocks collided forming megacontinent Volgo-Sarmatia • 2.0-1.95: the combined NW margin of Volgo- Sarmatia became the site of a wide continental magmatic arc facing an ocean;

48 strong deformation of Volgo-Uralia ‘s crust gabbro sills (Pekkarinen and Lukarinen, 1991; and upper mantle Niiranen et al., 2003; Bleeker and Ernst, 2006; • 1.94-1.90: the Lapland-Kola collision Salminen et al., 2014, Davey et al., 2017). Here we encompassed Archean Fennoscandia use whole-rock and trace element geochemistry • 1.93-1.83: the Svecofennian accretionary and Sm-Nd isotopes to test whether Marathon orogeny at SSW edge of the Karelian (Superior), Bear Mountain (Wyoming) and protocraton Tohmajärvi dykes and Misi sills (Karelia) were • 1.80-1.75: collision of Fennoscandia and generated under similar conditions and from a Volgo-Sarmatia; Baltica was created 1.7-1.5: common source. Halls et al. (2008) report a Gothian and Telemarkian accretion at the transition from enriched to flat trace element western Baltica margin patterns through time between 2125 to 2100 Ma • 1.55-1.40: the Danopolonian (in part in the Marathon dykes. This geochemical Hallandian) intracontinental orogeny progression provides an ancillary means in which • 1.35-1.25: intracontinental mafic to compare contemporaneous dyke swarms magmatism found in other cratons. If the Bear Mountain and • 1.0-0.9: Sveconorwegian collisional orogeny; Tohmajärvi dykes and Misi sills were fed by the Baltica participate in Rodinia supercontinent same magmatic pulses as the Marathon dykes, then the same secular changes in geochemistry should be observed, in addition to sharing comparable paleolatitudes, geometry, and ORAL geochronology.

Trace element geochemistry and Sm- Nd isotopes of 2.1 Ga mafic ORAL magmatism in the Karelia-Kola, Wyoming and Superior cratons Polyphase, transpressive deformation of the Archean Siilinjärvi Sarah Davey1, Wouter Bleeker2, Sandra Kamo3, Richard Ernst4 and Brian Cousens1 carbonatite complex, central Finland 1Carleton University, Canada, 2Geological Survey of 1 2 Canada, 3Jack Satterly Laboratory, University of Karin Högdahl , Bjarne S.G. Almqvist , Fredrik 3 4 5 Toronto, Canada, 4Carleton University, Canada, Tomsk Karell , Pietari Skyttä , Aleksi Salo , Alireza State University, Russia Malehmir2 and Pasi Heino5 1Dept. of Earth Sciences, Uppsala University and Geology and Mineralogy, Åbo Akademi University, The Karelia-Kola, Wyoming, and Superior cratons 2Dept. of Earth Sciences, Uppsala University, 3Geological are proposed “nearest-neighbours” within the Survey of Finland, 4Dept. of Geography and Geology, Superia supercraton reconstruction (Bleeker and Turku University, 5Yara Suomi Ltd Ernst, 2006). At 2.1 Ga, their kinship is best constrained by matching paleolatitudes in the The 2.6 Ga Siilinjärvi carbonatite complex is one Marathon (Superior) and Bear Mountain of few known Archean carbonatites and the (Wyoming) mafic dyke swarms, and overall oldest currently being mined. The 16 x 1.5 km N- similar apparent polar wander paths (Halls et al., S trending curved and tabular complex comprises 2008; Kilian et al., 2015). Although Karelia’s dominatly glimmerite with subordinate position within Superia is not as well constrained carbonatite, enclosed within a fenite halo, all cut by paleomagnetic data, it is hypothesized to have by three generations of mafic dykes. The complex been positioned at the southeast margin of has been affected by polyphase deformation, Superior based on the overall correlation of mafic including emplacement of the dykes and their magmatic events (“magmatic barcodes”) and the subsequent structural overprint. Strain is geometry of associated giant dyke swarms, heterogeneously distributed with the highest including the 2.1 Ga Tohmajärvi dykes and Misi strain localised into the glimmerite and the

49 contacts of more competent rocks represented by referred to as ‘intraorogenic’ with respect to the fenite blocks, mafic dykes, and glimmerite Svecofennian orogeny, e.g. by Stålhös (1991). hosting richterite and carbonates. The relationship between dyke emplacement and In the present study, twentyone samples of mafic deformation has been obtained using a dykes have been obtained from the Herräng type combination of structural data and magnetic area (Magnusson 1940), from the area around fabric measurements. The older dykes are mainly lake Limnaren south of Norrtälje (Lundegårdh steep, N-S to NW-SE trending, parallel to both the 1946), and the islets Fogdö and Riddarskäret overall structural grain and the magnetic between Väddö and Singö (Lundqvist 1959). The foliation, and narrow dykes are characterised by sampled rocks are dominantly composed of boudinage observed in both steep and sub- plagioclase and amphibole (presumably horizontal sections. Streching lineations within hornblende), with variable amounts of quartz and along the margins of these dykes are sub- and biotite, and accessory titanite, apatite, zircon vertical and coincides with the magnetic and opaque minerals. A couple of samples, lineation. Shear zones at dyke margins and however, have deviating mineralogy and elsewhere in the complex show dextral geochemistry. horizontal shear with a W-block-up vertical Geochemically, the sampled dykes are component. Later conjugate NNW-SSE dextral subalkaline basalts to andesites, with 48-60 wt% and NNE-SSW sinistral zones are likely related to SiO2. They have variable character on different folding of the youngest dyke generation. The discrimination diagrams: calc-alkaline or consistency between structural and magnetic tholeiitic; MORB, volcanic arc or within-plate, fabric measurements indicate two episodes of possibly reflecting their origin during extension dextral transpressive shear separated by an (perhaps incipient back-arc spreading) of extensional event related to emplacement of the juvenile subduction-related continental crust. youngest dyke generation. Initial Epsilon-Nd (at 1.87 Ga) falls between -0.1 This is an ERA-MIN StartGeoDelineation and +1.6, and initial Epsilon-Sr between +5 and contribution sponsored by Vinnova, SGU, Tekes, +24, suggesting a similar ‘mildly depleted’ mantle NIO and Yara. source as for other Svecofennian mafic rocks. Spot analysis of eleven titanite grains from one

sample yields a weighted average 207Pb/206Pb age ORAL of 1848 ± 13 Ma, interpreted to date amphibolite- grade metamorphism, and yielding a minimum Building or breaking Baltica – the age of crystallization. Svecofennian ’intraorogenic’ Herräng dyke swarm, east-central Sweden ORAL Åke Johansson1 1Department of Geosciences, Swedish Museum of High-Nb and adakite-like 1.86 Ga Natural History, Box 50 007, 104 05 Stockholm, SWEDEN magmatism in southern Finland

Jaakko Kara1, Markku Väisänen1, Hugh O'Brien2 The mafic Herräng dykes are found in the and Yann Lahaye2 Roslagen coastal area of east-central Sweden, 1Department of Geography and Geology, University of Turku, 2Geological Survey of Finland where they intrude early Svecofennian metavolcanics and granitoids (ca. 1.87-1.91 Ga), but are themselves cut by late- to post-orogenic Mafic to intermediate c. 1.86 Ga magmatism has pegmatites and metamorphosed to greenschist- been discovered within the boundary area or amphibolite-grade. This dominantly E-W- between central and southern Svecofennia in trending dyke swarm has thus traditionally been

50 southern Finland (Kara et al. 2016). The heterogeneity experienced during progressive magmatism occurs as NW-SE trending dykes and thin-skinned thrusting: a common feature of small intrusions which crosscut the surrounding modern orogens. Secondary oroclines are formed migmatitic country rocks. The magmatism can be in response to an orogen-parallel shortening, as divided into three different varieties based on witnessed by Paleoproterozoic coupled Bothnian their geochemical and isotopic characteristics: i) oroclines of Fennoscandia (Lahtinen et al., 2014). high niobium basaltic dykes (HNB), ii) high The main component of the Inari orocline is the magnesium basaltic dykes (HMB) and iii) high Lapland granulite belt (LGB) having an arcuate silica adakite-like rocks (HSA). shape geometry in the northern Fennoscandia. Recent studies of Tuisku and co-workers (e.g., The HNB are alkalic and enriched in HFSE, Tuisku et al., 2006; 2012; cf. Cagnard et al., 2011) particularly Nb (>20 ppm) and show high LREE, provide a solid base for the age and tectono- P2O5, TiO2 and F contents. In-situ zircon Hf- metamorphic history of the belt. Based on the analyses show very high average initial εHf value existing studies, new field and age data, and re- of c. +10. The HMB exhibit high MgO (up to 12 interpretations of geophysical data, we propose wt%) and Cr concentrations and show high following stages for the evolution of the LGB: 1) average initial εHf values of c. +3 and +5 (two extension and intrusion of enderbites at ca. 1.92 dykes). The HSA group is enriched in Sr and LREE Ga in a linear rift basin; 2) thrusting and and depleted in Y (<20 ppm) and Yb (mostly <1.9 recumbent folding during basin inversion at 1.92- ppm) among the other high silica adakite 1.91 Ga leading to peak metamorphic conditions; characteristic signatures (Martin et al. 2005). 3) intrusion of post-collisional appinites at ca. Two HSA-intrusions exhibit average initial εHf 1905 Ma; 4) extension and decompression value of zero and c. -3. melting at 1.90-1.88 Ga; 5) renewed shortening of the linear orogen at 1.88-1.87 Ga that lead to The ages as well as geochemical and isotope data upright folding and SW vergent thrusting; 5) are clearly different from the adjacent, c. 1.90- orogen-parallel shortening at ≤1.87 Ga. Our 1.88 Ga, arc-related igneous rocks suggesting a preliminary interpretation is that the Inari different kind of petrogenesis for these two age orocline, including the LGB, is a secondary groups. The similar ages and close spatial orocline formed during buckling about a vertical occurrences support a genetic link between the axis of rotation. 1.86 Ga groups. However, separate sources are likely due to differences in geochemistry and isotope signatures. ORAL

New paleomagnetic and isotopic data ORAL for the Late Paleoproterozoic mafic Paleoproterozoic Inari orocline of intrusions in the Blekinge Province northern Fennoscandia: progressive (southeastern Sweden) or secondary orocline Natalia Lubnina1, Svetlana Bogdanova2 and Ulf Raimo Lahtinen1, Mohammad Sayab1 and Stephen Söderlund2 1 Johnston2 Faculty of Geology, M.V. Lomonosov Moscow State University, Russia, 2Department of Geology, Lund 1Geological Survey of Finland, 2University of Alberta, University, Sweden Canada

Oroclines are curvatures of previously linear arcs To the east of the Sveconorwegian orogen, the (or belts), and are divided into two main types: Precambrian bedrock in Blekinge progressive and secondary (Johnston et al., contains granitoids of the Transscandinavian 2013). Progressive oroclines are formed by strain Igneous Belt to the north of the Småland-Blekinge

51 Deformation Zone (SBDZ), and the c. 1.76 Ga ORAL Tving granitoids in the south (Johansson et al. 2006). In this study, we have investigated the Early Paleoproterozoic mafic intrusions cutting the Tving granitoids. paleogeography of Karelian and Superior Cratons: new paleomagnetic The new paleomagnetic and AMS examinations of the Tving granitoids in eastern Blekinge show and AMS data from 2.45-2.1 Ga mafic NW-striking foliation parallel to the SBDZ. The intrusions of Central Karelian and studied mafic intrusions carry a stable Kianta terranes component with shallow downward NNW direction. The primary remanence is supported Natalia Lubnina1, Alexandra Stepanova2, Nikolay by positive contact tests. New isotopic data for Tarasov1 and Grigory Nazarov1 olivine gabbro and metabasic rocks using U-Pb 1Department of Dynamic Geology, M.V. Lomonosov baddeleyite and Ar-Ar amphibole geochronology Moscow State University, Russia, 2Institute of Geology Kar RC RAS, Petrozavodsk, Russia suggested a protolith age of ca 1760 Ma for these rocks. The mean paleopole for these mafic intrusions from Blekinge thus corresponds to the We present a new paleomagnetic and Anisotropy c. 1.76 Ga pole for Fennoscandia. of magnetic susceptibility (AMS) data from the Early Paleoproterozoic mafic dykes and Archean In the entire Blekinge, AMS lineations mainly dip host rocks within two terranes of the Karelian NW. The NNE upward overprint component is Craton, eastern Fennoscandian Shield. Three found in the Tving granitoids near the Karlskrona groups of dykes have been collected within Deformation zone, that is close to that in the 1.45 Pyaozero area of Central Karelian terrane: NE- Ga Karlshamn granites, probably due to regional trending ca. 2450 Ma gabbronorite and diorite heating and deformation of the Blekinge block dykes, NW-trending ca. 2310 Ma dolerite dykes, (Čečys & Benn 2007). AMS and structural data and NNW-trending ca. 2130 Ma continental indicate that the magnetic fabrics of the mafic MORB-type tholeiitic dykes (Stepanova et al. intrusions are continuous and the metamorphic 2014). All these dykes were typified based on the fabrics in the country rocks were formed during AMS data. Samples from 2130 Ma dolerite dykes ENE–WSW compression, and can be referred to within Tulos area of Kianta terrane were also the Danopolonian orogeny. The new collected. paleomagnetic pole is close to 1.45 Ga pole for Baltica (Lubnina et al. 2010). The paleomagnetic results show that a strong Svecofennian overprinting is pervasive in the

area.

All studied mafic dykes carried two stable components. Most typical is component of intermediate down to the NNW, corresponds to the Svecofennian remagnetisation (Mertanen 1995). Component of SE intermediate down

direction yielding a paleomagnetic pole 2450 Ma based on a positive baked contact test is interpreted to represent the primary magnetization.

The paleomagnetic results for dolerite dyke within Tulos area show that a strong Svecofennian overprinting is pervasive in the area, based on a negative baked contact test.

52 The new paleomagnetic data from the Karelia Tampere group 200 km further west. The Craton compared to similar-aged paleomagnetic voluminous granitoid magmatism took place in data from the Superior Craton does not support two stages, at ca. 1895 and 1885–1875 Ma. The the recently proposed Superia configuration latter phase can be divided into separate units on (Bleeker & Ernst 2006), based upon dyke swarm compositional bases, which display distinct field trajectories. relationships, although the obtained ages overlap within errors. Thus the earlier division into syn- We propose a new Early Paleoproterozoic and post-kinematic units should be abandoned. paleogeography at 2.45-2.1 Ga for the Karelia and Instead the units represent coeval magmas Superior craton. originating from different levels of the crust. Lower crust melts rose only locally to the present This is a contribution to projects RFBR 17-05- erosion level via favorable structures. 01270.

ORAL ORAL

Development of the Paleoproterozoic Kinematics and deformation regime Svecofennian orogeny, new of the Kynsikangas ductile shear constraints from Central Finland zone, SW-Finland. Sebastian Reimers1, Jon Engström2, Johanna Perttu Mikkola1, Esa Heilimo1, Jouni Luukas1 and Berckhan1 and Ulrich Riller1 Jukka Kousa1 1University of Hamburg, 2Geological Survey of Finland 1Geological Survey of Finland

The NW-striking Kynsikangas Shear Zone (KSZ) Significant amounts of new field and analytical is one of many prominent Paleoproterozoic data (whole-rock geochemistry, age ductile shear zones in SW Finland that formed determinations) were gathered by Geological during the Svecofennian orogeny. The Kokemäki Survey of Finland from a little studied area along segment of the KSZ consists of an approximately the southeast boundary of the Central Finland 16 km long and 2 km wide core of highly strained Granitoid Complex (CFGC). As the area is the metagranitoid and migmatite rocks displaying culmination point of several major geological variable mineral foliation (S) - lineation (L) units this new data allows revaluation of previous geometry. Moreover, the core hosts abundant interpretations and correlations. The new data small-scale kinematic indicators, such as C-S mostly affects the following aspects: fabrics, rotated rigid objects and folded Units belonging to the older Svecofennian metamorphic layering. Besides unravelling the magmatic phase (1.93–1.91 Ga) extend 100 km significance of major shear zones in the further southeast as tentatively suggested earlier. Svecofennian orogen, the KSZ allows us also to All of the paragneiss units in the area display elucidate to what extent small-scale kinematic similar detrital zircon patterns, defining ~1.92 Ga indicators are useful for identifying the overall as the maximum depositional age for most of the sense-of-shear of ductile deformation zones in samples. The eruptive ultramafic units occurring general. The central portion of the shear zone is as interlayers in different paragneiss units characterized by pronounced sub-horizontal L display differences in trace element patterns. But fabrics, which merge along-strike of the shear otherwise the earlier division of paragneisses zone in both directions into S > L fabric geometry. mainly reflects differences in deformation and East of the fault core, the curvature in the strike metamorphic history. The arc-type calc-alkaline of foliations, sub-horizontal mineral stretching magmatism in the area is similar in age (1895– lineation and C-S fabric geometry point to a 1875 Ma) and composition to that of the classical strong component of left-lateral displacement. By

53 contrast, foliation pattern and moderately to Ga Åland, and 1.58 Ga Satakunta dyke swarms in steeply plunging mineral lineations west of the Southern Finland. core indicate dip-slip. Despite complex internal ductile flow, evident by the along-strike variation The rotational transition to right-way-up Baltica in S-L fabric geometry, the KSZ seems to have within Rodinia (e.g. Patchett et al., 1978; Piper, accommodated a strong component of left-lateral 1980) is proposed to occurred between 1.12 Ga transpression. and 1.05 Ga (Salminen et al., 2009; Evans, 2009). It agrees with distinctive patterns of orogenesis and sedimentation around the common pivot point shared between Scoresby Sund, East ORAL Greenland, and Finnmark, Norway (Cawood et al., 2010; Evans, 2013). Long-lived Late Paleoproterozoic to Mesoproterozoic connection of Baltica and Laurentia - a ORAL paleomagnetic view Paleoproterozoic Osnitsk– Johanna Salminen1 Mikashevichi-Moscow Igneous Belt 1Physics Department, P.O. Box 64, 00014 University of Helsinki, Finland (OMMB): new geochronology and petrology data for the Russian

To understand processes occurring from the segment and tectonic implication planetary interior to the surface environment, a Alexander Samsonov1, Svetlana Bogdanova2, robust paleogeography of tectonic plates is Alexander Postnikov3, Viktor Spiridonov4, Yulia important. Paleomagnetism coupled with Larionova1 and Alexander Larionov5 geochronology is powerful quantitative method 1Institute of geology of ore deposits, petrography, for providing ancient latitudes and azimuthal mineralogy and geochemistry of RAS, Moscow Russia, orientations of continents. Mafic dykes are 2Department of Geology, Lund University, Lund, amenable for precise U-Pb dating and often Sweden, 3Department of Lithology, Gubkin State preserve a stable record of ancient magnetic University of Oil and Gas, Moscow, Russia, fields. Recently new high quality paleomagnetic 4VNIIgeosystem, Moscow, Russia, 5Isotope Research and geochronological data from Meoproterozoic Centre, VSEGEI, St Petersburg, Russia mafic dykes in Southern Finland have been produced allowing reconstructions of position of The OMMB is a large Paleoproterozoic north- Baltica (Salminen et al., 2014; 2016; 2017). east-trending belt in the central part of the East There is a general agreement that Baltica and European Craton (EEC). It is traced from Ukraine Laurentia form a tectonic "core" of the through Belarus to Central Russia (Bogdanova et Mesoproterozoic Nuna supercontinent in a al., 2006, 2016). The main part of the OMMB is geologically and paleomagnetically viable covered by platform sediments, thus sampling of connection between Northern Europe and North the belt is mostly provided by deep drill-hole America (NENA), where Baltica is in “upside- cores. Petrology, U-Pb zircon geochronology and down” position relative to Laurentia (Gower et Sm-Nd isotope data for the Russian segment of al., 1990; Salminen and Pesonen, 2004). the OMMB will be presented. However, contradicting reconstructions have Major results are listed as below: been proposed (Halls et al., 2011). We show that new high quality Mesoproterozoic paleomagnetic 1) In the Russian segment, the OMMB consists of data with new geochronology results for Baltica tonalite, trondhjemite, granodiorites (TTG) and support NENA connection. Those include data granites with subordinate gabbros, diorites and from 1.64 Ga Häme, 1.64 Ga Suomenniemi, 1.58 mafic metavolcanic rocks.

54 2) Granites from north-west flank of the OMMB related characteristics. Ca. 100 km to northwest, (Vorob’evo and Roslavl’ wells) yield U-Pb zircon the ca. 1.85 Ga diorites metamorphosed in ages of 1963 – 1970 Ma that is somewhat younger granulite facies at 1.80 Ga (Skridlaite et al., 2014) than the 2005 – 2028 Ma TTG and granites from were interpreted as evidencing the MLD margin south-east flank of the belt (Yasnogorsk, Kaluga continuation in central Lithuania. A new ca. 1.85 and Vorotilovo holes) . The latter may have Ga SIMS age obtained from a felsic granulite caused high-T low-P metamorphic event at 2020 (metatonalite) further west (in western – 2036 Ma, which has affected metapelites from Lithuania) confirms the extension of margin Ingul-Sevsk and Volgo-Don orogens of the Volgo- northwestwards. Sarmatia block near the OMMB rocks (Bogdanova et al., 2004; Savko et al., 2017 and our data). Gabbro-norites which intruded into the Randamonys complex at 1.79 Ga are tholeiitic,

3) The OMMB TTG, granites and related mafic have positive initial εNd, hence juvenile, mantled- igneous rocks have calc-alkaline affinities, derived characteristics. Some slightly older (ca. subduction-related geochemical features and 1.82-1.81 Ga) fine-grained gabbro-norite with a show variation of eNd(T) values from +2,5 to -1,4 very primitive REE distribution and positive where juvenile rocks with eNd(T)>0 initial εNd resembles oceanic crust. predominated. The 1.86-1.84 Ga continental margin appears to 4) All the data suggest that the OMMB was formed continue through the Baltic Sea and merge with in two stages, at 2.03 and 1.97 Ma along the the 1.87–1.84 Ga Askersund-Loftahammar Andean-type active margin of Volgo-Sarmatia. magmatic belt along southern Bergslagen in Sweden (cf. Stephens et al., 2009). Later, an Andean-type subduction in the present west was responsible for the formation of back-arc basins ORAL and 1.79 Ga mafic magmatism in the MLD, coeval 1.86-1.79 Ga magmatic events in the with the intrusions of the 1.81–1.76 Ga TIB-1 suite. Some remnants of ca. 1.82-1.81 Ga oceanic western East European Craton: from crust completely reworked elsewhere may be subduction to back-arc settings preserved in these back-arc settings.

1 1 Grazina Skridlaite , Laurynas Siliauskas , Andrius Rimsa2, Martin Whitehouse3, Ake Johansson3 and Svetlana Bogdanova4 1Institute of Geology and Geography, Nature Research Centre, Vilnius, Lithuania, 2Institute of Geosciences, Vilnius University, Vilnius, Lithuania, 3Swedish Museum of Natural History, Stockholm, Sweden, 4Department of Geology, Lund University, Lund, Sweden

Remnants of a ca. 1.86-1.84 Ga continental margin were found in southern part of the Mid- Lithuanian domain (MLD), the western East European Craton (Bogdanova et al., 2015), while some new data supports its continuation to the NW, towards central Sweden.

The Randamonys gabbro-diorite-granodiorite- granite in southern Lithuania of calc-alkaline affinity, metamorphosed in amphibolite facies, was emplaced between 1.86 and 1.84 Ga. The suite has volcanic-arc, and hence, subduction-

55 ORAL province (Stepanova et al., 2014, 2015, Vuollo, Huhma, 2005). Paleoproterozoic mafic dyke swarms in Archean Kola-Murmansk and Since 2060 Ma Karelian and Kola-Murmansk provinces are similar in events succession and Karelia provinces, eastern composition of mafic rocks. So huge ca. 1980 Ma Fennoscandia: barcode comparison event widespread both in Kola-Murmansk and and implications for paleocontinental Karelian provinces indicates Lapland-Kola Ocean reconstructions closure.

Alexandra Stepanova1, Alexander Samsonov2, The study is supported by RSF, grant 16-17- Ekaterina Salnikova3, Andrey Arzamastsev3, 10260. Svetlana Egorova1, Yulia Larionova2, Alexander

Larionov4, Ksenia Erofeeva2 and Maria Stifeeva3 1Institure of geology Karelian Research Center RAS, POSTER Petrozavodsk, Russia, 2Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry Mineral shape fabric analysis of the RAS, Moscow, Russia, 3Institute of Precambrian Geology and Geochronology, Saint-Petersburg, Russia, 4Centre Kynsikangas Shear Zone: Evidence for for Isotopic Research, VSEGEI, Saint-Petersburg, Russia a transpressive origin?

Johanna Berckhan1, Jon Engström2, Sebastian Eastern Fennoscandia consists of Archean Kola- Reimers1 and Ulrich Riller1 Murmansk and Karelian provinces, separated by 1University of Hamburg, Bundesstraße 55, 20146 ca. 1.98-1.85 Ga Lapland-Kola orogen (Daly et al., Hamburg, 2Geological Survey of Finland, 2006). New baddeleyite U-Pb (ID TIMS) and Betonimiehenkuja 4, FI-02151 Espoo zircon (SIMS) ages, geochemical and isotopic data for 2.65-1.86 Ga mafic dyke swarms in Kola- Murmansk province give insights into Lapland- The NW-SE trending Palaeoproterozoic Kynsikangas Shear Zone (KSZ) is a prominent Kola Ocean lifespan and clarify a position of Kola- Murmansk province within Superia supercraton ductile shear zone in the Svecofennian Orogen of (Bleeker and Ernst, 2010). SW-Finland. The shear zone is located at the boundary between the Western Finland and Wide-spread mafic magmatism of age 2650 Ma is Southern Finland Subprovinces. In the Kokemäki recognized in Murmansk domain. It is well area, the KSZ formed under high-grade correlated with 2640-2660 Ma magmatic event in metamorphic conditions in migmatite and Keivy terrane, Kola domain (Bayanova, 2004). gneissic rocks. The shear zone is believed to have Mafic magmatism of this age in Karelia is formed under left-lateral shear. A more complex unknown. It suggests strong differences in the kinematic, possibly transpressive, origin of the Neoarchean history of Karelian and Kola- shear zone, is evident from our analysis of Murmansk provinces. kilometer-scale pattern of metamorphic foliations, maximum principal stretching Nevertheless both Karelian and Kola-Murmansk orientations and small-scale kinematic provinces most likely belong to the Superia indicators. In order to elucidate the kinematic supercraton as suggested by Bleeker and Ernst regime of shear zone formation, we quantify the (2010). It supported by similarity in the events geometry and intensity of shape-preferred succession since 2500 to 2400 Ma. orientation (SPO) of metamorphic minerals. Therefore, oriented block samples from 50 The noteworthy differences occur within the stations are cut according to the principal planes period 2400-2060 Ma. Mafic dykes of such age do of finite strain and the SPO of elongate minerals not recognize in the Kola-Murmansk province and other strain markers are quantified by image yet. In contrast, several voluminous events of age analysis. The results of this classical analysis of ca. 2310, 2220 and 2140 Ma occur in the Karelian

56 SPO will be used to calibrate visual estimates of depositional ages vary between 1.9 and 1.8 Ga. fabric intensity across the Kokemäki segment of Ages as young as 1.75-1.8 Ga are reported, the KSZ and will be compared with more however, they may have been affected by sophisticated 3D fabric analysis techniques. metamorphism, hydrothermal alteration or inaccurate common lead corrections.

The presumed source of the clastic sediments is POSTER generally thought to be local.

Provenance of Paleoproterozoic The obtained geochronology data from northern clastic metasedimentary rocks in Sweden, together with available detrital ages Norrbotten, northern Sweden from northern Norway and Finland constitute a major database for building models of tectonic Anna Ladenberger1, Stefan Bergman1, Risto and lithostratigraphic evolution of the Kumpulainen2, George Morris1, Fredrik Fennoscandian Shield. Hellström1, Tonny B. Thomsen3, Edward P. Lynch1, Stefan Luth1, Susanne Grigull1, Martiya Sadeghi1 and Høgni Vesturklett3 POSTER 1Geological Survey of Sweden, Uppsala, Sweden, 2Stockholm University, Stockholm, Sweden, 3Geological Petrogenesis of c. 1.9 Ga meta- Survey of Denmark and Greenland, Copenhagen, volcanosedimentary rocks in the Denmark Nautanen-Aitik area, northern Sweden: Geological, lithogeochemical and Sm-Nd isotopic constraints. Provenance zircon ages (U-Pb geochronology by LA ICPMS) were obtained from twenty samples of Edward P. Lynch1, Tobias E. Bauer2, Hannu clastic metasedimentary rocks from several Huhma3 and David Drejing-Carroll4 supracrustal units in Northern Norrbotten. The 1Department of Mineral Resources, Geological Survey of majority belong to the Svecofennian sequences, Sweden, Uppsala, Sweden, 2Division of Geosciences and with a few samples representing stratigraphically Environmental Engineering, Luleå Technical University, 3 lower Karelian units. Luleå, Sweden, Geological Survey of Finland, Espoo, Finland, 4Exploration Division, New Boliden, Boliden, The Karelian rocks generally have unimodal age Sweden distributions with the main peaks at c. 2.7 Ma and 2.55-2.60 Ga. The maximum depositional age In northern Sweden, Orosirian metasupracrustal vary from c. 2.6-2.5 Ga for Tjärro quartzite and a successions provide critical insights into similar quartzite collected in the Vakko Zone. Svecofennian-cycle tectonothermal processes. Early Paleoproterozoic depositional ages Additionally, they commonly host iron oxide- (c.2.3Ga) occur in quartzite at Tärendo and in apatite and/or Cu ± Au mineralization, and thus arkosic metasandstone from the Sockberget represent key exploration targets. Characterising group. such rocks from a primary perspective is an In the Svecofennian metasedimentary rocks, important prerequisite in understanding bimodal age distributions dominate with major subsequent deformation, metamorphic and/or peaks at Middle Paleoproterozoic and hydrothermal events. We present new subordinate ones at Archean. The oldest single petrogenetic constraints for a polydeformed, c. ages are found in the Hauki quartzite 1.9 Ga metasupracrustal package in the (3742±19Ma), the Kiilavaara quartzite Nautanen-Aitik area (Norrbotten) hosting (3649±44Ma), the Stora Sjöfallet quartzite several economically significant Cu-Au deposits. (3732±10 Ma) and in metasandstone from the The investigated sequence mainly comprises Råneå group (3628±31 Ma). Maximum tuffaceous metavolcaniclastic rocks and

57 intercalated metasedimentary (epiclastic) stages and thus tectonic setting are vaguely horizons. Primary volcanic features include known. remnant feldspar phenocrysts, accretionary lapilli-like features/clasts and inferred Our focus is the onshore area and the archipelago agglomeritic horizons. Epiclastic layers locally around the Hanko peninsula. As the site was last display trough- and herring bone-type cross- researched before the plate tectonic theory was stratification, suggesting relatively shallow, established, the goal of this study is to update the subaqueous depositional conditions. geological interpretations of the area. The project Compositionally, the rocks are mainly andesitic, is ongoing and the results presented here are with lesser basaltic andesitic and dacitic preliminary. varieties, and have calc-alkaline series affinities. In the study area, at least three different ductile Chondrite-normalized REE patterns are LREE- deformation stages are recognized (D1, D2, D3). enriched (La /Yb = 4.2 – 18.6), with flat to N N During D1, the metasedimentary rocks were weakly negative Eu anomalies ([Eu/Eu*] = 0.59 N folded into tight to isoclinal folds with E-W – 1.16; avg = 0.88). Whole-rock ɛNd values (1.88 Ga) striking nearly vertical axial plane. The E-W range from -4.5 to -0.3 (n = 10), while trending horizontal to moderately plunging corresponding T model ages range from c. 2.2 DM mineral lineation is in places stronger than the to 2.5 Ga. foliation. The D2 developed open asymmetric The sequence attributes are broadly consistent folding with SE plunging fold axis. At this stage, with formation in a continental arc-type setting mineral lineation is common, but the foliation is undergoing extension, where precursor tephra difficult to observe. The D3 is represented by a accumulated within a syn-volcanic depocenter mineral lineation plunging towards NE. (cf. Wanhainen et al. 2012). Geochemical The leucosomes in the migmatites are folded signatures also suggest parental magmas derived twice. This suggests that melts were generated from a mixed continental-juvenile source. Given before or during D1. The E-W trending structures the spatial overlap of Orosirian and older indicate N-S (at present) compression at stage (Rhyacian) successions across the region, D1. During D2, the main shortening direction was however, a contribution from intracratonic likely in the NE-SW direction, whereas the D3 tholeiitic greenstones, remobilised by structures seem to represent a NW-SE Svecofennian-related magmatism, may also be shortening. valid.

POSTER

Deformation history of the Archipelago of Southern Finland

Kaisa Nikkilä1, Anna Saukko1 and Olav Eklund1

1Åbo Akademi University, Geology and Mineralogy, Finland

The Paleoproterozoic Svecofennian orogenic domain of Southern Finland consists principally of belts of strongly migmatized infra- and supracrustal rocks and granitoids in upper amphibolite to granulite facies, with areas of less migmatized rocks in between. The granite- migmatite belts are presumably related to each other, but their structural setting, deformation

58 POSTER

A ca.1.89 Ga magmatic complex in POSTER eastern Lithuania: a link connecting The Nisser Shear Zone – Discovery of with the domains in Estonia and the a Sveconorwegian crustal-scale Bergslagen terrane in Sweden detachment zone in southern Norway Laurynas Šiliauskas1, Gražina Skridlaitė1, Martin Espen Torgersen1, Iain Henderson2, Bernard Whitehouse2 and Alvar Soesoo3 Bingen2, Katia Svendby2 and Aziz Nasuti2 1Institute of Geology and Geography, Nature Research 1 Centre, Akademijos 2, LT-03223 Vilnius, Lithuani, Geological Survey of Norway-NGU and Dept. of 2 2Swedish Museum of Natural History,Box 50 007, SE- Geoscience and Petroleum-IGP, NTNU, Geological 104 05 Stockholm, Sweden, 3Tallinn University of Survey of Norway-NGU Technology, [email protected]

In the Telemarkia Lithotectonic Unit, S Norway, Concealed crystalline basement of the Latvia-East thick successions of metasedimentary and Lithuania (LEL) domain is covered by 200-500 m metavolcanics rocks, known as the Telemark- and thick sediments. It is mostly composed of basic to Nissedal supracrustals, are structurally overlying acidic intrusive rocks and their volcanic gneiss complexes. The contact relationships counterparts that host ore deposits. Bogdanova between low- and high-grade rocks, whether et al (2015) suggested correlations between the depositional or tectonic, are contentious, 1.89-1.87 Ga Bergslagen microcontinent and although notably poorly documented. Livonia megadomain (including Latvia-East As part of an ongoing multi-disciplinary project in Lithuania, South Estonia Granulite and West the Nissedal-Drangedal area (Bedrock Estonia domains). However, apart from a ca. Infrastructure in Telemark–BITE), field mapping 1.887±7 Ma metadiorite in the south-western reveals that the c.1200 Ma basalt-dominated LEL (Bogdanova et al., 2015) and a much younger Nissedal supracrustal rocks are separated from ca. 1.5 Ga AMCG suite in the south (Sundblad et al, the underlying c.1200 Ma granitic gneisses of the 1994), almost none of the rocks from the LEL Vråvatn Complex by a ductile to brittle shear have been properly dated. zone, here called the Nisser Shear Zone (NSZ). Four samples with calc-alkaline affinity from the The shear zone corresponds to a pronounced LEL were selected for zircon U-Pb SIMS dating: asymmetric negative magnetic anomaly, at least two samples of granodiorite from the southern 50 km long, on the high-resolution aeromagnetic part of the LEL that might be a part of a TTG suite, map. The NSZ is up to 200 m thick and comprises a sheared diorite and a meta-rhyolite from the a variety of high-strain rocks ranging from western border of the LEL. The two granodiorites ultramylonite to cataclasite and fault gouge. yielded concordia ages of 1892.3±5.7 Ma (MSWD Brittle structures appear to overprint ductile 1.01) and 1893.7±7.4 Ma (MSWD 1.9), whereas structures. It dips shallowly to the SE (c. 150/25) diorite is somewhat younger yielding 1876.1±4.8 and carries strongly developed SE-plunging Ma (MSWD 1.6). The meta-rhyolite recorded a mineral lineations and slickenlines. These are concordant age of 1898±8.3 Ma (MSWD 1.4). associated with kinematic indicators (e.g. sigmoidal porphyroclasts and s-c shear bands) Our newly obtained U-Pb zircon ages support the that consistently show a top-to-the ESE normal model proposed by Bogdanova et al. (2015) in shear sense. Mylonites developed in the footwall which the Livonia and Bergslagen terranes granitic gneisses show dynamic recrystallization formed simultaneously and can be correlated of K-feldspar, testifying to deformation above across central part of the Baltic Sea. It is also 500°C. consistent with the general southwest younging of terranes in the western East European Craton Provisionally, we interpret the NSZ as a crustal- (and Baltica). scale extensional detachment linked to the late-

59 Sveconorwegian orogenic decay. It exhumed convergent active-margin processes during the lower-crustal gneisses and juxtaposed them Danopolonian orogeny. against upper-crustal sequences of a similar age. Future studies will constrain the age, tectonic The research was financed from NCN grant no. setting and environmental conditions of the NSZ. 2015/17/B/ST10/03540

POSTER POSTER

AMCG Mazury Complex in NE Poland – A link between Mesoproterozoic a time frame of the suite formation basement of Lithuania and NE Poland by inherited metamorphic zircon Janina Wiszniewska1 and Ewa Krzeminska1 data 1Polish Geological Institute -National Research Institute Janina Wiszniewska1, Ewa Krzeminska1, Grazina Skridlaite2 and Svetlana, V. Bogdanova3

1Polish Geological Institute-National Research Institute, A Mesoproterozoic AMCG suite known from Warsaw, Poland, 2Nature Research Centre, Vilnius, covered part of the Eeast European Craton on the Lithuania, 3Lund University, Sveden border of Poland with Lithuania and Russia, was emplaced along E–W trending linear thrusting zone. An ~1.50 Ga crystallization age of the A number of metamorphic events between 1.7- rapakivi-like granitoids of Mazury Complex, 1.6 Ga were recognized within the hidden obtained on zircon grains, was one of the first basement of Lithuania Skridlaite et al., 2014) . In geochronological contribution, initiating more Baltica, , this period marks a tremendous change detailed investigations in the frame of in tectonic evolution (cf Bogdanova et al., 2008, EUROBRIDGE programme. Further age studies 2015), when an active accretionary margin have been focused mostly on the spatial shifted to its western edge (cf Bingen et al., chronology of the suite, controlled by A-type 2008). granitoids as a dominant phase across the region. At present, 1.7-1.6 Ga old zircons were found in A principal goal of recent studies was to constrain the Mazury area (NE Poland) by U-Pb age the time of emplacement of all AMCG determinations carried out at SHRIMP Lab, PGI, components, using U- Pb zircon ages determined Warsaw; cf Krzeminska & Wiszniewska, 2017). by SHRIMP method. The metaluminous, within- They represent an inherited component from plate, A-type Mazury granites were intruded 1.49-1.48 Ga peraluminous granite veins cross- between 1.53 and 1.50 Ga. The last pulse at cutting the Suwalki Anorthosite Massif (SAM). 1498±10 Ma was deciphered from westernmost The most of zircon grains have cores, containing part (Filipów hole). The geochemical and isotopic material derived from various Paleoproterozoic investigations pointed out that AMCG suite was sources. Important coherent group of inherited formed by multiple magma batches, assembled grains (about 20%) has cores in range of by pulses, often in the same locality. AMCG 1710±12 Ma - 1617±9 Ma, with signature typical merged pluton was finally intruded by a net for metamorphic crystallization e.g. Th/U<0.1, system of peraluminous granite veins, that were but the host rocks with these characteristics have crystallized between 1495 ±11 Ma -1488.7 ±4 Ma. not been identified so far in proximity of SAM . This event recorded in Mazury AMCG suite, This inherited population corresponds however predates a formation of AMCG massifs in western with the records of magmatic and metamorphic Lithuania (1447 -1445±8Ma Nemunas- Geluva), activity common in Lithuania and Belarus and regional magmatism (1.45 Ga) in Bornholm - (Skridlaite et al., 2014; Vejelyte et al., 2015, Blekinge area. It also predates a dynamic high- Bogdanova et al., 2001), where zircons and grade metamorphism in SW Sweden related to monazites from Randamonys (Lithuania) and

60 Grodno (Belarus) have documented reworking at 1.9. Micro-beam frontiers in 1668±9 Ma (and 1569±12 Ma) and granulite facies metamorphism at 1727±30 Ma. This magmatic, metamorphic, and may indicate genetic link between peraluminous hydrothermal systems the Mesoproterozoic vein granites and their basement, that could be similar in NE Poland and Lithuania at the level of magma generation. ORAL

U-Pb calcite and zircon dating by LA-

ICP-MS image mapping

1 1 2 David Chew , Kerstin Drost and Joseph Petrus 1Department of Geology, Trinity College Dublin, Dublin 2, Ireland, 2School of Earth Sciences, The University of Melbourne, Parkville, Australia

Traditionally, LA-ICP-MS geochronology employs spot ablations, with the limitation that the laser excavates material several tens-of-µm below the sample surface. LA-ICP-MS mapping (ablating a

series of parallel, adjacent lines in a single experiment) yields much shallower ablation depths (0.3-3 µm). The data contained in the parallel line scans are reduced with software (e.g. Iolite) to produce x-y-element concentration

and/or isotopic maps. We employ here a new flexible interrogation tool for LA-ICP-MS maps called Monocle (Petrus et al., 2017), and add-in for Iolite. In addition to inspectors tools such as size-and-shape adjustable loupes, user-defined regions-of-interest (ROIs) and live graphs (e.g. Wetherill or Tera-Wasserburg concordiae),

Monocle allows the selection and pooling of pixels that meet user-defined criteria. Potential applications of zircon U-Pb imaging include characterisation of complex polyphase zircons and characterising the U-Pb systematics of key

samples for TIMS dating. U-Pb calcite dating has important applications including dating unfossiliferous sedimentary rocks or ore-bearing mineralization events. The functionality of Monocle can circumvent limitations of the U-Pb

calcite system, including low U concentrations and/or high amounts of initial Pb. Pixels on a map can be pooled into “analyses” based on ECDFs of elements or isotopic ratios (e.g. 238U/204Pb) to create a spread of U-Pb data on concordia. Portions of the sample with elevated detrital components or chemically-different generations of carbonate can be rejected by defining exclusion

61 criteria (e.g. Rb<1ppm; Mg/Ca<0.004). data-reduction approaches that now accurately Stratigraphically well-constrained Paleozoic reproduce rock standards with a range of Rb/Sr limestones and shell fragments yield accurate and compositional matrices, expanding the utility ages with internal age uncertainties as low as of this method. We highlight several applications ±1%, confirming the feasibility of the technique. of the method, including measurements of plagioclase, volcanic groundmass, and archeological glass samples, and also simultaneous measurements of Sr isotopes and ORAL trace elements by laser-ablation split-stream Promises and pitfalls of in situ Sr analysis. isotope ratio measurements by LA- MC-ICPMS ORAL Graham Hagen-Peter1, Rasmus Andreasen1, Ole Skursch1, Mark Edwards2, Christian Tegner1, Gry In tandem K–Ca and Rb–Sr dating of Barfod1 and Charles Lesher1 potassic minerals by LA-ICP-MS/MS: 1Centre of Earth System Petrology and Aarhus Method and prospective applications Geochemistry and Isotope Research Platform, Denmark, 2Department of Earth Science, University of California, Axel S.L. Sjöqvist1, Thomas Zack1, K. Johan Santa Barbara, U.S.A. Hogmalm1 and Erik Kangas1

1Department of Earth Sciences, University of Gothenburg, PO Box 460, SE-405 30 Göteborg, Sweden The Rb-Sr isotopic system has been used for decades for geochronology and radiogenic isotope geochemistry. The advent of laser- Recent technical development in ICP-MS ablation plasma-source mass spectrometry (LA- instruments facilitates on-line chemical MC-ICPMS) enhanced the efficiency of Sr isotope separation of isobaric ions (e.g. 87Rb+ and 87Sr+) analysis and—more importantly—enabled by gas reactions, which enables dating of beta- spatially resolved measurements. However, over decay systems such as Rb–Sr by laser ablation of two decades since the first measurements of Sr by minerals without wet chemistry (Zack and LA-MC-ICPMS, there is still no standard routine Hogmalm 2016; Hogmalm et al. 2017). We have for accurate and precise determination of Sr analysed mica-group minerals of various ages for isotope ratios in Ca-bearing silicates with K–Ca and Rb–Sr isotopic ratios in tandem by LA- variable Rb/Sr ratios. This is largely because of ICP-MS/MS. Both Ca+ and Sr+ ions are highly + + the analytical challenges inherent to this method, reactive with SF6 gas, whereas K and Rb are not. including numerous elemental (Kr, Rb, doubly Ca and Sr isotopes were measured as charged REE) and molecular (CaAr, Ca2, among interference-free fluoride reaction products CaF+ others) interferences on the Sr isotopes of and SrF+, whereas 40K and 87Rb isotopes were interest. Previous studies have successfully inferred from 85Rb+ and 39K+. Overlap from measured Sr isotopes in situ in plagioclase, isotopes of Ar, present in the plasma, was carbonates, and phosphates, but interferences suppressed by adding H2 gas. have thwarted accurate measurements of materials with Rb/Sr > ~0.05. We test the By analysing K–Ca and Rb–Sr isotopes in tandem, effectiveness of several commonly used data- these dual systems with different decay rates are reduction approaches on a large set of LA-MC- analogous to the U–Pb decay series. Rb–K isotope ICPMS measurements of two in-house plagioclase ratios can be assessed on various concordia standards and widely used rock glass standards diagrams and reveal single-spot ages or open- with Rb/Sr up to ~0.7. Most approaches system disturbances. Since the non-radiogenic Ca effectively reproduce the plagioclase standards composition for the purpose of mica dating can be but yield highly inaccurate results for higher regarded as practically constant (cf. Valdes et al. Rb/Sr standards. We have developed custom 2014), the isochron method is not required and

62 single-spot ages can in principle be derived, us to reconstruct the Lesbos magma’s δ11B values which would be useful inter alia in provenance at its final holding stage prior to eruption, and studies of sedimentary micas. suggest that volcanic glass may be a reliable tool for investigation of subduction fluids in arcs.

ORAL ORAL Behaviour of boron isotopes during magmatic degassing: a case study Melt Inclusion studies on basaltic from Lesbos Island, Greece. magmas in Iceland

Konstantinos Thomaidis1, Frances M. Deegan1, Thor Thordarson1 Martin J. Whitehouse2, Valentin R. Troll1, Franz A. 1Faculty of Earth Sciences, University of Iceland, 101 Reykjavík Weis1, Angela H. Helbling3, Horst R. Marschall3 and Harri Geiger1 1Department of Earth Sciences, Uppsala University, Investigations of melt inclusions and their host Uppsala, Sweden, 2Swedish Museum of Natural History, macrocryst in erupted basalts from Iceland have Stockholm, Sweden, 3Goethe University Frankfurt, provided important insights into subsurface Frankfurt, Germany magmatic processes. This presentation is intended as an overview of studies on melt Boron is a fluid mobile trace element routinely inclusion in mafic magmas in Iceland. High-Mg# employed as a tracer of slab-derived fluids in (˃65) melt inclusions are among the most subduction zones. The fidelity of boron in primitive liquids known from Iceland, yet record volcanic glass as an accurate tracer of slab modification of mantle-derived melts by degassing is called into doubt, however, by differentiation and mixing. Furthermore, major experiments that show that boron isotopes and trace element compositions of inclusions (expressed as δ11B) can fractionate by up to spanning the basaltic spectrum demonstrate a several permil (‰) during magmatic evolution trace element disequilibrium between primitive and degassing at high temperature. In order to and evolved mafic melts, indicating that a range test for isotopic fractionation during magmatic of mantle melt compositions must have degassing in a natural case, we carried out SIMS contributed to the formation of the relatively analyses of boron-rich rhyolitic glass from Lesbos evolved and compositionally constrained mafic Island, Greece. Analytical points were set as magmas typifying the erupted products within traverses from bubbles into the surrounding the volcanic zones of Iceland. The erupted glass in order to test for variations in δ11B values magmas appear to have evolved with time via due to volatile exsolution. The glass records a polybaric storage at 1.5-8 kbars (= depths of ~5 post-eruptive average water content similar to to 30 km), with further modification up on ascent the calculated water solubility in the final pre- to eruption as evident from a common 0-1.5 kbar eruptive melt, suggesting minor pre-eruptive signal overprinted onto macrocrysts. Oxygen degassing took place. The average boron isotope measurements on host macrocrysts as concentration and δ11B value of the glass is 102 well as melt inclusions reveal highly variable d18O μg/g (n=61) and -4.9‰ (2SD=1.6‰, n=60), (3.3–5.4 per mil) implying some oxygen isotopic respectively, making it one of the most boron-rich variation within the mantle source. Volatile subduction zone glasses yet recorded. Moreover, measurements in melt inclusions indicate a the glass is statistically homogeneous at the 2σ typical pre-eruption concentration in the range of level, with mild heterogeneity at the 1σ level. This 0.2-1.0 wt% H2O, 250-˃3000 ppm CO2 and 1000- observation implies that during degassing at 2500 ppm sulphur. The sulphur data were used magmatic temperatures in rhyolitic systems, to propose a two-stage degassing model for boron is relatively immobile and its isotopes do basaltic fissure eruptions in Iceland, which now not significantly fractionate. Our findings allows has been confirmed by recent study on the

63 sulphur degassing during the 2014-15 eruption exceptional cases, sudden external pressure at Dyngjusandur, North Iceland. changes, such as from large crustal unloading caused by large landslides, may, similar to the “un-corking” of a champagne bottle, trigger fast ascent and explosive eruptions of water-rich ORAL magma and associated explosive ocean island Explosive ocean island volcanism eruptions. caused by high water contents in ocean island basalts ORAL Franz A. Weis1, Valentin R. Troll1, Frances M. Deegan1, Henrik Skogby2 and Juan Carlos Improved control on interferences in Carracedo3 laser ablation studies utilizing N2O as 1Uppsala University, Dept. of Earth Sciences, Section for a universal reaction gas: Applications Mineralogy, Petrology and Tectonics, SE-752, 2Naturhistoriska Riksmuseet, Dept. of Geosciences SE- to ore mineral related studies 114 18 Stockholm, Sweden, 3University of Las Palmas de Thomas Zack1 Gran Canaria, Dept. of Physics (GEOVOL), Las Palmas 1 de Gran Canaria, Spain Department of Earth Sciences, University of Gothenburg

Water fundamentally influences the physical Control on reaction chemistry of ions with a properties of the mantle and mantle-derived range of gases are instrumental in the magmas, including rheology, viscosity, buoyancy, development of minimizing interferences in ICP- and explosive potential at the surface. Ocean MS applications. A recent breakthrough was island basalts (OIBs) usually erupt effusively and achieved in this regard with the introduction of a generally contain ≤1 wt. % H2O. However, new generation of ICP-MS that utilizes a explosive eruptions of OIBs occur on occasion configuration called QQQ. It turns out that this is and are thought to relate either to a volatile- of particular importance for laser ablation-based enriched mantle source or to shallow gas studies as this technology precludes other segregation processes. Here we report on chemical treatments to remove interferences. explosively erupted, upper-mantle derived crystal-rich ankaramite lavas from Tanganasoga In the Microgeochemistry Laboratory at the volcano on El Hierro (Canary Islands) that record University of Gothenburg we are in the process of magmatic water contents up to 3.2 ±0.64 wt. %. evaluating different gases for their use of These H2O values are among the highest known interference removal/minimization. It turns out for OIBs to date and were determined through the that nitrous oxide (N2O) is particular potent analysis of hydrogen defects in clinopyroxene reaction gas. Rigorous testing has revealed that crystals. Notably, the Tanganasoga volcano this gas is not only able to remove 87Rb from 87Sr formed within the recent El Golfo giant landslide (therefore allowing in-situ Rb-Sr dating; embayment (87 – 39 ky), and its formation likely Hogmalm et al. 2017, JAAS 32, 305), but also reflects rapid magma ascent due to unloading serves as an almost universal reaction gas for following the El Golfo landslide. Our data also routine in-situ trace element analysis. Significant imply that the Tanganasoga magmas are not improvement in detection limits is achieved for a primary melts but record a usually hidden wide suite of elements: Si, P, Ca, Ti, V, Cr, Mn, Fe, snapshot of magma evolution in the sub-Canary Ge and Se. A major reason for this is the mantle. At this point strong volatile enrichment in minimization or removal of MAr+ and M2+ the magma is caused by fractionation processes interferences, respectively. within the underplating zone beneath the active ocean island, yet the vertical load of the island I will demonstrate that N2O as a universal impedes the magma’s ascent. However, in reaction gas leads to a more reliable analytical

64 protocol in laser ablation studies, in particular in range of new possibilities, with a focus on ore related studies where a wide variety of magmatic, metamorphic, and hydrothermal matrixes (sulphides, oxides, etc) leads to processes. We are open to discuss collaboration multitude of severe interferences that can easily opportunities. lead to false results (e.g., the well-known false Rh and Pd values in the presence of Cu).

POSTER

POSTER In situ Rb-Sr dating of snowball Earth tillite clasts for provenance study on New Scanning Electron Microscope the Chuos formation, Namibia. for automated mineralogical, crystallographic and chemical Martin Thor1 and Thomas Zack1 1Department of Earth Sciences, University of analyses Gothenburg

Nynke Keulen1 and Rikke Weibel2 1Petrology & Economic Geology, GEUS, Denmark, Provenance studies can assist with valuable 2Reservoir Geology, GEUS, Denmark insights into transportation distance and mode of

transportation when producing reconstructions The Geological Survey of Denmark and Greenland on ice sheet movement and mechanics. Recent (GEUS) recently acquired a ZEISS Sigma 300VP advancements in in situ Rb-Sr dating makes Field Emission Scanning Electron Microscope dating felsic clasts with Laser Ablation (SEM), and can now make automated Inductively Coupled Plasma Mass Spectrometry mineralogic, crystallographic and chemical (LA-ICP-MS) possible. This study applies these analyses on entire thin sections or polished techniques to produce accurate and precise Rb-Sr mounts relevant for all areas of geoscience dates on clasts from the Chous formation. research, including mining and exploration, as The Otavi group in Namibia, which contains both well as investigations of reservoirs (oil & gas and the Ghaub and Chous formations, has been the geothermal energy). The instrument is equipped subject of intense study focused on the snowball with 2 Bruker Xflash 6|30 129 eV EDS detectors, Earth hypothesis. The Ghaub and Chous an Bruker e-FlashFS EBSD detector, a 185-850 nm formations have been hypothesized to represent Light-Guide Cathodoluminescence detector, a snowball Earth deposits because of their cap back-scattered electron detector and three carbonates (Hoffman et al., 1998). Some of the secondary electron detectors, including an in- clasts in the tillite are of felsic composition, with lense detector. The SEM is able to work under abundant K-bearing mineral phases, making variable pressure conditions, with high vacuum them suitable for dating using Rb-Sr. condition of 3.25 x 10-4Pa and low vacuum conditions between 2-133 Pa. Also it is equipped Using in situ Rb-Sr dating with LA-ICP-MS paired with the Zeiss Mineralogic software platform for with an reaction chamber with N2O (Zack and mining and reservoir rocks. With this software, Hogmalm, 2016, Hogmalm et al., 2017), clasts we will be able to perform automated mineralogy from the Chuos tillite will be dated to examine on entire thin sections, polished mounts (e.g. drill whether their provenance can be determined. cores, heavy mineral separates, cuttings samples, The aim of this study is to investigate if a ores) or parts thereof. The strength of the new continental-scale transportation distance during SEM instrument lies in the combination the Sturtian glaciation can be inferred. The possibilities for the different detectors and results could potentially have an impact on how imaging techniques, which will shed a completely we view and interpret snowball Earth ice-sheet new light on geoscience microanalysis. In the dynamics. Initial tests have yielded ages from presentation, we will give an overview over the pegmatite clasts, 925 Ma and 975 Ma

65 respectively, which does not appear to have been 1.10. Geochemistry and reset or altered during the Damaran orogeny (550-495 Ma). modeling of Igneous Systems.

ORAL

Markov Chain Monte Carlo Inversion

of Mantle Temperature and Composition Beneath Iceland

Eric Brown1, Kenni Petersen1 and Charles Lesher1 1Department of Geoscience, Aarhus University

Basalts are formed by adiabatic decompression melting of asthenosphere, and thus provide records of the thermal, chemical and dynamical state of the upper mantle. However, uniquely constraining mantle temperature, composition and flow through the lens of melting is challenging given the inevitability that primary

basalts are aggregates of partial melts derived from heterogeneous mantle over a range of P-T conditions. We aim to place more rigorous constraints on the uniqueness and uncertainties of mantle source properties by coupling a Markov

Chain Monte Carlo (MCMC) sampling technique with forward modeling of polybaric near- fractional fusion of heterogeneous mantle using REEBOX PRO [1]. The MCMC method systematically samples the distribution of mantle

potential temperature (TP), and initial abundances and compositions of the source

lithologies that produce models that “fit” geochemical and geophysical observations within their associated uncertainties. We have applied the model to magmatism along Reykjanes Peninsula in Iceland, exploring melting of

depleted peridotite ± G2 pyroxenite [2] ± enriched KG1 peridotite [3] ± harzburgite. Best- fit models have depleted peridotite + enriched

peridotite/pyroxenite sources having TP ~122 ± 15 °C above ambient mantle with ~95% depleted peridotite and ~5% pyroxenite spanning likely compositions for G2 and KG1. The enriched

lithologies have EMORB-like [4] trace element compositions and Paleozoic mean ages, whereas the depleted peridotite exhibits very- incompatible element enrichments relative to DMM [5]. These results advance our

66 understanding of the petrogenesis of the Iceland hybridization of an upper asthenospheric melt source that differs significantly from depleted with small volumes (1-3%) of highly enriched mantle sampled by the global spreading ridge alkaline melts derived from the sub-continental system. lithospheric mantle, possibly lamproites. This scenario is also supported by the geodynamic setting of the FLC, emplaced within a Proterozoic mobile belt (Rokelide) and bordering an Archean ORAL craton (Man), as well as by the reported presence Enriched lithosphere contribution to of lamproites and kimberlites in the area. Origin of high-Ti magmatism of other Gondwana Large the genesis of the Freetown Layered Ignoeus Provinces (Karoo, Paraná-Etendeka) can Complex (Sierra Leone): Isotope likewise be explained by similar processes. systematics of a high-Ti CAMP intrusion. ORAL Sara Callegaro1, Andrea Marzoli2, Hervé 3 3 4 Bertrand , Janne Blichert-Toft , Laurie Reisberg , Evidence of liquid immiscibility in the Giancarlo Cavazzini5, Fred Jourdan6, Joshua Davies7, Urs Schaltegger7 and Massimo Chiaradia7 1.8 Ga Raftsund monzonite, Lofoten, 1CEED - University of Oslo, 2University of Padova, Northern Norway 3Université Lyon 1, ENS Lyon, 4CRPG - CNRS Nancy, 5IGG-CNR Padova, 6Department of Applied Geology, Nolwenn Coint1, Jakob K. Keiding1, Peter Ihlen1 Curtin University, 7Département des Sciences de la and Suzanne McEnroe2 Terre, Université de Genève 1Geological Survey of Norway, 2Department of Geoscience and Petroleum, Norwegian University of Science and Technology We present a geochemical and geochronological study of a mafic layered intrusion cropping out along the Atlantic coast of Sierra Leone – the The significance of silicate liquid immiscibility Freetown Layered Complex (FLC). and its petrogenetic role has been debated for Geochronology (40Ar/39Ar on plagioclase: many years. Although well documented in mafic 201.7±0.7 and 202.3±2.3 Ma; U-Pb on layered intrusions, it is not clear if liquid baddeleyite: 198.794 ± 0.048/0.071/0.22 Ma) immiscibility can occur in more evolved alkaline and crystal chemistry (high-TiO2 pyroxene) rocks. Here, we present evidence for this process demonstrate the connection between the FLC and in the 1.8 Ga Raftsund batholith; a monzonitic to the high-Ti magmatism of the Central Atlantic locally granitic ferroan intrusion. Fe-Ti-P-rich Magmatic Province (CAMP). Yet, Sr, Nd, Hf, Pb, mineralizations occurs as cm-scale up to 200 m x and Os isotopes reveal an unusual signature for 50 m large scattered bodies, displaying both the FLC compared to most other CAMP sharp and gradational contacts with the occurrences previously studied. Particularly surrounding host pigeonite-clinopyroxene distinctive of the FLC rocks are their low monzonite to syenite. The mineralizations are 206 204 207 204 Pb/ Pb and high Pb/ Pb, suggesting composed of anhedral rare pigeonite, Fe-rich involvement of an ancient component in the olivine (Fo22-29), subhedral clinopyroxene (Wo34- genesis of these magmas. Although some lower 45 En20-46 Fs23-44), anhedral magnetite and crustal assimilation is isotopically confirmed and ilmenite, scattered late hornblende and variable also suggested by the presence of a granulite proportions of subhedral ternary feldspars. xenolith in one of the analysed rocks, this process Inclusions of apatite, which can reach up to 12 alone cannot be responsible for the observed modal percent, are present in all minerals but isotopic fingerprint of the FLC. We rather propose ternary feldspars. The scarcity of pigeonite in the that the most straightforward way to confer the Fe-Ti-P-rich rocks and the presence of Fe-rich distinctive isotopic signature to the FLC is by olivine indicate that these rocks cannot represent

67 direct cumulate from the host monzonite and fractionate by more than 30%, implying large syenite. Bulk-rock compositional variations are volumes of magma were transported vertically to well explained by recent experimental work on shallower levels of the crust. For olivine liquid immiscibility (Charlier & Grove, 2012) with clinopyroxenites, LREE/HREE ratios record the enrichment in Fe, Ti, P, Mg, Ca, Sc, Co, Zn, Cu, V and importance of assimilation as well as fractional REE in the mineralizations. Clinopyroxene from crystallization. the mineralizations is enriched in Sc and to a lesser extent in Ti, Zn and depleted in V, Co, Sr, Y, With time, the intrusion evolved to more olivine- Nb, LREE and Al, which is consistent with co- rich and ultramafic cumulates, fractional precipitation of apatite and magnetite and the crystallization become more dominant over formation of such a melt by liquid immiscibility. assimilation, and the magmas leaving the conduit system became increasingly MgO-rich. These results may explain geochemical variations observed in flood basalt sequences (Yu et al ORAL 2015).

Evolution of a deep crustal magma conduit system ORAL Thomas B. Grant1, Rune B. Larsen1, Axel Müller2 and Suzanne McEnroe1 Unraveling the differentiation of a 1NTNU, 2NHM Oslo flood basalt sequence using Magma Chamber Simulator

Seiland Igneous Province (SIP), Northern Norway Jussi S. Heinonen1, Arto V. Luttinen2, Wendy A. represents the lower crustal plumbing system of Bohrson3 and Frank J. Spera4 a LIP where large volumes of ultramafic, mafic 1Department of Geosciences and Geography, University and alkaline-carbonatite melts were transported of Helsinki, 2Finnish Museum of Natural History, from the mantle to shallower levels of the crust. University of Helsinki, 3Department of Geological The Reinfjord mafic-ultramafic intrusion is a Sciences, Central Washington University, 4Department magma conduit system and offers an excellent of Earth Science and Earth Research Institute, location in which to study differentiation University of California Santa Barbara processes as magmas enter the crust (Larsen et al 2016). The Magma Chamber Simulator (MCS; Bohrson et Field relationships clearly show the Reinfjord al., 2014) models the effects of recharge, intrusion formed by progressive influxes of new assimilation, and crystallization on phase melts into earlier cumulates, resulting in a equilibria, mineral chemistry, major elements, sequence of gabbro – olivine clinnopyroxeneite – trace elements, and radiogenic isotopes through wehrlite – dunite from the margins to the core mass and enthalpy balance in a multicomponent- (Grant et al 2016). Here, we determine the multiphase magma + wallrock system. Here we relative contributions of fractional provide an example of utilizing MCS in crystallization, assimilation and recharge on the deciphering the differentiation history of a compositions of ultramafic cumulate layers. compositionally uniform continental flood basalt sequence characterized by strong crustal Trace elements in clinopyroxenes were geochemical signature from the Antarctic portion determined using LA-ICP-MS. Melts in of the Karoo large igneous province. Our equilibrium with the clinopyroxenes from modeling shows that only a few percent of Reinfjord have OIB-like characteristics, similar to assimilation of sialic crust may have profound picrite dykes in the SIP. For dunites and impact on the composition of the parental magma wehrlites, fractional crystallization was the (major elements, 16 trace elements, and Nd dominant processes. The magmas did not isotopes). Isobaric and continuously assimilating

68 models fail to produce the observed eruptive Four of the ultramafic complexes are exposed at compositions. Instead, we suggest that SIP in a right-way-up setting. They feature a contamination of the picritic parental magmas by marginal hybrid zone at the country rock assimilation of mid-crustal Archean TTGs (by contacts, then an olivine-mela-gabbro grading to stoping + hybridization or partial melting or pyroxenite, then an olivine-clinopyroxenite zone both) must have first taken place at depths of which is followed by a wehrlite zone and, finally, ~10‒20 km, where orthopyroxene and olivine pure dunite in the centre. From pyroxenite to are stable phases in the magma. Most of the dunite, olivine composition changes from Fo72 to subsequent differentiation happened in a Fo85 and clinopyroxene from Di80 to Di92 i.e. complex network of dikes and sills in the shallow forming a reverse fractional crystallization upper crust without additional assimilation. inwards. Parental melts were komatiitic to There, the large temperature gradient between picritic with 16-21 wt% MgO, 1594 ppm Cr and magma in narrow feeding channels and country 611 ppm Ni and were emplaced at 1450-1500 oC. rock precluded anatectic melt formation and Melts are OIB-like with LREE enriched over effectively shielded the magma from HREE. The high abundance of carbonated and incorporation of wallrock partial melts. This hydrated mineral assemblages imply a volatile- example illustrates the capabilities of MCS in rich nature of the mantle source region also testing possible petrogenetic scenarios and corroborated by unusually high abundance of encourages application of the MCS tool to magmatic sulphides. different igneous environments and tectonic settings where assimilation takes place. Essentially, the ultramafic complexes in SIP comprise deep-seated transient magma chambers that facilitated mixing and homogenization of a rich diversity of fertile ORAL asthenospheric melts en route to the upper parts of the continental crust. Deep crustal homogenization of diverse mafic and ultramafic LIP- forming mantle melts: Lessons from ORAL the Ediacaran Seiland Igneous Province (SIP), Norway Geochemistry of the Feragen ultramafic body, Central Norway. Rune B. Larsen1, Thomas S. Grant1, Bjørn E. Sørensen1, Suzanne McEnroe1 and Christian Anna Pryadunenko1, Lars P. Nilsson2 and Rune B. Tegner2 Larsen1 1Dep. of Geosciences and Petroleum, NTNU, Trondheim, 1Department of Geoscience and Petroleum, NTNU - 2Earth System Petrology, D. of Geosciences, Århus Norwegian University of Science and Technology, University 2Geological Survey of Norway

SIP contains >5000 km2 of mafic/ultramafic Tectonically dismembered ophiolite fragments intrusions with minor alkaline, carbonatite and stretch for several hundred kilometres along the felsic rocks emplaced at depth of 25 - 35 km Swedish-Norwegian border [1]. One of the during the formation of the Central Iapetus fragments, the Feragen ultramafic body, located Magmatic Province at 610-550 Ma (CIMP) and 30 km east of the town of Røros represents an exposes 85-90 % layered gabbros, 8-10 % excellent natural laboratory for studying upper peridotitic complexes, 2-4 % alkaline intrusion mantle melting and melt extraction processes. emplaced within <10 Ma. Gravimetric data Upper mantle rocks in Feragen are represented suggests that SIP features six deep lithospheric by harzburgite, that occasionally changes roots of ultramafic rocks extending in the depths composition towards lherzolite and a of > 9 km that resembles the conduit systems. subordinate amount of dunite. In the north-

69 western part of the massif, close to a presumed present the first comprehensive comparison of mantle-crust boundary, the amount of dunite mica from the Tørdal, Evje-Iveland and Froland exceeds that of harzburgite. Dunitic rocks were pegmatite fields. Mica from Tørdal is significantly observed both as replacive dunites with gradual enriched in both Li2O wt% and F % compared to transitions to harzburgite up to several meters mica from the Evje-Iveland and Froland. The wide, and as dunite channels with sharp borders Tørdal mica contains up to 5.4 wt% F and 6.0 wt% to host harzburgite and a maximum width of 50 Li2O, while only up to 2.6 wt% F and 0.6 wt% Li2O cm. Harzburgite relicts of various shape are often are measured from the Evje-Iveland field and 1.2 present within the dunite channels and the wt% F, 0.3 wt% Li2O in the Froland mica. A replacive dunites. similar pattern is seen in the K/Rb ratios with the lowest values found in the Tørdal mica ranging Olivine present in the rocks is higly magnesian from 3.63 to 27.5 contrary to 16.5-365 and 29.9- with Mg numbers ranging from 90 to 91 in 62.5 from Evje-Iveland and Froland, respectively. harzburgite and from 92 to 94 in dunite. NiO The Tørdal pegmatite field contains the most content of olivine in all the rock types does not evolved mica and thereby the most evolved exceed 0.4 wt %. Some of the dunites are rich in pegmatites. The strong enrichment of Li, F and Rb chromian spinel. Cr numbers for spinel are suggests that the source of the Tørdal pegmatite between 0.4 and 0.6. TiO2 content of spinel melts might be different than for the Evje-Iveland minerals is as low as 0.15 wt % [2]. Chromitites and Froland fields. The latter are thought to be of show extreme depletion in Pt and the overall PGE anatectic origin. content implies depleted mantle composition for the rocks analysed. Low TiO2 content of spinel and high Fo content of olivine suggest a high degree of melting, that is greater than 25% ORAL

Chronology of the Nebo Granite, Bushveld Complex ORAL Ole Skursch1, Christian Tegner1, Fernando Corfu2 Mica chemistry - a genesis indicator and Charles E. Lesher1 of the Sveconorwegian pegmatites, 1Earth System Petrology Group, Dept. of Geoscience, southern Norway Aarhus University, Aarhus, Denmark, 2Dept. of Geosciences, University of Oslo, Oslo, Norway Nanna Rosing-Schow1, Axel Müller2 and Henrik Friis1 The world’s largest A-type granite unit (the Nebo 1Natural History Museum, University of Oslo, P. O. Box Granite)overlies the layered mafic and ultramafic 1172, Blindern, 0318 Oslo, Norway, 2Natural History Museum, University of Oslo; Natural History Museum, cumulate rocks of the Rustenburg Layered Suite Cromwell Road, London, UK (RLS) Together with minor granophyre and other granites these units make up the Bushveld Complex, South Africa. The Nebo Granite often Mica minerals are the third most common cuts the RLS and existing zircon U-Pb chronology component of granitic pegmatites. They contain supports the view that the granite is slightly important major and trace elements including Li, younger and essentially unrelated to the RLS.The F, and Rb, which can be used for pegmatite age of the RLS is very well constrained at classification and to better understand the origin 2055.91±0.26 to 2054.89±0.37 Ma (Zeh et al., and genesis of pegmatites (Marchal et al. 2003; 2015)We present new ID-TIMS zircon U-Pb Breiter et al. 2017). Southern Norway is known chronology for 9 samples of the Nebo Granite and for its large pegmatite province with more than a related granophyric variety. We show that the 5000 pegmatite bodies, occurring in the ages obtained from the Nebo Granite are Sveconorwegian orogeny (1.1-0.9) and forming indistinguishable from each other and from the one of the world’s largest pegmatite clusters. We age of the RLS. Moreover, the granite also

70 contains minor amounts of zircon that are slightly Geochemistry and Isotope Research Platform (<9 m.y.)older than the crystallization age. The (AGiR), Aarhus University, using pseudo-high older zircons are morphologically similar to the resolution and sample-standard bracketing. Fe young zircons and are found in all samples we isotope compositions of Thingmuli lavas range have investigated. Their ages also overlap the age from δ56Fe = 0.042 ‰ to 0.118 ‰ for mafic and of the earliest phase of magmatism in the intermediate compositions, and 0.124 ‰ to Bushveld LIP.These observations suggest that the 0.650 ‰ for rhyolites. The heaviest values older zircons are inherited from magmatic rocks correspond to the most evolved, Fe-poor lavas. that formed during the earliest phase of Bushveld Preliminary Si isotope data ranges from δ30Si = - magmatism and are not xenocrysts from older 0.36 ‰ to -0.06 ‰ and shows a positive linear basement rocks. Even though the Nebo Granite is correlation with whole rock SiO2 (wt. %) content. probably an assembled body, it crystallized too Forward modeling of the stable isotope fast for its temporal evolution to be compositions shows that Fe3+/Fe2+ partitioning resolved. Contemporaneity between the RLS and between melt and crystallizing solids is the the Nebo Granite challenges the view that they principal contributor to iron isotope are essentially unrelated and introduces the fractionation, except during the final stages of possibility of consanguinity between the two crystallization where high melt polymerization units. affects the coordination environment and fractionation of iron. In contrast, Si isotope fractionation reflects the degree of Si- polymerization of melt and solid phases ORAL throughout the crystallization sequence. Fe and Si isotope systematics of the

Thingmuli volcano, Iceland: the roles of crystal – melt fractionation, oxygen ORAL fugacity and melt structure Geochemical discrimination criteria Niklas Stausberg1, Christian Tegner2, Gry Barfod2 for indium-potential granites in the and Charles Lesher2 Fennoscandian Shield 1Department of Geoscience, Aarhus University, Høegh- Guldbergs Gade 2, 8000 Aarhus-C, 2Earth System Krister Sundblad1, Ivan Alexeev2, Matti Vuorisalo3, Petrology, Department of Geoscience, Aarhus University Bence Balogh3 and Susanna Metso3 1University of Turku, Finland and State University of St Petersburg, Russia, 2State University of St Petersburg, The Tertiary Thingmuli volcano, Eastern Iceland, Russia, 3University of Turku, Finland is a classic example of tholeiitic differentiation spanning the compositional range of basalt to rhyolite. Whole rock and mineral compositions Spectacular discoveries of indium-rich coupled with forward modeling indicate polymetallic sulphide/oxide deposits have fractionation of olivine, pyroxene, plagioclase and recently been reported from the Fennoscandian FeTi-oxides buffered at an oxygen fugacity Shield; Pitkäranta, Russian Karelia (Valkama et slightly below the FMQ buffer. The well- al., 2016a) and Sarvlaxviken, southern Finland constrained liquid line of descent for Thingmuli (Cook et al., 2011; Valkama et al., 2016b; Broman provides an opportunity to investigate stable et al., 2017). These sulphide/oxide deposits are isotope crystal-liquid fractionation for the two closely associated with A-type granites, hosted by most abundant major elements, Fe and Si. Iron marbles (Pitkäranta) at km-distance from the isotope fractionation is expected to be sensitive 1.54 Ga Salmi Batholith or various granite types to redox condition, while Si is not. Fe and Si were (Sarvlaxviken) within the 1.64 Ga Wiborg chemically purified and analyzed for δ56Fe and Batholith. δ30Si with a Nu Plasma II MC-ICPMS at Aarhus

71 The batholiths display complex magmatic POSTER evolution trends from gabbro-anorthosites, via wiborgites, pyterlites and transitional granite Chronology and geochemical and phases to evolved late-stage plutons. The structural evolution of dykes wiborgites and pyterlites have typical WPG intruding the Reinfjord ultramafic to geochemical patterns with shallow REE patterns mafic intrusion in the Seiland Igneous and significant negative Eu anomalies but did not create any hydrothermal systems or metal Province accumulations. Alf Andre Orvik1, Bjørn Eske Sørensen1, Rune 1 1 In contrast, some (but not all) late phase granite Larsen and Thomas Grant 1 plutons (< 1 km diameters), provided metals and Department of Geoscience and Petroleum, NTNU, Norway heat for the metal-rich hydrothermal fluids and thus indium-rich polymetallic accumulations. These plutons have also WPG characteristics This study investigates the chronology, (although fake “syn-collisional granite” signals geochemical and structural evolution of dykes are seen in some discrimination diagrams due to intruding the Reinfjord Ultramafic Complex hydrothermal influence). (RUC) consting of large volumes of ultramafic, mafic, silicic and alkaline melts intruded the Zr/Hf Rb/Ba lower crust (~30 km) from 570-560 Ma in an Wiborgites, Sarvlaxviken 43-50 < 0.2 extensional regime. The RUC was nested to baltica the Caledonian orogeny. Earlier studies Pyterlites, Pitkäranta 28-40 < 0.3 have indicated horizons with anomalous concentrations of Pt+Pd+Au+Os and enriched Transitional phases (Repomäki and Nietjärvi), horizons of Cu-Ni. Pitkäranta 15-24 2- 18 The ultramafic rocks are cut by several Late granite phase (Marviken), Sarvlaxviken 17- generations of dykes ranging from replacive 22 11- 23 dunite dykes intruded into the semi-consolidate Late granite phases, Pitkäranta 7-14 10-150 host-rock with gradual contacts, to late gabbroic dykes that has a chilled margin. The dykes have The late igneous phases can be evaluated by complex crosscutting relations and in areas it several geochemical criteria but the low Zr/Hf constitutes up to 50 % of the outcrop volume. ratios, high Rb/Ba ratios and enrichments of Large variability in chemistry and volatile heavy REE are the most characteristic features content ranging from wherlites, olivine for the ore fertile granites (Torppusuo, Ristinoja- clinopyroxenites, hornblende bearing olivine Mosautodor and Uuksu in the Pitkäranta area and clinopyroxenites, hornblende gabbro, alkaline Marviken in the Sarvlaxviken area). and lamphrophyric dykes.

A relative chronology of the dykes was established by the cross cutting relations of the dykes during field work and post processing of 3D photogrammetry from drone images will be

used to estimate the melt volumes within the different dyke types and their orientation evolution over time within selected locations of the central series. Petrographic descriptions of attained samples together with chemical analysis, and hopefully radiometric dating, will in combination with the photogrammetric data give

insight in the evolution of the melt related to the

72 dykes. Our ambition is that the data will provide formulas for PGM identification. Based on the valuable information and constrain the results, it is clear that despite a sub-economical chronological progression of the geochemistry grade, the RUC provide a valuable insight in to the and tectonomagmatic association of the dykes. ore forming potential for deep-seated layered intrusions.

POSTER

Platinum Group Minerals in the Reinfjord Ultramafic Complex

Even Sunnanå Nikolaisen1, Rune Berg-Edland Larsen1, Thomas Grant, Bjørn Eske Sørensen1 and Suzanne McEnroe1 1Norwegian University of Science and Technology (NTNU), Department of Geoscience and Petroleum. Sem S

An upwelling mantle plume 560 - 570 Ma formed the Seiland Intrusive Province (SIP), a 5400 km2 area of felsic to ultramafic rocks in Northern Norway. The Reinfjord Intrusive Complex (RUC) is the southernmost part, exposing 25km2 of ultramafic rocks that are generated from three intrusive magmatic events and crystal fractionation. These events show evidence that RUC is representing an open magma chamber, connected to a conduit system at 25-30km depth and subjected to extensive magma replenishment.

Exploration drill cores in RUC in 2011 (RF-1 and RF-2) show two spikes for economic elements, one Cu-Ni reef low in PGE at depth of 86-93m and a PGE reef low in Cu-Ni at 107-113m

A detailed analysis of a 6 m drill core section, suggest PGE being segregated in different lithologies, which combine to a total of 0.79 ppm PGE. When comparing the δ34S signature of the PGE reef with the Cu-Ni reef shows a distinct difference -0.40 (PGE) and -4.56 (Cu-Ni), indicating different sources.

This study looks into the details of the PGE’s, with the aim of identifying the ore forming processes. SEM imaging and mapping, EPMA, magnetic analysis and whole rock geochemistry are used to find cryptic variations in the PGE rich lithologies. BSE and EDS detects and identify the PGE’s, with EPMA data to calculate empirical

73 1.11. Open session on petrology analyses of Rb-Sr isotope systematics are currently being conducted, and the preliminary and geochemistry results are concordant with the age determined by the U-Pb systematics.

ORAL

Additional constraints to the ORAL evolution of the early solar system? A The EARTHTIME Initiative: A U-Pb systematics study of ungrouped community working to accelerate the differentiated achondrite NWA4587. development and application of Yuri Amelin1 and Elin Rydeblad2 integrated methodologies for the 1Australian National University, 2Uppsala University quantification of geological time.

Daniel Condon1 The study of meteorites can help us answer 1British Geological Survey, Nottinghamshire, NG12 questions still under debate regarding the early 5GG, UK solar system and the processes therein. It could help us unify a timescale for the development of the solar system, help us fully understand how The EARTHTIME Initiative is an international our planets formed, and tell us about the nature community effort to 'To accelerate the of elemental dispersal throughout the early solar development and application of integrated system (Amelin and Ireland, 2011). It will also methodologies for the quantification of geological allow us to investigate how our solar system time for the underpinning of Earth sciences'. The compares to other solar systems – giving us an first phase (from 2004 and ongoing) was focused invaluable tool in the search for other habitable on addressing urgent shortcomings in the ‘high- planets and possible life, and future celestial precision’ geochronometers (e.g., U-Pb and 40Ar- exploration (White, 2011). 39Ar), issues that limit widespread application at the quoted levels of precision/accuracy. Many of This study aims to add additional constraints to these (e.g., inter-laboratory bias) have been the evolution of the early solar system by the addressed through experiments conducted over isotopic analysis of ungrouped differentiated the past 13 years and the accuracy and precision achondrite North West Africa (NWA)4587. of both of these widely used dating systems has been significantly improved. The EARTHTIME All sample processing was performed at the Initiative has brought the 40Ar-39Ar and U-Pb SPIDE2R laboratory facilities, located at the isotope dilution sides together (for both Research School of Earth Sciences (RSES) at the experiments and application) but also expanded Australian National University (ANU). For the U- to include a range of decay schemes (e.g., Re-Os Pb systematics, four separate hand-picked and U-Th) and analytical approaches (e.g., pyroxene fractions were analysed. The fractions microbeam U-Pb). Perhaps the most significant were chosen based on mineral grain texture, outcome has been the development of a strong colour, and size. This study employed an acid and lasting sense of a 'geochronology leaching and dissolution protocol, combined with community'. single- and double pass μ-column protocols. The Pb ratios and isotopic composition of the samples Whilst these Phase 1 activities continue, the were analysed using a thermal ionisation mass original motivation for accelerating progress in spectrometer. the various dating methods has been that they underpin a wide range of Earth science research The age of NWA4587 is 4563.63±0.55 Ma, areas. Starting in 2016 a second phase of suggesting that its parent body was formed EARTHTIME has been initiated, following two during early planetary accretion. Further

74 community workshops, with a renewed emphasis element triggering intense extension in a on engagement of the geochronology community subduction setting (slab rollback) is low with the 'end-users' of geochronology. This subduction velocities -as numerical models have presentation will provide a summary of predicted4, which can be attributed to the EARTHTIME efforts since 2004 to present to transitory stage of Pangea (mid Permian– calibrate and inter-calibrate the Triassic). Hence, subduction of the paleo-Pacific geochronometers, and will provide a vision and oceanic plate beneath paleo-South America has strategy for the second phase of the EARTHTIME been a continuous process from early Paleozoic Initiative. times onwards; and Pangea assembly, the setting behind the observed changes in the magmatism and not the cessation of subduction as previous models have invoked. ORAL

Pangea assembly and its implications to the mid Permian–Triassic ORAL magmatism on the southwestern Tourmaline textures and structures margin of South America as a tracer for the magmatic- Álvaro del Rey1, Katja Deckart2, César Arriagada2 hydrothermal transition in SW and Fernando Martínez2 England 1Natural History Museum of Denmark, University of Copenhagen, Copenhagen, Denmark, 2Departamento de Kristian Drivenes1, Rune Larsen1, Bjørn Eske Geología, Universidad de Chile, Santiago, Chile. Sørensen1 and Sam Hughes2 1Norwegian University of Science and Technology, 2Camborne School of Mines, University of Exeter The Chilean Frontal Andes batholiths (28°–31°S) represent part of the extensive late Paleozoic– Triassic magmatism along the southwestern Tourmaline is a common mineral throughout the margin of South America. Despite its importance, granites of SW England. It occurs in multiple a consensus regarding the tectonic model textural and structural varieties, including veins, controlling the magmatism has not been reached. quartz-tourmaline orbicules, massive quartz- Several models1,2,3 have proposed cessation of tourmaline rocks (MQT), pegmatitic pockets, and subduction as the reason behind the apparent disseminated in the granite. Field relations lack of typical arc magmas and abundance of indicate both magmatic tourmaline and post- within plate signatures. Yet the causes for this magmatic, hydrothermal tourmaline, occuring as cessation differ and do not provide a disseminated grains and veins, respectively. In comprehensive model for coeval units along the addition, more genetically complex textures are margin. Here, new LA-ICPMS U–Pb in zircon ages, observed as gradual exsolutions of quartz- and geochemical and isotope analyses (Rb-Sr, tourmaline rocks within the granite, with or Sm-Nd, Lu-Hf, Re-Os and d18O) indicate that mid without associated veining. These appear on the Permian–Triassic granitic magmatism originated cm scale and up to several meter large bodies. in a slab rollback extensional setting with Such structures are observed in localities several increasing thinning towards Triassic times. km apart, and are a regional feature. Occasionally, Subduction and anataxis of lower crust were the the gradual transition from granite to MQT to main magma-generation mechanisms, the latter miarolitic tourmaline or a pure tourmaline zone, caused by decompression and subsequent can be observed over tens of cm. The accumulation of underplating basalts. A microtextures are strongly linked to the comparison with other igneous units along the macroscopic structures, reflecting the diverse Chilean–Argentinian border allows extension of processes that formed the different tourmaline this model from at least 21° to 40°S. The key occurrences. Strongly birefringent, green,

75 acicular tourmaline dominates in vein-style residual system for silicate magmatic rocks. The tourmaline; disseminated tourmaline in the inter-dendrite residual melt pocket physiography granite is weakly zoned and brown; tourmaline (3rd or 5th order arms) allows to attempt an from MQT is brown with blue rims. Later ambitious fractal numerical simulation modelling tourmaline generations overgrow earlier of the crystallization of the early solar system generations, adding to the complexity. Cassiterite asteroid/planetoid metallic cores. Agpalilik will is only associated with the hydrothermal green serve as an empirical constraint for numerical acicular tourmaline. Tin concentrations in other dendritic crystallization modelling, based on a tourmaline-rich rocks are less than 100 ppm, and simplified Fe-S system, believed to approximate these rocks are not a part of the mineralizing (Fe,Ni)-S well. It is first in the latest years that it events of the Land’s End granite. has been possible to tackle the numerical simulation challenges involved, Misztal MK, Bærentzen JA (2012); Misztal MK, Erleben K, Bargteil A, (2014). We present a first foray ORAL overview of the scope of this challenging multi- Dendritic Core Crystallization in disciplinary study.

Minor Planets – An empirically constrained Numerical Simulation Study ORAL

Kim Esbensen1, Henning Haack2, Kenny Erleben3 Age and geochemistry of granitoids in and Marek Misztal4 the Precambrian basement of Öland, 1GEUS, AAU, KHE Consulting, 2Maine Mineral and Gem SE Sweden – implications for the Museum, Maine, USA, 3Department of Computer extension of the Transscandinavian Science, Copenhagen University, 4Niels Bohr Institute Igneous Belt in the Baltic Sea region

The Cape York meteorite shower typifies the Evgenia Salin1, Krister Sundblad1, Hugh O'Brien2, magmatic iron meteorites. The Agpalilik mass Yann Lahaye2 and Jeremy Woodard3 1 displays characteristic oriented, elongated University of Turku, 20014 Turku, FINLAND, 2Geological Survey of Finland, 02151 Espoo, FINLAND, troilite nodules, interpreted to testify to a 3University of KwaZulu Natal, Westville (Durban), X5 dendritic crystallisation mode of surrounding 4001, SOUTH AFRICA (Fe,Ni) metal phase (Esbensen (1981, 2017);

Esbensen & Buchwald (1982); Esbensen et al. (1982; Haack & Scott (1992). The troilite The Precambrian crust in the Baltic Sea region is accessory mineralogy testifies that the fractional mostly covered by Phanerozoic sedimentary crystallisation / late magmatic differentiation rocks but can be studied in drill cores. Two history of asteroid cores can be modelled in the granitoids from the crystalline basement below Fe –Ni –S- P system. Accessory schreibersite and Öland were collected from the archives of the high-Ni taenite are found lining the metal/ troilite Geological Survey of Sweden and analyzed for interface, representing very late crystallisation geochemistry and dated with the U-Pb method on from an evolved Fe-Ni-S-P liquid. A zircons. The Böda Hamn granitoid (northern troilite/taenite eutectic represents the ultimate Öland) has a monzodioritic composition and an liquid-solid transformation product (the age of 1799.8±3 Ma while the Valsnäs granitoid paragenesis shows that schreibersite (central Öland) has a quartz monzonitic precipitated prior to taenite crystallization, composition and an age of 1784.9±5.7 Ma. These effectively purging the system for P), allowing the geochemical-isotopic characteristics are ultimate crystallisation to be modeled in the compatible with those of generation 1 of the residual Fe-Ni-S system, which thus defines an Transscandinavian Igneous Belt (TIB) in the iron meteorite analogue to the petrogenetic Fennoscandian Shield, ≥30 km west of Öland.

76 A more detailed review of the TIB-1 generation consistently radiogenic 87Sr/86Sr compositions shows that two sub-generations (1a and 1b) can (0.7127-0.7129). These compositions are be distinguished on each respective side of the inconsistent with an origin as xenocrysts from Oskarshamn-Jönköping Belt (OJB). Sub- early formed mafic volcanics or from generation 1a (north of OJB) has an age span of metamorphosed carbonates in the basement. We 1794-1808 Ma while sub-generation 1b (south of interpret these high-An% cores to be early OJB) has an age span of 1769-1793 Ma. According formed phenocrysts crystallizing from more to this subdivision, the Böda Hamn monzodiorite primitive and relatively water-rich magmas in the belongs to sub-generation 1a, which also can be deep crust. Their radiogenic Sr isotope followed to southernmost Gotland (Sundblad et compositions suggest that these early magmas al. 2003) and the Valsnäs quartz monzonite already had a significant crustal component, belongs to sub-generation 1b, which can be consistent with other evidence for important followed to the Latvian/Lithuanian border, involvement of a subducted sediment component where a marginally younger granitoid was during magmatism. The resorbed nature of the reported from off shore drill core E-7 (Salin et al. high-An% cores is interpreted to reflect 2016). Taken together, these data suggest that resorption during rapid magma migration into the Transscandinavian Igneous Belt can be traced the upper crust. Lower An% rims of these same across the Baltic Sea from the exposed parts plagioclases show increases in 87Sr/86Sr (up to within the Fennoscandian Shield to the 0.7132) that are consistent with interactions with Latvian/Lithuanian border. crust in upper crustal magma chambers. The plagioclase Sr isotope data therefore provide evidence for both source and crustal contamination during petrogenesis of the Cabo ORAL De Gata andesites. Sr isotope zoning in plagioclase from

Cenozoic andesites from Cabo De Gata, Spain: evidence for shallow and POSTER deep contamination Recycling of continental material Tod Waight1 and Jakob Tørnqvist1 through the suprasubduction zone 1Department of Geosciences and Natural Resource Mawat ophiolite, NE Iraq Management (Geology Section), Copenhagen University Heider Al Humadi1, Markku Väisänen2, Sabah Ismail3, Yann Lahaye4, Hugh O’Brien4, Jaakko Subduction-related andesites from the Cabo De Kara2 and Marja Lehtonen4 Gata region in Southern Spain are part of the 1Dpet. of Geogr. and Geo. Uni. of Turku, Finland/Dept. of larger Alboran Magmatic Province which Appl. Geo. Uni. of Babylon, Iraq, 2Department of stretches from Northern Africa, through the Geography and Geology, FI-20014 University of Turku, Alboran Sea into Southern Spain. The province is Finland, 3Department of Applied Geology, College of of interest due to the penecontemporaneous Sciences, University of Kirkuk, Iraq, 4Geological Survey occurrence of a wide variety of magma of Finland, FI-02151 Espoo, Finland compositions (incl. tholeiitic basalts, calc-alkaline andesites, explosive rhyolites, peraluminous The fate of subducted continental material is not crustal melts and lamproites) and temporal fully understood. It is estimated that up to 20% of overlap with the Messinian Salinity Crisis. Many it is recycled back to the crust (Clift et al. 2009), plagioclase phenocrysts within andesite domes at mainly in volcanic arcs. Recently, Cabo De Gata are characterized by resorbed high- suprasubduction zone ophiolites formed above An% cores (An ) surrounded by oscillatory 73-85 subduction zones have also been shown to zoned plagioclase (An ). Sr isotope analyses of 40-60 contain recycled continental minerals (Robinson the high An% cores of these plagioclases show et al. 2015).

77 We have analysed zircons and monazites from limit of 695 ± 17 Ma is defined by detrital zircon three felsic dykes and zircons from two mafic U-Pb from shaley beds in the Banda Alta Fm. (Frei rocks from the mantle section of the et al. 2017). Preliminary results from borehole suprasubduction zone Mawat ophiolite in NE samples (Vetria borehole 28-32) support Iraq. Laser ablation single-grain U-Pb results previous findings with a positively fractionated show a wide range of ages from the Late- authigenic Cr isotope signature throughout the 53 Cretaceous to Paleo-Archean (c. 95-3500 Ma). stratigraphic section (d CrSRM979 = 0.80 ± 0.25 The youngest 95 Ma age represents the formation ‰, 2s, n=26/28). This indicates a continental of the Mawat ophiolite whereas the bulk of the source of oxidized Cr, implying high atmospheric zircons are inherited from older unknown mixed O2 levels in the late Neoproterozoic. continental material. Lu-Hf isotopes on zircons from a felsic sample show average initial εHf = – 2.4. The results indicate that the magma POSTER originated from an older source possibly contaminated in the mantle wedge. In contrast, Quadlab – A 40Ar/39Ar and noble gas the initial ε values of the mafic sample display an Hf isotope laboratory at the Natural average of + 9.4, indicating a juvenile magma source. History Museum of Denmark

The results show that the felsic rocks of the Michael Storey1 and Daniel Wielandt1 Mawat ophiolite formed in a forearc position 1Quadlab, Natural History Museum of Denmark partly from recycled older continental material which was most likely subducted as the upper In this poster presentation we provide an layer of the Neo-Tethyan oceanic crust. The effect overview of Quadlab, a Villum Foundation funded of the older crustal material on the newly-formed 40Ar/39Ar age-dating and noble gas isotope mafic crust is significantly less based on the Hf laboratory that has recently been established at data, but nevertheless is in clear evidence by the the Natural History Museum of Denmark. The occurrence of old xenocrystic zircon. laboratory has two noble gas mass- spectrometers: (1) A Nu Instruments Noblesse

from 2005 - equipped with 3 ion counters (high, POSTER axial and low mass positions) and a high mass Faraday detector; (2) A Thermo-Fischer Helix MC Oxidative weathering in the Late high-resolution noble gas mass-spectrometer Neoproterozoic: Preliminary Cr (commissioned spring 2016), equipped with 5 Isotope results from the Urucum dual faraday/ion counting detectors with 1012 and 1013 ohm amplifiers for improved (signal to District, Brazil noise ratio) of argon isotopes. The Helix has a 120 Trygvi Bech Árting1 and Robert Frei2 degrees magnet with a standard resolution of 1University of Copenhagen, Øster Voldgade 10, 1350 900, allowing full resolution of hydrocarbon Copenhagen K, Denmark, 2University of Copenhagen, isobars in the Ar mass range 36 to 40. The high- Øster Voldgade 10, 1350 Copenhagen K, Denmark resolution mode on channel L2 has a resolution of 1700 allowing psudeoresolution of the HCl isobar from 36Ar. Three independent laser-sample gas The Fe and Mn deposits in the Urucum district preparation systems supply the 2 mass- (Banda Alta Fm.) in Mato Grosso do Sul, Brazil, spectrometers, with one preparation system which are associated with glaciogenic deposits, designed and dedicated specifically for are among the youngest and largest Cryogenian cosmogenic nuclide exposure dating (3He, 21Ne) sedimentary Fe and Mn formations (IF, MnF). The applications. This system is equipped with a Janis Urucum IF comprise plane-parallel, stratified closed cycle cold trap system (CCSTRAP- hematite-chert iron with interspersed HT/204N) to 7K for sequential release and manganese micro- and mesobands. A lower age

78 measurement of the different noble gases. We are are also currently working on projects related to mainly applying these tools to Quaternary meteorites and impact structures. problems, such as hominin evolution and the relationship between volcanism and climate. We

79 2. Metamorphic rocks and processes 2.1. Geodynamic and geological were arrested in fault-bounded half-grabens at Kvalpynten, while bypass and erosion is apparent evolution of the Arctic towards the East. Accretion during a subsequent transgression documents continued high sedimentary input during relative sea-level rise. ORAL Paleocurrent and shaling out attest to local influx from an E/NE source around Kvalpynten, while at When a platform-edge meets a Svartpynten the regional NW trend is apparent. platform: 3D sedimentary Svartpynten reveals a more shore-line proximal architecture of a large-scale location, and following transgression, tidal bars prograding paralic system, SW indicate proximity to the fluvial source. At Edgeøya, Svalbard Kvalpynten laterally extensive subtidal sand- sheets grade into distinctly flat-based lens- Ingrid Anell1, Daniela Röhnert1, Alvar Braathen1, shaped sand-bodies, likely shoaling barrier Kei Ogata2, Per Terje Osmundsen3, Aleksandra sands. A variety of channel-fills is documented in Smyrak-Sikora4, Harmon Maher5, Snorre the overlying succession, which consists Olaussen4, Gareth Lord6, Ivar Midtkandal1, Mark predominately of highly bioturbated sheltered Mulrooney1 and Simon Buckley7 intertidal mud-flats grading and interfingering 1Department of Geosciences, University in Oslo, Norway, with vegetated coastal plain. 2Vrije University, Amsterdam, Holland, 3Geological Survey of Norway, Trondheim, Norway, 4Department of Arctic Geology, University Centre in Svalbard, Norway, 5University of Nebraska at Omaha, USA, 6Tyr ORAL Exploration AS, Trondheim, Norway, 7Uni Research AS, Bergen, Norway Late Triassic sandstone provenance of the Barents Shelf; a regional

The study combines facies analysis from comparison of preliminary detrital sedimentary logs with pseudo 3D zircon geochronological and photogrammetric observations to provide a petrographic data large-scale regional understanding of the Carnian depositional development around SW Edgeøya, Trond S. Harstad1, Mai Britt E. Mørk1 and Trond which was filled by strongly tidally influenced Slagstad2 deltaic systems. Prism-scale NW advancing 1Norwegian University of Science and Technology (NTNU), 2Geological Survey of Norway (NGU) Triassic clinoforms are documented in seismic data on the northern Barents Shelf. The sigmoidal clinoforms progressively form low-angle, linear Several scientific contributions have been tabular geometries, as the prograding system published in the last years on Triassic sandstone approaches Edgeøya. The studied succession provenance in the Barents Shelf and Arctic areas. documents very low angle infill from deep basin A southern or eastern Uralide component is well to coastal plain reflecting the advance of the established in parts of the Triassic, in particular clinoform system across the high. The study in south-eastern areas of the shelf. More recently, provides understanding of how the scale of the possible sediment contributions from a possible system, sandbody geometry and sedimentary northern Uralide source area in the Late Triassic processes were affected by more limited has been discussed. In our study, we aim to accommodation and increased tidal reworking. identify and compare sandstone provenance signatures in selected locations of the Upper The studied succession documents an early base- Triassic De Geerdalen and Snadd formations in a level fall during which large amounts of sand north - south transect from Svalbard to the

80 Nordkapp Basin. Petrographic observations metamorphic reaction to a unique fingerprint for reveal lithic and feldspathic sandstone these minerals. The Fiskenæsset complex in compositions, notably with plagioclase Greenland is used as an area of case study. dominating over K-feldspar, and characterised by Isochemical pressure-temperature sections were lithic fragments of volcanic, metasedimentary calculated based on electron microprobe and and sedimentary origin. The polycrystalline whole-rock geochemistry analyses, and quartz content represents deformed quartzite as compared to field observations. Rubies were well as chert and spiculites. Chromium spinel, formed resulting from a reaction between apatite, garnet, rutile, tourmaline and zircon olivine/serpentine and anorthite, triggered by heavy minerals are observed in varying the intrusion of a pegmatite. Al is sourced from abundance. Preliminary detrital zircon age the anorthite, the pegmatite reacts to spectra from Svalbard, are similar to published anthophyllite, Cr3+ is mobile in the pegmatitic zircon spectra of the larger Arctic region, fluid, giving colour to the rubies. The ruby- including Triassic peaks of nearly syn- forming reaction occurs at 640 °C and 7 kbar. In depositional ages. A dominance of Permian to order to establish the unique fingerprint for this Carboniferous zircons is compatible with an ruby-bearing ultramafic complex, laser-ablation earlier inferred Uralide provenance to the east. inductively-coupled-plasma mass-spectrometry However, a significant Caledonian age trace element measurements, oxygen isotope component has also been identified, which compositions, optical microscopy and scanning suggests a possible contribution from western electron microscopy were applied. Due to the areas. Currently, petrographic analysis of central setting in an ultramafic rock-anorthosite- and southern areas of the transect will be leucogabbro complex, the fingerprint of the compared with results in progress from ongoing rubies from the Fiskenæsset complex is rather zircon analysis, and current regional geological unique. Fiskenæsset complex rubies contain high knowledge, for better constraining alternative Cr, intermediate Fe, and low V, Ga, and Ti source area signatures. concentrations, low oxygen isotope values (1.6 to 4.2 ‰) and a rarely-observed combination of optical growth features and mineral inclusions like anthophyllite+biotite. Results for other ORAL Greenlandic localities are presented and Formation and Origin determination discussed as well. Even though these are derived from ultramafic rock settings too, they record by geochemical fingerprinting of ruby different trace element ratios and oxygen isotope and pink sapphire from the values, resulting from variations in the ruby- Fiskenæsset complex, Greenland forming reaction.

Nynke Keulen1, Tonny B. Thomsen1, John C. Schumacher2, Majken D. Poulsen3, Per Kalvig1, Torsten Vennemann4 and Rita Salimi1 ORAL 1Geological Survey of Denmark and Greenland (GEUS), Denmark, 2Department of Geology, Portland State Norsk Polar Navigasjon’s archive of University, Portland, 3Geological Survey of Denmark old exploratory wells on Svalbard and Greenland (GEUS), Denmark & Greenland, 4Institute of Earth Surface Dynamics, University of Kirsti Midttømme1 Lausanne, Géopolis, Switzerland 1Christian Michelsen Research AS

Metamorphic petrology observations on rubies During a 30 year period from the 1960's to 1990's found in-situ in their host-rock are combined several deep exploratory wells for oil drilled on with geochemical measurements and optical Svalbard . The deepest well at Ishøgda was microscopy observations on the same rubies, 3304m deep. Norsk Polar Navigasjon (NPN), the with the aim to connect the ruby-forming

81 first Norwegian oil company, was involved in structures can be generated and account for the nine of the drillings. NPNs archive with following first order observations: i) curvature in information from the drillings has been made the fossil ridge, ii) transcurrent margins of available for this study. opposite motion, and ii)asymmetry of the basin. These results elucidate the consequences Though oil or gas was detected in the wells at of sea-floor spreading in the Amerasia Basin and Ishøgda, Tromsøbreen and Sarstangen, all wells help to constrain opening scenarios. was plugged and abandoned.

Geological and geophysical information from the wells are limited, but there are interested ORAL information of borehole stratigraphy, gas hydrates and geothermal gradients that will be Tectonostratigraphic atlases: further presented and discussed perspective in Arctic research

Oleg Petrov1, Sergey Shokalsky1, Nikolay Sobolev1, Sergey Kashubin1, Eugeny Petrov1, Denis Leontiev1 ORAL and Tatiana Tolmacheva1 1Russian Geological Research Institute (VSEGEI) DEVELOPMENT OF THE AMERASIA

BASIN: WHERE ARE WE NOW? Intensive study in the Arctic during last 15 years Victoria Pease1, Hemin Koyi2 and Faramarz has resulted in the accumulation of new data on Nilfouroushan3 the geology of the region, including those 1Stockhkolm University, 2Uppsala University, obtained during geophysical sounding of the 3University of Gävle ocean floor, examination of bottom rock material,

studying geology of islands and the continental The Amerasia Basin is separated into the Canada part of the Russian Arctic. One of the Basin and the Makarov-Povodnikov basins by the international projects is the Atlas of Geological Alpha-Mendeleev Ridges. Published data Maps of the Circumpolar Arctic at a scale of supports a conjugate relationship between the 1:5,000,000, which includes geological and Alaskan and Canadian Arctic margins, in which tectonic maps, potential field maps, and mineral counterclockwise rotation of Arctic Alaska from resources map. Modern level of knowledge of the Arctic Canada resulted in the opening of the Arctic allows the analysis of tectonostratigraphy Canada Basin. Thus the tectonic development of and litho-geodynamics of the region and the Canada Basin is ‘broadly’ understood, interpretation of geological complexes in terms of although the precise timing and the role of the tectonic settings of stratigraphic sequences Chukchi Plateau remain disputed. This leaves the formation based. The Atlas “Geological History of Amerasia Basin and we identify two significant the Barents Sea” (2009) by Russia and Norway barriers to understanding its tectonic was first experience in the implementation of this development: i) The northward extent of the work. Canada Basin fossil spreading ridge, and ii) the In 2014, geological surveys of the Arctic states role of LIP magmatism. In assessing the former, complied the “Tectonostratigraphic Atlas of the we simulated extension in a series of two-plate North-East Atlantic region”. Currently, the analogue models with properties homologous of Russian Geological Research Institute (VSEGEI) homogeneous continental crust around a actively works on compilation of the common rotation axis. In all models, a triangular “Tectonostratigraphic Atlas”, covering the (ocean) basin forms between the two ‘diverging’ eastern Russian Arctic continental part and plates, however, depending on the mode of eastern Eurasian basin. opening and initial plate configuration transpressive, transtensive, and ‘pure’ strike-slip

82 Compilation of the Atlas as a set of systematic )sedimentary successions, possibly a hint for a modern geological information is of great northern microcontinent. High velocity lower importance for understanding the geology and crust may be related to igneous activity during history of tectonic development of this several rift episodes and/or impact by High Arctic insufficiently studied region. Large Igneous Province magmatism. A correlation appears to exist between topography, Together with the NPD and the NGU, we are going Moho depth and the location of dykes in Nansen to compile the Tectonostratigraphic atlas for the Sound suggesting the same tectono-magmatic Barents-Kara region. The work at origin of these features. Lincoln Sea shows Tectonostratigraphic atlases is a new stage in the consistently thin crust likely related to rifting. development of the international cooperation in the Arctic.

POSTER

ORAL Details on the Cretaceous ocean formation in the High Arctic based on Crustal structure of the Eurekan satellite gravity data Orogen on Ellesmere Island, Arctic Canada Arne Døssing1, Carmen Gaina2, Ole Baltazar Andersen1 and H. Ruth. Jackson3 1 2 Christian Schiffer and Randell Stephenson 1DTU Space, Denmark, 2CEED, University of Oslo, 3(4) 1Department of Earth Science, Durham University, Geological Survey of Canada Atlantic, Dartmouth, Nova 2School of Geosciences, University of Aberdeen Scotia

Receiver function analysis of new broadband- Understanding the evolution of ocean basins, seismological data provides images of crustal critical for global studies in plate tectonics, structure along an approx. 500 km long transect mantle dynamics, and sea-level through time, across Ellesmere Island. The gravity response of relies on identifiable tectonic plate boundaries. this crustal transect is consistent with regional Based on the latest generation of global satellite gravity anomalies. The new data are, gravity models, recent marine geophysical data furthermore, integrated with existing crustal and vintage aeromagnetic data, we document information to produce regional maps. Distinct consistent tectonic details on the remote and ill- crustal features are identified, such as crustal defined Canada Basin spreading system: the thickness variations, the presence of high oldest ocean system in the High Arctic and part of velocity/density lower crust, thick the long-disputed greater Amerasia Basin. We metasedimentary layers as well as shallow interpret two distinct phases of possibly younger sedimentary successions. Cretaceous sea-floor spreading: the early stage being sub-orthogonal and intermediate- Moho depths can be interpreted in terms of spreading (~50 mm/yr) of possible Barremian- Eurekan (Cenozoic) and Ellesmerian (Palaeozoic) Aptian age, while the late stage being highly deformation. A zone of thick metasedmentary oblique, segmented, and slow-spreading (20–40 layers in central Ellesmere Island correlates with mm/yr) of possible Aptian age. We further areas of dominantly Ellesmerian accretion. A demonstrate that the southern part of the Canada WSW-ENE orientated zone of shallow Moho Basin spreading system may serve as an ancient (Hazen Stable Block) underlies crust strongly analogue of modern mid-ocean ridge propagation deformed in the Palaeozoic but essentially into continental crust. undeformed in the Cenozoic. A block of thick crystalline crust in the north of Ellesmere Island is clearly separated from the North American- Greenland Craton by the deep (meta-

83 POSTER information will narrow down the area with good soapstone occurrences considerably, such that Soapstone from Nuuk: fingerprinting citizens wanting to investigate for undiscovered the origin and geological history of localities with good quality soapstone will know soapstone (steatite) suitable for to which part of the Godthåbsfjord-Ameralik carving in the Godthåbsfjord- region their investigations for new small-scale mining areas should be directed. Ameralik region (southern West- Greenland).

Nynke Keulen1, Majken D. Poulsen2, Robert Frei3, POSTER Kisser Thorsøe4 and Rebekka J. Knudsen5 1Geological Survey of Denmark and Greenland (GEUS), A large Devonian ultra-high-pressure Nuuk GLD & Copenhagen, DK, 2Geological Survey of province in northeastern Greenland Denmark and Greenland (GEUS) Nuuk, GLD & Dept of Geosciences Nat.Res., KU, DK, 3Department of Thorsten Nagel1, Kathrin Fassmer2, Nikolaus Geosciences and Natural Resource Management, Froitzheim2, Peter Sprung3 and Carsten Münker3 4 Copenhagen University, Denmark, Geological Survey of 1Department of geoscience, Aarhus, Denmark, 5 Denmark and Greenland (GEUS) Nuuk, GLD, Greenland 2Steinmann-Institut, Bonn University, Germany, Perspective, Natural History Museum of Denmark, 3Department for Geology and Mineralogy, Cologne Copenhagen University, DK University, Germany

Soapstone was mined and traded by the Saqqaq, The Caledonian orogen in northeastern Dorset, Norse, and Morovian cultures living in Greenland consists of a 1200 km long, west- Greenland through time, and still has a good vergent nappe pile. It has traditionally been potential for small-scale mining as a raw material viewed as the retro-wedge of the Scandinavian for carving of art products and for the tourist Caledonides. This concept, however, was industry. We collected soapstone from outcrops challenged by the finding of widely distributed around Nuuk, which hold Greenland’s best eclogites as well as the large amount of horizontal quality of soapstone, and analysed their whole- shortening accommodated in the nappe pile. rock geochemistry, Sm-Nd and Rb-Sr isotopes for Existing U-Pb-zircon- and Sm-Nd-garnet ages for fingerprinting for geological and archaeological high-pressure metamorphism in the central purposes, such that historic artefacts that were section of the Greenlandic Caledonides scatter traded far away from Nuuk through time, might around 420 to 390 Ma. A single UHP- be traced back to the Nuuk area. Fieldwork in the metamorphic location in a structurally internal Nuuk area showed that the quality of the position yielded an exceptionally young zircon soapstone in the Godthåbsfjord-Ameralik region age of 360 ±5 Ma and a Sm-Nd-garnet age of actually varies widely; however, a correlation around 330 Ma interpreted to record peak- exists with the age and/or the metamorphic pressure conditions and cooling, respectively history of the rocks. The best quality soapstone (Gilotti et al. 2004). We present new petrologic occurs in a broad band cutting through the fjords and Lu-Hf garnet age data from three locations. in the Nuuk area. This area roughly covers the Samples from Danmarkshavn record ultra-high- area with occurrence of Eo-Archaean gneisses. pressure metamorphic conditions in eclogites However, the same area was also subject to and grt-pyroxenites by means of SiO2-exsolutions intense metasomatism of the soapstone in cpx, opx-exsolutions in cpx and precursor-rocks associated with fluid activity thermobarometric estimations. An eclogite along the Ivinnguit fault zone. Further work will yielded a Lu-Hf garnet-whole-rock age of 357.5 be directed to investigate which of those ±2.9 Ma thus confirming the existing zircon age processes played the major role. Expectedly, one for UHP metamorphism obtained 140 kilometers or both factors will provide a good fingerprint of to the north. Samples from two other locations the Nuuk soapstone. Additionally, this preserve the typical high-temperature-

84 moderate-pressure eclogite-facies conditions of 53-76 and 51-69 mW/m2 respectively. When and yield ages of 383 ± 17 Ma and 398 ± 14 Ma, considering the potential enhanced surface heat respectively. Results suggest that besides the 400 flux from radiogenic heat production in the crust, Ma event, Devonian ultrahigh-pressure rocks in these variable measurements are broadly in line northeastern Greenland may be much wider with predictions from uniform extension models distributed than previously known creating for continental crust. An upper mantle seismic major puzzles for tectonic reconstructions. anomaly in the vicinity of the North Pole might therefore have a compositional as well as thermal component. This complexity highlights the difficult in disentangling temporally and spatially POSTER evolving crustal, lithospheric and mantle New heat flow measurements from processes to present-day surface heat flow contributions. central Arctic Ocean

Grace Shephard1, Steffen Wiers2, Evgenia Bazhenova3, Lara Pérez4, Luz María Mejía5, Carina Johansson6, Martin Jakobsson6 and Matt O'Regan6 1Centre for Earth Evolution and Dynamics (CEED), University of Oslo, 2Department of Earth Sciences, Uppsala University, 3Center for Coastal and Ocean Mapping, University of New Hampshire // St Petersburg State University, 4Department of Geophysics, Geological Survey of Denmark and Greenland (GEUS), 5Geological Institute, Department of Earth Sciences, ETH, Zürich, 6Department of Geological Sciences, Stockholm University

Constraining the thermal evolution of the Arctic Ocean is hampered by notably sparse measurements of heat flow. Furthermore, previous results from the central Lomonosov Ridge and the adjacent central Amundsen Basin reveal variable magnitudes, including those higher than expected considering plate cooling or simple uniform stretching models. Here we present new heat flow results gathered from 17 sediment cores acquired during the “Arctic Ocean 2016” and “SWERUS-C3” expeditions on the Swedish icebreaker Oden. Three sites located in the Amundsen Basin reveal heat flow in the order of 71-95 mW/m2, in line-with or slightly higher (1-21 mW/m2) than expected from oceanic heat flow curves. These values are substantially lower than values of another study, with 104-127 mW/m2 found on similarly aged oceanic crust in the Amundsen Basin located approximately 100- 200 km away. Sites from the submerged continental fragments of the Lomonosov Ridge and Marvin Spur recovered heat flow in the order

85 2.2. Deformation original crystal lattice. De-polymerization starts along dislocation cores in the crystal lattice that and metamorphism of rocks: serve as element exchange pathways and are also Microstructures, processes, and sites of porosity formation. In our samples, the physical properties amorphous material resulting from this de- polymerization occupies large volumes in a syn- metamorphic interconnected porosity network. The direct transformation of the mineral into the ORAL amorphous state enables element transfer A novel gel-mediated reaction decoupled from the presence of ionic solutions. mechanism in metamorphic rocks Precipitation of secondary amphibole occurs directly by re-polymerization of the amorphous Matthias Konrad-Schmolke1, Ralf Halama2, material at the product surface. Richard Wirth3, Nico Klitscher3, Luiz Morales4 and

Franziska Wilke3 1Earth Science Department, University of Gothenburg, ORAL Sweden, 2School of Geography, Geology and the Environment, Keele University, UK, Connection between grain shape, 3GeoForschungsZentrum Potsdam, GFZ, Potsdam, Germany, 4ETH Zürich, Switzerland chemical zonation and texture as indicator for fabric development in eclogites Fluid-mediated mineral dissolution and re- precipitation is a key mechanism for mineral Kai Neufeld1, Holger Stünitz2, Ane Kongsro reactions in different fields of Earth and Material Finstad1 and Jiri Konopásek1 Science. Mineral reactions in the solid Earth 1Department of Geosciences, University of Tromsø, constrain many geodynamic and geochemical Norway, 2Department of Geosciences, University of processes, such as density changes in subducted Tromsø, Norway; Institut de Sciences de la Terre, oceanic crust, the release of carbon dioxide in Universit subduction zones and the precipitation of ore minerals from percolating fluids. Detailed knowledge about rate-limiting mechanisms Eclogites are the most important piece of during such mineral reactions is fundamental for evidence of high pressure conditions in the quantification of rock transformations and subduction zones. Their fabric development is an the associated element transport. Unresolved interesting topic and may allow to determine the questions regarding fluid-mediated mineral deformation rates in subduction zones. Most dissolution and re-precipitation are the previous studies suggested dislocation creep to formation of permeability and the quantification be the principal process causing the fabric of the element transport during mineral development, because many eclogite fabrics are transformation. Here we present examples where quite strong. The viability of this may be tested by the entire cycle of mineral dissolution, element studying the chemical zonation of garnet and transport and re-precipitation of new omphacite in order to track and quantify texture equilibrium phases is visualized in high-pressure and microstructure development in eclogites. metamorphic rocks that experienced re- The aim of this study is to assess the influence of hydration in a subduction zone. The replacement crystal growth on mineral preferred orientation of primary amphibole and pyroxene in our and therefore its role in fabric development in samples occurs via coupled dissolution-re- eclogite-facies rocks. precipitation that involves the formation of an Variscan and Alpine eclogites from two different amorphous alkali-Al-Si-rich material. This locations have been studied. In both cases, amorphous material forms directly from the asymmetric but still concentric chemical zoning reacting minerals by de-polymerization of the developed during prograde garnet growth

86 together with elongated garnet grain shape and Recent studies of deformation-enhanced can be related to a corresponding prograde (in reactions en route to eclogite-facies conditions terms of pressure change) chemical zoning in within sheared gabbro have demonstrated omphacite grains. Crystal plastic deformation of progressive destruction of plagioclase in reaction garnet can be excluded based on chemical with pyroxene and oxides and growth of garnet, zonation patterns. Chemical, microstructural and to superplastic behavior in garnet by grain- texture data indicate a direct relationship boundary sliding. Plausibly, during this, between the growth of garnet and omphacite rheological differences between deforming grains in the principal stretching direction, gabbro and gneisses were minimal. Thus, gabbro- causing a strong fabric development during gneiss contacts are most commonly decorated by prograde and peak metamorphic conditions. No 1-10m thick layers of strongly foliated, fine- dynamic recrystallization microstructures were grained garnet-rich eclogite, and nearby small detected. Thus, the textures are interpreted as eclogite bodies are usually similar in texture and growth fabrics. Dislocation creep as a possible composition. fabric formation process is excluded. Instead, diffusion creep (grain scale precipitation These observations suggest that the gneisses may producing elongation in the stretching direction) not have partially melted during HP-UHP is concluded to be the dominant deformation conditions, but rather by fluid-absent partial mechanism. melting of micas during exhumation to <2 GPa. The resulting changed ductility contrast between mafic and felsic rocks produced myriad gabbro and eclogite boudins that characterize the region, ORAL allowing access to aqueous fluids facilitating growth of secondary hornblende. Contacts of Shear deformation in the some gabbros show various processes: Some transformation of gabbro to eclogite: contacts decorated by fine-grained foliated Potential key to rheological contrasts eclogite, locally retrograded to foliated garnet in the change from HP/UHP amphibolite. Other contacts with little eclogitized conditions to later amphibolite-facies gabbro, directly sheared against gneiss at a late stage, but converted locally by infiltrating fluid to deformation isotropic hornblende gabbro.

Peter Robinson1, Michael P. Terry2 and Florian

Heidelbach3 1Geological Survey of Norway (NGU) N-7491 ORAL Trondheim, Norway, 2PO Box 553, Naples, NY 14512, USA, 3Bayerisches Geoinstut, Universität Bayreuth, Record of a Lower Crustal Fossil D95440 Bayreuth, Germany Earthquake Initiated by CO2 Flux and

Reaction-driven Strain Softening The Proterozoic ~1700-1550 Ma Baltican basement of the northern Western Gneiss Region, Bjørn Eske Sørensen1, Thomas Grant1 and Rune Norway, consists of coarse granitoid gneisses Larsen1 locally intruded by 1466 and 1250 Ma gabbros. 1Department of Earth Science and Petroleum, NTNU, Norway Progressive relative rheological behavior of this diverse assemblage during Scandian (420-375 Ma) subduction to HP/UHP metamorphic The ultramafic rocks of the Reinfjord intrusion in conditions (2.5-4 GPa) and exhumation back to the Seiland Igneous Province is cut locally by near-surface conditions, is key to understanding narrow (mm-cm) thick extensional shearzones, tectonic development through multiple phases of containing extremely fine-grained material with thrusting, recumbent folding, and extension. a distinct shape-preferred orientation. These shearzones offset dykes across numerous micro-

87 faults are documented in areas close to the major with water (i.e. eclogitization, serpentinization). fault zone cutting through the area. Within the In these systems, the transformation may induce shearzones olivine and clinopyroxene reacts to density variations which generate stresses form orthopyroxene and dolomite at controlled by the rock confinement, also called approximately 7-11 kb and 750-850 degrees force of crystallization. Here, we study a Celsius according to the reaction: retrograde metamorphic reaction model, the hydration of periclase, MgO, into brucite, Olivine + Clinopyroxene + CO2 = Dolomite + Mg(OH)2, to quantify the coupling between Orthopyroxene reaction, stress generation, porosity evolution and fracturing. Samples of a microporous MgO As evidenced by coronas of orthopyroxene and ceramic were reacted at 170-210°C, 5-80 MPa dolomite between olivine and clinopyroxene and confining pressure, 6-95 MPa differential stress by large olivine grains proximal to the shearzones and 5 MPa pore fluid pressure. Three- displaying a microstructure with subgrain walls dimensional X-ray microtomography images decorated by rounded grains of dolomite and were acquired in situ every five minutes during more irregular and elongated grains of the reaction. Results imply that below 30 MPa orthopyroxene. With clinopyroxene at least mean pressure, the hydration reaction coupled hundreds of microns away this suggested at least with the MgO ceramics fracturing. The some material transport within the shearzone. transformation rate followed a sigmoidal kinetics The shearzones thus gives a unique view into curve with a slow initiation, a fast reaction

CO2-Metasomatism of the lower crust. Moreover coupled to fracturing and the generation of a the shearzones provide a unique insight into the transient porosity pulse, and a slow-down until interplay between CO2-metasomatism and an almost complete transformation of periclase reaction accommodated strain softening. This is into brucite. Conversely, above 30 MPa, the also confirmed by fractures extending into large reaction kinetics was slower and following the olivine grains proximal to the shearzones. The commonly admitted reaction curve but without

CO2 cracking and mineral reaction also serves to fracturing. Considering the driving force of the reduce grain-size , making grain-boundary hydration reaction, stress generation should be sliding an efficient process, further enhancing the several hundreds MPa, whereas the present rheological contrast between the shearzone and experiments show that fracturing occurs only the host rock. The sudden decrease in rock below 30 MPa. One interpretation is that the strength lead to sudden fast deformation and we stress created by the reaction may overcome the suggest a relation to pseudotachylites and hence disjoining pressure at the grain-grain interface, also earth quakes in near proximity of the micro- expelling the water film trapped there and shearzones. reducing dramatically the kinetics of reaction.

ORAL

The effects of confinement on reaction-induced fracturing during an hydration reaction

Xiaojiao Zheng1 1University of Oslo

Several geological processes involve mineral transformations where nominally dry rocks transform into hydrated ones when left in contact

88 POSTER constrain the fluid source which is thought to be either magmatic or meteoric. Late magmatic-hydrothermal alteration and deformation of ultramafic rocks and dikes from the Reinfjord Ultramafic Complex

Frederik Valentin Reinhard1, Bjørn Eske Sørensen2, Thomas Wagner1 and Rune Berg- Edland Larsen2 1RWTH Aachen University, 2NTNU Trondheim

This study concerns hydrothermal alteration of ultramafic rocks comprised by dunites and subordinate wehrlite and dykes of ultramafic to mafic and lamprophyric composition in the the Reinfjord Ultramafic Complex the Seiland Igneous Province, northern Norway. The dikes and host ultramfic rocks went through three main alteration stages:

Alt1. Microfaults with orthopyroxene, dolomite and olivine. Alt2. Yellowish magnesite-tremolite- talc alterations, comprised by central thin magnesite veins (orientation 55/110) surrounded by thicker metasomatic sides of tremolite and magnesite and then a thin talc rim towards the host ultramafic host. When intersecting the more pyroxenitic dykes the alteration gives a blueish green color. Alt3 Late serpentinisation intersecting all other structures.The study focuses on alteration type 2. The usually less than cm wide magnesite-bearing veins are surrounded by up to dm wide metasomatic sides. The weathered surface of the veins form massive, creamy yellow to rust red colored magnesite bearing mineral assemblages. The metasomatic sides stand out with a more yellow color than the weathered host rock and is comprised by a magnesite and tremolite bearing assemblage, rimmed by a mm-thin talc rim towards the host rock. Furthermore the veins also crosscut the different generations of dykes, resulting in different alteration assemblages.

The aim of the study is to use different alteration assemblages to constrain PTX-fluid conditions and determine ore remobilization. Furthermore stable isotope data of O, H, S, and C will be used to

89 3. Sedimentary rocks and processes 3.1. Sedimentology posters POSTER Topographic Development as a result

POSTER of regional incision, faulting, and deposition at the onset of relative Early mid-Devonian volcanism dates sea-level rise; The upper Entrada initiation of the Orcadian basin in the Sandstone and the lower Curtis Orkney Islands, Scotland Formation, Utah, USA.

Lars Eivind Augland1, Anders Mattias Lundmark2, Sigrid Østmo da Costa1, Nikoline Bromander1, John F. Brown and Audun D. Bjerga Valentin Zuchuat1, Alvar Braathen1, Anja Sundal1 1CEED, University of Oslo, 2Department of Geosciences, and Ivar Midtkandal1 University of Oslo 1University of Oslo

Early mid-Devonian sedimentary rocks forming A 43 km North-south section on the North- the Orcadian basin constitute large parts of the Eastern margin of the San Rafaell Swell has been exposed geology on the Orkney Islands. The studied, focusing on the Upper Jurassic eolian lower sedimentary pile rest unconformably on Entrada Sandstone, the J-3 regional foliated granites of the ca. 430 Ma Orkney granite Unconformity, and the overlying Curtis complex and marks the onset of Lake Orcadia in Formation of Oxfordian age. Emphasis is on the the Orkney Islands with deposition of the lower distribution of sedimentary facies in direct Stromness flagstones (LSF), comprising contact with the unconformity, and those affected alternating lacustrine strata of fine grained by erosional topography during deposition. sandstones and shales. In the lower part of the Stromness flagstone sequence we have identified The J-3 Unconformity displays at least 3 and dated, using zircon U-Pb ID-TIMS, a rhyolite generations of erosive incision, possibly 6. The dome or flow that constrain the age of the LSF and composite unconformity has been subaerially essentially the onset of Lake Orcadia to ca. 390 eroded by eolian and fluvial action, besides tidal Ma. This new age combined with recent denudation postdating the onset of regional cyclostratigraphic results provide an improved deposition. Present-day erosional relief, estimate for the Efelian-Givetian boundary and magnitude, and wavelength contribute to multi- the Kačák event marked by the top of the phase erosional processes resulting in Achanarras level (Sandwick Fish Bed) inconsistent erosional patterns, and distribution constituting the top of the LSF. The rhyolite of sedimentary facies above and below the magmatism on Orkney is overlapping in age with unconformity. Tectonic activity has influenced intrusive rocks on Shetland and we suggest that the development concerning substratum this magmatism is related to an episode of fluidisation and brittle deformation. important displacements on the Great Glen Fault. Generations of J-3s erosive incision varies regionally and locally across the section. A series of 5-10 m deep channel-like scours linked to a stratigraphic level several meters above the J3 Unconformity, erode to a deeper stratigraphic

level than J3s original level. Intra-formational faults in Entrada Sandstone suggest contribution to focused erosion at the Entrada-Curtis boundary.

90 Similarly, erosive lower boundaries of tidal yellowish concretions or cemented intervals sandstone bodies in direct contact with J3 suggest proved to be pyrite, altered to different alteration that repeated relative sea-level changes lead to products (e.g. jarosite, szomolnokite). The deeper stratigraphic erosion of the J3 mineral distribution at the microscopic scale can Unconformity. easily be shown by applying the Mineralogic software of the SEM. Altogether, investigations at The on-going investigation will improve a smaller scale can therefore explain the constraints on how reservoir-quality sandstone appearance of sandstones at the outcrop scale, volumes are affected by erosional topography in and this appearance is largely depending on the tidal environments, by determining type and abundance of the cementing phases. distributional factors. Distinguishing between local and regional variability is a target, to filtrate basin-specific anomalies.

POSTER

Recognizing sandstone diagenesis from outcrop to microscopic scale

Rikke Weibel1, Nynke Keulen2, Mette Olivarius2 and Margrethe Thorup Nielsen2 1GEUS (Geological Survey of Denmark and Greenland), 2GEUS

Sandstone diagenesis is visible on many scales, ranging from the microscopic scale to the outcrop scale. Traditionally, diagenetic features are investigated by optical microscopy on core and outcrop samples. Extending the investigations to micron scales may help to define a set of features, which might be recognized in the field and hence useful for future field campaigns. The mineralogy and petrography of the sandstones are evaluated from thin sections by transmitted and reflected light microscopy, and from carbon-coated thin sections and gold- or platinum-coated rock chips by scanning electron microscopy (SEM), applying GEUS’ Zeiss Sigma 300VP field emission SEM, besides X-ray diffraction of bulk rock samples. Among the studied sandstone types, ‘rusty’ sandstones proved to be siderite-cemented where the siderite had partly altered to iron- oxide/hydroxides during diagenesis. Sandstone boulders or cliffs were intensively calcite- cemented, though with calcite of smaller/larger crystal sizes and different morphologies. Spectacular reddish and purple colored sandstones contained opal cement, which enclosed iron-oxides/hydroxides. Bluish or

91 3.2. Depositional basins

ORAL

ORAL Flint in the Danian København Triassic of the Wandel Sea Basin, Limestone Formation North Greenland Jens Galsgaard1 1Rambøll 1 1 1 Morten Bjerager , Peter Alsen , Jussi Hovikoski and Sofie Lindström1 1GEUS The Danian age København Limestone Formation was examined in 219 cored boreholes drilled in connection with the “Cityringen” metro project in In Triassic times the Wandel Sea Basin formed central Copenhagen. Shape and colour of flint the western continuation of the basins in the bodies were described during macroscopic visual southern part of the Barents Sea and the northern inspection of core samples, as well as from digital continuation of the Danmarkshavn Basin offshore core photos, and four diagnostic flint types were Northeast Greenland. The results of recent GEUS identified in the limestone. They are 1) grey flint fieldwork campaign in the area show that the bands, 2) light grey flint bars, 3) irregular flint exposed Triassic of North Greenland spans a near bodies, and 4) dark grey flint blots. The well- complete Induan (Dienerian) – Norian known informal tripartition of the København succession, up to 700 m thick. The succession Limestone Formation into the upper regularly rests unconformably on Upper Permian bedded, the middle nodule-rich and the lower sediments and it is unconformably overlain by laminated unit (Stenestad 1976, Knudsen et al. Upper Jurassic – Lower Cretaceous deposits. 1995, Klitten et al. 1995, Olsen & Nielsen 2002) is largely supported by the distribution of the four The Lower Triassic (Dienerian, Induan) consists flint types: Type 1 dominates the upper unit, Type of marine sandstones, fluvial conglomerates and 2 dominates the middle unit, while Type 4 is the sandstones, and muddy flood-plain deposits. It is only type found in the lower unit. Types 1, 2 and conformably overlain by the Lower Triassic 3 all occur to some extent in both the upper and (Smithian – lower Spathian) offshore mudstones middle unit. Type 4 is also characteristic of the with minor sand-dominated intervals. The upper underlying Bryozoan Limestone, making it Spathian to Ladinian is represented mainly by difficult in core samples to determine the shallow marine sandstones in the western boundary between København Limestone and proximal part and laminated mudstones with Bryozoan Limestone. minor thin sandstone units that were deposited in slope and deep basinal settings in the eastern The conspicuous changes in shape and colour of deeper part of the Wandel Sea Basin. A marked flint bodies up through the København Limestone erosional unconformity characterises the base of Formation seem to indicate that the flint bodies the overlying Upper Triassic (Carnian – Norian) display different stages of flint formation and that of marine massive sandstones, conglomerates as this limestone may conceal narratives yet to be well as cross-bedded and biomottled marine told about flint formation and depositional sandstones and minor mudstone units. The environment. Triassic succession of the Wandel Sea Basin represents a well-constrained basin margin to deep basin transect and thus forms an excellent outcrop analogue to the time equivalent intervals in the western Barents Sea basins and the

Danmarkshavn Basin offshore North-East Greenland.

92 ORAL suggests that hyperpycnal flows are capable of delivering sand onto the basin floor. Evidence of hyperpycnally fed turbidites in a basin floor setting,

Eocene of Spitsbergen, Arctic Norway ORAL

Sten-Andreas Grundvåg1 and William Helland- Stratigraphic treasures of an “ugly Hansen2 duckling”: towards an integrated 1Department of Geosciences, UiT–the Arctic University of Norway, 2Department of Earth Sciences, University of basin model of the Lower Cretaceous Bergen Rurikfjellet Formation, Arctic Svalbard The Eocene of Spitsbergen, Svalbard, has Mads E. Jelby1, Sten-Andreas Grundvåg2, Peter received considerable attention in the literature Alsen3, Kasia K. Śliwińska3, Lars Stemmerik1, because of its spectacular seismic-scale William Helland-Hansen4 and Snorre Olaussen5 clinoforms exposed along many fiords and 1Natural History Museum of Denmark, University of valleys. Previous investigations particularly Copenhagen, 2Department of Geosciences, UiT The focused on the slope segment of the clinoforms Arctic University of Norway, 3Geological Survey of and demonstrated how sustained-type, Denmark and Greenland, 4Department of Earth Science, hyperpycnal flows deriving from shelf-edge University of Bergen, 5Department of Arctic Geology, deltas played a major role in bringing sand onto The University Centre in Svalbard the slope, contributing to slope accretion. Periodic sand delivery beyond the slope is The Lower Cretaceous (Valanginian– evident by the presence of sandstone-dominated Hauterivian) Rurikfjellet Formation in turbidite lobes in the basin floor segment of some Spitsbergen, Svalbard, forms an up to c. 300 m clinoforms. By combining outcrop and core data thick succession of fine-grained shelf and lower from central Spitsbergen, our study focus on shoreface shales, siltstones and sandstones sedimentary processes that formed these (Dypvik et al. 1991). The formation constitutes turbidite lobes. At bed-to-bed scale, many of the the regressive part of an >1000 m thick first- turbidite beds deviate from the classical Bouma- order sequence which formed during a long-term type facies patterns typical of deposition from shoreline progradation (the Rurikfjellet surge-type, low-density turbidity currents. Thick Formation) and back-stepping (the Helvetiafjellet (0.5–3 m) turbidite beds characterized by and Carolinefjellet formations) in response to a pervasive amalgamation, internal scouring full cycle of relative sea-level change (Gjelberg & surfaces, and various soft-sediment deformation Steel 1995). In contrast to the overlying Lower structures dominate. Further, beds exhibiting a Cretaceous succession, the Rurikfjellet Formation lower sandstone-dominated turbidite division has received relatively little attention and is succeeded by a mud-rich upper division relatively poorly exposed. Its age is also rather containing abundant coal/plant fragments occur uncertain. We present a revised basin-scale frequently. The latter bed architecture is typical sedimentological and sequence stratigraphic of deposition from hybrid sediment gravity flows model of the formation, tied to a new and indicate that some turbidity flows biostratigraphic framework. The model is based transformed into slurry flows or debris flows on on data recently collected across the Lower their way to their final destination on the basin Cretaceous outcrop belt, including >3500 m of floor. The dominance of thick, amalgamated measured outcrop sections; seven subsurface turbidite beds and the abundance of coal/plant cores; >130 palaeocurrent measurements; fragments documented in this study, as well as >50,000 photos; three bulk-rock δ13C curves the presence of hyperpycnal flow turbidites on org with a mean resolution of 2 m; and hundreds of the slopes documented in previous studies, dinocyst, ammonite, belemnite and bivalve

93 biostratigraphic samples. Our data reveal a calculated by means of P-wave velocity and regionally persistent regressive–transgressive density data (Fabricius, 2003). The model allows sequence development of the formation, as well to estimate the degree of cementation and hence as several hitherto unrecognised progradational the Biot´s coefficient by comparing the elastic pulses of apparently diachronous clastic wedges. modulus obtained by P-wave measurements with We argue that their depositional architecture and the theoretical one obtained under the interfingering were controlled by prodeltaic assumptions of either particles in suspension or coupled storm-dominated and hyperpycnal close-packed particles. The results show sedimentation across a wide, low-gradient ramp, similarity between the two locations concerning with important implications for the elastic moduli and porosity, but not for the palaeogeographic reconstructions for the same sample. This discrepancy could be caused Valanginian–Hauterivian of Svalbard and nearby either by a different heating history or by areas. different texture.

ORAL ORAL

Elastic moduli, stiffness and effective The Miocene-Pliocene Skade-Utsira stress of chalk from Zealand aquifer, North Sea: Updated maps and (Denmark) and from Dan field (North new insights in depositional patterns Sea). and syn-sedimentary deformation

Laura Paci1, Irene Rocchi1 and Ida Lykke Fridtjof Riis1, Tor Eidvin1 and Yngve Rundberg2 Fabricius1 1Norwegian Petroleum Directorate, 2YR Geo AS 1Technical University of Denmark,Department of Civil Engineering,Nordvej Building 119 2800 Kgs.Lyngby During Miocene-Pliocene the deltaic system east of Shetland prograded into the Norwegian sector The successful employment of the Underground of the North Sea. Sands were deposited in a slope Thermal Energy Storage in the subsurface of and basin setting. Thick deposits of high porosity Copenhagen is investigated. The study considers and high permeability Utsira and Skade the geotechnical and physical properties (i.e. formations cover an area more than 300 km long stiffness and porosity) of the medium depth (400- and 60 km wide. The maximum total thickness of 800 mbgl) Chalk Group. The majority of sands in the aquifer reaches more than 500 m. geotechnical data available covers shallow depth, Maps of the aquifer were published by the NPD as while deep well logs data are fewer and of part of the CO2 Storage Atlas (www.npd.no). variable quality. In order to overcome the lack of information, this work evaluates Dan field as an In this updated study, NPD has included new well analog for the chalk from Zealand comparing the and seismic data, as well as new results from effective stress and stiffness at the two locations. micropaleontology and Sr isotope stratigraphy. The chalk formation is found at much greater In addition to the lower Miocene Skade depth in the Dan field (1800 mbsl compared to an Formation and the upper Miocene to lower average of 200 mbsl in Zealand), resulting in a Pliocene Utsira Formation, the top of the middle greater overburden stress. However, the effective Miocene sandy unit (Eir formation, informal) is stress is comparable to the maximum value also available. The depocenter of the Skade encountered in Zealand (i.e. before uplift and Formation is found in the central part of the area. erosion), due to overpressure. The results shown During the middle Miocene there was a shift to were obtained calculating the maximum effective the north, while in the late Miocene, a major lobe stress based on the burial anomaly as studied by developed in the south. During the latest late Japsen (1998). In addition, the stiffness was

94 Miocene and the Pliocene the basinal depression and Red Clay deposits revealed a systematic was filled in, and a shelfal setting is interpreted. pattern, whereby the aspect ratio decreased with increasing grain size, indicating systematic shape The whole basin region is strongly affected by sorting occurred during the aeolian large scale soft sediment deformation. transportation of these dust particles. Also Mobilization of sands took place where sandy evident from our DIA data was a subtle but formations were sealed by deep-water clay and systematic downwind decrease in the aspect ooze. Evacuation structures, pillow-like ratio of the particles in the loess units. This structures and injectites are found at several observation suggests that elongated and/or flat stratigraphic levels and were apparently particles (with a low aspect ratio) were triggered by deposition of turbidites or mass transported further downwind than more flows. symmetrically shaped particles (with a high aspect ratio). This study indicates that DIA of

grain size and shape characteristics can be an ORAL additional powerful tool for fingerprinting grain size and shape sorting trends and reconstructing Aeolian silt transport processes as the transportation pathways of silt-sized aeolian fingerprinted by dynamic image sediments. analysis of the grain size and shape characteristics of Chinese loess and Red Clay deposits ORAL

Yuan Shang1, Anu Kaakinen1, Christiaan J. Beets2 A new observation of a biosiliceous and Maarten A. Prins2 opal bearing sequence in the Miocene 1Department of Geosciences and Geography, P.O. Box Lark Formation in the Danish North 2 64, 00014, University of Helsinki, Finland, Department Sea. of Earth Sciences, Faculty of Earth and Life Sciences, Vrije Universiteit Amsterdam, De B Henrik Sulsbrück1 and Jørgen Toft1

1Mærsk Olie og Gas A/S This study applied dynamic image analysis (DIA) to characterize the grain size and shape of The Paleogene – Lower Neogene Lark Formation Chinese aeolian sediments in order to fingerprint of the Danish North Sea consists of a biosiliceous, their transportation processes. We selected four opal-bearing sequence of sediments which well-studied Quaternary loess-palaeosol extend into the German, Norwegian and UK sequences along a north-south transect across sectors of the North Sea. The uppermost 50-100 the Chinese Loess Plateau and compared their m part of the Lark Formation is characterized by grain size distribution obtained by DIA with that abundant biogenic silica in the form of diatoms, yielded by laser diffraction(LD) particle size radiolarians, Bolboforma and sponge spicules. analysis. The results demonstrated that DIA is This biosiliceous-rich section is of Early to Mid- able to characterize clearly spatiotemporal Miocene age and formed during a period of variations in the grain size records of loess- climatic optimum. The interval can contain up to palaeosol sequences formed during the last two 40% biosiliceous material, together with detrital glacial and interglacial periods. This is consistent clay and quartz. Carbonate stringers and pyrite with grain size results obtained using LD. DIA is occur in minor amounts. The content of organic also able to characterize spatial variations in the matter can be significant with TOC’s of up to 8%. more fine-grained aeolian Red Clay deposits and In the lower parts of Lark (Early Miocene), to allow the quantification of the fluvial diagenesis has transformed the biogenic silica contribution to Red Clay sequences. DIA of the from Opal A into Opal CT. No Opal has been grain shapes characteristics in loess-palaeosol observed in the Oligocene part of the Lark

95 Formation. This talk discusses the key presented, thus providing age estimations for th characteristic of this biosiliceous section of the e fossil-bearing horizons. Lark Formation, and the regional controls on it’s development. Landscape of the Ulantatal formation is characterized by flat lined topography with low uplands and small gullies. Outcrops of the area show a uniform pattern predominated by fine- ORAL grained massive sediments occasionally interbedded with coarser grained horizons. The Across the Eocene-Oligocene sequence produces fossils along most of the Transition in inland Asia: Bio-, Litho-, section, with the richest fossil occurrences in the and Magnetostratigrapy of Ulantatal, lower half of the sequence. Our magnetic section Inner Mongolia, China suggests a correlation in magnetozones C15n to C9n, with an age range of about 35-27 Ma, and Joonas Wasiljeff1, Anu Kaakinen2, Johanna places the lowermost fossil site in Ulantatal in the Salminen3 and Zhaoqun Zhang4 latest Eocene. 1Department of Geosciences and Geography, P.O. Box 64, FI-00014 University of Helsinki, Finland, 2Department of Geosciences and Geography, University of Helsinki, Finland, 3Department of Physics, University of Helsinki, Finland, 4Institute of Vertebrate Paleontology and Paleoanthropology, Chinese Academy of Sciences, China

Coherent terrestrial sequences are critical in scrutinizing past environmental and climatic changes through successive fossil and sedimentary records. Central Asia has been an exquisite locality for past and ongoing paleontological investigations for Eocene to Oligocene aged mammalian faunas. Transition from Eocene to Oligocene (EOT) at ~34 Ma signified considerable changes in climate, flora, and fauna, externalized by the decrease of mean annual temperature and the change in vegetation from Eocene forests to more bare lands of the Oligocene. The faunal transition in inland Asia was characterized by replacement of Eocene perissodactyl-dominant faunas to the Oligocene rodent-lagomorph-dominant faunas.

Ulantatal is a renowned Oligocene mammalian fossil locality in Inner Mongolia, China. Although the area has produced a significant collection of vertebrate faunas, knowledge of the stratigraphy, ages and depositional environments have remained poor or nearly non-existent. Litho- and magnetostratigraphic context, and correlation of the Ulantatal area sediments with the Geologic Time Scale (GTS) is

96 3.3. Composition of siliciclastic but that internal differences in the east is a sorting effect. The western group was fed from rocks the Massif Central and the eastern group from the Bohemian Massif. We conclude that interpretation of detrital zircon ages preferably ORAL are separately for different size classes, because zircon studies performed on broad grain-size How can provenance and sorting intervals without considering possible size-age effects be differentiated from detrital correlations may disguise sorting effects that zircon data? Example from the potentially can lead to a misleading source-area German Triassic Buntsandstein interpretation. Group

Carita Augustsson1, Thomas Voigt2, Kristin ORAL Bernhard2, Marian Kreißler2, Reinhard Gaupp2, Andreas Gärnter3, Mandy Hofmann4 and Ulf Middle Triassic siliciclastic deposits 4 Linnemann of Svalbard as a part of source to sink 1Institutt for Petroleumsteknologi, Universitetet i Stavanger, 4036 Stavanger, Norway, 2Institut für framework of the Arctic Geowissenschaften, Friedrich-Schiller-Universität Jena, 1 2 Burgweg 11, 07749 Jena, Germany, 3Senckenberg Urszula Czarniecka , Beyene Girma Haile and naturhistorische Sammlungen Dresden, Köningsbrücker Krzysztof Krajewski1 Landstr. 159, 01109 Dresden, Germany, 4Senckenberg 1Institute of Geological Sciences, Polish Academy of naturhistorische Sammlungen Dresden, Köningsbrücker Sciences, Twarda 51/55, 00-818 Warszawa, Poland, Landstr 159, 01109 Dresden, Germany 2Department of Geosciences, University of Oslo, P.O.BOX 1047, Blindern, 0316 Oslo, Norway

This study stresses how sorting and provenance effects can be differentiated by combining zircon- Sandy facies of the Bravaisberget Formation grain length and U-Pb-ages for individual detrital (Middle Triassic) exposed at the southernmost grains. We exemplify this by a provenance study part of Spitsbergen (Svalbard archipelago) for continental deposits of the Lower Triassic, represent an uplifted part of the northwestern continental Buntsandstein Group in central corner of the Barents Sea shelf. The deposits are Germany. The study is based on > 1000 zircon interpreted as an effect of shallow marine and grains from 12 sandstone beds. The unbroken deltaic sedimentation and their facial equivalents grains in seven of the zircon separates have mean in the Barents Sea are considered as good lengths of 190-220 µm and five are composed reservoir rocks for hydrocarbon accumulation. 100-140 µm long grains in average. All have a The aim of this study was to characterise and main population of 340-320 Ma ages, recognise potential source areas for the Middle representative of granitoid from the Variscan Triassic siliciclastics based on petrological and Orogen of the Massif Central and the Bohemian geochemical methods. Standard quantitative Massif. This detritus was mixed with abraded petrographical analysis of thin sections and bulk grains from Ediacaran to Palaeozoic rock geochemistry technics have been (meta)sedimentary units feeding the basin with supplemented by U-Pb and Lu-Hf zircon analysis. 610-460 Ma (Ediacaran to Ordovician) and 2 Ga age grains. The 610-460 Ma age population is The studied deposits have quartz-dominated common only in five samples with mean grain framework composition, with minor content of lengths of 100-140 µm. Those grains mainly are < feldspars and lithoclasts therefore they have been 130 µm in the east, but equally common in all classified as quartz arenites, subfeldsarenites, grain sizes in the west. This indicates that the sublitharenites. Concentrations of major, trace east-west age difference is a provenance effect elements and REE point to silicic source rocks

97 composition. Distribution of zircon ages shows The quartz arenite from Southern Norway has an domination of Paleo- and Mesoproterozoic ages intergranular volume of ca. 20%, and close to with significant content of Archean ages, minor 100% of the initial porosity has been replaced by Caledonian zircons and lack of Uralian grains. quartz cement. For most samples, other This provenance signature has been compared authigenic cement minerals, together with with data from other areas of the Arctic region. detrital phyllosilicates, represent < 5% of the present-day composition. Preliminary The area analysed in this study represents only petrological investigation on the Hardeberga small part of the whole Arctic sediment routing Formation points to similar quartz-dominated system existed in the Mesozoic time and the chemical diagenesis. This indicates that the investigated deposits have provenance signature sediment composition was extremely quartz-rich which is consistent with the Triassic provenance already during deposition throughout signatures from Canadian Arctic and Greenland Scandinavia, as is supported by the high SiO2 and linking their proto-sources to Laurentia, but content averaging at 95.6%. Sediment reworking the deposits components were recycled from by waves, and subsequent removal of early older sedimentary rocks, likely from Devonian authigenic components produced from strata. subsurface leaching of unstable grains are likely to have influenced the composition severely. The

findings contribute to an increased ORAL understanding of the formation of both quartz- rich sediment and the end products of Quartz cementation and diagenetic cementation processes. effects in sandstone – an analog study of

Cambrian quartz arenite from Scandinavia ORAL

Sanne Lorentzen1, Carita Augustsson1, Johan P. IMPACT OF METEORIC-WATER Nystuen2, Jens Jahren2 and Niels H. Schovsbo3 DIAGENESIS ON RESERVOIR QUALITY 1Department of Petroleum Engineering, University of Stavanger, 2Department of Geoscience, University of IN PALEOCENE TURBDITIC Oslo, 3Geological Survey of Denmark and Greenland SANDSTONES, UK CENTRAL GRABEN, NORTH SEA Lower Cambrian quartz arenitic deposits have a Howri Mansurbeg1 world-wide occurrence. Nevertheless, diagenetic 1Petroleum Geosciences at Soran effects are rarely taken into consideration to University/Kurdistan Region-Iraq, and KPS Metal, explain the existence of these mature, shallow Czech Republic marine deposits. In this study, petrographic, geochemical and mineralogical analyses were carried out on core and outcrop samples from the This petrographic and stable isotopes study on quartz-rich Ringsaker Member from Southern the distribution of diagenetic alterations and of Norway and the corresponding Hardeberga their impact on reservoir-quality evolution of Formation from Bornholm in Denmark and Paleocene marine turbidite successions Scania in Sweden. The sandstone units have been (Andrews Formation, UK Central Graben, North examined in a state of complete quartz Sea) revealed the important roles of tectonic cementation in order to study the diagenetic setting, depositional facies, and changes in the history and the effects leading to destruction of relative sea level. Diagenetic modifications porosity and permeability. Quartz cementation include dissolution and kaolinitization of was estimated by comparing the amount of framework silicates, cementation by carbonates cement present to the modelled amount of quartz and quartz, mechanical compaction of cement based on its time-temperature history. sedimentary rock fragments, and chemical

98 compaction of detrital quartz. Despite tens of km different degrees of bioturbation. The stylolite distance from the paleoshore line, kaolinitization forming processes involved differential is attributed to meteoric-water flux during major compaction in several stages of diagenesis: 1) fall in the relative sea level. The wide range of Initial mechanical compaction inducing folding of 13 δ CV-PDB values of calcite cement (about -18‰ to softer clay-rich lamina. 2) In deeper burial +22‰) is attributed to the input of dissolved chemical diagenesis with enhanced grain carbon from microbial methanogenesis and dissolution at clay contacts accompanied with methane oxidation. The wide range of δ18O values quartz cementation and 3) continued stylolite (about -17‰ to -1‰) of this cement might growth involving also dissolution of earlier reflect the involvement of various fluids including precipitated quartz cement. Micro shear-zones marine, meteoric, and evolved formation waters) along stylolite fold limbs are interpreted in terms and wide range of precipitation temperatures. of dissolution-enhanced differential compaction. Preservation of porosity and permeability in Deformation accompanying quartz cementation sandstones from the passive margin basins (up to is evidenced by a frequent distribution of 30% and 1 Darcy, respectively) is attributed to dauphine twins at adjacent cement – cement the presence of abundant rigid quartz and contacts, revealed by use of SEM-backscattered feldspar grains and to dissolution of carbonate electron diffraction techniques. The latest stage cement as well as mica and feldspars. of diagenesis involved abundant pyrite crystallization, in particular along stylolites, questioning if stylolites could have acted as conduits for fluid migration. Further research is ORAL suggested to examine regional tectonic and Factors influencing stylolite thermal influences on the distributions of extensive quartz cementation in some of the development and quartz cementation westernmost areas of the Barents Shelf. in the Jurassic Stø Formation sandstone, Tromsø Basin, SW Barents

Sea ORAL

1 Mai Britt E. Mørk Stiffening effect from temperature 1NTNU, Department of Geoscience and petroleum, N- 7491 Trondheim, Norway. and stress on sandstones from the deep North Sea Basin

Stylolites are common diagenetic structures in Tobias Orlander1, Katrine Alling Andreassen1 and quartz cemented sandstones and provide records Ida Lykke Fabricius1 of extensive chemical compaction. As 1Technical University of Denmark documented and modelled in the diagenesis literature, the development of stylolite seams in sandstone involves dissolution of quartz grains as We investigate effects of temperature, stress and well as “re”-precipitation of the dissolved silica as stress symmetry on the dynamic stiffness of two quartz cement. This study compares sandstones from depths of approximately 5 km in microstructures of stylolite and quartz cement in the North Sea Basin. The studied temperature strongly cemented Jurassic sandstones from a range was 25-170°C, whereas the studied stress well in the southwestern-most part of the Barents range was 2.5-15 MPa. Two stress symmetries Sea to interpret diagenesis and deformation were compared: 1) hydrostatic stress and 2) structures. The impact of sedimentary fabric and uniaxial stress with constant confining stress. We bioturbation in development of stylolites is derived dynamic compressional and shear emphasized based on comparison of sandstone moduli from density and ultrasonic P- and S-wave cores of velocities and show that the stiffness can increase with up to 20% and 100% for respectively

99 increase in temperature and stress. We link the depend on occurring digenetic phases and not increased stiffness to two physically different depositional environment. The dominating mechanisms, both resulting in closure of diagenetic phases are eogenetic microcrystalline ruptured grain contacts created by equilibrating quartz, mesogenetic precipitation of illite, sample material to atmospheric conditions. extensive mesogenetic quartz overgrowth and Eventually, the increase is hence recovery extensive Fe-dolomite and ankerite cementation. stiffness by mechanisms of: 1) frame deformation The different diagenetic phases are present in all due to increase in stress and 2) thermal three depositional environments. Diagenesis had expansion due to increase in temperature. That a major impact on either preserving or contact ruptures (micro-cracks) can full or destroying porosity, but did in all cases highly partially close by 1) is an accepted mechanism for reduce the permeability. The different diagenetic partial recovery of in-situ stiffness. We show that phases can be recognized in the Ravn-1 well and stiffness recovery by 1) or 2) have different in less degree in the Ravn-2 well. magnitude, but that both are most pronounced for sandstones with a low degree of cementation. This is probably because cementation hinders ORAL progression of micro-cracks during deloading and cooling. The results demonstrate the Terrestrial paleoweathering and the significance at testing samples at their natural presence of deep biosphere in stress and temperature. fractured granites, Utsira High, Norwegian North Sea

ORAL Lars Riber1, Steven G. Driese2, Henning Dypvik1, Gary E. Stinchcomb3, Ronald Sørlie4 and Liz The diagenetic impact on reservoir Thompson4 sandstones of the Heno Formation in 1Department of Geosciences, University of Oslo, the Ravn-3 well, Danish Central 2Department of Geosciences, Baylor University, 3Watershed Studies Institute and Department of Graben, Denmark Geosciences, Murray State University, 4Lundin Norway AS Simone Suhr Pedersen1, Niels Hemmingsen

Schovsbo2 and Rikke Weibel2 1 University of Copenhagen, Department of Geosciences Whereas the global stratigraphic record is and Natural Resource Management, 2GEUS, Geological dominantly marine, deeply buried paleoregolith Survey of Denmark and Greenland, Øster Voldgade 10, profiles are rare and important remnants of the DK-1350 Copenhagen K, Denmark terrestrial paleoenvironment. On the Utsira High,

Norwegian North Sea, the crystalline basement The Upper Jurassic Heno Formation in the Ravn- was probably close to the surface from the 3 well is the deepest producing sandstone Permo-Triassic until the early Cretaceous reservoir in the Danish North Sea. A combined (Ksienzyk et al., 2016). Recent K-Ar ages of illite approach including petrography, geochemistry, clays from weathered granites in the area porosity and permeability analysis and core suggested commencement of regolith/paleosol description have been achieved to investigate formation in mid-Triassic (Fredin et al., 2017). variations in diagenesis up through the formation Drill cores from well 16/1-25S in the Rolvsnes and how post-depositional changes impacts the discovery include ~21 m of fractured and sandstone reservoirs. Three depositional weathered granite below Cretaceous cover. In the environments characterize the reservoir studied regolith, two intensely weathered, clay- sandstones: lower shoreface, middle shoreface rich intervals were identified in the upper part of and foreshore. Results show that the reservoir the profile. They contain randomly interstratified potential of the sandstones predominantly mixed-layer illite-smectite and poorly crystalline

100 2 kaolinite clays, pseudomorphically kaolinitized grains, while adsorption of SO4 - counteracts the biotite, and dendritic aggregates of fine-grained initially positive surface charge, leading to a hematite. Although quartz is preserved, feldspars decrease of the repulsive forces. For kaolinite, are affected by chemical weathering with differences in potential between the silica and plagioclase nearly completely removed. The alumina faces as well as the edges can either lead fracture network facilitated deep percolation of to repulsion between particles or to flocculation meteoric water and in samples more than 20 m depending on ionic strength and ionic species of below the basement-sediment contact the fluid. For quartz, relatively high porosity for weathering is evidenced by minor amounts of powders saturated with sodium chloride brine well-crystallized kaolinite and moderately indicates that Na+ is a potential determining ion altered feldspars. Estimates of MAP and MAT for the quartz surface. The repulsive pressure using the Paleosol-Paleoclimate Model (PPM1.1) inferred from the experiments could be (Stinchcomb et al., 2016) from the clay-rich correlated to zeta potential measurements intervals indicate formation under subhumid and available in the literature. temperate conditions. Use of geochemical proxies is complicated because of heterogeneous protolith composition, truncation of the original paleosol, and the likelihood of multiple alteration episodes. Mycorrhizal fungal hyphae have been observed down to about 20 m below the basement-sediment contact, indicating the presence of deep biosphere.

POSTER

Impact of electrostatic forces on sediment porosity

Leonardo Teixeira Pinto Meireles1, Einar Madsen Storebø1 and Ida Lykke Fabricius1 1Technical University of Denmark, Kogens Lyngby, Denmark

In this paper, we assess the impact of electrical double layer related forces on sediment porosity using low field Nuclear Magnetic Resonance Spectrometry. Samples of Calcite, Quartz or Kaolinite powder were saturated with brines containing ions found in seawater (Na+, Ca2+, 2+ - 2− Mg , Cl and SO4 ) at varying ionic strengths and as a non-polar reference, with ethylene glycol. The difference in porosity between a sample saturated with ethylene glycol and a sample saturated with a given brine reflects the repulsive pressure resulting from the electrostatic forces.

We found that for calcite samples, saturation with solutions containing divalent cations (Ca2+ and Mg2+) lead to higher repulsive forces between the

101

4. Tectonics and structural geology 4.1. Trans-Atlantic correlation 1735±6 Ma. This ca. 45 Ma older age falls in the range of the Illua Plutonic Suite (1755-1728 Ma). of Proterozoic collisional belts and Paleoproterozoic The Amitsoq Island is underlain by a complex set Metallogeny of the Arctic of igneous and metamorphic rocks with intrusive ages (ca. 1700 Ma) never reported for the Ketilidian Orogen before. The new data indicate that its geology is more complex than previously ORAL thought, which highlights the need for remapping The Amitsoq Plutonic Suite – a newly and reinterpretation, to improve our understanding of the geological history and discovered suite in the Ketilidian economic potential for gold deposits. Orogen, South Greenland

Katrine Baden1, Leon Bagas2, Jochen Kolb3, Tonny B. Thomsen1 and Tod E. Waight4 ORAL 1Geological Survey of Denmark and Greenland, 2China University of Geosciences, 3Karlsruhe Institute of A new configuration of crustal-scale Technology, 4University of Copenhagen shear zones controlling copper-gold mineralization in northern Sweden The study area is situated in the ca. 1855-1735 Tobias E Bauer1 and Edward P Lynch2 Ma Ketilidian Orogen of South Greenland. Six 1Division of Geosciences and Environmental fine- to medium-grained felsic rocks from the Engineering, Luleå University of Technology, Sweden, northeast coast of Amitsoq Island were dated by 2Department of Mineral Resources, Geological Survey of LA-ICPMS (U/Pb zircon). Observations from Sweden fieldwork show show complex mixing and mingling structures of feldspar-phyric monzonite and leucogranite. Both rocks have an intrusive Northern Sweden is a well-mineralized area in contact with granodiorite, which itself intrudes a Europe and contains three major metallogenic metasedimentary rock. North of the belts; namely, the Gold Line, Skellefte and metasedimentary rocks, a banded, Northern Norrbotten ore districts. Gold and/or porphyroclastic felsic gneiss occurs. copper deposits occur in all three belts as orogenic Au, Au-rich VMS and IOCG-style The gneiss yields an age of 1784±7 Ma, that is mineralization. Regardless of mineralization interpreted as the intrusion age of a felsic style, however, most deposits appear to be precursor. This age overlaps with regional peak spatially controlled by a set of crustal-scale metamorphism (1790-1770 Ma) and the late Paleoproterozoic shear zones, which share stage of the Julianehåb Igneous Complex (1781- similar structural characteristics and 1807 Ma). The fine-grained metasedimentary deformation histories. rock gives a spread of concordant ages from ca. 1800-2800 Ma, supporting its sedimentary Reappraisal of regional geological and origin. The feldspar-phyric monzonite has an geophysical data, coupled with structural intrusion age of 1680±8 Ma, which is mapping, suggests crustal-scale shear zones form indistinguishable from the 1704±11 Ma intrusion continuous, c. N-S-trending zones extending from age of the granodiorite. Homogeneous monzonite the Gold Line in the south to Northern from the same site yields an intrusion age of Norrbotten. An example from Norrbotten is a zone that extends SSW from Karesuando in the

102 north towards Svappavaara. While this zone has Formation. The Kangilleq formation shows traditionally been inferred to continue SW dominantly within-plate, alkali basalt towards Arjeplog (i.e. the KADZ, Karesuando- geochemical signatures. Arjeplog deformation zone, Bergman et al. 2001), we favour its deflection SSE into the Nautanen- A unique sequence of meta-volcanic rocks (~100 Aitik trend, which mimics the configuration of m) occurs in the Central Kangiusap Kuua. These analogous zones to the east and west. rocks differ from all other rocks of the Kangilleq Furthermore, we tentatively suggest splays of formation in that they: 1) show tholeiitic arc-like this major zone continue south through the Laver affinities; 2) contain felsic volcanic rocks; and 3) area and terminate in the Skellefte district close contain VMS-type sulfide mineralization. The to Björkdal and Boliden. basal ~60 m consist of pillow basalt lava containing flow top breccias and hyaloclastite Crustal-scale shear zones show a long-lived indicating subaqueous eruption. Overlying the deformation history with several reactivation- pillows is an ~30 m sequence of mafic hydrothermal events. The most important ore volcaniclastic rocks where normal to reverse forming events along these zones can be assigned grading, massive to crudely bedded, and to an early phase of crustal extension at c. 1.90 Ga channel/scour structures suggest emplacement (Skyttä et al. 2012), and two phases of crustal by mass debris flows. The mafic volcaniclastic shortening at around 1.87 and 1.80 Ga, coinciding beds are overlain by a rhyolite breccia ~5 m), with major Svecofennian-cycle tectonothermal which is capped by a strongly silicified rock (~2 events (c.f. Bauer et al. 2016, 2017). m). The felsic breccia hosts stringer to massive sulfide (pyrite, pyrrhotite ± sphalerite, chalcopyrite).

ORAL Our work documents the first occurrence of a tholeiitic, bi-modal volcanic sequence with arc- Paleoproterozoic volcanogenic like signature, and VMS-type mineralization massive sulfide mineralization, within the Karrat Group. Thus, it has important Karrat Group, Central Kangiusap implications for mineral exploration, and the Kuua, West Greenland interpretation of the geodynamic setting of the Kangilleq formation. Yvonne Michelle DeWolfe1, Jochen Kolb2 and Diogo Rosa3 1Mount Royal University, Department of Earth and ORAL Environmental Sciences, Calgary, Canada, 2Karlsruhe Institute of Technology, Institute of Applied Geosciences, Geochemistry and Economic Geol, A new reef-type PGE-enriched zone in 3Geological Survey of Denmark and Greenland, the early Paleoproterozoic Copenhagen, Denmark Näränkävaara Layered Intrusion,

northeastern Finland The Karrat Group of Central West Greenland is Ville Järvinen1, Tapio Halkoaho2, Jukka composed of the Qeqertarssuaq (Lower Karrat Konnunaho2 and O. Tapani Rämö1 Group), Qaarsukassak, Mârmorilik, Kangilleq, and 1University of Helsinki, Finland, 2Geological Survey of Nûkavsak formations (Upper Karrat Group). All Finland volcanic rocks of the Karrat Group are placed in the Kangilleq formation (informal), which is defined as a package of meta-volcanic The 2.44 Ga Näränkävaara layered intrusion is (greenschist) rocks that unconformably overlie located 100 km south of the Arctic Circle. It meta-sedimentary rocks of the Qeqertarssuaq belongs to a belt of 2.45-2.43 Ga mafic layered Formation and are conformably overlain by intrusions formed during continental extension meta-sedimentary rocks of the Nûkavsak (Lauri et al. 2012). These intrusions contain

103 contact-, reef- and offset-type PGE deposits ‘SEGMENT’ expedition and mapped in Google (Rasilainen et al. 2010). Earth for structural and petrological investigations. This approximately 40-km-wide The intrusion is 25 km long and 5 km wide. exposed part of a much more extensive igneous Geophysical modelling infers a triangular keel province is made up of more than 160 roughly E- extending up to a depth of 10 km. Wall rocks are W trending dykes, which constitute 5-15 % of the Archean TTG, migmatites, gneisses and outcrop. Within Umivik we recognize at least two metavolcanic rocks (Alapieti 1982). The intrusion slightly oblique cross cutting sub-swarms with consists of four principal units (stratigraphic similar geochemical signatures. Their thickness in parentheses): a basal dunite (2 km), compositions are comparable to those of the a peridotitic-pyroxenitic unit (700 m), a gabbroic Scourie dyke swarm, across the conjugate rifted unit (400 m), and a quartz-dioritic unit (200 m). margin in Scotland (Myers, 1987), which may all Parental magma has boninitic or siliceous high have been derived from the same metasomatised magnesium basalt affinities except for the basal sub-continental lithospheric mantle source dunite, which is komatiitic. (Hughes et al., 2014). According to Nilsson et al (2013) and Davies & Heaman (2014), these dykes Five drill holes intersect a 10–25 meter thick were emplaced between 2.42-2.36 Ga, during the PGE-enriched zone located at the border zone break-up of the Superia supercontinent. between the pyroxenitic and gabbroic units Subsequently, dykes were variably deformed (Lahtinen 2005). Average intersection is 15 through a combination of conjugate shear and meters with 0.25 ppm Pt+Pd+Au. Highest assay is thrust zones during the 0.39 ppm Pt+Pd+Au in a 1 meter long sample. The Nagssugtoqidian/Laxfordian orogeny, with the Pd/Pt is 2.5–8.7. Sulfides are rare (highest southernmost extent of this orogen’s analyzed S at 2440 ppm and Cu at 262 ppm). The deformation front coinciding with the Umivik PGE-enriched zone is continuous along strike for area. With the exception of a few less deformed at least 5 km. ‘crustal enclaves’, mafic intrusions become This type of PGE-enriched zone has not been progressively more deformed and found in similar stratigraphic position from metamorphosed across this nearly 150 km wide other Finnish 2.43-2.45 Ga layered intrusions deformation front, exemplified by four case study (e.g. Iljina et al. 2015). Lithologically it resembles areas up along the coast. The Atlantic Ocean the PGE mineralization in the Munni Munni eventually separated the Greenlandic and Complex (Barnes & Hoatson 1994). Scottish part from each other and our primarily aim is to use both structural and petrological evidence provided by mafic intrusions to bring these two craton fragments tighter together ORAL within their post-Nagssugtoqidian and pre- Atlantic configuration. Linking the Umivik and Scourie dyke swarms tighter into a pre-Iapetus plate configuration

Martin Klausen1, Riaan Bothma1 and Thomas

Kokfelt2 1 Department of Earth Sciences, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa, 2Geological Survey of Denmark and Greenland, GEUS, Oester Voldgade 10, 1350 København K, Denmark

The mafic Umivik dyke swarm in SE Greenland (64˚10-30’N) was sampled during the GEUS 2012

104 ORAL the youngest of the ca. 1.82 Ga granites crosscut the high-T fabrics, indicates that exhumation was Architecture of the Rinkian Orogen a fast tectonic process and not driven by erosion. between Svartenhuk and Holm Ø, western Greenland ORAL Jochen Kolb1, Crystal LaFlamme2, Annika Dziggel3 and Kristine Thrane4 Sniffs of ‘IOCG-style(?)’ chalcopyrite 1Institute of Applied Geosciences, Karlsruhe Institute of Technology, Germany, 2ARC Centre of Excellence in Core mineralisation in northwestern to Crust Fluid Systems (CCFS), University of Western Greenland Australia, Aus, 3Institut für Angewandte Mineralogie und Lagerstättenlehre, RWTH Aachen University, Crystal LaFlamme1, Kathleen Bathgate1, Jochen Germany, 4Geological Survey of Denmark and Kolb2, Diogo Rosa3, Marco Fiorentini1 and Kristine Greenland Thrane3 1Centre for Exploration Targeting, University of Western Australia, 2Karlsruhe Institute of Technology, The Paleoproterozoic Rinkian Orogen extends 3GEUS from Nuussuaq to north of Holm Ø along the Greenlandic western coast. It has recently been interpreted as northern extension of the The Nutaarmiut Complex was identified during a Nagssugtoqidian Orogen that continues west in 2016 field campaign in the Paleoproterozoic the Trans-Hudson Orogen of Canada. We Rinkian Orogen. It is notable for: 1) blebby concentrate on the high-grade metamorphic chalcopyrite and extensive malachite staining, northern part of the Rinkian Orogen. and 2) being low grade and undeformed compared to the adjacent strongly deformed and The rocks are characterized by Archean granulite-facies lithologies. Field mapping orthogneiss, ultramafic rocks, amphibolite, defined locally chalcopyrite mineralized, gabbro Paleoproterozoic paragneiss, charnockite of the and syenite layers. Further petrologic, 1.90-1.87 Ga Prøven Igneous Complex (PIC), and geochronological, geochemical, and isotopic ca. 1.82 Ga granite. The PIC has a diameter of investigation has since demonstrated that these ~100 km, with increasing foliation intensity lithologies rather form locally mineralized towards the outer contact. In the south, rocks of metasomatic rocks. the PIC are thrust E on top of Paleoproterozoic paragneiss, which records peak metamorphic The ‘felsic’ layers comprise sericitised orthoclase conditions at 750-800°C and < 4 kbar. In the and albite. At least two generations of north, contact relationships between the igneous assemblages are observable in the ‘mafic’ layers: rocks of the PIC and paragneiss are complex. The 1) near-vertical, several km wide Tussaaq shear quartz+albite+epidote+biotite+chlorite+sericite, zone marks the boundary between the PIC and and 2) an overprinting assemblage of Paleoproterozoic paragneiss. From this shear hematite+ilmenite+chalcopyrite+apatite+monaz zone to the N, the fabrics flatten progressively, ite+zircon. The second assemblage contains turning into a NW-vergent fold-and-thrust abundant iron oxides that are intimately structure. Leucosomes are ubiquitous, most associated with blebs and stringers of abundant around the Tussaaq shear zone and chalcopyrite. Sulfur isotope measurements of form syn-deformational structures, indicating chalcopyrite yield δ34S of +10‰, indicating high temperature metamorphism. These sourcing of sulfur from an oxidised fluid. A‘felsic’ leucosomes coalesce into pegmatites and plutons, layer yielded metamict uraniferous (up to 8000 which are dated at 1.82 Ga. Similar ages for peak ppm) zircon. The zircon with the lowest uranium metamorphism indicate a tectonothermal event content (<2000 ppm) are used to constrain a some 50 m.y. after emplacement of the PIC, 207Pb/206Pb age of ca. 1783 Ma. Regionally, this exhuming rocks of the middle crust. The fact that hydrothermal event follows peak high-T

105 metamorphism by about 40 m.y., coinciding with and-fold belt fold patterns, such as abrupt fold the timing of metamorphic titantite and resetting terminations. The recognized major basement of hornblende Ar-Ar ages. In the Churchill structures comprise fault-bound, approximately Province, this age corresponds to magmatism of E-W trending horsts and an orthogonally cross- the post-orogenic Nueltin Suite, which is sourced cutting central graben. The basement structures from lower crustal and mantle melts. Petrological were generated under synchronous extension in observations, geochronology, sulfur isotopes and both NE-SW and NW-SE orientations, which we mineralisation style define a package of attribute to development of a pull-apart basin metasomatic rocks that is consistent with fluids with pre-existing basement weakness zones, at that, in other areas, form IOCG-style an overstepping zone between two major N-S mineralisation. This remote area of northwestern deformation zones. This indicates that the N-S Greenland could be prospective for IOCG structures experienced lateral slip during the mineralisation. break-up of the Archaean continent at around 2.45 Ga, and the inferred setting explains why PB did never progress into a proper rift. Recognition of the major basement structures significantly ORAL improves targeting of mineral exploration in PB. Structural inheritance and basement- cover linkages within the Palaeoproterozoic Peräpohja Belt, ORAL Northern Finland Linking orogenesis across the North- Pietari Skyttä1 and Simo Piippo2 Atlantic; the Grenvillian and 1Dept. of Geography and Geology, University of Turku, Sveconorwegian orogens, different in Finland, 2Dept. of Geosciences and Geography, style, but geodynamically coupled University of Helsinki, Finland Trond Slagstad1, Nick M. W. Roberts2 and Evgeniy Kulakov3 Correlation of regional-scale bedrock structure 1Geological Survey of Norway, Trondheim, Norway, and stratigraphy within the Peräpohja Belt (PB), 2NERC Isotope Geosciences Laboratory, Keyworth, UK, Northern Finland, shows that the evolution of the 3Centre for Earth Evolution and Dynamics, University of Palaeoproterozoic cover sequences have an Oslo, Oslo, Norway intimate relationship with the underlying Archaean basement. By recognizing the basement control the heterogeneous nature of the The Sveconorwegian orogeny in SW contractional structural overprint within PB may Fennoscandia comprised a series of be explained by one progressive south-verging geographically and tectonically discrete events thrusting event instead of several compressional between 1140 and 920 Ma (Slagstad et al., 2017). events with highly contrasting palaeostress Thrusting and high-grade metamorphism at orientations. Compressional deformation was 1140–1080 Ma in central parts of the orogen additionally controlled by strain localization into were followed by long-lived arc magmatism and a basin-wide basal detachment zone ultra-high-temperature metamorphism at 1070– accommodated by a mechanically weak unit. 920 Ma in the westernmost part of the orogen. In Hard linkages between the basement and the the eastern part of the orogen, crustal thickening cover is shown by exposure of the deepest parts and high-pressure metamorphism took place at of the PB stratigraphy in the hanging walls of 1050 in one domain and at 980 Ma in another. reverse faults, which consequently must continue These discrete tectonothermal events are best down to the basement and represent reactivated explained as series of accretionary events of basement structures. By contrast, soft linkages fragmented and attenuated crustal blocks of the are shown by deviations from the typical thrust- SW Fennoscandian margin behind an evolving

106 continental-margin arc. In contrast, the coeval the emplacement of the Kangilleq formation Grenvillian orogeny is ascribed to long-lived volcanic rocks, one in which active, synvolcanic collision with Amazonia. We argue that roughly faulting caused the formation of one or more coeval, but tectonically different events in the basins restricting both the deposition of Sveconorwegian and Grenville orogens may be volcaniclastic debris, and the distribution of lava linked through the behaviour of the Amazonia flows. plate. Subduction of Amazonian oceanic crust, and consequent slab pull, beneath the The meta-volcanic rocks of Kangilleq formation Sveconorwegian may have driven long-lived are greenschist facies consisting of amphibole collision in the Grenville. Conversely, the and chlorite with variable proportions of development of a major orogenic plateau in the carbonate, quartz, feldspar, titanite, apatite, Fe- Grenville may have slowed convergence, thereby oxides +- biotite. Immobile element affecting the rate of oceanic subduction and thus lithogeochemistry characterize these rocks as orogenic evolution in the Sveconorwegian. Our alkali basalt, with minor tholeiitic basalt, that model shows how contrasting but coeval display significant light REE enrichment and high orogenic behaviour can be linked through field-strength element concentrations suggestive geodynamic coupling along and across tectonic of within-plate basalts. Volcanic lithofacies and plates, and cautions against comparing and structures, combined with lithogeochemistry correlating orogenic belts mainly based on suggest the Kangilleq formation erupted in a geochronological data. localized intracratonic rift, possibly associated with mantle plume activity.

ORAL ORAL Paleoproterozic volcanism of the Indicator minerals obtained by gold Karrat Group sluicing in Lapland, a clue to possible Erik Vest Sørensen1, Michelle Y DeWolf2 and deposit types in the area Simon Mose Thaarup1 1Geological Survey of Denmark and Greenland, 2Mount Pekka Tuisku1 Royal University 1University of Oulu

Exceptionally well exposed and preserved meta- Lapland gold rush started 150 years ago, when volcanic rocks of the Paleoproterozoic Kangilleq visible gold was panned at Ivalojoki in September formation (informal), Upper Karrat Group. are 1868. A wide spectrum of ore minerals has been found throughout the Karrat region. This allows obtained since then as byproduct of gold sluicing. us to characterize the Kangilleq formation and Astonishingly, only few studies have been made the volcanic environment prior to- and during the to use this material as exploration tool in the area. early formational stages of the Nukavsak The reason for this might be, that the claims are Formation that comprises the bulk of the usually small and many times run by manpower. Paleoproterozoic stratigraphy. There are also societal and nature conservation reasons that possibly repulse explorers interest Through field-observations and 3D-mapping we in the region. Also, the Lapland Granulite Belt document that the stratigraphy of the Kangilleq (LGB) bedrock is quite monotonous. The formation varies from one dominated by mafic indicator minerals may be grouped to PGMs and tuff breccias with subordinate pillow and massive associated minerals as chromian magnetite; Fe- basalt lavas to one dominated by alternating, thin Ti-oxides together with some silicates; different (1 – 10 m) pillow and massive basalt lava flows types of corundum; tantalite, columbite, ferberite with lesser mafic volcaniclastic rocks. This and related minerals; different gold nuggets suggest a dynamic subaqueous environment for sometimes together with pieces of parent rock;

107 REE minerals, especially abundant monazite; and photogrammetry to get Digital Surface Models objects with possibly extraterrestrial origin. (DSM) and geometrically corrected orthomosaics. In total 6.4 km2 of the VMS A variety of PGMs has been found but the study showings in Kangiusap Kuua at Svartenhuk were has mostly targeted to new species rather than covered. The VMS showings are hosted in the using the mineral compositions and assemblages Nûkavsak Formation of the Paleoproterozoic to identify the parent deposit type(s). Karrat Group. In certain stratigraphic horizons Isoferroplatinum is the most common of the within the meta-turbidites, meta-basalt with PGMs. The inclusions indicate enrichment of Ru, associated sulfide-rich sea-floor alteration Ir and Os which is usual to chromitite associated occurs. Flight plans were set to cover both deposits. This is reinforced by the occurrence of alteration and host rock. A validation dataset chromian magnetite and chromite in the includes sampling and spectral characterisation concentrate. Some mineral associations as of selected hand specimens. kashinite-laurite-cooperite could indicate Alaskan-type intrusion parent. Gossan and associated alteration of host rock is easily mappable by integrated morphological and Tantalite-columbite etc. and possibly monazite, spectral analysis as they form ridges with a could be derived from the marginal zone of the distinct iron feature. Moreover, traces of LGB, which is characterized by anomalous REE fractures and faults, their spatial distribution and concentration. relation to the altered horizon are retrieved.

This further highlights the capability of drone- borne application for high-resolution ORAL reconnaissance mapping within short turn- Drone-borne mineral exploration in around times. Intermediate insights from the project Multi-sensor drones for geological Central-West Greenland: New mapping (MULSEDRO) will facilitate the insights from the Paleoproterozoic application of drones under unfavourable Karrat group conditions.

Robert Zimmermann1, Rosa Diogo2 and Richard Gloaguen1 1Helmholtz-Zentrum Dresden-Rossendorf, Helmholtz POSTER Institute for Resource Technology, 2Geological Survey of Denmark and Greenland, Department of Petrology and New U-Pb geochronology for the Economic Geology Archean basement, Karrat Group cover sequence and later intrusions During the last two field seasons, two different of the Ray Province, West Greenland. types of Unmanned Aerial Systems were tested 1 and evaluated for mineral mapping in central Kristine Thrane 1Geological Survey of Denmark and Greenland West Greenland. A fixed-wing system turned out to be more suitable as large areas can be covered faster and more efficiently. The Ray Province of West Greenland comprises Archean orthogneisses and overlying In 2017, a sensefly ebeePlus fixed-wing system Paleoproterozoic supracrustal rocks, the Karrat with a 4 channel multispectral Sequoia camera (4 Group. The Karrat Group is traditionally divided channels in VIS-NIR with 1.2 MP and an into a lower Qeqertarssuaq Formation that is additional 16 MP RGB camera) was deployed. overlain by the Nukavsak Formation [1]. The Flight altitude was set to achieve 11cm ground Archean basement and the Karrat Group are sampling distance (GSD). Processing followed in- intruded by the Prøven Igneous Complex at 1.90- house routines using Structure-from-Motion 1.87 Ga and all were reworked to varying extents

108 and metamorphic grades during the 4.2. Caledonian orogenic cycle: Paleoproterozoic [1,2,3]. the Greenland-Svalbard- New U-Pb data from the Archean orthogneisses Scandinavia connection yield ages of ca 3.1-3.0 Ga in the central Rae

Province of West Greenland, which give way to younger ages of ca. 2.7 Ga to the north. This ORAL apparent progressive younging either reflects a different terrain to the north or northward Chemistry, age and tectonic evolution growth of the craton. of the western Trondheim Nappe The Qeqertarssuaq and Nukavsak formations Complex in the Oppdal area, Central yield distinctly different detritus patterns. The Norway Qeqertarssuaq Formation is dominated by ages corresponding to the underlying Archean Bjørgunn H. Dalslåen1, Deta Gasser2, Tor Grenne3, basement, whereas the Nukavsak Formation Lars Eivind Augland1, Fernando Corfu1 and Arild yields detritus pattern dominated by Andresen1 Palaeoproterozoic ages, typically with a 1University of Oslo, 2Western Norway University of 3 significant mode at ca. 2.00-1.95 Ga [3]. Applied Sciences, Geological Survey of Norway

Metamorphic monazite ages from the Nukavsak Formation reveal multiple metamorphic events, The evolution of, and along-strike correlations the earliest being coeval with the intrusion of the within the Iapetus-derived western Trondheim Prøven Igneous Complex at 1.90-1.87 Ga. A later Nappe Complex (TNC) have been debated for metamorphic event ranges in age from ca. 1.83- almost a century. The area close to Trondheim is 1.80 Ga. Granitic intrusions of similar age are also best studied. It consists of the Løkken, Vassfjellet present in the northern part of the Province. The and Bymarka (LVB) ophiolitic fragments in the young ages may be related to convergence and NW, and the Støren s.s. greenstones in the SE, eventual collision of the Superior and Rae which both are unconformably overlain by Mid- provinces. Ordovician to Silurian volcanic and sedimentary rocks of the Hovin and Horg successions. Until recently, the TNC in the Oppdal area to the south has been less studied, but metabasaltic and metasedimentary rocks have been correlated with the LVB/Støren, Hovin and Horg units, and a large-scale tectonic inversion has been inferred.

Here we present new lithological and structural field observations, geochemical data, and detrital and magmatic zircon ages from the Oppdal area, and suggest a new tectonic model for this southern part of the TNC. Our results indicate

that the area consists of four different units: (1) a ~480-472 Ma volcanic and sedimentary succession comprising submarine basaltic and minor rhyolitic flows, (2) a ~472-469 Ma volcanic unit dominated by intermediate to rhyolitic pyroclastic deposits, (3) a <450 Ma sedimentary and volcanic succession, and (4) an

unconformably overlying <430 Ma sandstone and volcanic succession. The rocks in the area record the change from marginal basin or ocean floor spreading to subduction-related and continental

109 volcanism. The study has consequences for along- and included a substantial, granulite facies strike correlations within the TNC and offers component. further insight to the complexity of the Iapetus Ocean closure preserved in this part of the Scandinavian Caledonides. ORAL

The North Atlantic Caledonides - from ORAL Scandinavia and Greenland to Svalbard and the high Arctic The Seve subduction system in the Scandes David G. Gee1 and Jaroslaw Majka1 1Uppsala University, Sweden David G. Gee1, Per-Gunnar Andreasson2, Håkan Austrheim3, Christoph Hieronymus1, Iwona Klonowska1, Jaroslaw Majka1 and Remi Vachon The type area of the Caledonides in the UK and 1Uppsala University, Sweden, 2Lund University, Sweden, Ireland is disrupted by major late- to post- 3Oslo University, Norway orogenic, orogen-parallel faults. Western Scandinavia provides a more coherent section through the orogen and, together with The Seve Nappe Complex (SNC) in the complementary parts of northeastern Greenland, Scandinavian Caledonides provides some of the comprise an excellent laboratory for best exposed evidence on land for the character understanding this collisional orogen. The of a highly attenuated, magma-intruded, outer southernmost Scandes also suffer from similar margin of a continent (including the continent- problems to those in Scotland, with the Oslo rift ocean transition zone). The last forty years of disrupting the Caledonian foreland basin. research has shown that this Baltoscandian Nevertheless, the whole 1700 km long Scandian margin of continent Baltica was initially rifted mountain belt provides an amazingly coherent and locally intruded during the late Tonian and eastern flank of the Orogen, with well-preserved Cryogenian and subsequently extensively Ordovician and Silurian foreland basin injected by mafic magma during break-up and successions, abundant evidence of Ordovician separation of Baltica from Laurentia in the early HP/UHP subduction of the outermost Ediacaran at c 600Ma. Partial eclogitization of the Baltoscandian margin during accretion of SNC was recognized in the late 1960s and more Iapetus-related terranes, and culminating Siluro- recent studies of the metamorphic history have Devonian, Scandian underthrusting of Laurentia shown that Ordovican UHP metamorphism, with by Baltica, involving vast lateral displacement of microdiamonds in garnets, is widespread in the allochthons. Northeastern Greenland, providing host metasediments of the SNC over a vast area, the complementary western flank of the Orogen, apparently related to subduction beneath is also dominated by major thrust systems, all outboard volcanic arcs during closure of the comprising parts of the Laurentian margin, Iapetus Ocean (now preserved in the overlying emplaced at least 200 km westwards onto the Köli Nappe Complex). It is suggested here that the platform. increase in density related to eclogitization of the mafic magma-rich margin, promoted the In the deep hinterland of both the Scandinavian subduction process. The SNC is dominated by and Greenlandian Caledonides there is abundant upper crustal components – psammitic and evidence of late-orogenic, early Devonian axial pelitic metasediments, hosting the dolerites and extension, superimposed on the nappe pile; also, gabbros; most of the underlying attenuated, hinterland-vergent extension. Both these magma-intruded, lower crustal “basement” was phenomena are prominent in the Svalbard apparently eclogitized and lost into the mantle. Caledonides, where the rock units and tectonic Our preferred hypothesis is that most of this history of deposition and thrusting is so similar to subducted basement was of Sveconorwegian age northeast Greenland; only in southwestern

110 Spitsbergen, in the domain of the Cenozoic fold- preserved and can be found on favourably and-thrust belt, is there a Caledonian terrane weathered surfaces. with affinities to northernmost Greenland, Pearya and the Timanides, providing key The interpretation of the lithologically mixed unit evidence for understanding Caledonian orogeny between Bergen and Tynset is challenging, in the Arctic. because, no geochronological evidence of the early rift stages from within the unit have yet been reported. Moreover, the unit may have been reworked between the latest Cambrian and early ORAL Mid-Ordovician (Jakob et al. 2017). However, an original lithostratigraphic succession of the Remnants of the pre-Caledonian ancient Baltica rifted margin may be preserved in Baltica rifted margin preserved in a a thrust nappe north of Lesja (Jakob et al. this lithologically mixed unit between volume) and may help to shed light on the origin Bergen and Tynset, Scandinavian and pre-Scandian history of the mixed unit Caledonides, South and Central between Bergen and Tynset. Norway

Johannes Jakob1, Joost M. van den Broek1 and ORAL Torgeir B. Andersen1 1The Centre for Earth Evolutions and Dynamics, Subduction and thrust emplacement Department of Geosciences, University of Oslo, Norway of the Lower Seve Nappe in the

Scandinavian Caledonides: Pressure- Remnants of the magma-poor and magma-rich Temperature-Deformation pre-Caledonian rifted margin of Baltica are constraints along the COSC-1 preserved in the allochthons of the Scandinavian borehole in Åre Caledonides. The transition from magma-poor to the magma-rich domain corresponds to the Pauline Jeanneret1, Johanna Holmberg1, Iwona northern termination of the Jotun Nappe Klonowska1, Jaroslaw Majka1, Henning Lorenz1, Complex. Solitary metaperidotite bodies abound Bjarne S.G. Almqvist1, Anna Ladenberger2, in the magma-poor segment and the transition Karolina Kośmińska3 and David G. Gee1 zone. 1Department of Earth Sciences, Uppsala University, Villavägen 16, 752 36 Uppsala, Sweden, 2Geological The metaperidotite bodies display a Survey of Sweden, Villavägen 18, 751 28 Uppsala, characteristic early flattening fabric. The Sweden, 3Faculty of Geology, Geophysics and flattening fabric is well-developed in the Environmental Protection, AGH – University of Science ultramafic bodies enclosed in the and Technol metasedimentary units structurally below the large crystalline basement nappes of Southern The Scandinavian Caledonides comprise thrust Norway including the Jotun, Lindås, and upper sheets transported onto the Paleozoic platform Bergsdalen nappe complexes, but can also be successions of the Baltoscandian margin. These found in the metaperidotite lenses between thrust sheets are subdivided into the Lower, Vågåmo and Tynset. Pre-Scandian contact Middle, Upper and Uppermost allochthons. The relationships between those deformed tectonostratigraphically highest part of the metaperidotites and the metasediments have Middle Allochthon is the Seve Nappe Complex, been obliterated during the Scandian Orogeny. the target for the Collisional Orogeny in the However, well-recrystallised, pre-Scandian, Scandinavian Caledonides (COSC-1) scientific extensional and sedimentary “ghost structures” drilling project. A continuous ~2.4 km long drill within the metaperidotite bodies are locally core through the metamorphic Lower Seve

111 Nappe (LSN) has been retrieved. The Seve nappes preserved. This has led to the norm of are considered to have been still hot when subdividing the SNC in different thrust nappes. emplaced and, consequently, the COSC-1 profile We propose, however, a model where the Seve in provides a unique opportunity to relate the Norrbotten represents a more continuous section pressure-temperature-deformation (P-T-D) through the magma-rich, attenuated margin of history of this critical allochthon to the tectonic Baltica and that the metamorphic overprint, structures that formed during emplacement rather than representing decoupling and re- under mid-crustal condition. Moreover, this stacking, represent differential reactivity of research will endeavor to establish a coherent individual lithologies with different reaction model of mid-Palaeozoic (Scandian) mountain potential. High strain zones are present building. Our research focuses on deciphering the throughout Seve but the need for large internal complete P-T-D evolution of the LSN based on a thrusts juxtaposing older rocks on top of younger combination of established and innovative is not present internally in the Seve. This has methodologies of P-T estimates (QuiG barometry dramatic consequences for, not only the and TitaniQ thermometry). The finite ductile understanding of the mountain building in the strain pattern of the LSN results from the Caledonides, but may also open a new interest for superposition of two major tectono- the Seve as a place to study the deep processes of metamorphic events M1-D1 and M2-D2. M1-D1 magma-rich passive margins, which are often lost features are interpreted as the consequence of in subduction and in general difficult to study in the LSN subduction, and M2-D2 event seismic lines due to masking of high velocity corresponds to the final exhumation and mafic intrusive and extrusive rocks. thrusting of the LSN above the underlying allochthons.

ORAL

ORAL UHP metamorphism in the Seve Nappe Complex in the Scandinavian A new tectonic model for the Seve Caledonides Nappe Complex in Norrland, Sweden Iwona Klonowska1, Jaroslaw Majka1 and Marian Hans Jørgen Kjøll1, Torgeir Andersen1 and Loic Janák2 Labrousse2 1Uppsala University, Sweden, 2Slovak Academy of 1Centre for Earth Evolution and Dynamics (CEED), Sciences University of Oslo, Norway, 2Universite Pierre et Marie Curie, Paris, France Evidence for ultrahigh-pressure metamorphism (UHPM) and deep subduction of the Baltican The Seve Nappe Complex (SNC) in Norrbotten, outer margin in provided by diamond-bearing Sweden has classically been mapped as a series of gneisses in three localities, on Tväråklumparna nappes formed by the telescoping of the rifted and Åreskutan in west-central Jämtland and near margin of Baltica. Typically, the SNC is sub- Saxnäs in southern Västerbotten. These UHP divided into the lower, middle and upper nappe- gneisses are found within the Middle Seve Nappe. series. The lower Seve generally constitutes slivers of basement and are overlain by meta- Microdiamonds are identified by microRaman sedimentary and meta-igneous rocks spectroscopy and are found as inclusions in representing both the middle and upper Seve garnet as well as in zircon. The UHPM within this nappes. The peak metamorphism varies rocks is also confirmed by the phase equilibrium considerably within the Seve from local eclogite modelling. The peak pressure conditions of the facies to a more regional amphibolite facies and Åreskutan gneiss are estimated to 4.1-4.2 GPa domains where original pre-Caledonian contact and 830-840ºC, whereas of the Marsfjället gneiss metamorphism related to dolerite intrusions are (Saxnäs) to ~3.6 GPa and 750ºC. Monazites from

112 all three localities were chemically dated and complexity of the SBP is a key for understanding they yielded Ordovician ages of migmatization of whole Svalbard together with adjacent area. (post-UHP stage). The dating for Åreskutan and Tväråklumparna gneisses shows that the This work was supported by the National Science diamond-bearing gneisses underwent partial Centre (Poland) through the “NAC” project no. melting between 445 and 435 Ma, whereas the 2015/17/B/ST10/03114. post-UHPM in Marsfället gneiss is older (ca.

470Ma). The timing of the UHPM and diamond formation still remains to be resolved, however ORAL the recent studies provide important information about the tectonometamorphic evolution of the Syn-collisional Scandian extension Seve Nappe Complex in the Swedish and magmatism on the Orkney Caledonides. Islands, Scotland

Anders Mattias Lundmark1, Lars Eivind Augland1 1 ORAL and Audun Dalene Bjerga 1University of Oslo, Department of Geosciences, PO Box A review of magmatic and 1047 Blindern, 0316 Oslo, Norway metamorphic events recorded by crystalline basement of Southwestern The Orkney Islands, NW Scotland, are dominated Svalbard by sedimentary rocks of the Devonian Orcadian Karolina Kośmińska1 and Jarosław Majka2 basin. The sparsely outcropping basement has 1AGH Univeristy of Science and Technology, Kraków, received less attention than its cover, but is Poland, 2Uppsala University, Uppsala, Sweden typically interpreted as Grampian or Scandian granites intruding Neoproterozoic Moine schist. New structural, TIMS age and geochemical data Svalbard’s Southwestern Basement Province demonstrate that a grey and a pink granite (SBP) consists of numerous tectonic units intruded metasedimentary gneiss at 432 ± 0.5 Ma juxtaposed by major strike-slip faults and thrust and 430 ± 1 Ma, respectively, to form the Orkney zones of early Paleozoic (perhaps also granite complex during the Scandian phase of the Neoproterozoic) to Cenozoic age. Felsic and mafic Caledonian orogeny. Inherited zircons in the igneous rocks of various affinities are of Ectasian- granites give ages typical of Moine schist. Both Stenian, Tonian and Cryogenian-Ediacaran age. granites display geochemical characteristics of Sedimentary successions were deposited during the Scandian high Ba-Sr granite suite in the Mesoproterozoic, Neoproterozoic and early northern British Isles. Both the granites and the Paleozoic. Majority of both igneous and gneiss are cut be previously undocumented metamorphic rocks have been affected by at least extensional mylonite zones, which are one metamorphic event. Metamorphic events overprinted by similarly oriented extensional were associated with the Torellian (c. 640 Ma), phyllonites, and in one case by similarly oriented Caledonian and Ellesmerian (c. 360 Ma) extensional brittle faults. Three such deformation orogenies. The grade of metmorphism varied zones are observed: in the north, the Yesnaby from greenschist and amphibolite to blueschist shear zone display top-to-north extensional and eclogite facies. The SBP is definitely a shear sense and in the south the Stromness and composite terrane assembled piece by piece the Graemsay shear zones display top-to-south during the aforementioned orogenic events as extensional shear sense. Successive emplacement well as the Eurekan orogeny that shaped final of granite, pegmatite and aplite into the shear tectonic framework observed nowadays. zones, cross-cutting some structures while being Comprehensive recognition of the geological deformed by others, allow dating of the deformation. We propose that the ductile to

113 brittle evolution of the shear zones reflect This work was supported by the National Science deformation during emplacement and cooling of Centre (Poland) through the “NAC” project no. the granite complex at a relatively shallow crustal 2015/17/B/ST10/03114. depth. The N-S extension on Orkney during Scandian overall NW-SE directed collision likely reflects transcurrent faulting associated with the ORAL nearby Great Glen Fault. Integration of palaeomagnetic,

isotopic and structural data to ORAL understand Svalbard Caledonian Are Southwestern Svalbard and the Terranes assemblage Pearya Terrane counterparts? Krzysztof Michalski1, Geoffrey Manby2, Krzysztof Nejbert3, Justyna Domańska Siuda3 and Mariusz Jarosław Majka1 and Karolina Kośmińska2 Burzyński1 1Uppsala University, Uppsala, Sweden, 2AGH University 1Institute of Geophysics, Polish Academy of Sciences – of Science and Technology, Kraków, Poland Centre for Polar Studies KNOW, 2Natural History

Museum, London, Great Britain, 3Department of Geology, University of Warsaw, Poland Svalbard’s Southwestern Basement Province

(SBP) and the Pearya Terrane of northern Ellesmere Island are thought to be possible During the PALMAG project (2012-2016) a total counterparts dismembered by long-distance number of 828 palaeomagnetic specimens of strike-slip faults. Both terranes indeed share metacarbonates and metabasites from 46 sites some similarities including Mesoproterozoic to representing all three of Svalbard’s Caledonide Neoproterozoic igneous rocks and associated Terranes were demagnetized in the Laboratory of sedimentary successions locally intruded by Palaeomagnetism (Institute of Geophysics Polish younger mafic dykes as well as thick Academy of Sciences) to recognize their NRM Neoproterozoic sedimentary successions that patterns. Simultaneously, 13 samples of mica include horizons of diamictites of possible glacial schists and amphibolites from the Western and origin. However, there are also dissimilarities Eastern Terranes and mylonites from the between the two terranes. The SBP bears a record Kongsfiord, Billefiord and Eolussletta Fault Zones of the Torellian orogeny (c. 640 Ma), which is were subjected to in situ laser ablation hitherto lacking in Pearya. Also, clearly 40Ar/39Ar age determinations at the CEPSAR subduction related Caledonian blueschist facies (The Open University, UK). Integration of rocks are known only from the SBP. On the other palaeomagnetic and isotopic experiments hand the Pearya Terrane comprises a vestige of accompanied by detailed structural observations the Ordovician island arc, which could have been lead to the following palaeogeographic and a part of the same subduction system. The Pearya tectonic conclusions: (a) the results confirm the Terrane also hosts Devonian intrusives which do complete remagnetization of the investigated not occur in the SBP. Despite these dissimilarities, metamorphic complexes of Spitsbergen (West of it can be stated that both the SBP and the Pearya Hinlopenstretet) during Caledonian tectono- Terrane form a coherent system of tectonically genesis (Burzyński et al. 2017); they also confirm juxtaposed sub-terranes, but much more the amalgamation of Svalbard with Baltica in Late comprehensive tectonic, petrological and Silurian time (Michalski et al. 2012, 2014); (b) the geochronological research in both terranes is results indicate a significant reorganization of the needed to decide whether they are true geometry of the sampled sectors of the West counterparts or not. Spitsbergen basement by listric faulting related to the opening of the North Atlantic-Arctic Ocean Basins (Michalski et al. 2017); (c) In

114 Nordaustlandet (East of Hinlopenstretet), relicts explain the post-Ordovician deformation as a of a pre-Caledonian (primary?) magnetization combination of the Telychian extension, and the appears to have survived; (d) analyses of the meteor impact. The gas produced in the Siljan palaeolatitudes derived from the Murchisonfiord Ring is biogenic and likely from biodegradation of (Nordaustlandet) samples do not confirm the residual oils (Rouchon et al., 2015). The gas positioning of Eastern Svalbard near to Eastern seeping activity however, is likely due to the Greenland in Neoproterozoic time, the results decompression (around 200 bar) from the suggest, rather, that Eastern Svalbard constituted withdrawal of the Weichselian ice cap and the a separate microplate or could have been located associated subglacial basement water flow near the N. Greenland/Pearya blocks. patterns. (manuscript in revision).

ORAL ORAL The Siljan Ring; A Lower Paleozoic Timing of collision initiation and petroleum system with kitchens in a location of the orogenic suture in the Telychian rift basin, disrupted by Scandinavian Caledonides meteor impact and rejuvenated by biological and Quaternary glacial Trond Slagstad1 and Christopher L. Kirkland2 processes 1Geological Survey of Norway, Trondheim, Norway, 2Centre for Exploration Targeting–Curtin Node, Curtin John Michelsen1, Ganjavar Khavari-Khorasani and University, Perth, Australia Jollinus Salehy 1Gigawiz Ltd. Co The Scandinavian Caledonides formed during The oils in Siljan are thought to have formed by Baltica–Laurentia continent-continent collision Frasnian impact heating of the Katian Fjäcka in the late Silurian. We propose that initial shale (Vlierboom et al., 1986). However, oil contact along continental-margin promontories remains are not unique to the Siljan crater and led to a drop in convergence rate, resulting in occur throughout the subsurface of central increased slab roll-back along parts of the margin Sweden (Sandström et al., 2006). By reexamining still undergoing oceanic subduction. Slab roll- published seismics (Juhlin et al., 2012; Muhamad back caused extension of the overlying 2017), well descriptions (Lehnert et al., 2012; lithosphere with orogen-wide emplacement of Muhamad et al., 2015) together with our own mafic layered intrusions, ophiolite formation and source rock observations, we demonstrate that bimodal magmatism at 438–434 Ma, in what the oil formed in kitchens in a Telychian rift basin immediately thereafter became the upper plate prior to the impact. We see no evidence of NW-SE (Laurentia) in the Scandian collision. Initial oriented Ordovician facies belts (Lehnert et al., collision at promontories may be challenging to 2013), and imaged major normal faults and the identify due the metamorphic effects of full- Mora structural high are Telychian rather than fledged collision shortly thereafter. However, impact related. The major unconformity seen in rapid deposition of sediments from eroding the Mora 1 well (Lehnert et al., 2012) is the base orogenic highs just prior to or during the 438– of a 200m+ deep NNW-SSE oriented 600m+ wide 434 Ma period may represent a tell-tale sign of incised valley, triggered by associated normal early collision. An example of such early Silurian faulting. We suggest the rift basin formed due to deposits may be present on Magerøya, in the extension over the flexural bend in front of the northernmost Scandianavian Caledonides (Corfu Caledonian orogeny. We also observe younger et al., 2006), where the sediments appear incised valleys, possibly related to the penecontemporaneous with mafic intrusive units Sheinwoodian glacially triggered regression. We likely formed in a back-arc setting. This model

115 provides a tight constraint on the timing of The Bangenhuk unit of the Nordbreen Nappe is collision initiation, and provides a framework by composed mainly of granitic gneisses whose age which some tectonic units comprising the was estimated to c. 1750 Ma (Johansson et al. Scandinavian Caledonides can be assigned a 1995, Bazarnik et al. 2017). However, older (c. Baltican or more exotic heritage, where other 2709 Ma) quartz-monzonite has also been found methods, such as detrital zircon (DZ) chronology (Hellman et al. 2001). Both gneisses and cannot, as proved by DZ statistical similarity right metasedimentary covers are intruded by mafic across the entire North Atlantic region (e.g., dykes of unknown age. Slagstad & Kirkland, in press). Tracking the suture through the intrusive model highlights A sample of metamorphosed gabbro was that many units conventionally ascribed a collected from the southern coast of Mosselbukta, Baltican heritage are in fact much more far near a small cottage on the Bangenhuken travelled. peninsula, during the CASE 18 Expedition in 2015. It forms a dyke cutting thorough gneisses and striking approximately north-south. The gabbro is composed mainly of plagioclase, POSTER pyroxene, amphibole and garnet with minor amount of apatite, ilmenite, quartz and zircon. The age of metagabbro from the Bangenhuk unit, Atomfjella Complex, U-Pb zircon dating was performed in the Micro- Ny-Friesland, Svalbard Analyses Laboratory in Polish Geological Institute in Warszawa using SHRIMP IIe/MC. Jakub BAZARNIK1, Jarosław MAJKA2, Jarosław About 40 fragments of euhedral zircon grains MAJKA3, Karolina KOŚMIŃSKA3, William C. with oscillatory zoning have been analyzed. The MCCLELLAND4, Karsten PIEPJOHN5, Zbigniew obtained result ca. 1382 Ma has not been CZUPYT6 and Tomáš MIKUŠ7 recorded in the Ny Friesland area before. Similar 1Polish Geological Institute – NRI, Carpathian Branch, ages were noticed in Zig-Zag Dal Formation in Skrzatow 1, 31-560 Krakow, Poland, 2Department of eastern North Greenland (Upton et al. 2005). Earth Sciences, Uppsala University, Villavägen 16, 752- 36 Uppsala, Sweden, 3Faculty of Geology, Geophysics and Environmental Protection, AGH–UST, Krakow, Poland, 4Department of Earth and Environmental POSTER Sciences, University of Iowa, Iowa City, Iowa 52242, USA, 5Bundesanstalt fur Geowissenschaften und Detrital zircon signatures of the Rohstoffe, Geologie der Energierohstoffe, Hanover, metasedimentary rocks of the Lower Germany, 6Polish Geological Institute – NRI, Address 4, Rakowiecka Street, 00-975 Warszawa, Poland, 7Earth Seve Nappe in the COSC-1 drillhole, Science Institute, Slovak Academy of Sciences, Åre, Sweden. Ďumbierska 1, 974 01 Banská Bystrica, Slovakia Yuan Li1, David G. Gee2 and Anna Ladenberger3 1State Key Laboratory for Continental Tectonics and The Bangenhuk unit is a part of the Atomfjella Dynamics, Chinese Academy of Geological Sciences,, Complex and belongs to the Svalbard’s Eastern 2Department of Earth Sciences, Uppsala University, Basement Province. Whole Complex has been Sweden., 3Geological Survey of Sweden metamorphosed in amphibolite facies during the Caledonian Orogeny (Witt-Nilsson et al. 1998). The ICDP- “Collisional Orogeny in the The rocks of the Atomfjella Complex crop out in Scandinavian Caledonides” (COSC) drilling western Ny-Friesland and form north-south project, targeted the Lower Seve Nappe, located trending antiform, which includes metagranitic in the footwall of the microdiamond-bearing basement covered by younger metasediment Åreskutan Nappe of the Seve Nappe Complex (Gee & Tebenkov, 2004). (SNC) in western Jämtland; it penetrated 2500m of mainly psammitic metasediments,

116 amphibolites and a few felsic, usually pegmatitic 4.3. Evolution of the North intrusions. U-Pb dating by LA-ICPMS of zircons in these lithologies provides evidence of a mainly Atlantic margin: from Mesozoic Mesoproterozoic provenance of the rifting to Cenozoic inversion metasedimentary rocks and it also confirms evidence of mid Ordovician felsic magmatism (Li et al. 2014). The age of the mafic rocks is difficult ORAL to constrain because they have all been subject to a complex metamorphic history (Jeanerette et al, Deltaic growth-faults of the Triassic this volume). Over twenty samples of the Barents Shelf; structural style and psammitic schists and gneisses have been deformation mechanisms controlling analysed. As in previous investigations of the SNC basin configuration (Gee et al 2014) and underlying Särv Nappes (Be´eri-Schlevin et al 2011) in central Jämtland, Alvar Braathen1, Mark Mulrooney1, Aleksandra and farther north near the border to Västerbotten Smyrak-Sikora2, Beyene Haile1, Ingrid Anell1, Kei (Kirkland et al 2011) and also southern Ogata3, Harmon Maher4, Per Terje Osmundsen5 Norrbotten (Gee et al 2015), the zircon and Ivar Midtkandal1 populations are nearly all dominated by 1Department of Geosciences, University of Oslo, Norway, Sveconorwegian signatures; many also by a 2Department of Arctic Geology, UNIS, Norway, 3Vrije strong late Palaeoproterozoic component. At the University, Amsterdam, Holland, 4University of base of the hole, there is a significant late Archean Nebraska at Omaha, USA, 5Geological Survey of Norway zircon population. Along with the data from the Kalak Nappe Complex correlatives of the SNC and Deltas represent major sedimentary Särv Nappes in northernmost Norway (Kirkland accumulation zones with distinct subaqueous, et al 2007), the new data emphasize the common sigmoidal geometry and principal deposition character of the provenance of the sediments in concentrated near the top, which are inherently all these nappes, derived from the outer margin prone to instability that leads to mass wasting of Baltica. and/or structural collapse. We compare tectonic and collapse-related faults associated with delta progradation of the upper Triassic succession of Edgeøya (SE Svalbard), to collapse structures in a more “typical” Last Chance Delta (Utah). Common

for both investigated delta systems is that faults have listric geometries instigated by linkage of variously oriented segments above well defined detachment zones. Hanging walls form rollover folds, locating accommodation in the half- grabens towards faults. Infill is characterized by wedge-shaped, sand prone bodies that attest to

rapid slip increments on faults contemporaneous to mild erosion along the crests of fault blocks. In the footwall (underneath) of listric faults, mud pillows or triangle-zones are developed. Related smaller structures attest to a transition from

hydroplastic shear to brittle, frictional flow deformation along with diagenesis and cementation.

Edgeøya half-grabens arrested high amounts of sand in the prodelta realm, whereas the Last

117 Change delta records deposition mainly in the geological profiling including seismic and deltatop. The trigger and driving mechanism for potential field measurements to investigate the delta collapse by faulting is the localized, characteristics and settings of the Ramså Basin. differential loading of the sand bodies of Specimens were analyzed sedimentologically, channels/mouth bars and fault-controlled basins. petrologically/mineralogically and Faults move material towards the free surface of geochemically. Four new boreholes were core- the delta-front. Complementary, compaction of drilled and are currently subject to further prodelta muds offers localized and gradual analyses. mechanical decoupling from overlying denser sand. Further, the compaction front below deltas This integrated study provides an enhanced can trigger faulting in the prodelta realm, with understanding of the geometry and tectonic land-ward dipping faults facing the prograding settings of the Ramså Basin as a set of a NE-SW delta-front. oriented normal faulted half-graben, which developed in the latest stage of the opening of the Andfjorden Basin. Our results indicate weathering in a tropical to sub-tropical climate, ORAL and K/Ar dating reveals Late Triassic age. Two newly found Mesozoic sub-basins south of the The Mesozoic basin of Ramså in Ramså Basin confirm repeated erosion and Northern Norway: Characteristics, transgression phases with a burial depth of the Development and regional impact sediments not exceeding more than 2 km.

Marco Brönner1, Tor Arne Johansen2, Børre Davidsen3, Håkon Rueslåtten3, Bent Ole Ruud2 and Tormod Henningsen4 ORAL 1Geological survey of Norway, Trondheim; Department for Geoscience and Petroleum, NTNU, Trondheim, Correlation of the Oligocene – 2University of Bergen, Bergen, Norway, 3Geological Pliocene succession in Norway, survey of Norway, Trondheim, Norway, 4University of Denmark & UK Tromsø, Tromsø, Norway Tor Eidvin1, Erik S. Rasmussen2, Fridtjof Riis1 and Karen Dybkjær2 The Ramså Basin on Andøya, Northern Norway 1Norwegian Petroleum Directorate (NPD), P. O. Box gives a unique insight into the Mesozoic 600, N-4003 Stavanger, Norway, 2Geological Survey of sedimentary strata onshore the mainland of Denmark and Greenland (GEUS), Øster Voldgade 10, Norway. It experienced a great deal of attention 1350, Copenhagen K, Denmark. since the 19th century and was studied geologically several times. However, extensive geophysical mapping was missing and the The almost complete, mainly deltaic, upper tectonic development of the basin itself is still Paleogene-Neogene succession from Jylland, disputed. Denmark was investigated for Sr-isotopes, micro- fossils, and palynology in order to make a robust Moreover, the basin is part of the well developed stratigraphic framework for the North Sea strandflat of eastern Andøya where remains of area. The investigation shows that the Danish deeply weathered basement around and succession correlate readily with lithological underneath the sedimentary strata indicate a units, in the Norwegian North Sea, the Norwegian history of repeated uplift and erosion which Sea shelf and the East Shetland Platform. In makes it to a key location to understand the particular, Bolboforma and dinocyst correlations development of this remarkable landscape show that the upper part of the Danish Gram widely observed along the Norwegian coast. In a Formation correlates with the base of the Molo cooperation project of NGU and the University of Formation in it’s southern part, and that this part Bergen we carried out extensive geophysical and of the Molo Formation corresponds to the

118 middle/upper part of the Kai Formation Danish Basin. In the Jurassic – Early Cretaceous, (Norwegian Sea shelf). The new robust the Kattegat segment changed into an correlation between the North Sea and North asymmetric, northeast dipping graben, the Atlantic realm is fundamental in the Kattegat Graben. In the Late Cretaceous, understanding the palaeogeography during the maximum subsidence returned to the southwest late Paleogene and Neogene. For instance, The into the Danish Basin, while the Kattegat Graben Bolboforma assemblages have their origin in the was inverted during backward tilt of the graben Norwegian Sea and therefore, due to the presence block. in the Danish area, confirm that it was an open strait in the northern North Sea (the only seaway The ENSB formed the northeast flank of the passage into the North Sea Basin during the Central North Sea Dome (2). The Jurassic – Miocene). The glauconitic Utsira Formation Cenozoic structural evolution of the ENSB was (approximately 5.7-5 Ma), in the threshold area governed by the rise and fall of the Central close to the opening to the Norwegian Sea, overlie Graben rift dome: 1) synrift rise in the Jurassic – erosional unconformities comprising 21 and 13 Early Cretaceous, 2) Late Cretaceous transition my. We believe that this unconformity was partly phase with collapse of the Central Graben rift, 3) related to the activity of strong currents in the Cenozoic postrift subsidence (3). A model of the narrow strait between Norway and the Shetland Mesozoic crustal tectonics associated with the platform and partly related to the Messinian ENSB illustrates the interrelationship between glacio-eustatic level drop. the evolution of the Kattegat – Skagerrak segment and the Central Graben Dome across the eastern North Sea Basin (4).

ORAL

Late Cretaceous basin inversion in ORAL the Kattegat – Skagerrak segment, Mesozoic basin inversion governed Sorgenfrei – Tornquist Zone, by crustal extension in the Bornholm Denmark, and Mesozoic – Cenozoic area, Sorgenfrei-Tornquist Zone, crustal tectonics of the eastern North Denmark Sea Basin Ole Graversen1 1 Ole Graversen 1Department of Geosciences and Natural Resource 1Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark Management, University of Copenhagen, Denmark.

Basin inversion describes the deformation of The Sorgenfrei – Tornquist Zone is a NW-SE asymmetric grabens characterized by folding and trending, 50-100 km wide fault zone that cut off thrusting, i.e. horizontal shortening, associated the East North Sea Block (ENSB), i.e. the Mesozoic with uplift of the sedimentary graben fill above basement of the Eastern North Sea Basin, from regional (1). The compressive stress field has the Baltica Palaeozoic platform. The break was been interpreted in a plate tectonic concept as a established in the Triassic, where the ENSB was result of continent-continent collision that established as the hangingwall block in the established a compressive stress field in the Kattegat area; by contrast, the Baltica platform orogenic foreland (2, 3). develloped as the hangingwall block in the Fjerritslev halfgraben to the northwest (1). However, structural analysis of basin inversion in the Sorgenfrei – Tornquist Zone illustrates, that In the Kattegat area, the Triassic faulting basin inversion was the result of superposition of established a staircase fault block trajectory with asymmetric extensional fault basins dipping in downfaulting towards the southwest into the opposite directions. The evolution of the graben

119 basins, took place during successive extensional the western margin of the Thetys Basin where tectonic regimes separated by stillstand intervals. extensional faulting with an offset exceeding 1s During subsidence of the superposed, extensional TWT on the seismic profiles is observed. This is basin, the primary basin was tilted backward, and often associated with dramatic failure of the the basin was inverted during local compression uplifted footwall where vast quantities of between the primary footwall blocks. sediment slid into the Thetys Basin, apparently instantly, which suggests relatively fast The Mesozoic fault block pattern of the Bornholm propagation of the fault system. The time of area illustrates, that the NW-SE trending breakup is constrained in the seismic data by Sorgenfrei – Tornquist Zone was extended in two magmatic intrusions dated to peak in the earliest directions: The main extension was in a NE-SW Eocene. Both a southwards deepening erosional direction across the strike of the fault zone, and a incision, as well as several vents associated with secondary NW-SE extension along the fault zone the de-gassing of intruded magma coincides with trend. the continental breakup. This seismic marker is clearly truncated by the failure of the footwall as Based on the changing graben activity, the well as offset by the fault, which shows that the Mesozoic has been divided into Triassic, Jurassic faulting occurred in post-breakup times, during a – Early Cretaceous and Late Cretaceous tectonic phase where no faulting on the “passive” extensional tectonic regimes. Graben subsidence margin is expected. Significant progradation started in the Triassic, and basin inversion was associated with tilting and erosion superseded active in the Jurassic – Early Cretaceous and again the observed faulting. This indicates that active in the Late Cretaceous (4, 5). The tectonic regimes tectonism may explain the exhumation and were separated by turnover intervals progradation observed on the Northeast characterized by only minor tectonic activity in Greenland margin during the Neogene. the late Late Triassic and the early Late Cretaceous.

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ORAL The late Cenozoic evolution of the Evidence of post-breakup tectonism mid Norwegian Margin on the Northeast Greenland shelf: Helge Løseth1 and Eilert Hilde1 Implications for “passive” margin 1Statoil ASA, R&D Trodnehim conditions

Thomas Guldborg Petersen1 Even though North Atlantic post break-up 1Technical University of Denmark, DTU sediments are well recorded on the structural rather simple mid Norwegian passive margin, the unconstrained ages and uncertain paleo- The break-up between the Eurasian and North geographic reconstructions has led to debate. The American plates during the Paleogene is well aim of this paper is to constrain the late Cenozoic constrained by geophysical data. The structural geological evolution with focus on vertical history of Northeast Greenland following the movements of the inner margin and positions of breakup is on the other hand still very much an coast-lines. The database consists of regional 2D area of discussion. Here, analysis of seismic data and 3D seismic and well data. offshore Northeast Greenland constrains the timing of the post-breakup tectonic events by Prior to the Miocene compression phase, Eocene correlation with the well-dated magmatic to lower Miocene coastlines were located intrusions in the region and their associated landward of the subcrop with an unresolved thermal uplift and venting of gasses. Previous eastward extent. The mid to late Miocene studies have mapped large-scale faulting along compression phase, which formed inversion

120 structures more than 1000m high and 300km the palaeostress and slip tendencies of five fault long, also caused dramatic shifts in base levels types in the Swaen Graben. These faults were along the inner passive margin. The base level fell selected based on the assumption that they are 100’s of meter at onset of compression and the strike-slip faults, flower structures, riedel shears, coastline shifted ocean-ward. The Mid Miocene isolated-erosionally decoupled faults, and small- Unconformity developed and the syn-tectonic Kai scale transfer faults. The principal palaeostress Formation was deposited. Upon termination of tensor associated to the faults, was determined the compression phase the base level rose in the based on the relationship between the slip order of 500m. Sediments from the following tendency values and the measured displacement. transgression (lower Molo Formation) is Our model shows a sub-vertically oriented σ1 documented for the first time. The younger coast- plunging 76.9º along a N246.4º azimuth for all the parallel 600km long upper Molo Formation shelf five fault types. The orientations of σ2 and σ3 are delta is overlain by the Quaternary glacio-marine sub-horizontal. Slip tendency values for the faults Naust Formation. The inner shelf was tilted 0.5° varies from 0 to 1. Most of the Type 1 faults show westward during the glacial period due to isotatic slip tendency values 0 to 0.67. Type 3 and 5 faults adjustments from onshore erosion and offshore have the highest slip tendency values. deposition. Hydrocarbon leakage factor ranges from 0.16 to 1 and is highest within the Type 3 and 5 faults. We The observed vertical base level fall and show that these faults are extensional with the subsequent rise of the inner passive margin Type 5 faults acting as transfer faults connecting occurred with the onset and termination of the two disparate fault systems. The studied faults compression phase. Similar shifts may occur are analogous to modern day examples in the along any passive margin. East African Rift Systems.

ORAL ORAL

Palaeostress analysis and Influence of late Cenozoic erosion and hydrocarbon leakage potential of deposition on temperature disparate fault sets within the Swaen distribution beneath the north- Graben eastern part of the Mid-Norwegian

Nathalia Mattos1, Kamaldeen Omosanya2, Ståle continental margin (the Lofoten- Johansen3 and Tiago Alves1 Vesterålen area) 13D Seismic Lab, School of Earth and Ocean Sciences, Cardiff University, 2Department of Geoscience and Yuriy Maystrenko1, Laurent Gernigon1, Odleiv Petroleum, Norwegian University of Science and Olesen1, Dag Ottesen1 and Leif Rise1 Technology, 3Geoscience and Petroleum, Norwegian 1Geological Survey of Norway, Trondheim, Norway University of Science and Technology

A 3D thermal pattern beneath the north-eastern The Swaen Graben represents one of the part of the Mid-Norwegian continental margin Cretaceous structural elements of the SW Barents (the Lofoten-Vesterålen area) and adjacent areas Sea whose growth and development remains of the continent has been investigated to poorly described in the literature. Majority of the understand the thermal effect of relatively high previous works undertaken in the study area erosional and depositional rates observed during proposed a close connection between the Swaen the Pleistocene. Graben and the Eastern Loppa High with the likelihood of a strike-slip tectonics being the A lithosphere-scale 3D structural model of the dominant process for fault growth on the western Lofoten-Vesterålen area from Maystrenko et al. section of the graben. In this work, we assessed (2017) has been used as a realistic approximation

121 of the geometries of the sedimentary infill, crustal scale, cut large thicknesses of crystalline crust and lithospheric mantle during a heterogeneously layered lithosphere and 3D thermal modelling. The 3D thermal modelling facilitated fundamental margin processes such as has been performed by use of the commercial post-orogenic equilibration, deformation software package COMSOL Multiphysics. The coupling and eventual excision or near excision of Earth's surface and sea floor have been taken as continental crust. Many of them can be classified an upper thermal boundary condition with taking as extensional detachment faults, and they into account palaeoclimatic changes during the performed different types of work on the Cenozoic. The lithosphere-asthenosphere lithosphere and occupy different locations in the boundary has been used as a lower thermal margin architecture. The array of associated boundary. The erosion and deposition have been synrift basins thus record the changing state of also included in the 3D thermal calculations. the continental lithosphere as the crystalline crust was nearly or wholly excised in a series of The modelled thermal influence of the late major deformation stages. The association of Cenozoic erosion within the Lofoten-Vesterålen synrift supradetachment basins with margin segment is reflected by a positive thermal fundamental modes of crustal thinning explains anomaly within the areas where sedimentary the particular locations of distinct basin styles in and/or crystalline rocks were eroded. A negative the margin architecture and provides the basis thermal effect has been modelled in the areas for a broad classification. Supradetachment affected by deposition of sedimentary rocks. The basins appear to dominate the population of erosion-induced, positive, temperature anomaly synrift basins on the margin scale. They were o is up to +27 C at depths of 17-22 km beneath the draped by a basin that post-dated local block eastern part of the Vestfjorden Basin. Two rotation but pre-dated breakup, and that was still deposition-induced, negative, temperature strongly affected by a subsidence pattern that o anomalies have minimal values of around -70 C much reflected the earlier large-magnitude o at 17-20 km depth and -48 C at 12-14 km depth faulting. beneath the oceanic Lofoten Basin and the north- eastern part of the Vøring Basin, respectively.

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ORAL The source area of the Miocene Ribe Group, Eastern North Sea basin: the Extensional detachments, breakaway control of climate and tectonism. complexes and supradetachment basins in rifted margin formation: Erik S. Rasmussen1, Mette Olivarius1, Karen examples from offshore Mid Norway Dybkjær1, Torsten Utescher2 and Peter Japsen1 1Geological Survey of Denmark and Greenland (GEUS), Per Terje Osmundsen1 and Gwenn Péron-Pinvidic2 [email protected], 2Steinmann Institute, University of Bonn, 1Geological Survey of Norway, 7491 Trondheim, Nußallee 8, 53115 Bonn and Senckenberg Research Norway & Dept. of Geosciences, P.O. box 1047, Universit, Institute. 2Dept. of Geosciences, P.O. box 1047, University of Oslo, 0316 Oslo, Norway The sediment provenance was investigated by comparing radiometric age dating of the sink area The large-magnitude faults that control crustal to the comprehensive data available from the thinning and excision at rifted margins combine source area. The basement in southern Norway into laterally persistent structural boundaries and southwestern Sweden, and possibly its that separate margin domains of contrasting derived sediments, is the primary source of the morphology and structure. We term them Miocene sand. However, smaller age populations breakaway complexes. At the Norwegian rifted show that the rivers had a larger catchment area. margin, the constituent faults operated on the Overall, it is the same type of sediment that was

122 fed from source to sink during the early Miocene, broadband 3-D seismic reflection data allow us to but heavy mineral analyses show that the study the extent, geometry and orientation of maturity of the sediment varies, presumably in these deep crustal structures in unprecedented response to changes in the erosion rate. The detail. The data contain a wide range of study of the source area encompasses frequencies (2.5-155 Hz) and provides high- investigations of clay minerals, flora, and fission resolution, three-dimensional images of deep track data, in order to unravel the climate and crustal reflectors. The improved imaging allows uplift history. The initial topography of the source us to map a high-amplitude lower crustal area (Fennoscandian Shield) was relatively low, reflection package over an area of more than less than 500 m in the earliest early Miocene 4000 km2. The package varies in depth from 20 to when a pronounced phase of uplift and erosion in 30 km with elevations coinciding with footwalls this region began according to interpretation of of major N-S trending normal faults. apatite fission-track data. The elevation of the source area during the early Miocene is Deep crustal reflectivity observed in the northern coincidence with a major reorganisation of North Sea has been explained by eclogized sediment routing systems in the eastern North continental crust using a combination of 2-D Sea region. This occurred during a period of seismic, gravity and magnetic data. This study climatic stability and thus most likely an explores alternatives to this explanation. More indication of tectonic activity in the source area. precisely, we examine the role that igneous An increased relief of the hinterland is revealed intrusions, Caledonian thrusts and Devonian from steadily higher contents of mountain extensional shear zones could have played in the elements in the pollenflora and by the end of the generation of the observed reflection package. early Miocene, at app. 15 Ma, the highest peaks in Moreover, we examine the timing and interaction the source area likely exceeded 1500 m. between these structures and subsequent tectonic faults.

ORAL POSTER Deep crustal structures in the Pliocene Pockmarks in the eastern northern North Sea rift: observations Danish Central Graben, North Sea - from new 3-D seismic reflection data Formation and Significance Thilo Wrona1, Haakon Fossen1, Robert L. 1 2 Gawthorpe1, Jan Inge Faleide2 and Marit Stokke Kaziwa Mohammadi and Katrine J. Andresen 1 2 Bauck3 Student, Supervisor

1Department of Earth Science, University of Bergen, Allégaten 41, 5007 Bergen, Norway, 2Department of In this study, we describe abundant Pliocene Geosciences, University of Oslo, P.O. Box 1047 Blindern, N-0316 Oslo, Norway, 3CGG, P.O.Box 43 Lilleaker, 0216 circular depressions from the Danish Central Oslo, Norway Graben, mapped using 3D-seismic data which are courtesy of Maersk Oil, Operator of DUC. We interpret the depressions as buried pockmarks Pre-existing basement structures can affect the formed due to focused fluid-venting to the nucleation, growth and linkage of normal faults in seafloor during the Pliocene. The origin of the rifts and rift systems. The northern North Sea rift fluids and the significance of the fluid-venting are developed on top of an extremely heterogeneous not fully understood. Our preliminary analyses crust containing structures from the Caledonian show that the majority of the pockmarks occur on orogeny to Devonian extension. Our one distinct surface suggesting a very confined understanding of these structures has long been timing of formation. The distinct pockmarked limited by poor imaging of the basement with surface is comprised within a westward conventional 2-D seismic reflection data. New prograding set of clinoforms suggesting that the

123 pockmarks may have formed in response to sea- Norwegian-Barents Sea-Svalbard margin, level changes and/or climatic fluctuations. The contourites are not described from the SW pockmarks furthermore occur spatially clustered Barents Sea. Using 2D-seismic data, we here in a large pockmark field, which could be describe a contourite drift covering a substantial controlled by lithology variations along the part (~20,000 km2) of the SW Barents Sea slope, clinoforms. Alternatively, deeper structural located mainly beneath the Bear Island Trough elements vertically below the pockmark field Mouth Fan. From correlation to commercial well such as the Coffee Soil Fault, which marks the data, this mounded drift covers a time span from eastern edge of the Danish Central Graben, could early Neogene to early Quaternary. This drift have focused migration of deep thermogenic therefore likely started to form at the onset of fluids and controlled the spatial distribution of alongslope flow similar to the present circulation the pockmarks. Hence, our seismic observations following the opening of the Fram Strait gateway point towards a combined control of pockmark and the subsidence of the Scotland – Faroe – formation from both deep structures and Iceland – Greenland ridge. It continued to depositional environment. Our further analysis of accumulate sediments following the onset of the the pockmarks will include borehole data and will northern hemisphere glaciations in late Neogene focus on constraining the timing and the until glacigenic deposits completely dominated controlling factors in more detail. We will this part of the slope. Parts of the drift has been investigate the origin of the escaped fluids and remobilized, thus it has influenced on the stability the possible relations with regional events in the of the continental slope, most likely because of Late Neogene-Quaternary such as climatic stress exerted by up-flank accumulation of fluctuations and maturation of thermogenic glacigenic sediments causing the drift deposits to source rocks in the Central Graben. fail. We will discuss the onset of drift growth and its implications for the evolution of the margin, and – for the first time, present sedimentation rates and sediment volume for a high-latitude POSTER contourite drift.

Origin and sediment budget of an early Neogene - early Quaternary contourite drift system on the SW Barents Sea margin

Tom Arne Rydningen1, Gert Høgseth1, Amando Lasabuda2, Jan Sverre Laberg2 and Polina A. Safronova3 1Dep. of Geosciences, University of Tromsø, 2Dep. of Geosciences, University of Tromsø; Research Centre for Arctic Petroleum Exploration (ARCEx), 3ENGIE E&P

Norge AS

Alongslope ocean currents distribute sediments across continental slopes surrounding ocean basins, making contourite drifts deposited from such currents important paleoceanographic archives. Furthermore, on high-latitude margins submarine failures often relate to contourites, as they may act as weak layers due to their lithological character and/or physical properties. Although identified several places along the

124 4.4. Vertical movements, points. Examples were determination of burial depth (approx. 5km) during Carboniferous of a changes in plate motion and suevite from the Ritland impact crater, Norway, mantle dynamics: observations and determination of palaeotemperatures of and models in the north-east sediments in the Barents Sea.

Atlantic domain

ORAL ORAL Early postglacial rebound tectonics An undereexplored method for within the Tjörnes Fracture Zone, determination of paleotemperature North-Iceland. and burial depth. Bryndís Brandsdóttir1, Sigríður Magnúsdóttir1, Claus Beyer1 Neal Driscoll2, Robert Detrick3 and Jeffrey Karson4 1CB-Magneto AS 1Institute of Earth Science, University of Iceland, Reykjavik, Iceland, 2Scripps Institution of Oceanography, UC San Diego, USA, 3Incorporated A number of methods are used to estimate Research Institutions for Seismology, Washington DC, palaeotemperatures. Fluid inclusions studies give USA, 4Syracuse University, Syracuse NY, USA a direct measure of the palaeo temperature. Other methods are based on changes in The multi-branched plate boundary across mineralogy, e.g. Quartz cementation at 70°C. Clay Iceland is made up of divergent and oblique rifts, transformation from smectite to potassium rich and transform zones, characterized by complex illite happens in several stages with increasing tectonics. The Tjörnes Fracture Zone (TFZ) links temperatures. Fission track analysis is based on the northern rift zone (NVZ) on land with the formation of damage trails formed by radioactive Kolbeinsey Ridge off shore. The TFZ lacks the decay in apatite and subsequent annealing as a clear topographic expression typical of oceanic function of temperature. Methods based on fracture zones and consists of broad zone of blocking temperatures are based on diffusion of a deformation roughly 150 km wide (E-W) by 50- gas out of the crystal lattice at certain 75 km long (N-S), involving a complex array of temperatures. oblique-slip faults bounding (NS) rifts and right- lateral (WNW) strike-slip faults, active Other methods are based on the combined effect throughout Holocence. The magma-starved of temperature and the time of exposure to this southern extension of the KR, the ~80 km NS and temperature. One such method is a hitherto 15-20 EW Eyjafjarðaráll rift (ER), is made up of underdeveloped method based on the dominantly extensional faults merging magnetisation of a sediment or rock. If the southwards a system of right-lateral strike-slip magnetic grain size is favourable, the rock may faults with vertical displacement up to 15 acquire and preserve a magnetisation which will m.within the Húsavík Flatey Fault Zone be added to the already present magnetisation. If (HFFZ). A 500-700 m deep asymmetric rift, with a rock changes position by folding at a certain 20-25 m vertical displacement on normal faults point in time, this new magnetisation will have a characterizes the northern ER whereas transform different direction and may be easily defined. along the HFFZ has created a NW- striking pull- Knowing the temperature, the duration of the apart basin with frequent earthquake swarms. rock being in its present position may be We present the tectonic framework of the ER and calculated. Knowing the time period, the Skjálfandadjúp (SK) basins multibeam temperature may be calculated. In addition, the bathymetry, high-resolution seismic reflection age of the component may be calculated from the data (Chirp) and seismicity. Both basins contain palaeopole to which the magnetic component post-glacial sediments of variable thickness.

125 Correlation of Chirp reflection data and erosion are required to preserve these tephrachronology from a sediment core within landscapes. Norway south of Hardangervidda the SK basin reveal major rifting episodes must therefore have been buried below Mesozoic between 10-12.1 kyrs BP activating both basins, sediments that have subsequently been removed. followed by smaller-scale fault movements No kaolinitic weathering of the Pre-Cambrian throughout Holocene. These vertical fault rocks of Hardangervidda took place because they movements reflect increased tectonic activity were covered during the Mesozoic by Caledonian during early postglacial time coinciding with metamorphic rocks. isostatic rebound enhancing volcanism within Iceland.

ORAL

ORAL Burial and exhumation history of the Upper Jurassic sediments on Andøya, The surface below ca 900 m altitude northern Norway based on AFTA and in southern Norway was probably VR data buried by late Mesozoic sediments and re-exposed by Neogene uplift and Peter Japsen1, Paul F. Green2, James A. Chalmers1 3 erosion and Johan M. Bonow 1GEUS, 2Geotrack International, 3Geovisiona James Chalmers1 1Geological Survey of Denmark and Greenland Outliers of Middle–Upper Jurassic sediments

occur onshore and in the coastal zone of Norway Analysis of the ASTER DEM over southern near Bergen, Trondheim and in the Lofoten Norway confirms that the landscape of southern archipelago (Bøe et al. 2010). But only on the Norway above an altitude of about 900 m consists island of Andøya (Lofoten) do they crop out; here of 3 sub-horizontal surfaces separated by steeper a coal-bearing Jurassic–Cretaceous succession of slopes and incised by deep glacial valleys 900 m occurs in a small, partly fault-bounded (Lidmar-Bergstöm et al., 2000). The surface of the area on the eastern part of the island. We have Pre-Cambrian basement rocks below 900 m in measured vitrinite reflectance (VR) on samples southwest and south Norway consists of a from Norminoil well B (courtesy of the uniform rough slope dipping to sea-level or to the Norwegian Petroleum Directorate) that strandflat, also incised by deep glacial valleys. penetrated the entire Jurassic sequence on Field work shows that the landforms below 900 Andøya (Petersen et al. 2013); the mean VR value m asl and between the deep glacial erosion is 0.48% for 6 samples from depths between 218 consist of "hilly relief" and "joint valleys" as and 520 m. This value corresponds to a interpreted onshore in southern Sweden where palaeotemperature of 78°C, and for any they were buried below Late Cretaceous reasonable palaeogeothermal gradient this limestone (Lidmar-Bergstöm, 1994). Similar implies that a km-thick cover of Jurassic and structures observed on seismic sections offshore younger sediments must have covered the western Norway and south-west Sweden have Jurassic–Cretaceous sediments exposed on been buried by Late Jurassic and Cretaceous Andøya; e.g. around 2 km for 25°C/km and a rocks respectively. Hilly relief and joint valleys palaeo-surface temperature of 20°C. New apatite formed during warm wet climates during the Late fission-track analysis (AFTA) data from samples Mesozoic by weathering of feldspars in fractures of Jurassic sediments and basement from the to produce kaolin. Subsequent erosion of the Lofoten region provide results that are consistent kaolin produces joint valleys where the fractures with the interpretation of the VR and provide are aligned and hilly relief where there are information about when cooling (exhumation) intersecting sets of fractures. Burial and later from maximum palaeotemperatures (burial)

126 began. Our results thus suggest that thermal topography. The effect of the Pleistocene subsidence following rift climax in the late Middle sediment redistribution on the subsurface Jurassic (Hansen et al. 2012) led to burial of temperature has also been modelled. The Lofoten and the adjacent region by a thickness of occurrence of earthquake swarms is to some sedimentary cover equivalent to the altitude of degree correlating with high mountains located the highest peaks in the present-day landscape. along the wide Nordland strandflat.

Two presumably postglacial faults (Stuoragurra F. and Nordmannvikdalen F.) have been subject ORAL to more detailed studies such as trenching, ground penetrating radar and resistivity Neotectonics in Norway profiling. The Stuoragurra F. in Finnmark and the Grønna F. in Nordland are seismically active Odleiv Olesen1, John Dehls1, Sofie Gradmann1, faults in Norway. These results are entering an Yuriy Maystrenko1, Lars Olsen1, Conrad updated neotectonic map of Norway. Lindholm2, Ilma Janutyte2, Halfdan Kierulf3, Jan 4 4 1 Michalek , Lars Ottemöller , Dag Ottesen , Lei 1 5 6 Rise , Maria Ask , Tom Rune Lauknes and Fridtjof Riis7 1Geological Survey of Norway, 2NORSAR, 3Norwegian Mapping Authority, 4University of Bergen, 5Luleå University of Technology, 6Norut, 7Norwegian Petroleum Directorate

We summarize results of the 2013-2017 NEONOR2 project (Neotectonics in Nordland – implications for petroleum exploration) and compare it to previous research projects (e.g. NEONOR project 1997-2000) and other recent relevant discoveries. The NEONOR2 project is a collaboration project between NGU, Kartverket,

NORSAR, Norut, NPD and the universities in Bergen and Luleå. The project is sponsored by the

Norwegian Research Council and ten petroleum companies. The project investigates neotectonic phenomena onshore and offshore through a multidisciplinary approach including geological, seismological and geodetic studies combined with rock mechanics, applied geophysics and numerical modeling.

Within this project, a 26 seismograph network monitored the seismicity within a 2.5 year period. More than 1000 earthquakes were registered and 123 focal mechanisms have been derived. An updated compilation of all geodetic stations in Norway and Fennoscandia were analyzed for regional and local present-day strain patterns. Numerical modelling of the present-day stress field evaluated the effect of ridge push, sediment loading/unloading, glacial isostasy and

127 4.5. Open Session: Structural Deviations from this pattern are attributed to fracturing caused by non-coaxial deformation Geology and Tectonic along shear zones.

ORAL ORAL Coupling of the ductile and brittle structures of the bedrock in Sand tectonics - sand mobility linked Hyvinkää, Southern Finland to faulting and the influence on depositional systems Bence Balogh1, Eemi Ruuska1 and Pietari Skyttä1 1University of Turku, Department of Geography and Kristine Halvorsen1, Susanne Tveterås1, Alvar Geology, FI-20014 Turun yliopisto Braathen1, Ivar Midtkandal1 and Valentin Zuchuat1 1University of Oslo There is a general difficulty in understanding the attitudes of the inherently discontinuous fractures of the bedrock in contrast to the Mobility of sand by fluidisation, so-called sand continuous ductile structures. This study aims at tectonics, can drive surface movements and linking the ductile and brittle features and, implicity have a significant impact on sediment consequently, getting a better control over the distribution and sand body geometries. Although fracture occurrence and orientation within the similarities between sand- and salt tectonic- poorly-exposed bedrock. This study relates to related structures exist, substantial differences in studying the relationship between the bedrock deformation style and geometries occur. We and the overlying glacifluvial aquifers of the First adress the understanding of sand tectonic Salpausselkä formation in Hyvinkää, Southern processes. Three outcrops in the Upper Jurassic Finland. The results provide input data for the Entrada Sandstone and Curtis Formation in Utah ongoing implicit modelling, and bedrock DEM (USA) have been used to characterise the interpolation development in the future. Based structural and sedimentary response to the on existing geological and geophysical data, and underlying mobilisation of sand. Key new mapping observations, three principal, observations are assembled from mapping of sag- structurally homogeneous domains were upwarp and fault geometries, as well as from defined. Brittle and ductile data from two of the logging and description of growth succession. domains correlate with the E-W main branches The latter deposits attest to channelised sub- to and NE-SW splays of the regional-scale shear inter-tidal depositional environments. Data show zone, whereas fracturing within the third domain that mild sand mobilisation results in meter-scale is more irregular, controlled dominantly by a gentle sag and upwarps (sand pillows). Increased regional scale, upright fold and secondarily by N- sand mobility leads to progressively higher and S structural trends. On individual outcrops, steeper relief between upwarps and sags, which mutually parallel fractures were assigned into links to nucleation of faults and thereby fracture sets. The sets were then correlated with development of small fault-bound grabens. the regionally dominant fracture and foliation During fault activity, growth sequences attest to orientations, and reassigned into representative repeated fault movement events, demonstrating sets within the respective structural domains. the strong structural control on the basin fill. Fracturing is dominantly of cubic type with the After graben formation, many of the faults in main fracture set (R1) orientation strongly higher positions of the grabens are truncated and controlled by the foliation. The second most removed by erosion. Subsequent lenticular- abundant set (R2) tends to be approximately at a shaped basin fill reflects a wider channelized right angle to R1 and the third group (R3) depositional body than that of the grabens. consists of horizontal to sub-horizontal fractures. However, the grabens seem important in locating

128 these channels. The result from our analysis may similar chance for reactivation in either current provide important input applicable to both CO2 or future stress states. storage operations and the petroleum industry.

ORAL ORAL Target-rock weakening mechanisms Brittle fault systems of deep during peak-ring formation of the geological nuclear waste repository Chicxulub impact crater inferred at Olkiluoto, SW Finland from IODP-ICDP Expedition 364

Nicklas Nordbäck1 and Jussi Mattila2 Ulrich Riller1, Felix Schulte1, Michael Poelchau2, 1Geological Survey of Finland, 2Posiva Oy Auriol Rae3, Richard Grieve4, Joanna Morgan3, Naoma McCall5 and Sean Gulick5 1Institut für Geologie, Universität Hamburg, Olkiluoto Island has been selected as the site for Bundesstrasse 55, 20146 Hamburg, Germany, deep geological repository for high-level nuclear 2Universität Freiburg, Geologie, Albertstr. 23b, 79104 waste. This study aims to improve the Freiburg, Germany, 3Department of Earth Science and characterisation of the brittle structures Engineering, Imperial College London, UK, 4Earth intersecting the repository. The objective is to Sciences Sector, Natural Resources Canada, Ottawa, gain a better understanding of the structural Ontario, Canada, K14 0E4, 5Institute for Geophysics, evolution of the site, with the ultimate goal of University of Texas, Austin, TX, USA enhancing the understanding of the reactivation potential of different fault systems and associated The floors of large impact craters are largely flat seismic hazard. and contain one or more morphological rings. The structural complex of Olkiluoto is composed The formation of the innermost ring, the so-called of ductile and brittle structural systems, which peak ring, and the causes of target rock both have a long and complex history. The ductile weakening leading to the observed flat crater systems comprise ductile structures, formed floors are not well understood. Constraining during several different phases of these mechanisms is the prime structural Paleoproterozoic ductile deformation. The geological objective of Expedition 364 “Drilling ductile deformation has affected the bedrock the K-Pg Impact Crater”, using the Chicxulub properties, resulting in prominent anisotropy crater, Mexico, as a terrestrial analogue for the and manifested by ductile structures such as formation of planetary impact basins. The target foliation, folding and ductile shear zones, which rocks of the crater are replete with cratering- all form planes of weakness in the bedrock. These induced, microscopic to mesoscopic deformation type of structures have also played an important structures including: (1) pervasive grain-scale role in the localisation and development, of the fractures, (2) centimeter-thick cataclasite zones, brittle structures in Olkiluoto. The brittle (3) striated shear faults, (4) crenulated mineral structural system is composed of brittle foliations, and (5) ductile band structures. structures such as joints, veins, single plane faults Structural overprinting criteria point to a relative and fault zones. The faults were in this study age for these structures. Specifically, cataclasite classified into fault systems, with each system zones cut grain-scale fractures displaying jigsaw being composed of fault zones with similar geometry and are consistently displaced by shear tectonic history and structural properties. The faults. Impact melt was emplaced in zones of classification can be employed in the assessment dilation, often localized by shear faults. These of the reactivation potential of the faults at the observations indicate that pervasive site, as the faults in each fault system are fragmentation was respectively followed by considered to have similar properties and thus, a localized cataclastic deformation, shear faulting, and emplacement of melt into dilation zones. This

129 succession of deformation mechanisms is corroborated by the observation that melt bodies are devoid of shear faults. As melt bodies were POSTER viscous during formation of ductile band East Greenland 72-74° N Inland to structures, these structures formed after the shear faults. Based on the overprinting Coast Thermo-tectonic Evolution relationships, we relate the deformation Jensen, Peter K.1; Hansen, Kirsten2 1Strandparksvej structures to cratering stages known from impact 12, 1 MF, DK-2900 Hellerup, Denmark; mechanics. [email protected]

2Natural History Museum of Denmark, University of Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen POSTER K, Denmark; [email protected]

3D model of the lithotectonic units and regional deformation zones in Fission track analysis of eight samples from East the bedrock of Sweden Greenland yields information of the exhumation history. Modelling the thermal evolution of the Phil Curtis1, Carl-Henric Wahlgren1, Stefan samples indicates that essential elements of the Bergman1, ldikó Antal Lundin1, Claes Mellqvist1, recent landscape were established before 250 Stefan Luth1 and Sverker Olsson1 Ma. Thus, altitude variations of 2-3 km at that 1SGU time are like present values. From before 350 Ma to before 200 Ma, starting form SW, deep valleys A three-dimensional model has been created were incised into a plateau being more than 3 km representing the lithotectonic units and their above the present landscape. After about 200 Ma bounding regional deformation zones in the the exhumation rate of the overall area was bedrock of Sweden. The model, including a brief moderated, however with an increase especially description and basis for modelling of each in the valleys after 50 Ma. modelled deformation zone and lithotectonic unit, is a development of the existing lithotectonic Our interpretation is based on a simulation of subdivision included in the bedrock map of temperature history through time intervals Sweden at the scale 1:1 million (Bergman et al. derived from the track length distribution. We 2012). The aim is to visualize the interpretation use signal analysis theory to enhance the of the overall geometrical relationships between resolution of the time-temperature information the various lithotectonic units on a national scale of the fission tracks. Statistical noise and biases and provide a basic framework and background such as track annealing anisotropy are taken care for more detailed regional and local scale models. of. We calculate the thermal history backwards in The aim is to link the model to general geological time and analyse the results as erosion/burial descriptive texts aimed at schools and other depths, which leads to our interpretation of the interested parties as well as scientific gradual inland erosion. presentations. All measurements are performed in transmitted light on prismatic faces, however, horizontal

track lengths are measured without angle to the

c-axis.

130 fracture densities. These together may be used to evaluate the existing DEMs of unexposed bedrock POSTER surfaces based on sparse data, and as input data in future development of the DEM interpolation Modelling the fracture characteristics tools. of crystalline bedrock for the purposes of bedrock surface interpolations POSTER

Eemi Ruuska1, Antti Kallanranta2, Pietari Skyttä1 Mechanical separation of crust from and Michael Hillier3 slabs subducted below the transition 1Department of Geography and Geology, University of Turku, FI-20014 Turun yliopisto, 2Dept. Geosciences and zone Geography, University of Helsinki, PL-64 00014 Helsingin yliopisto, 3Geological Survey of Canada, Anders Vesterholt1, Thorsten Nagel1 and Kenni Ottawa Dinesen Petersen1 1Department of Geoscience, Aarhus University

The purpose of the study is to characterize the bedrock fracturing and its spatial variability As oceanic crust subducts into the mantle, it which may be subsequently used in interpolating eclogitizes and becomes negatively buoyant the digital elevation models (DEMs) of the relative to the peridotitic upper mantle. However, glacially eroded bedrock surface. The work experimental studies indicate that, at depths focusses at testing and developing the implicit between 660 km to 800 km, below the mantle modelling approach and tools, validating the transition zone, MORB compositions are results by using explicit models and compared to positively buoyant at certain conditions. This has fracture networks defined with the Discrete raised the possibility that oceanic crust can Fracture Network modelling tool (DFN). The used become mechanically separated during implicit modelling approach, by contrast to the subduction below the 660 km discontinuity. conventional explicit approach, allows Several conceptual and simple physical models generation of more objective, time-efficient and have been proposed for such crustal segregation. repeatable 3D-models. Here we present a 2D thermomechanical model that employs recent experimental constraints This study is conducted in the Hyvinkää area, that indicate that majoritic garnet is relatively southern Finland, under an umbrella of a broader weak at transition zone conditions. We show that Salpausselkä project investigating the channel-like upward flow within oceanic crust relationship between the bedrock structures and can occur in the density-inversion window the overlying glacifluvial aquifers. The principal between 650 and 750 km depth. Depending on input data of this study are fractures, correlated geometric and thermal boundary conditions, this with foliation data and regrouped into sets as flow is sufficient to cause runaway instabilities, determined within a parallel ongoing study. episodic mechanical separation of crust from the downgoing slab and thus the formation of stable As a central tool, a new functionality “Local crustal patches at the lower-upper mantle Anisotropy Interpolator” of SURFE plug-in for boundary. Our results have far-reaching GOCAD has been developed. With this tool, we are implications for our understanding of the able to generate a grid with an interpolated compositional stratification of the mantle, its fracture plane at each grid cell displaying the convective circulation and the seismic velocity local variations within the anisotropy of the structure near the mantle transition zone. bedrock across the study area. The resulting anisotropy will provide improved control over the fracture orientations, and the results of the DFN models will provide constraints on the

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5. Mineralogy 5.1. Mineralogy and its applications ORAL

The fumarolic minerals of the ORAL Fimmvörduhals 2010 eruption

Occurrence of indium with late-stage Tonci Balic-Zunic1, Kristjan Jonasson2 and Anna intrusions in the Kymi granite stock, Katerinopoulou3 Southern Finland 1Department of Geosciences and Natural Resource Management, University of Copenhagen, 2Icelandic Thair Al-Ani1, Timo Ahtola1 and Janne Kuusela1 Institute of Natural History, 3Haldor Topsøe A/S 1Geological Survey of Finland

The eruption at Fimmvörduhals, Iceland, lasted The Kymi granite stock contains hydrothermal from March to April 2010 followed by the well- greisen and quartz vein type F––Sn and Zn–– Pb– known Eyjafjallajökul explosion. It formed two –Cu sulphide mineralization. These intrusions are craters, Magni and Móði and expelled a enriched in indium and rare earth elements, substantial amount of volcanic gasses. roquesite (CuInS2) being a major indium-carrier. The accessory minerals are fluorite, zircon, The samples of fumarolic minerals were collected apatite, cassiterite and different sulphides, such in three campaigns in 2010, followed by two in as sphalerite, chalcopyrite and galena. The subsequent years. The locality temperatures o indium and REE-bearing mineral assemblages ranged from around 50 to almost 800 C. were studied by a combination of optical and field The mineral parageneses can be divided in five emission scanning electron microscopy (FE-SEM) main types: and electron probe micro-analyzer (EPMA) techniques. Roquesite occurs as microscopic 1) Aluminofluorides and silicofluorides of Na, Mg grains (10–40 micron) in galena. EPMA analyses and Ca, including two recently described new of these grains yield an average composition of minerals characteristic for Icelandic fumaroles, 26.16% S, 0.02% Fe, 25.06% Cu, 0.03% Zn, 1.06% plus two new minerals under investigation. They As, 0.31% Sb and 47.14% In. Indium are characteristic for sites with lower formation incorporation into the galena structure probably temperature (<200oC) found south from craters, occurred according to the relation Pb2+S2- outer rim of Magni and north from Móði crater. ↔Cu+In3+S2-, whereas zinc present in the galena was probably replaced by indium. Therefore 2) Halite-dominated associations. They include coupled substitution 2(Pb2+ Zn+) = Cu+In3+ may both low-temperature associations (<100oC) also have occurred. with hydrous sulfates found south of craters, and occurrences at high-temperature fumaroles (>500oC) in the northern part of Magni crater.

3) Anhydrous and hydrous sulfates characteristic for low to medium-temperature fumaroles (<300oC) occurring south of craters and on Móði. They are represented by various Na-K-Mg-Ca-Al phases, two of them new species.

132 4) High-temperature Na-K sulfates found at linarite, PbCu(SO4)(OH)2) and at places native temperatures >600oC on the rim of the Magni sulphur. The source of chlorine is likely to be the crater and in one crevice south from crater. Arsuk fjord, bordering the deposit. The presence of S in three oxidations states reveals a 5) Other high-temperature Na, K, Mg and Ca progressive oxidation event at places, but also sulfates forming at similar temperature subtle variations in secondary mineralogy within conditions as 4) and also found on the rim of the same sample. A similar oxidation situation Magni crater. has been observed for S and As in arsenopyrite (FeAsS), which is being replaced by kaňkite Exceptional for Fimmvörduhals fumaroles is that (FeAsO ·3.5H O) and native sulphur. the high-temperature sites contain acidic K and 4 2 Na hydrogen sulfates mercalite (KHSO ) and a 4 new mineral with composition Na3H(SO4)2. ORAL

ORAL Nanoscale observations of ‘invisible gold’ from the Olympias mine, Greece Element mobility and new paragenses of the Ivigtut cryolite Takeshi Kasama1, Platon N. Gamaletsos1, deposit, South Greenland Stephane Escrig2, Berit Wenzell1, Louise H.S. Jensen2, Anders Meibom2, Dimosthenis Sokaras3, Henrik Friis1 Tsu-Chien Weng3, Dimitrios Dimitriadis4 and 1Natural History Museum, University of Oslo, P.O. 1172, Athanasios Godelitsas5 Blindern, 0318 Oslo, Norway 1Technical University of Denmark, Kongens Lyngby, Denmark, 2École Polytechnique Fédérale de Lausanne, Lausanne, Switzerland, 3SLAC National Accelerator The Ivittuut, formerly Ivigtut, cryolite deposit has Laboratory, CA, USA, 4Hellas GOLD S.A., Athens & been known since the late 18th century as a Chalkidiki, Greece, 5National & Kapodistrian University source of unique minerals in particular fluorides of Athens, Athens, Greece of which cryolite was mined for almost 100 years. The majority of scientific publications about Ivittuut have focused on the formation of the In some gold deposits, gold exists as invisible deposits, the fluorides or the sulphides. However, form in pyrite or arsenopyrite. Such gold is not little is known about the alteration mineralogy recovered readily from ore materials. The and consequently element mobility in this unique identification of the gold form and distribution fluorine-rich environment. may provide some insight into the recovery of gold. Here, we use electron microscopy, A fieldtrip to Ivittuut in the summer 2016 NanoSIMS and high energy resolution specifically targeted various paragenesis fluorescence detection X-ray absorption showing signs of alteration. Consequently, we spectroscopy (HERFD-XAS) to investigate have discovered 11 minerals new for Ivittuut ‘invisible gold’ from the Olympias Au-Ag-Pb-Zn including a series of alteration stages of primary polymetallic carbonate replacement deposit, sulphides and the first Rare Earth Element (REE) northern Greece. paragenesis. Bulk analyses show that given ore samples Galena is one of the main sulphide minerals and contain gold up to ~30 ppmw and gold has to date only cerussite (PbCO3) and wulfenite positive relationships with arsenopyrite and

(PbMoO4) are known secondary Pb-minerals at probably As-containing pyrite. The arsenopyrite ivigtut. However, new types of galena alteration and pyrite make up 15% and 19% of the samples, have been observed consisting of Pb-chlorides respectively. Assuming that all the gold is and carbonates (cotunnite, PbCl2, and phosgenite, accumulated in arsenopyrite, each arsenopyrite

Pb2CO3Cl2) and sulphates (anglesite, PbSO4, and grain would contain ~200 ppmw. NanoSIMS

133 suggests that gold is present primarily in concept in more detail, I am working with Dr. arsenopyrite and is distributed with large Eero Hanski of Oulu University and Dr. Richard variations along the growth direction. Pyrite also Wunderman, former Smithsonian institution, on contains some gold but the concentration is even the concept. This serves as a discussion for the lower than that in arsenopyrite. TEM was used to anthropocine's impact on geology of the future.) examine the near-surface of arsenopyrite, where gold is usually concentrated. However, no gold precipitates were observed, which might suggest POSTER that gold is present in the form of ions in either the crystal lattice or interstitial position. This Prediction of swelling potential using result is also supported from the HERFD-XAS the Atterberg limits study, in which gold is likely present as a higher Aikaterini Biotaki1, Irene Rocchi1, Jeppe Bendix oxidation state (e.g., Au3+) occurring as a Regel2 and Helle Foged Christensen2 chemically bound form in the structure. Thus, 1Technical University of Denmark (DTU), 2GEO gold may have been incorporated into arsenopyrite and pyrite during relatively rapid growth of them. Expansive soils are known to cause numerous problems on surface and underground

constructions. In the oil and gas industry, they ORAL may cause operational problems during drilling Plasticite, (Plas-TI-Kite) an ore and completion, workover, production, and stimulation procedures. The use of water-based mineralization from the late mud during drilling operations can cause clay Anthropocine swelling and consequently wellbore instabilities that, in extreme cases, could lead to complete well Erik Nilsson1 abandonment. Moreover, swelling clays can affect 1Luleå Technical University/Oulu University the quality of the reservoir and lead to problems

during the conventional hydrocarbon The Late Anthropocine has caused a noticeable production, or Enhanced Oil Recovery (EOR). shift in the ability for new minerals to form via Therefore, to avoid serious complications and human mechanisms. One such mineral, plasticite, excessive operational costs in the case of is a relatively abundant mineral at Earth's surface hydrocarbon operations, it is of high importance deriving from plastic. The general chemical to fully understand the behaviour of swelling clay formula for plasticite and all plasticite like and quantify the volume change, linking it to the minerals (with a plastic provinance) are mineralogy.

(Contact author for better formatting) Throughout the years, several researchers studied the correlation between the Atterberg \centerline{$(C_{2}H_{4})_{n}\pm(F^{-},Cl^{- limits and the swelling potential or swelling },Br^{-},I^{-})\pm(Pb,Sn)$} pressure of soils providing numerous empirical correlations. During this study, data acquired The discussions in the last chapter details a from 12 different publications were examined to proposal for mineralis, a new mineral category determine whether there is a correlation taking into account the prospect of between the Plasticity Index (PI) and the Swelling anthropogenic minerals having a class of their potential (SP) for varying samples and own to accommodate for the potentials of the methodologies. A linear correlation between the rapidly increasing carbon mineral category. SI and PI was found, with a coefficient of (note: this can also be considered under the determination (R2) = 0.731, which is rather "Other category" but I won't double submit until satisfactory given the different methodologies the committee allows me, I can also explain the and soil conditions used. The influence of the

134 mineralogy was assessed using the Casagrande The instrument should be installed in spring chart and it was found that the montmorillonitic 2018 and we invite users from the mineralogy samples resulted in a significantly higher community in Scandinavia to come to Oslo for coefficient of determination. their single-crystal diffraction work.

POSTER

A new single-crystal XRD for mineral sciences in Scandinavia

Henrik Friis1 1Natural History Museum, University of Oslo, P.O. 1172, Blindern, 0318 Oslo, Norway

The natural history museum in Oslo has purchased a state of the art single-crystal XRD, which is dedicated to mineral sciences. The instrument is a Rigaku Synergy-S dual-beam instrument equipped with Mo and Cu μ-sources and a HyPix-6000HE hybrid photon counting area detector. The instrument comes with various options for Gandolfi movement making it ideal for mineral identification of minute grains and aggregates as well as powders. The Gandolfi data can be exported in various file-formats making it importable into a range of other software used for traditional powder XRD search and match functions.

The high-intensity μ-sources combined with the fast detector read-out time makes it possible to collect data rapidly. The Cu-source is more intense than the Mo-source, which is particularly beneficial for data collection of low absorbent materials and the Gandolfi methodology. The software controlling the instrument (CrysAlis Pro) is combined with on-site license of AutoChem, which makes it possible to solve structures while data is collecting. This function combined with the high-intensity sources and fast detector enables rapid screening of crystals to identify the best suitable for full data collection. The software handles up to eight twins or intergrowth domains for full structure determination. The software for data reduction and face indexing can be downloaded for free and consequently all data processing can be carried out off-site.

135

6. Paleaontology 6.1. Paleozoic and Mesozoic were hoplitinids and gastroplitinids are found together in assemblages, or at precisely defined stratigraphy, levels within a faunal succession. Recently, an paleoceanography and ammonite-rich horizon was discovered in an paleoclimate otherwise rather unfossiliferous Albian succession in Kilen, North Greenland. It contains

an assemblage with both gastroplitinid ORAL representatives of the Arctic Province and hoplitinid representatives of the European At the boundary between the middle Province. The ammonites thus represent a rare Albian hoplitinid and gastroplitinid and unique occurrence record of a mixed hoplitinid-gastroplitinid assemblage. ammonite provinces: linking the Arctic with northwest Europe with ammonites in North Greenland . ORAL

Peter Alsen1 The secret wonders of the middle 1The geological survey of Denmark and Greenland Danian (GEUS) Bodil Wesenberg Lauridsen1, Kasper Blinkenberg1, Trine Edvardsen1 and Lars Stemmerik1 The Albian is characterized by pronounced 1Natural History Museum, Denmark provincialism, and within the Boreal Realm endemic faunas form defines separate faunal provinces with only limited faunal The Danian is named after and known for the communication. Palaeobiogeographic imposing bryozoan mounds of Stevns Klint and subdivision of the Albian in the Boreal Realm the cold-water coral mounds of Faxe. Less includes a Boreal-Atlantic Subrealm, an Arctic attention has been on the middle Danian chalk Subrealm and a Boreal Pacific Subrealm localities in the northwestern part of the Danish (Lehmann et al 2015). During the middle Albian Basin. Here the chalk is soft, with a low diversity the Boreal-Atlantic is characterized by hoplitinids benthic fauna and a relatively high degree of and corresponds to the European or hoplitinid unevenly distributed flint. The fauna composed province of Owen (1979, 1996, 2007). Hoplitinids mostly of irregular echinoids, bryozoans and were dispersed widely in the European shelf seas crinoids. However, a detailed look into the Danian but also towards the north, where impoverished chalk in Dalbyover, northern Jutland, reveals a faunas are recorded in Greenland and Svalbard. much more vivid ecosystem. Echinoids (both The ammonite zonation based on the hoplitinids regular and irregular), bryozoans, brachiopods, form a standard for the European Province. In the bivalves, serpulids, sponges, asterozoans and neighbouring Arctic or gastroplitinid province to crinoids were thriving in this relatively deep and the north hoplitinids are totally absent and the nutrient poor setting. The species all show special issue of accurately dating the gastroplitinids of adaptations to survival in the environment and the Arctic from correlation to the hoplitinid many are Mesozoic survivors from the Late zonation has been a long-lasting problem and Cretaceous chalk sea. One of the dominating commonly discussed in the literature. North-East species, the irregular echinoid Echinocorys Greenland (Donovan 1957) and Svalbard sulcatus appears to be crucial for the ecosystem (Yershova 1983; Nagy 1970), where faunas are and is a true wonder of the middle Danian. reported to overlap, have, however, no localities

136

ORAL ORAL Biostratigraphic correlation of the Triassic biostratigraphy (ammonoids Cretaceous to Neogene succession of and palynology) and organic δ13C- the western and eastern margins of isotope record of the Wandel Sea the Labrador – Baffin Seaway. Basin, North Greenland Henrik Nøhr-Hansen1, Graham L. Williams2 and Sofie Lindström1, Peter Alsen1, Morten Bjerager1 Robert A. Fensome2 and Jussi Hovikoski1 1Geological Survey of Denmark and Greenland, GEUS, 1GEUS Øster Voldgade 10, Dk-1350 Copenhagen K, Denmark., 2Natural Resources Canada, Geological Survey of Canada (Atlantic) Bedford Institute of Oceanography The presence of Triassic sedimentary rocks in North Greenland was first reported from the New analyses of the palynological assemblages in Danish Peary Land Expedition 1948-49 by 13 offshore wells on the Canadian margin and six Troelsen (1950). The first descriptions of Triassic on the West Greenland Margin, in conjunction fossils, mainly ammonoids, were made by with onshore data, have led to a new Kummel (1953), and later by Peel et al. (1974). biostratigraphic framework for the Cretaceous– During the Triassic the Wandel Sea Basin (WSB) Cenozoic strata of the Labrador Sea – Davis Strait constituted a continuation of basins in the – Baffin Bay (Labrador–Baffin Seaway) region southern part of the Barents Sea to the east, and and the first broad biostratigraphic correlation of of the Danmarkshavn Basin offshore Northeast the Canadian and Greenland margins. This Greenland to the south. The Triassic succession of framework is based on 167 last occurrences and the WSB was deposited unconformably on Upper 18 local or regional, peak- or common- Permian sediments and succeeded by Upper occurrence events for dinocysts (which include Jurassic – Lower Cretaceous deposits (Håkansson three new genera and 16 new species), acritarchs et al. 1991). During recent field campaigns (including one new species), miospores (2012–2013) several outcrop sections and a (including one new species), fungal spores and cored drilling were sampled for palynology, massulae of the fresh-water fern Azolla. Our macrofossils, and organic δ13C-isotope analysis. findings delineate several local and regional The integrated ammonoid faunas and spore- hiatuses on both sides of the seaway. The pollen biostratigraphy shows that the exposed palynomorph assemblages show that most Triassic succession of the WSB encompasses a Aptian to Albian sediments were deposited in near complete Induan (Dienerian) – Norian generally non-marine to marginal marine succession. The ammonoid faunas are correlated settings, interrupted by a short-lived shallow- with the established zonation for Arctic Canada marine episode in the Aptian. A marine (Tozer, 1994), and spore-pollen assemblages transgression commenced in the Cenomanian– correlate well with those of Svalbard and the Turonian and led to the most open-marine, Barents Sea (Vigran et al. 2014). oceanic conditions in the Campanian–Lutetian. An especially detailed organic δ13C- Subsequent shallowing probably began in the late isotope record is registered for the Smithian– Lutetian and continued into the Rupelian, when Spathian interval, which can be correlated inner neritic and marginal marine with previously reported records globally (e.g. palaeoenvironments predominated. Throughout Galfetti et al., 2007, Grasby et al., 2013). the rest of the Cenozoic, inner neritic palaeoenvironments alternated with marginal marine conditions on the margins of the Labrador–Baffin Seaway. Our findings broadly

137 reflect the tectonic evolution of the seaway, with new abiotic climate proxies based on brachiopod rift conditions prevailing from Aptian to Danian 18O data. Together, these three lines of evidence times, followed by drift through much of the provides a highly interesting novel perspective Paleocene and Eocene, and post-drift from on the event. Oligocene to the present.

ORAL ORAL Stratigraphic context and Biodiversity, climate and time – environmental changes in the Tuxen resolving the scale, tempo and and Sola Formations (Barremian- drivers behind the Great Ordovician Early Aptian, North Sea): new results Biodiversification Event from high-resolution carbon and

Christian M. Ø. Rasmussen1 oxygen stable isotopes, major and 1Natural History Museum of Denmark trace elements, sedimentology and calcareous nannofossils

The early Palaeozoic witnessed two significant Nicolas Thibault1, Kresten Anderskouv1, Emma pulses in biodiversity increase and a catastrophic Sheldon2, Jon Ineson2, Anastasios Perdiou1 and mass extinction. All are fundamental events and Mohammad J. Razmjooei1 notably the two radiations had a lasting impact on 1IGN, University of Copenhagen, 2GEUS Phanerozoic ecosystems. The early Palaeozoic has traditionally been considered a super- greenhouse period. This interpretation was The Barremian to lower Aptian Tuxen and Sola primarily based on two lines of evidence: Formations have been investigated in the North modelling scenarios suggesting CO2 levels 15–20 Jens-1 well (Danish Central Graben, North Sea) times PAL, and a general perception of warmer for environmental changes based on a revised climate due to what was likely a Phanerozoic sea calcareous nannofossil biostratigraphy, level maximum during the early Late Ordovician. geochemical analysis of 316 samples (stable The interpretation of early Palaeozoic climate, isotopes, hand-held XRF element analysis) and however, is currently undergoing a paradigm quantitative nannofossil abundance counts of 75 shift. Increasing evidence is suggesting a cooler samples. Our results delineate the well- climate throughout most of the Ordovician established Barremian rise in carbon isotopes as Period, and the short-lived icehouse conditions well as the typical excursions across the early traditionally linked to the end Ordovician mass Aptian Oceanic Anoxic Event (OAE) 1a extinctions now appear to continue well into the characterized by two short and prominent Silurian. In the midst of this paradigm shift lies negative excursions right below and at the base of the Great Ordovician Biodiversification Event the Fischschiefer laminated black shale horizon, (GOBE) – the greatest marine speciation event of followed by the long-lasting positive carbon the entire Phanerozoic. Thus, this event now isotope excursion of the lower to upper Aptian. seems to have been unfolding against a Our new results also show significant cyclic background of cooler climate instead of a super- changes in the Barremian carbon cycle with a greenhouse, but the exact onset of the GOBE is number of new possible negative and positive obscured by contradicting biodiversity estimates. excursions that could be defined and used for The current talk presents ongoing efforts to refinement of the stratigraphy of this stage. unravel the speed and causes of the GOBE by Oxygen isotopes and calcareous nannofossil combining three approaches: 1) the construction assemblages highlight the coupling of of a new, high-resolution biodiversity estimate significantly warm episodes associated to for the early Palaeozoic, 2) an astronomically eutrophic conditions during deposition of the calibrated timescale through the GOBE, and 3) lower Barremian Munk marl and early Aptian

138 Fischschiefer laminated horizons whereas a confirmed by Multioistodus sp., Drepanoistodus significant cooling associated to oligotrophy sp., Periodon sp. The youngest Middle-Upper triggered the deposition of nannoconid chalk in Darriwilian ages of the section are based on the upper Barremian. Major and trace elements findings of Belodina sp., Periodon sp., Panderodus suggest rather similar environmental contexts in sp., Drepanodus sp., Protopanderodus sp. The bottom-waters for the deposition of the Munk conodonts have Laurentian biogeographic marl and Fischschiefer and advocate for these affinity, supporting conclusions based on levels but we denote a conflicting sequence conodonts from Hornsund and Ny Friesland. stratigraphic context for the Munk Marl in the North Sea and the equivalent Hauptblätterton in the Lower Saxony Basin of North Germany. POSTER

The Silurian Lau event – testing plant ORAL weathering as driver for ocean anoxia The Ordovician conodonts of the west and animal extinction Sørkapp Land (Southern Spitsbergen) Julius Havsteen1, Álvaro del Rey1 and Tais Tatiana Tolmacheva1, Aleksandr Larionov1 and Wittchen Dahl1 Natalia Kosteva2 1Natural History Museum of Denmark, University of 1A.P. Karpinsky Russian Geological Research Institute, Copenhagen 2Polar Marine Geosurvey Expedition

The Silurian period witnessed several climatic The Ordovician in the Sørkapp Land is known events expressed as large positive carbon since the 50-ies, yet it is relatively poorly isotopic excursions in the carbonate rock record. examined and its faunas are studied One of these – the Ludfordian Lau event – is the insufficiently. The western Sørkapp Land part greatest isotopic excursion in the Phanerozoic between the Olsokbreen and Bungebreen was (δ13C increases by ~9‰). Marine carbonates surveyed in 2013. Here the Ordovician (Sørkapp exposed on Gotland (Sweden) preserve this Land Gr - Hornsundtind and Nigerbreen Fms) and record. Here, we present new isotope data presumably Ordovician-Silurian (Arkfjellet Fm) obtained from bulk carbonate rocks using Cavity have been found to form an NE-striking Ring-Down Spectroscopy. Several extinction tectonostratigraphic antiform. The section is events are observed in conjunction with the dominated by various limestones that range in isotope excursions. During the Lau event, marine color from almost black to light; layers of chert- animals from the pelagic zone to the benthos bearing limestone also present. The antiform’s SE were affected in less than 200 kyr. We limb contains two psammitic layers as well as hypothesize that the Lau event reflects an organic layers of schists and conglomerate. The Early carbon burial episode driven by the colonization Paleozoic rocks are unconformably overlain by of vascular plants on land. At this time, the first the Devonian red sandstones and/or Triassic. rooted plants appeared in the fossil record. They could have intensified weathering rates and Conodonts imply that the Hornsundtind and sourced more of the biolimiting nutrient, Nigerbreen Fms embrace the Floian to the Middle phosphorus, into the oceans. This increased Darriwilian stratigraphic interval. The lower marine primary productivity and ultimately Floian part of the section yelded Wandelia guyi organic carbon burial – now recorded in higher Smith, Paroistodus proteus Lindstrom, δ13C values in carbonate sediments. We test this Colaptoconus quadraplicatus (Branson et Mehl), relationship using uranium isotopes in the same Oepikodus sp., Parapanderodus striatus (Graves samples to constrain the oxygenation state of the et Ellison). The conodont assemblages are Silurian oceans. Uranium’s long oceanic dominated by Wandelia guyi typical for the East residence time (~400 kyr) and the preferential and North Greenland. The Early Darriwilian is

139 incorporation of 238U relative to 235U into anoxic proxies (Rb/Zr, Zr/Al, Si/Al) suggest a sea level sediments makes δ238U a powerful proxy for rise synchronous with the change to a more global marine anoxic sediment burial. marine source of organic matter and the onset of the T-OAE.

POSTER POSTER Chemostratigraphy across the Toarcian Oceanic Anoxic Event in the Seawater temperature change across Aubach section of SW Germany the Pliensbachian–Toarcian transition – new isotope data from 1 2 Iben W. Hougaard , Jørgen Bojesen-Koefoed , the Aubach section in SW Germany Oluwaseun O. Edward1, Małgorzata Rizzi1, Clemens V. Ullmann3 and Christoph Korte1 Christoph Korte1, Clemens V. Ullmann2, Jesper A. 1Department of Geosciences and Natural Resource Frederiksen1, Robert Frei1, Iben W. Hougaard1 and Management, University of Copenhagen, Denmark, Małgorzata Rizzi1 2Geological Survey of Denmark and Greenland (GEUS), 1Department of Geosciences and Natural Resource Denmark, 3Camborne School of Mines and Environment Management, University of Copenhagen, 2Camborne and Sustainability Institute, University of Exeter, School of Mines and Environment and Sustainability Penryn, Institute, University of Exeter

Early Jurassic strata, covering the Toarcian In the Wutach area of SW Germany, Oceanic Anoxic Event (T-OAE), are exposed in the biostratigraphically well-defined Late Aubach section, Wutach area, SW Germany. The Sinemurian to earliest Aalenian siliciclastic and T-OAE is characterized by significant organic carbonate sediments are exposed along the matter burial, numerous geochemical anomalies Aubach stream (Riegraf, 1980; Riegraf et al., and one of the most significant negative carbon 1984; Schlatter, 1997; Urlichs, 1997). The locality isotope excursions (CIE) in the Mesozoic (Jenkyns was sampled in high resolution during several and Clayton, 1997; Küspert, 1982; Röhl et al., field campaigns in the last years, and carbon, 2001). In the present study, we generated new oxygen and strontium isotope datasets have been organic and inorganic carbon isotope values as generated from Low-Mg-Calcite fossils (mainly well as element concentrations (Mn, V, Mo), belemnites) which were screened for diagenesis common organic geochemical data and (see Ullmann and Korte, 2015). Known carbon biomarkers of bulk rock samples. The results are isotope fluctuations for this period (e.g. Korte and currently utilized to determine fluctuation in the Hesselbo, 2011; Peti et al., 2017) are expressed carbon cycle, to evaluate bottom water redox clearly in the Aubach data, including an about 2 conditions during sediment deposition, and to ‰ negative excursion across the Sinemurian– determine variation in the source of organic Pliensbachian boundary, a positive excursion in matter. the Late Pliensbachian margaritatus Zone, a The first results show the well-known negative negative excursion in the spinatum Zone organic carbon isotope excursion from the (hawskerense Sz), a negative excursion of across semicelatum to exaratum Subzones and the the Pliensbachian–Toarcian boundary and organic geochemical characterization allow the relatively heavy values up to +4 ‰ in the preliminary interpretation that the organic falciferum Zone. The oxygen isotope values show matter source changed to a more marine source an increase across the Sinemurian–Pliensbachian during the T-OAE. Fluctuation in the anoxia boundary, reaching heaviest values of ~ +1 ‰ proxies Mo and V are asynchronous suggesting (with periodic fluctuations) in the margaritatus that the restricted conditions occurred in a larger and early spinatum zones (Late Pliensbachian basin and the reduced conditions prevailed Cool Mode; Korte et al., 2015). The values start to throughout most of the falciferum Zone. Sea-level gradually decrease in the higher hawskerense

140 Subzone (with some heavy values in the We attribute this link to changes in the sea level semicelatum Subzone), lasting till the earliest due to fluctuations in ice coverage during the late Toarcian tenuicostatum Zone. The new data Jurassic – early Cretaceous and suggest that, with indicate that relatively cool temperatures have falling sea level, the connection between the existed in the Swabo-Franconian Basin at Neuquén basin and the proto-Pacific got palaeolatitudes below 40° for most of the shallower, resulting in stratification of the basin Pliensbachian, and that the Toarcian warming with warm fresh water sealing off the deeper may have preceded the negative carbon isotope basin. With rising sea level, the connection to the excursion of the T-OAE. ocean deepened and the stratifications weakened. Nutrients were mainly supplied by continental run-off from the south of the basin POSTER due to monsoonal activity during winter, which varied with the precessional cycle. Warm, Orbital forcing of organic matter hypersaline waters were synchronously formed quality and quantity in a source-rock in the south-east of the basin during summer. formation: the case of the Vaca This led to the formation of a hypersaline lens in Muerta Formation, Tithonian- the deepest part of the basin and thus cutting it Valanginian, Neuquén Basin, off from oxygen supply. Argentina POSTER Johannes Monkenbusch1, Alain Lejay2, Mathieu Martinez3, Heiko Pälike4 and François Gelin2 The giant Lower Triassic sponge- 1 Department of Geosciences and Natural Resource microbial build-ups from Neotethys Management, University of Copenhagen, Øster Voldgade, 2TOTAL, CSTJF, Avenue Larribau, 64000 Pau, Sylvain Richoz1, Evelyn Friesenbichler2, Aymon France., 3Université de Rennes, UMR 6118 Géosciences Baud3, Leopold Krystyn4, Katrin Heindel5, Lilit Rennes, Campus de Beaulieu, 35042 Rennes cedex, 6 7 8 France., 4MARUM, Centre for Marine Environmental Sahakyan , Jörn Peckmann and Joachim Reitner Sciences, Leobener Strasse 8, Universität Bremen, 1Department of Geology, Lund University, Sölvegatan 28359 Bremen 12, Se-223 62, Sweden, 2Paleontological Institute and Museum, University of Zurich, Karl-Schmid-Strasse 4, 8006 Zurich, Swit, 3BCG, Parc de la Rouvraie 28, CH- The Vaca Muerta Formation from the Neuquén 1080 Lausanne, Switzerland, 4Department for Basin is an important petroleum source-rock Paleontology, University of Vienna, Althanstraße 14, 1090 Vienna, Austria, 5GeoZentrum Nordbayern, formation in Argentina. A cyclostratigraphic Fachgruppe Paläoumwelt, University of Erlangen- study was conducted, based on a set of Nürnberg, Loewenichstraße 28,, 6Institute of Geological continuous data from four wells. The Total Sciences, National Academy of Sciences of Armenia, 24a Organic Content (TOC) was measured using the Baghramian Avenue, 37, 7Institute for Geology, LIPS method to investigate the control of orbital Universität Hamburg, Bundesstraße 55, 20146 forcing on the variation of organic matter Hamburg, Germany, 8Department of Geobiology, Centre distribution. Moreover, the integration of the of Geosciences, University of Göttingen, Rock Eval 6 Hydrogen Index (HI) and Oxygen Goldschmidtstraße 3, 37077 Index (OI) were tested to understand the climatic conditions which favoured the deposition and After the end-Permian mass extinction the upper preservation of organic matter. Paleozoic skeletal carbonate factory was abruptly Cyclic changes are attributed to astronomical replaced by a non-skeletal carbonate factory and forcing. The main driver of the oxygenation of the Permian-Triassic boundary microbialites basin was the obliquity. HI, OI and TOC correlate (PTBMs) were flourishing. These PTBMs were with the precession and the eccentricity. abundant in low-latitude shallow-marine carbonate shelves in central Tethyan continents

141 and present during at least four events in the 6.2. Open session in Lower Triassic. Palaeontology, palaeoecology The investigated PTBMs from three different and paleoenvironments sites in southern Armenia were formed in a distal open marine setting on a pelagic carbonate ramp. They grew during two microbial growth phases ORAL in Griesbachian times, whereas the microbialites from the first microbial growth phase co-occur Pushing research boundaries: with calcium carbonate crystal fans (CCFs). The Benefits of temperature ramped gas microbes formed predominantly thrombolites chromatography in EA-IRMS that vary in size between 5 cm to 1.5 m. The biggest thrombolite has a cone-shaped build-up Christopher Brodie1, Oliver Kracht, Andreas geometry and an asymmetrical growth, which Hilkert and Søren Dalby indicates the influence of a steady bottom 1Dr. current. It consists of numerous thrombolite domes with a top head diameter of up to 8 m width and a total height of up to 12 m. The The Thermo ScientificTM EA IsoLinkTM IRMS microbialites are surrounded by a bioclastic System has fundamentally improved analysis by wackestone that mainly contains ostracods, EA-IRMS using temperature ramped gas foraminifers, microgastropods, thin-shelled chromatography with a single GC column and a bivalves. patented helium management system that reduces cost per analysis. These innovative Carbon isotope studies were performed on both features open doors to push research boundaries the microbialites and the surrounding sediment. at new levels, especially for the analysis of very 13 A comparison between the δ Csediment and small concentrations and on very high C/N and 13 δ Cmicrobialite revealed that there is little difference C/S ratio samples. (<0.4‰) between these values in the microbialites that formed during the second This presentation will principally focus on the microbial growth phase. In contrast, the advantages of using temperature ramped gas microbialites and CCFs from the first microbial chromatography. Traditionally, gas growth phase show differences in the δ13C values chromatography in EA-IRMS employed a GC of up to 2.3‰, which could be due to microbial column held at an isothermal temperature as the activity. gases eluted. However, using temperature ramped gas chromatography in the EA IsoLink IRMS System, a feature common in GC-MS and GC-IRMS, the temperature of the GC column can

be quickly changed as analyte gases are eluting, improving peak separation, peak fidelity, analysis of very small sample amounts and precision of replicate measurements.

We will discuss these improvements in peak separation, background determination,

troubleshooting of the combustion, pyrolysis and chromatographic processes, blank determination and analysis of very small sample concentrations. Our improved GC technique is illustrated in Figure 1, which shows a chromatogram of a NCS analysis on wood (C/S ratio of 7900:1) from a single sample drop. Complete baseline separation

142 of each analyte is achieved with sound The distribution of the Recent bryozoans with a background correction and peak fidelity, dominant ascophoran lepraliomorphs of including for very large (7000 μg C) and very Schizoporelloidea – the most richly represented small (11 μg N and 1 μg S) analyte amounts. For 5 superfamily as well as umbonulomorphs replicate measurements on wood, δ13C = - illustrate a dynamic evolution of the highly 24.10±0.06‰; δ15N = 3.20±0.23‰ and δ34S = endemic Antarctic fauna. The bryozoan’s colonial 5.92±0.26‰. growth-form could be used as a potential tool in interpretation of the different Cenozoic ecosystems and climatic regimes ranging from ORAL greenhouse to icehouse.

Bryozoan biota as a proxy for the climatic changes in Cenozoic of West ORAL Antarctica Elements of Eoarchean life trapped in Urszula Hara1 mineral inclusions 1Polish Geological Institute-National Research Institute Tue Hassenkam1, Martin P. Andersson1, Kim N. Dalby1, David M. A. Mackenzie2 and Minik T. Bryozoans in the marine and glacio-marine Rosing3 Cenozoic sedimentary sequences form a 1Nano-Science Center, University of copenhagen, morphologically and taxonomically diversified Denmark, 2Center for Nanostructured Graphene (CNG), biota in West Antarctica. During the late Early- Department of Micro- and Nanotechnology, Technical late Eocene of the La Meseta Fm. they are Univers, 3Natural History Museum of Denmark, dominated by hemispherical, multilamellar University of Copenhagen, 1350, Denmark cyclostome cerioporines, cheilostome ascophoran lepraliellids and anascan Metasedimentary rocks from Isua, West microporoideans with a high number of a new Greenland (> 3.7 billion year old) contain 13C taxa for the science, a great value for the austral depleted carbonaceous compounds, with isotopic biogeographical connections, as well as with ratios consistent with a biogenic origin. considerable evolutionary interest, including the Metamorphic garnet crystals in these rocks oldest stratigraphical records (Hara, 2001). contain bands of carbonaceous material Bryozoans occur at least intermittently through contiguous with carbon-rich sedimentary beds in the late Miocene-Pliocene glaciomarine Hobbs the host rock, where carbon is fully graphitized. Glacier Formation of the James Ross Island group Here we studied carbonaceous inclusions (Pirrie et al. 1997; Jonkers, 1998). The late armoured within garnet porphyroblasts by in- -21 3 Pliocene assemblage from the shallow-marine situ Infrared absorption on ~10 m domains pectinid-rich biofacies preserved in the near- within these inclusions. The absorption spectra shore Pecten Conglomerate (= Cockburn Island are consistent with carbon bonding to N and O Formation) of Cockburn Island in the James Ross and likely to phosphate. C-H or O-H bonds could Island area (NE Antarctic Peninsula) contains the not be detected. These results are consistent with abundance of the encrusting colonies. biogenic organic material isolated for billions of years and thermally matured at temperatures The majority of the late Pliocene cheilostomes are around 500 oC. They therefore provide spatial known from the Mid-Late Cretaceous, the others characterization for potentially the oldest are considered to have originated in the biogenic carbon relics in Earth’s geologic record. Paleogene (Eocene-Oligocene), evolving in the Antarctic region and becoming widespread through the Neogene to the Recent, along with one well-represented wholly Neogene

Microporellidae family.

143 mammal fossils suggest relatively humid and possibly more forested and wooded ORAL environments for the primate-bearing locality. This challenges the scenarios suggesting arid and Sedimentology, stratigraphy and highly seasonal conditions for Central Asia since palaeoenvironments of the Miocene Early Miocene. primate-bearing sequence in Inner Mongolia, China ORAL Anu Kaakinen1, Leena Sukselainen1, Zhaoqun Zhang2, Johanna Salminen3 and Mikael Fortelius1 Sinemurian-Pliensbachian 1Department of Geosciences and Geography, University of Helsinki, 2Institute of Vertebrate Paleontology and abundance and size changes in the Paleoanthropology, Chinese Academy of Sciences, calcareous nannofossil 3Department of Physics, University of Helsinki Schizosphaerella – relation to

climatic and palaeoenvironmental Central Inner Mongolia has been an area of great change in the Paris Basin palaeontological interest since the beginning of the 20th century. Although the area has produced Nicolas Thibault1 and Peti numerous diverse collections of Miocene faunas, 1Leonie fossil records from the early Miocene of Inner Mongolia are relatively rare. Abundance and size changes in the calcareous Our field investigations in Damiao, Inner nannofossil Schizosphaerella have been Mongolia have yielded more than 30 new investigated through the Early Jurassic (late fossiliferous localities, which have produced a Sinemurian to early Toarcian) of the Sancerre- rich mammalian fauna, including pliopithecid Couy core (Paris Basin). Measurements are remains. We present a multidisciplinary study of compared to variations in CaCO3 content, total the Damiao sequence, integrating organic carbon (TOC) content, and isotopic sedimentological, stratigraphical, geochemical trends in carbon and oxygen. Our results confirm and diverse palaeontological data. that Schizosphaerella was better adapted to proximal areas than coccoliths as expressed by We have interpreted the Damiao sequence as the the stepwise rise in abundance of remains of a fluvio-lacustrine system comprising Schizosphaerella, followed by a rise in abundance channels, subaerially exposed floodplains and of coccoliths during the major transgression of ephemeral/marginal lacustrine environments. the Sinemurian. The results show that changes in The bulk of the vertebrate fossils have been the size of Schizosphaerella were mostly a recovered from three main fossil horizons: The response to Early Jurassic temperature variations paleomagnetic results and faunal evidence (icehouse and coolhouse versus-greenhouse suggest a correlation of lowermost fossil horizon conditions) but comparison to belemnite oxygen producing relatively rich small mammal isotope data show that temperature alone cannot assemblage to the early Miocene, roughly in 20– explain all the patterns observed in size changes. 21 Ma age range. The pliopithecid locality level Biometry statistics suggest the presence of 3 represents latest middle Miocene and has an age main morphotypes. The large morphotype is estimate of about 12.1 Ma while the youngest present mostly during proximal, cool localities with cervoids and abundant and diverse environmental conditions of the upper small mammal fauna represents the earliest late Sinemurian. The medium morphotype was Miocene with an age estimate of about 11.6 Ma. adapted to more distal conditions and cool surface waters whereas the small morphotype is Hypsodonty, estimated mean annual associated with warm episodes an higher precipitation, local sedimentology, and large nutriency.

144 Gauti Trygvason Eliassen1, Martin Muravchik1, POSTER Rob Gawthorpe1, Gunn Mangerud1 and Gijs Henstra1 The microstructure of Euselachian 1University of Bergen, Department of Earth Science (Chondrichthyes) tooth and scales from Late Permian of Lithuania- Rift basins have proven economically significant Latvia Region as hydrocarbon provinces and, furthermore, record the structural, sedimentary and climatic 1 1 Darja Dankina-Beyer , Andrej Spiridonov and evolution of the basins and associated catchment 1 Sigitas Radzevičius areas. The aim of this study is to utilize 1 Department of Geology and Mineralogy, Vilnius palynological methods to constrain rift basin University, M. K. Čiurlionio 21/27, LT03101, Vilnius, evolution and provide insight into eastern

Mediterranean late Pliocene climate The Late Permian palaeoichthyofauna of the development. Lithuanian-Latvian border Region is poorly In this study, we take a closer look at the active known due to lack of the information and Corinth rift, Greece, whose early syn-rift deposits comparative isolated material from Southern are spectacularly exposed on the northern Permian Basin. The studied region is located Peloponnese peninsula. So far, research and generally on the flat coastal zone of the existing literature has focused on the western northeastern shore of the Zechstein Sea (Dankina part of the onshore stratigraphy, whereas the et al. 2017). The assemblages of the fish central and eastern areas have received less microremains such as teeth and scales of attention. The study area is the northern Sythas chondrichthyans and osteichthyans from Naujoji Valley, where late Pliocene to early Pleistocene Akmenė Formation (northern Lithuania) and deep-water deposits of the Rethi-Dendro Alši, Kūmas, and Auce Formations (southern Formation (RDF) are exposed in extensive cliff Latvia), Lopingian, Upper Permian were found. sections. Previous studies on tooth and scale enameloid The RDF has been mapped using traditional field microstructure provided a single crystallite methods combined with digital outcrop data enameoid (SCE) as a monolayer in the most (LiDAR). Furthermore, three drill cores that cover primitive chondrichthyan taxa (Botella et al. c. 750 m of stratigraphy are being retrieved. 2009). However, the dental and dermal denticle Palynological analysis suggests a strong microstructure of the Paleozoic ichthyofauna has sedimentary facies dependence of the yet to be investigated. We have studied the palynomorph assemblage. The findings of marine crushing tooth and some scales microstructure of dinoflagellate cysts suggests periods of the Late Permian chondrichthyans. As a result, connectivity between the proto-Gulf of Corinth the investigation with scanning electron and the Mediterranean at an earlier stage than microscope (SEM) has shown the presence of the previously reported. The results may prove vital crown and superficial cap of single crystallite for understanding the structural evolution of the enameloid of euselachian-type scales as well as basin as they imply that by Late Pliocene time the tubular dentine on the Helodus sp. tooth. northern margin of the rift had already migrated close to its present location. POSTER

Palynological investigation of the late Pliocene to early Pleistocene proto- Gulf of Corinth, Greece

145 Krabbe et al., 1994; Dam & Surlyk 1998; Koppelhus & Hansen 2003). All fossils were POSTER screened for diagenetic alteration (see Ullmann and Korte, 2015) using the Scanning Electron Late Toarcian to Early Bajocian Microscope (SEM) and element ratios. Sr/Ca vary climate and environmental changes between 0.533 and 2.595 mmol/mol and Mn/Ca in Europe and East Greenland – between 0.002 and 29.661 mmol/mol. Oxygen geochemical records from calcite (vary between - 3.41 and 4.09 ‰ PDB) and the fossils and sediments carbon isotope values (-11.11 and 1.90 ‰ PDB) were recently measured and altered data will be Jesper Allan Frederiksen1, Suzanne Pultz1, Gerd culled as the next research step. Organic carbon Dietl2, Stéphane Bodin3, Peter Alsen4, Günther isotope measurements on bulk rock samples are Schweigert5, Clemens Vinzenz Ullmann6 and currently in progress. Christoph Korte1

1Department of Geology and Natural Resource Management, Østre Voldgade 10, 1350 København K, POSTER Denmark., 2Staatliches Museum für Naturkunde Stuttgart, Rosenstein 1, 70191 Stuttgart, Germany., Surface analyses of fossil leaves 3University of Aarhus, Department of Geoscience, Høegh-Guldbergs Gade 2, 8000 Aarhus C, Denmark., Magnus A. R. Harding1 and Tais W. Dahl1 4GEUS, Geological Survey of Denmark and Greenland, 1Natural History Museum of Denmark, University of Østre Voldgade 10, 1350 København, Denmark., Copenhagen, Øster Voldgade 5-7, DK-1350 Copenhagen 5Staatliches Museum für Naturkunde Stuttgart,

Rosenstein 1, 70191 Stuttgart, Germany, 6Camborne School of Mines and Environment and Sustainability Recent studies show that the metallome and Institute, University of Exeter, UK chemical composition of living plants depend on

the geology as well as nutritional quality of the This study becomes the first author’s Master soils in which the plants grew (e.g. Husted et al. Thesis, and the aims are to use the isotope values 2004; Laursen et al. 2011; Mie et al. 2014). Few from collected bulk rock samples and from studies, however, have examined the chemical pristine fossils to reconstruct climate and makeup of fossil plant material. In this study, environmental fluctuations during the late Early μXRF, ToF-SIMS, LA-ICP-MS and FTIR techniques and early Middle Jurassic (Late Toarcian– are applied to a fossil conifer (Cupressaceae) Bajocian) Middle European epicontinental from the Naujât Member, West Greenland in an Swabo-Franconian and Paris Basins, the French attempt to identify and distinguish pristine Subalpine Basin and the East Greenland Jameson organic matter preserved as well as the Land Basin. Belemnite rostra and bulk rock diagenetic history of the fossil. Moreover, the samples were collected in SW Germany in Zell strengths and weaknesses of the various unter Aichelberg at the Pliensbach stream (upper analytical techniques are compared. Organic Posidonienschiefer Fm., Jurensismergel Fm., matter within the fossil was identified, but it is lower Opalinuston Fm.), and in Balingen uncertain whether it has a pristine or a bacterial Zillhausen at the Wasserfall section (Opalinuston origin. The Naujât conifer fossil is permineralized Fm.), and at the Roschbach section in calcite with small spots of iron sulphides (Comptumbank, Eichberg Fm., and present mainly where the fossil is thickest. The Subfurcatenoolith, Ostreenkalk Fm.) (see fossil is embedded in a siderite concretion formed Quenstedt 1856-1858; Bloos et al., 2005). Coeval in kaolinite-rich sediment. Based on the samples were taken from the La Baume section in observations, a model for the fossilization of the SE France (Aalenian–Bajocian) (see De Baets et plant is proposed. al., 2008), from different localities in Luxembourg, and from the Sortehat Fm. (only Aalenian) in Jameson Land, East Greenland (see

146

POSTER POSTER

Carinodens – a new addition to the Biostratigraphy and palaeoecology of Late Cretaceous mosasaur fauna of calcareous nannofossils in the Lower Denmark Cretaceous Munk Marl Bed, Danish North Sea Jesper Milàn1, John W.M. Jagt2, Johan Lindgren3 and Anne S. Schulp2 Sarah D. Møller1, Emma Sheldon2 and Jan Audun 1Geomuseum Faxe, Denmark, 2Natuurhistorisch Rasmussen3 Museum Maastricht, The Netherlands, 3Department of 1Department of Geosciences and Natural Resource Geology, Lund University, Sweden Management, Københavns Universitet, 2GEUS, Geological Survey of Denmark and Greenland, 3Fossil- og Molermuseet, Museum Mors The small durophagous mosasaurine mosasaur (Reptilia, Mosasauridae) genus Carinodens is exceedingly rare in north European chalk The Lower Cretaceous Munk Marl Bed of the deposits, with published finds limited to a small Tuxen Formation (Danish Central Graben) marks number of shed tooth crowns and two partial a change in the depositional environment within dentaries from The Netherlands and Belgium, all a chalk unit. Here we investigate the calcareous assigned to Carinodens belgicus. A newly nannofossils from this interval of the Danish discovered isolated, shed tooth crown from the Boje-2C well with emphasis on biostratigraphy UNESCO world heritage site of Stevns Klint and palaeoecology to better understand the expands the known geographical distribution of pelagic environment at the time of deposition. A another species, C. minalmamar, first described total of seventy-two samples were analysed from from Morocco, to Denmark. The specimen was the well. The samples correlate to the upper found within the uppermost metres of the Lower Barremian nannofossil zones BC14 and Maastrichtian chalk deposits, thereby placing it LK20B. An acme of nannoconid ‘tops’ is proposed within the last 50.000 years of the Cretaceous. as a new biostratigraphical event characterising The new tooth crown represents the the middle part of the Munk Marl Bed. High northernmost occurrence of the genus abundances of thermophile taxa suggest warm Carinodens. Previous finds of mosasaur dental surface water conditions at the time of and skeletal materials from Denmark have all deposition. Indicators of increased fertility show been assigned to the hypercarnivorous particularly low abundances indicating a mosasaurids Mosasaurus hoffmannii and decrease in surface water fertility, presumably Plioplatecarpus sp. Thus, the new specimen related to an increased detrital input. provides important new information on Correspondence analysis ordinates samples in ecological niche partitioning amongst large relation to identified palaeoecological proxies marine reptiles during the latest Maastrichtian. and reflects palaeotrophic levels in the surface water within the section. The analysis shows that the calcareous nannofossils indicate a period of more oligotrophic surface water in the middle of the section.

147 POSTER

Middle Jurassic palaeoenvironmental ORAL events in Europe - evidence from Sable nickel isotopes measured in situ palynology and carbon and oxygen from fossilized microorganisms isotopes Anna Neubuck, Marek Tulej2, Reto 1 1 Suzanne Pultz , Jesper Allan Frederiksen , Sofie Wiessendanger2, Magnus Ivarsson3, Valentine 2 3 1 Lindström , Stéphane Bodin and Christoph Korte Grimaudo2, Pavel Moreno2, Curt Broman1, 1Department of Geosciences and Natural Ressource Andreas Riedo4, Wolfgang Bach5, Martin Management (IGN), University of Copenhagen, DK, Whitehouse6, Peter Wurtz2. 2Geological Survey of Denmark and Greenland (GEUS), DK, 3Deparment of Geosciences, Aarhus University, DK 1Department of Geological Sciences, Stockholm University, 22Physics Institute, University of Bern, Switzerland, 3Department of Paleobiology and Nordic During the early Middle Jurassic, several biotic Centre for Earth Evolution, Swedish Museum of 4 and climatic changes took place. A major event Natural History, Leiden Observatory, Sackler Laboratory for Astrophysics, Leiden University, The occurred at the Aalenian to Bajocian transition, Netherlands, 5MARUM - Center for Marine and is associated with a negative carbon isotope Environmental Sciences, Universität Bremen, 6 excursion in carbonate and organic matter Germany, Department of Geosciences at the Swedish Museum of Natural History (Bartolini et al., 1996; Hesselbo et al., 2003). This negative excursion is, in turn, succeeded in the Early Bajocian by a poorly understood positive Precise in situ measurements of nickel isotopes in carbon isotope excursion, associated with floral fossilized microorganisms holds great potential and faunal turnovers (Sucheras-Marx et al., 2015; for differentiation between non-biologic and Bodin et al., 2017). In contrast, dinoflagellates biologic microstructures in rocks. Stable nickel underwent a major evolution and radiation from isotopes are well known to be fractionated by the Late Aalenian to Early Bathonian, and biological processes under laboratory conditions. changes in relative sea level are thought to have Less is known, however, due to instrumental controlled the stratigraphic pattern of obstacles and alteration processes, if biologic dinoflagellate cysts (Wiggan et al., 2017). These signatures of Ni isotope fractionation are paleoenvironmental perturbations are also preserved in fossils in the geologic rock record. reflected in the carbon isotopes of terrestrial Using transition metal isotopes as biomarkers in organic matter and marine carbonate, with microfossils has traditionally been difficult lighter values in the marine palynofacies because of its usually low concentration (Hesselbo et al., 2003). In the present study, preserved in the fossil. It has until now been currently in progress palynological and isotopic technically impossible to reliably measure Ni investigations of latest Toarcian to Bajocian isotopic fractionation pattern in situ in fossilized samples from three different regions in Europe – microorganisms, where the elemental (1) SE France (La Baume section), (2) SW concentration has sometimes been as low as Germany (sections in Zell unter Aichelberg at the 0.1wt%. Here we show both that biologic isotopic Pliensbach stream, and Balingen Zillhausen at the fractionation signatures are preserved in Wasserfall and at the Roschbach), and (3) in S microfossils and that the instrumental Sweden (Vilhelmsfält core) (Guy 1971) – are development has reached a milestone in being presented. The aim is to document the presence able to measure such signals accurately. We also and abundance of marine and terrestrial demonstrate that abiotic signatures are strongly palynomorphs as well as to identify carbon and deviated from the biological signatures, pointing oxygen isotopes trends in the investigated out the eligibility of using stable nickel isotopes successions in order to replace them within the as biosignatures. framework of Middle Jurassic climatic and environmental changes.

148 7. Climate 7.1. Climate from the indicating a sea-level fall of 70-80m (Møller et al. 2009). Palaeogene to the Anthropocene - bridging Identification and correlation of the Miocene timescales and approaches glacial events are important for understanding lithology distribution and can be further used for prediction of potential reservoir sands.

ORAL

Miocene glacial events and their ORAL influence on lithology distribution Eocene bryozoan biota vs climatic within the Danish North Sea area events (Seymour Island, West Karen Dybkjær1, Erik Skovbjerg Rasmussen1 and Antarctica) Emma Sheldon1 1The Geological Survey of Denmark and Greenland Urszula Hara1 (GEUS) 1Polish Geological Institute-National Research Institute

During the Miocene, episodes of global cooling The earliest Antarctic late early Eocene caused repeated, rapid, eustatic sea-level falls in bryozoans of the La Meseta Fm., Seymour Island the order of 25-50 m. In proximal settings within are connected with the major phase of the North Sea Basin (onshore Denmark) these cheilostome evolution; clear preponderance of sea-level variations affected the distribution of cerioporoidean cyclostomes along with lithologies with deposition of well-sorted delta numerous microporoideans. The internal moulds sand or basin floor fans during the glacial events. of the loose, small zooecia in the lowermost part These sand deposits form important subsurface of this formation, includes the cheilostomes of aquifers in the western part of Denmark (Jylland). Beanidae, Catenicellidae, Savignyellidae, which nowdays are widely distributed in the tropical- Based on the dinocyst zonation of Dybkjær & warm, temperate latitudes in the shallow-water Piasecki (2010) it has been possible to correlate settings (Hara 2015). 90% of taxa reveal the three successive, prograding, fluvio-deltaic sand multilamellar growth-form connected with a bodies with the early Miocene glacial events; Mi- short-term episode in the lower part of Telm1, 1a, Mi-1b and Mi-2 of Miller et al. (1991). In more during their long in situ evolution. The bryozoans distal areas (offshore Denmark), the glacial from the (Telm4-5) are the microporoideans and events did not have any (significant) effect on the the first lunulitiform (free-living) bryozoans of lithology, but can be recognised by increased Lunulites and Otionellina, ever reported from abundances of freshwater algae and diatoms. Antarctica. Their disc-shaped colonies are today indicative of tropics and subtropics but skeletal New data from the uppermost Miocene (upper mineralogy is also important in view of the Tortonian and Messinian) have led to the transition of such bryozoans from calcitic to recognition of some of the climatic events known bimineralic to aragonitic on the K/T boundary. from this time-interval - and to related sand Recent, free-living lunulitiforms occur in warm, deposits. A Messinian glacial event, probably shallow-shelf conditions, in temperatures of 10- correlatable with the Mediterranean “Messinian 29˚ C, on coarse, sandy to muddy bottom with low salinity crisis”, was recently recognised in the to moderate deposition in fairly high velocity Nora-1 well. This event correlates with a currents. Contrary to that, the bryozoans prograding depositional system and incision, recognized in the upper part of the formation

149 (Telm7) are composed of the impoverished higher and waters more nutrient-rich compared bryozoan biota of scarse lepraliomorphs and to the inner fjord. Conversely, in the inner fjord, fragmented cyclostomes, which are accompanied these production proxies follow an opposite by the crinoids and brachiopods, gadiform fish pattern. The seasonal sea-ice proxy IP25 and sea- remains, penguin bones and whales. The well- ice-dwelling taxa are present in varying documented distribution of the bryozoans in the abundances, which reflects the seasonal stratigraphical profile of the La Meseta Formation character of the sea-ice cycle together with illustrates the climatic changes connected with species-specific habitat preferences of these taxa. the EECO, MECO as well as the EOT. Our results support the notion that future warming and freshening will likely have a negative impact on primary productivity and organic matter sequestration. This implication ORAL may be assessed by reconstructing changes Tracers of sea ice, primary during past warm periods using the new sediment core records from the area. production and meltwater inputs: distribution of biogenic proxies in a High Arctic fjord system, Northeast ORAL Greenland Investigating phase-relationships Maija Heikkilä1, Kaarina Weckström1, Mikael Sejr2, Petra Tallberg1, Guillaume Massé3, Audrey between ice margin instabilities and Limoges4 and Sofia Ribeiro5 oceanographic conditions in Baffin 1University of Helsinki, 2Aarhus University, Bay during the last deglaciation and 3Université Laval, 4University of New Brunswick, early Holocene 5GEUS Rebecca Jackson1, Anne de Vernal2, Marit-Solveig Seidenkrantz3, Anders Carlson4, Claude Hillaire- The coastal ecosystems of Northeast Greenland Marcel2 and Michal Kucera5 are vulnerable to the enhanced melt of 1Geological Survey of Denmark and Greenland (GEUS) continental and sea ice as a result climate and MARUM / Universität Bremen, 2Université du warming, however little is known of past Québec à Montréal, 3Aarhus University, 4Oregon State ecosystem changes in the region. We present the University, 5MARUM / Universität Bremen distribution of an array biogenic proxies (dinoflagellate cysts, pollen, diatoms, biogenic Freshwater forcing from Northern Hemisphere silica, C/N and their isotopes, IP25, HBI III) from ice sheets during the last deglaciation likely a transect of 13 surface-sediment samples from played an important role in modulating deep- Young Sound-Tyrolerfjord, NE Greenland (74°N), water formation, and thus global climate. The in order to assess their relevance as tracers of mechanisms of ice margin instabilities and its past changes in sea ice, primary production and exact phase relationship with climatic change, terrigenous inputs. The Greenland Ecosystem such as paleoceanographic variation, are not fully Monitoring program provides a unique High understood. Arctic time-series of hydrological, atmospheric and biological measurements from the fjord since Baffin Bay represents an important conduit for the mid-1990s, against which the sediment freshwater transported into the Labrador Sea, signatures can be compared. The proxy data released from the Greenland, Innuitian and show an overall good agreement with the Laurentide ice sheets. We take advantage of two monitoring data. Organic carbon contents, radiocarbon-dated marine sediment cores from diatom production, HBI III and heterotrophic central Baffin Bay that span the last deglaciation dinoflagellate cyst abundance were higher in the and early Holocene (ca. 17-10 kyr BP). These outer fjord, where turbidity is lower, salinity

150 archives provide co-registered records of detrital variety of different applications in paleoclimate input from the surrounding ice sheets and reconstructions. sufficient biogenic carbonate for the reconstruction of paleoceanographic conditions. In this work we will present measurements of δ13C and δ18O from solid carbonate samples, DIC Two distinct detrital carbonate-rich layers, and δ18O of water with new laser technology, with originating from ice sheets surrounding northern case study where Delta Ray was in the field Baffin Bay and dated at 14.2-13.7 kyr BP and (Karstic cave) performing for more than a year 12.7-11 kyr BP, indicate that ice sheet retreat collecting high frequency data on δ13C and δ18O . events occurred during both interstadial and stadial periods and were asynchronous with We have demonstrated usage of a Thermo Heinrich events. Despite previous evidence for an Scientific™ Delta Ray™ IRIS with URI Connect oceanic trigger of these events, records here on certified reference materials and confirmed indicate change in deep water properties and the high achievable accuracy and a precision 13 18 stronger inflow of warmer Atlantic water via the better then <0.1‰ for both δ C and δ O, in the West Greenland Current postdated the first laboratory or the field with same precision and event. The second event was not preceded by any throughput of samples. With equilibration 18 major change in oceanographic conditions but method for determination of δ O in water likely a response to a combination of a samples, which we present in this work, achieved consistently stronger West Greenland Current as repeatability and accuracy are 0.12‰ and well as climatic forcing. Results suggest that there 0.68‰ respectively. were different mechanisms responsible for ice Applying new methods for measurement of the margin instability events in Baffin Bay during the samples important for paleoclimate investigation last deglaciation and early Holocene. one can come to the results already in the field.

ORAL ORAL

Paleoclimate and paleoceanography Deglacial – Holocene 13 18 data based on isotope C and O paleoceanography of Herald Canyon, measurements with the new Chukchi Sea measurement tool Christof Pearce1, Matt O'Regan2, Jayne Rattray3, Magda Mandic1 David Hutchinson2, Tom Cronin4, Natalia 1 ThermoFisher Scientific, Bremen, Germany Barrientos2, Helen Coxall2, Igor Semiletov5 and Martin Jakobsson2 1Department of Geoscience, Aarhus University, The contents of stable carbon and oxygen 2Department of Geological Sciences and Bolin Centre isotopes, 13C and 18O, in secondary precipitated for Climate Research, Stockholm Unversity, Stockh, carbonates and sediments can provide important 3Energy Bioengineering and Geomicrobiology Research information about paleoclimate conditions of the Group, University of Calgary, Calgary, Alberta, C, 4U.S. area. Environmental factors like temperature, Geological Survey, Reston VA, USA, 5Tomsk National concentration of atmospheric CO2, chemical Research Polytechnic University, Tomsk, Russia composition of water, isotopic composition of water, CO2 and deposited are influence the The Herald Canyon is a local depression across isotopic composition. For many decades different the Chukchi Sea shelf, and acts as one of the main instrumental methods involving generations of pathways for Pacific Water to the Arctic Ocean the isotope ratio mass spectrometers with after entering through the Bering Strait. We different periphery units for sample preparation, analyzed sediment samples of two piston cores have provided scientifically required high from Herald Canyon, collected during the 2014 precision, and high throughput of samples for

151 SWERUS-C3 Arctic Ocean Expedition. Core 2-PC1 resources have sustained human settlements in from the shallow (57 mwd) flank contains the late both Arctic Canada and Greenland for millennia. Holocene at high resolution (> 2m/kyr), while Within the framework of the ICE-ARC project: Ice, Core 4-PC1 from the central canyon (120 mwd) Climate and Economics - Arctic Research on extends back in time to ~13 ka. The lower part of Change (EU FP7, http://www.ice-arc.eu/), we 4-PC1 contains an abrupt increase in biogenic aim to reconstruct changes in climate, sea ice, and silica and a carbon isotopic shift towards more marine resources in the NOW region using an marine values, which are interpreted as the signal integrated approach combining proxy records of the Bering Land Bridge flooding and water from marine sediment cores, remote sensing of exchange through the Bering Strait (Jakobsson et sea ice, and historical data. We will present the al., 2017). This major oceanic event is dated to latest results from a multi-proxy investigation of ~11ka and thus occurs in the very early sediment core records from the high Arctic Holocene, contrary to most previous earlier Inglefield fjord (Qaanaaq) and from a new 5,4 m estimates suggesting a Younger Dryas age for the high-resolution sediment core from the NOW, opening of the gateway. The chronology of Core spanning the last ca. 3500 years. Our proxy 2-PC1 is based on 17 radiocarbon dates and the results will be discussed in the light of historical 3.6 ka Aniakchak CFE II tephra, which is used as and archaeological sources in order to identify an absolute age marker to calculate the marine possible links between past changes in climate radiocarbon reservoir age (Pearce et al., 2017). and marine resource availability in this high Analysis of sea ice biomarkers and phytosterols arctic “oasis” with known cultural transitions in indicate relatively stable sea ice conditions Greenland. throughout the entire late Holocene, however ending with an abrupt increase of phytoplankton sterols in the very top of both sediment ORAL sequences which corresponds to the rapid ice retreat observed in recent decades. Holocene temperature trends in the

Northern Hemisphere high latitudes – model-data comparisons ORAL Heikki Seppä1, Yurui Zhang1, Hans Renssen2 and Sea ice, marine productivity, and Paul J. Valdes3 human settlement dynamics in the 1Department of Geosciences and Geography, University North Water Polynya-Qaanaaq region of Helsinki, Finland, 2Department of Natural Sciences and Environmental Studies, University College of (NW Greenland) during the late Southeast Norway, 3School of Geographical Sciences, Holocene University of Bristol, UK

Sofia Ribeiro1, Audrey Limoges2, Martin Nissen3, Steffen Olsen4, Naja Mikkelsen1 and Guillaume Regional differences in Holocene climate trends Massé5 in the Northern Hemisphere high latitudes are 1Geological Survey of Denmark and Greenland, primarily determined by orbital-scale insolation 2University of New Brunswick, Canada, 3Danish Geodata variations and melting ice sheets. Previous inter- Agency, 4Danish Meteorological Institute, 5TAKUVIK, model comparisons have revealed that multi- Laval University, Canada simulation consistencies vary spatially. We compared multiple model results with proxy- based reconstructions in Fennoscandia, The North Water (NOW) is the largest polynya in Greenland, north Canada, Alaska and Siberia. Our the Arctic, a large extension of recurrent open model-data comparisons reveal that data and waters surrounded by sea ice, in northern Baffin models generally agree in Fennoscandia, Bay. This polynya is the most productive Greenland and Canada, with the early-Holocene ecosystem north of the polar circle, and its living warming and subsequent gradual decrease to 0

152 ka BP. In Fennoscandia, simulations and pollen Greenland’s total mass loss. To evaluate whether data suggest a 2.0°C warming by 8 ka, but this is this recent increase of mass loss was an less expressed in chironomid data. In Canada, a outstanding event or occurs, centennial or strong early-Holocene warming is suggested by millennial timescales, sediment cores in fjords both the simulations and pollen results. In with marine-terminating glaciers can be Greenland, the magnitude of early-Holocene investigated since they constitute high-resolution warming ranges from 6.0°C in simulations to sedimentological records that reflect past 8.0°C in δ18O-based temperature reconstructions. changes in glacier stability. Simulated and reconstructed temperatures are mismatched in Alaska. Pollen data suggest a In glacimarine fjords, sand-sized sediment is strong early-Holocene warming, while the predominantly transported and deposited by simulations indicate constant Holocene cooling, melting of sediment-laden icebergs. Therefore, and chironomid data show a stable trend. ice-rafting can be reconstructed by quantifying Meanwhile, a high frequency of Alaskan peatland the downcore variations in sand content. Even initiation before 9 ka can reflect either high though the interpretation of IRD as a proxy for temperature, high soil moisture or large glacier stability (iceberg production) is common, seasonality. In high-latitude Siberia, the many glaciological and sedimentological simulations and proxy data depict high Holocene complexities are involved in interpreting IRD temperatures, but the signals are noisy owing to records. A better understanding of those a large spread in the simulations and between complexities can be achieved by investigating the pollen and chironomid results. On the whole, the relationship between IRD variability and recent Holocene climate trends in most regions observations of climatic and glaciological (Fennoscandia, Greenland and Canada) are well changes. established and understood, but important In this study, we quantify the IRD variability of questions regarding the Holocene temperature four short cores (~2 m) from Upernavik Isfjord, change and mechanisms remain for Alaska and West Greenland. Ice-rafting is reconstructed back Siberia. to 1930 and compared to climatic measurements and a record of glacier terminus position changes,

derived from historical expeditions and satellite ORAL imagery. We discuss spatial trends of ice-rafting An evaluation of IRD as a proxy for and the different processes that modulate its glacier change: results from variability. This information aids the general understanding and interpretation of IRD in Upernavik Isfjord. paleoceanographic research.

Flor Vermassen1, David Wangner1, Laurence

Dyke1, Amalie Cordua2, Sabine Schmidt3, Kurt Kjær4 and Camilla Andresen1 1Geological Survey of Denmark and Greenland, København K, Denmark, 2Institüt für Geologie, University of Hamburg, Hamburg, Germany, 3EPOC, UMR5805, University of Bordeaux, Pessac, France, 4Natural History Museum of Denmark, København K, Denmark

The sudden increase of mass loss of the

Greenland ice sheet at the onset of this century has spurred investigations regarding ice- discharge at marine terminating glaciers, a process that is thought to contribute up to 50% of

153 ORAL sediment output of Jakobshavn Isbræ is discussed. A 2000-year record of ocean influence on Jakobshavn Isbræ calving activity, based on marine sediment cores

David J. Wangner1, Anne Jennings2, Flor Vermassen1, Laurence Dyke1, Kelly A. Hogan3, Kurt POSTER H. Kjær4 and Camilla S. Andresen1 1GEUS – Geological survey of Greenland and Holocene oceanographic variability Denmark in coastal southeast Greenland 2INSTAAR - Institute of Arctic and Alpine Research, Boulder, Colorado 1 1 3British Antarctic Survey, Cambridge, United Laurence M. Dyke , Camilla S. Andresen , Marit- Kingdom Solveig Seidenkrantz2, David J. Wangner1 and Flor 4Natural History Museum of Denmark, Vermassen1 Copenhagen, Denmark 1GEUS, Department of Glaciology and Climate, Øster Voldgade 10, DK-1350, København K, Denmark., 2Centre for Past Climate Studies, Aarhus University, Høegh- Guldbergs Gade 2, DK-8000, Aarhus C, Denmark The Greenland Ice Sheet has experienced significant mass loss in recent years. A substantial component of this is attributable to the retreat of The coastal waters of southeast Greenland are the marine-terminating outlet glaciers, which lost interface between the Atlantic Ocean and the vast mass through increased calving and meltwater Greenland Ice Sheet. Oceanographic processes discharge. Jakobshavn Isbræ is the most have been implicated in the recent loss of ice from productive marine-terminating glacier in marine-terminating glaciers across the region. Greenland, yet relatively little is known about its Ocean processes here are also important as they history before the first instrumental observations modulate global thermohaline circulation; this of local climatic conditions ~140 years ago. occurs both through the influx of meltwater from the ice sheet, and through mixing of water masses Three marine sediment cores were collected on the continental shelf. Understanding how from locations north-west to the mouth of these processes have varied in the past is crucial Jakobshavn Isfjord in Disko Bay. These cores for predicting future behavior. were analyzed to reconstruct changes in glacier behavior in response to past climatic and We present two complementary sediment core oceanographic changes; this provides context records of oceanographic variability from the against which to assess the significance of recent continental shelf of central southeast Greenland. changes. The sediments deposited at this site Radiocarbon and lead-210 dating demonstrates reflect oceanographic and climatic changes as that these cores cover the last 5000 and 9000 well as the discharge of ice rafted debris from years respectively. We analysed benthic and Jakobshavn Isbræ. planktonic foraminifera to reconstruct variability in water masses at both the surface and seabed. Radiocarbon dates of plant material combined We use independent, but complimentary, with a 210Pb profile indicates that the cores measurements of sortable silt to reconstruct the cover a time span of ~2000 years. X-Ray images strength of ocean circulation at the sea bed and and a high-resolution grain size analyses reveal build a holistic picture of oceanographic clear changes in the sedimentation regimes over conditions from the mid-Holocene to the present. time. The influence of ocean water temperature derived from benthic foraminifera record as well Combining our new results with records from as the impact of a floating glacier tongue on the further north in the region yields a unique resource with which to assess the variability of

154 oceanic currents at a regional scale. We use this species, indicating enhanced carbonate to examine the factors that have driven the dissolution. This was likely in part caused by a oceanographic development of the region. We reduction of the influx of IC water and increased then identify how oceanographic changes in entrainment of the East Greenland Current into southeast Greenland have influenced oceanic and the WGC. The reduction of IC water influx also climatic conditions across the wider North allowed increased influx of the cold, corrosive Atlantic region. Baffin Bay Deep Water. These cold subsurface water conditions persisted throughout the late Holocene, only interrupted by short-lived climate fluctuations superimposed on this cooling trend. POSTER

Late Holocene paleoclimatic and palaeoceanographic development of POSTER the eastern Baffin Bay area Spatiotemporal differences in varve Katrine Elnegaard Hansen1, Isabelle Billy2, Pierre structure and preservation over the Francus3, Eleanor Georgiadis2, Jacques last 200 years in Lake Lehmilampi, 2 2 Giraudeau , Philippe Martinez , Guillaume St. Eastern Finland Onge4, Guillaume Massé5 and Marit-Solveig Seidenkrantz1 Sarianna Salminen1, Eeva Haltia1 and Timo 1Aarhus University, 2University of Bordeaux, 3Institut Saarinen1 4 National de la Recherche Scientifique, Université du 1University of Turku Québec à Rimouski, 5Université Laval

A wide variety of studies considering varved lake A 738 m long marine sediment core, AMD14-204 sediments as a climate proxy have been CasqC, was retrieved from the eastern Baffin Bay performed in Finnish lakes. Nevertheless, none of during a research cruise on board CCGS them is considering spatial distribution of varves Amundsen in 2014. The study of benthic within an entire lake, although it is essential to foraminiferal assemblages, XRF core scan data acquire data not only from the deepest point of a and CT-scans supported by radiocarbon dating of lake but also from more shallow areas. The this core allows the reconstruction of the distribution of varves within the entire lake has palaeoceanography and palaeoclimate of the only been studied in a few lakes in Europe (Jenny eastern Baffin Bay during the last ~4800 cal. BP. et al. 2013). Several major changes in oceanographic conditions and climate are reconstructed during In previous work the changes in the presence of this time interval in the eastern Baffin Bay area, varves within the whole lake during the past 200 which also influenced the nearby Upernavik years, arriving at a conclusion in changes in Isstrøm glacier. Our study reveals that relatively hypolimnetic hypoxia (2mg/l (Roberts et al. warmer subsurface waters prevailed during the 2009)), were investigated. As a result the extent final phase of the warmer ‘Holocene Thermal of hypolimnetic hypoxia has clearly changed Maximum’, linked to the entrainment of relatively during the past 200 years in the lake due to warm Irminger Current (IC) water into the West climate. Greenland Current (WGC). This relatively strong advection of IC may also have resulted in In this study the differences in sediment relatively strong melting of the Upernavik composition in varved and non-varved sections Isstrøm glacier, causing influx of meltwater to the are studied with SEM (scanning electron area. However, at ~3100 cal. BP, the onset of the microscopy), μXRF (X-ray fluorescence) and X- Neoglaciation, the area experienced an abrupt ray radiography to investigate the factors transition to dominantly agglutinated benthic influencing varve formation in the lake. The aim of this study is to investigate spatiotemporal

155 differences in varve structure, formation and preservation within the whole lake.

8. Quaternary geology 8.1. Ice and climate history in alluvium, sandy channel fills as well as cryoturbated sediments and solifluction deposits. the Arctic and subarctic The sedimentary succession has been summarised in a facies model for an emergence cycle following deglaciation. ORAL Our study encompasses only the upper 15 m of A 200 ka glaciation history from NW the coastal cliff sections at Kongsfjordhallet Svalbard (succession A of Houmark-Nielsen and Funder 1999), and there is an additional ~20 m of Helena Alexanderson1, Mona Henriksen2, Heidi T. sediments below our Unit 1, which is promising Ryen3, Jon Y. Landvik2 and Gustaf Peterson4 for future studies aiming to go further back in 1Lund University, 2Norwegian University of Life time. Sciences, 3Norwegian Water Resources and Energy Directorate, 4Geological Survey of Sweden

ORAL Late Quaternary sedimentary units at Kongsfjordhallet, NW Svalbard, represent five Reindeer kill dates record late cycles of glaciations and subsequent Holocene glacier lake outburst floods deglaciations during high relative sea levels. The in East Greenland high sea-level events are interpreted as glacioisostatically induced and imply preceding Anders Bjørk1, Morten Meldgaard1, Jeppe Møhl1, regional glaciations, which we constrain in time Kristian Gregersen1, Shfaqat Khan2, Romain by luminescence and radiocarbon ages to just Millan3, Kristian Kjeldsen2, Svend Funder1, Mike prior to ~195 ka, ~130 ka, ~85 ka, ~60 ka and Willis4, Laurence Dyke5, Nicolaj Larsen6 and Kurt ~14 ka. Combined with the stratigraphical record Kjær1 from nearby Leinstranda (Alexanderson et al. 1Natural History Museum of Denmark, 2DTU Space, 2011) we identify six, possibly seven, major 3University of California, Irvine, 4University of Colorado, glacial advances during the last 200 ka in the Boulder, 5GEUS, 6Aarhus Universitet Kongsfjorden region. Two of these occurred during the Saalian and at least four during the Weichselian. In the summers of 2004 and 2005 a surprising find of the remains of several dead reindeers was The results are based on detailed done in East Greenland. The carcasses were sedimentological, stratigraphical and melting out of a snowbank in a small valley next chronological investigations of the uppermost 15 to the village Ittoqqortoormiit at the mouth of m of the 40-m-high Kongsfjordhallet coastal Scoresbysund fjord-system. The radio-carbon sections. The succession is dominated by ages of the 30 animals showed a surprising sediments of marine and littoral origin, spread with several episodes of reindeer- representing partial shallowing-upward deposition within the last four thousand years. sequences due to isostatic rebound. Only one We argue that the only phenomena capable of subglacial till was recognized. Interestingly, killing and positioning the animals at the exact alluvial and periglacial deposits, not commonly same location over multiple millennia are glacier recognized in this type of setting, occur in the lake outburst floods (GLOFs). In the catchment, sequence. These include weathered coarse glaciers and topography capable of creating

156 GLOFs are indeed present. Thus, our pile of dead moraines proximal to present glaciers which reindeer became an unlikely proxy of glacial were suspected to relate to LIA fluctuations. presence, and moved the onset of neo-glacial build-up in the region by a thousand years. Our preliminary results support recent researches that suggest 36Cl exposure dating method as plausible to improve significantly the deglacial history of Iceland, especially where ORAL presence of tephra and organic material for dating is limited. Preliminary results based on 24 new 36Cl exposure datings reveals asynchronous deglacial history of ORAL Tröllaskagi peninsula, central north Advances in Deglaciation on Svalbard Iceland Wesley R. Farnsworth1, Ólafur Ingólfsson2, Skafti Brynjólfsson1, Nuria Andrés2, David Michael Retelle3, Lis Allaart4, Lena Håkansson5, Palacios2 and Þorsteinn Sæmundsson3 Anders Schomacker6, Riko Noormets7, Snorre 1Icelandic Institute of Natural History, Akureyri, Olaussen8, Alexander Prokop8 and Aleksandra Iceland, 2Universidad Complutense, Physical Geography, Smyrak-Sikora8 Madrid, Spain, 3Institute of Life and Environmental 1University Centre in Svalbard (UNIS) & UiT, The Arctic Science, Reykjavík, Iceland University of Norway, 2University of Iceland &

University Centre in Svalbard (UNIS), 3Bates College, ME, USA & University Centre in Svalbard (UNIS), 4UiT, At present the Tröllaskagi peninsula, located in The Arctic University of Norway, 5University Centre in central north Iceland hosts 150 cirque and valley Svalbard (UNIS), 6UiT, The Arctic University of Norway glaciers. The landscape is characterised by steep & Natural History Museum of Denmark, 7University narrow glacially carved valleys separated with up Centre in Svalbard (UNIS), Dept. of Arctic Geology, N- to 1500 m high peaks and ridges. The glacial 9171 Longyearbyen, 8University Centre in Svalbard history of Tröllaskagi suffer from lack of direct (UNIS), Dept. of Arctic Geology, N-9171 Longyearbyen, dating. Previous studies indicate Tröllaskagi Norway peninsula was mostly ice covered during the last glacial maximum. Several lowland end moraines Despite warm regional fjords, a variety of data and raised beaches indicate recurrent glacial re- suggest extensive glacier advances on Svalbard advances during the deglaciation , which was during the Pleistocene-Holocene transition. We completed about 10 Ka ago. Most of the present present the first well-constrained (in age) end glaciers are considered to have reached moraine formed during the Lateglacial-early maximum Holocene conditions during the late Holocene (LGEH) in Svalbard, De Geerbukta, NE Little Ice Age. Spitsbergen. The landform was deposited by an We sampled 24 rock samples from erratics and outlet glacier re-advancing into a fjord extending moraine boulders for 36Cl exposure dating in 4.4 km further than the late Holocene maximum. order to improve the glacial history of the area. We compare the synchronicity of this glacier Preliminary results indicate asynchronous advance to paleoclimate records and 15 other deglaciation pattern over the peninsula. Some proposed glacier advances from Svalbard. mountain ridges and summits were deglaciated Furthermore, we introduce 35 additional LGEH at least about 16 Ka ago. Furthermore, some glacier deposits identified through remote highland valleys were deglaciated about 13-14 Ka sensing were glaciers also advanced into a high ago while others probably remained glaciated at relative sea level. Glacial deposits were wave- least until early Holocene. Finally we obtained washed or cut by early Holocene raised marine average ages 2.66 Ka and 0.7 Ka from two shorelines, suggesting the landforms were deposited before or during high relative sea level stands, thus exhibiting a similar LGEH age.

157 Contrary to current understanding, our new to derive Pleistocene exposure and burial evidence suggests that the LGEH glaciers were histories. We expect bedrock erosion rates to be more dynamic, exhibited re-advances and amongst the lowest reported for the northern extended well beyond the extensively studied Fennoscandian shield. late Holocene glacial expansion. Given the widespread occurrence of the LGEH deposits on Svalbard, we suggest that the culmination of the ORAL Neoglacial advances during the Little Ice Age does not mark the maximum extent of most Svalbard Constraining the evolution of the last glaciers since deglaciation; it is just the most Eurasian ice sheets: progress towards studied and most visible in the geological record. DATED-2

1 2 Anna Hughes , Richard Gyllencreutz , Jan Mangerud1 and John Inge Svendsen1 ORAL 1University of Bergen & Bjerknes Centre for Climate Research, 2Stockholm University 10Be and 26Al exposure and burial histories for ancient granite tors in In 2016 we published an empirical arctic Finland. reconstruction of the evolution of the extent of the last Eurasian ice sheets, that is fully Adrian Hall1, Marc Caffee2, Karin Ebert1, Jakob documented, specified in time, and includes Heyman3 and Johan Kleman1 uncertainty estimates (DATED-1; Hughes et al. 1Department of Physical Geography, Stockholm 2016). This was the culmination of a 10-year University SE 106 91 Stockholm Sweden, 2Purdue Rare Isotope Measurement Laboratory, Purdue University, effort to compile and archive all published dates 525 Northwestern Avenue, West Lafayet, 3Department relating to the build-up and retreat of the British- of Earth Sciences, University of Gothenburg, PO Box Irish, Scandinavian and Svalbard-Barents-Kara 460, SE 405 30 Göteborg Sweden Seas ice sheets. Over 5000 dates were assessed for reliability and used, together with published geomorphology-based ice-sheet margin The ice-divide zone of northern Finland positions, to reconstruct time-slice maps of ice experienced low erosion beneath successive extent for every 1000-years 25-10 ka and four cold-based Fennoscandian ice sheets (Hall et al., periods between 40-27 ka. All uncertainties (both 2015). One indicator of this are the many tors that quantitative and qualitative e.g. precision and occur on hill tops and flanks. Published 10Be and accuracy of numerical dates, correlation of 26Al inventories for two tor summit surfaces near moraines, stratigraphic interpretations) were Vuotso indicate ~0.8 Myr of exposure and burial combined based on our best glaciological- (Darmody et al., 2008). These samples came from geological assessment and expressed in terms of tabular tors that may have lost granite sheets to distance as a ‘fuzzy’ margin. Since the DATED-1 glacial erosion. Schmidt Hammer values are high, census (1 January 2013), the volume of new indicating limited weathering of these rock information (from both dates and mapped glacial surfaces despite apparently long exposure. Hence geomorphology) has grown significantly (e.g. published data may relate to one or more phases 32% increase in the number of dates), although of glacial erosion rather than to tor surface the spatial distribution of information remains erosion. In contrast, nearby tors retain delicate similar. Here, we present work towards an superstructures and give low rock hardness updated version of results, DATED-2 (census: 1 values, features consistent with little or no glacial January 2017), that attempts to further reduce modification, more advanced weathering and and explicitly report all uncertainties inherent in longer exposure of the tor summit surfaces. We the ice sheet reconstructions, and discuss the will present new 10Be and 26Al isotope results for implications of the revised margins. these surfaces and use Monte Carlo simulations

158

ORAL ORAL

Local ice caps response to Holocene Deglaciation patterns of the Lake climate variability in Kobbefjord, District Ice Lobe of the Scandinavian West Greenland Ice Sheet in SE Finland during the Younger Dryas Nicolaj K. Larsen1, Astrid Strunk1, Laura B. Levy2, Jesper Olsen3, Anders Bjørk4, Torben L Lauridsen5, Juha Lunkka1, Niko Putkinen2 and Anu Seppänen2 Erik Jeppesen5 and Thomas A. Davidson5 1Geoscience Research Unit, Oulu Mining School. P.O. Box 1Department of Geoscience, Aarhus University, 3000, FI 90014 University of Oulu, Finland, 2Geological 2Department of Geology, Humboldt State University, Survey of Finland, P.O. Box 97, FI-67101, Kokkola, 3Department of Physics and Astronomy, Aarhus Finland University, 4Natural History Museum of Denmark, University of Copenhagen, 5Department of Bioscience, Aarhus University The deglaciation pattern of the Lake District Ice Lobe (LDIL) of the former Scandinavian Ice Sheet (SIS) in the Salpausselkä zone, southern Finland The sensitivity of glaciers and ice caps (GICs) in were studied. Glaciofluvial landforms (i.e. eskers, Greenland to prolonged warm periods is poorly glaciofluvial deltas and subaquatic fans and constrained and geological records documenting sandurs) were mapped using Digital Elevation the long-term glacial history are needed to put Model (DEM) data with 10 metre-resolution and recent observations into a broader perspective. Light Dedection And Ranging (LiDAR) data with 2 Here we report the results from three proglacial metre-resolution. Hillshading was used to make a lakes where fluctuations in local glaciers located DEM-generated 3D-landscape in order to help the at different altitudes in Kobbefjord, southwest recognition of landforms and their surface Greenland have been recorded. Our results show deformation. Based on these observations ice that the lakes received meltwater from the initial lobe re-advance and retreat phases, and their deglaciation of the area ~9.2 cal. ka BP until ~8.7- extent across the Salpausselkä zone were defined. 7.9 cal. ka BP when the meltwater input ceased as the glaciers most likely disappeared. Regrowth of The results indicate that the LDIL of the SIS glaciers began again at ~5.5 cal. ka BP at ~1,370 retreated as far as 40 kilometres north of the m a.s.l., ~3.6 cal. ka at ~1,170 m a.s.l., and ~1.6 proximal side of the present Second Salpausselkä cal. ka BP at ~1,000 m a.s.l., clearly reflecting ridge most likely prior to the Younger Dryas. This strong altitudinal control of the GIC response to retreat phase was followed by a re-advance and Neoglacial cooling. Our results highlight that GICs the deposition of the First Salpausselkä in front of in Kobbefjord, southwest Greenland are the LDIL ice margin. Subsequently, ice retreated primarily influenced by changes in summer air further north and the Second Salapusselkä in temperatures and winter precipitation and that front of the LDIL margin was formed. Optically they are facing a rapid decay that most likely will stimulated luminescence dates indicate that the result in their disappearance within the next Second Salpausselkä was deposited during the centuries as a consequence of global warming. Younger Dryas.

159 compared with our reconstruction when ice sheets, or ice sheets and meltwater, are included in the models (Zhang et al. 2016).

ORAL

Molluscs show an early and exceptional warm Holocene Thermal ORAL Maximum around Svalbard, which is Local or distant centre of uplift, a case not found in climate models study from Northwest Iceland Jan Mangerud1 and John Inge Svendsen1 1 1Dept. of Earth Science, Univ. of Bergen, Norway and Hreggviður Norðdahl Bjerknes Center for Climate Research 1Institute of Earth Sciences, University of Iceland

Several species of shallow-water marine molluscs Contemporary studies of glacio-isostatic uplift at that cannot presently live around Svalbard due to the Vatnajökull glacier in Iceland have revealed a the cold-climate occur frequently in raised Early more or less instantaneous accelerating rates of Holocene deposits. The most warmth demanding uplift as high as 35 mm·a-1 due to negative glacier of these species, Zirfaea crispata, currently has a mass-balance. During the late Weichselian northern limit 1000 km farther south. Based on deglaciation of Iceland, uplift rates exceeded radiocarbon ages of this species we conclude that 160 mm·a-1 when relative sea-level regressed the August temperatures on Svalbard were as from the marine limit in West Iceland some 14.7 much as 6 °C warmer than today during the cal ka BP. period 10,200 to 9,200 calendar years ago Glacial striae in Northwest Iceland are arranged (Mangerud & Svendsen 2017). The blue mussel, in an apparent radial pattern with the striae Mytilus edulis, re-appeared on Svalbard in 2004, orientated towards the outer coasts of NW- in response to the recent warming of the Arctic. Iceland implying that the striae were formed by This happened almost 4000 years after Mytilus actively eroding glaciers retreating towards the disappeared from the shores of Svalbard, centre of the peninsula. Numerical modelling of excluding a short re-appearance during the the Weichselian retreat of the Icelandic Ice Sheet Medieval Warm Period 900 years ago. After the (IIS) has returned local ice-caps in NW Iceland last Ice age, Mytilus arrived for the first time in when the IIS reached a temporary minimum in Svalbard as early as 11,000 years ago, indicating Bølling-Allerød times. Thus, the existence of that the climate was then as least as warm as independent late Weichselian ice-caps in NW today. Iceland seems plausible and also that they If we, as an example, postulate that the winter influenced glacio-isostatic uplift in the area, precipitation pattern during the period 10,200 – especially when considering temporal and spatial 9,2000 years ago was similar to the present isostatic equilibrium during deglaciation. pattern, then a summer warming of 6 °C would Raised shoreline features are found throughout have raised the equilibrium line altitude (ELA) on lowland areas of NW Iceland from present sea- glaciers by about 900 meters, and all glaciers on level and up to or slightly above 80 m a.s.l. The Svalbard would have melted away. aim of this paper is to examine if altitudes of We also note that climate models simulate a much raised shorelines can be used to decide if glacio- later and not-so-warm Thermal Maximum isostatic uplift of the NW Iceland was controlled by reduced crustal load (uplift) of a local ice cap

160 or if, and then to what extent, the uplift was shows that warmer ocean conditions played key influenced by the wastage of the IIS in central part in the retreat of Jakobshavn Isbræ, one of the Iceland. largest ice streams in West Greenland, which has been shown to have collapsed at 12.2 kyr BP (Rinterknecht et al. 2014). Our results show that ice retreat occurred mainly by calving during the

YD period while surface/subsurface melt dominated during a warmer climate before and after the YD. Our results emphasize the ocean`s ORAL significant role for ice sheet stability under the current climate change. Younger Dryas ice margin retreat triggered by warming of the ocean surface in central-eastern Baffin Bay ORAL

1 2 Mimmi Oksman , Kaarina Weckström , Arto Marine environmental changes in Miettinen3, Stephen Juggins4, Dmitry Divine3, front of the Scandinavian Ice Sheet Rebecca Jackson5, Richard Telford6, Niels J. Korsgaard7 and Michal Kucera5 during the last deglaciation 1Department of Geosciences and Geography, University 1 2 of Helsinki, Finland, 2Department of Environmental Nadine Quintana Krupinski , Andreas Mackensen , Sciences (ECRU), University of Helsinki, Finland, Yasmin Bokhari Friberg1, Karen-Luise Knudsen3, 3Norwegian Polar Institute, Norway, 4School of Anne-Sophie Fanget3, Jeroen Groeneveld4, Ellen Geography, Politics and Sociology, Newcastle Martin5, Marit-Solveig Seidenkrantz3 and Helena University, UK, 5MARUM - Center for Marine Filipsson1 Environmental Sciences, University of Bremen, 1Lund University, 2Alfred Wegener Institute, 3Aarhus Germany, 6Department of Biology, University of Bergen, University, 4MARUM, University of Bremen, 5University Norway, 7Nordic Volcanological Center, Institute of of Florida Earth Sciences, University of Iceland, Iceland

The Kattegat-Baltic Sea region shows evidence of The Greenland Ice Sheet stability is linked to fast- strong coupling with North Atlantic climate over flowing ice streams that are strongly influenced recent glacial-interglacial cycles, but insufficient by sea surface temperatures (SSTs) at their front long, high-resolution Baltic area climate records (Holland et al. 2008; Nick et al. 2013). As the ice have limited evaluating such links. New ultra- mass loss from the Greenland Ice Sheet is high-resolution sediment cores collected during accelerating (Shepherd et al. 2012), there is a IODP Expedition 347 can provide such records, need for high-resolution marine proxy data to including foraminiferal and mollusc understand interactions between the ocean and geochemistry records reflecting seawater the ice sheet. Here we present the first diatom- environmental changes directly adjacent to the based high-resolution quantitative Scandinavian Ice Sheet (SIS) during the most reconstruction of sea surface conditions from recent deglaciation. central-eastern Baffin Bay covering the period from 14.0 to 10.2 kyr BP. Our reconstruction We present benthic foraminiferal stable isotope reveals warmer sea surface conditions from 13.4 (δ18O and d13C) and trace element (Ba/Ca, Mn/Ca kyr BP to the end of the Younger Dryas (YD) and Mg/Ca) records as well as mollusc Sr isotope period (11.7 kyr BP) and strong interaction data from IODP Site M0060 (located between between the ocean and the West Greenland ice Sweden and Denmark in the southern Kattegat) margin. These warmer ocean conditions were to constrain bottom water salinity, temperature caused by an enhancement of Atlantic-sourced and oxygenation changes from ~18-13ka. water inflow together with increased insolation Because of the large salinity changes (fresh to and amplified seasonality. Our sediment record marine) during the past 20ka in this region, we

161 interpret δ18O as reflecting salinity changes more away by 15 ka and there are no indications that a than temperature here, while d13C reflects regrowth of glaciers took place during the ventilation, productivity, and salinity. Ba/Ca, Younger Dryas. A significant warmer climate Mn/Ca, and Mg/Ca may indicate salinity, prevailed during the Holocene period. The oxygenation, and temperature variations, combination of AMS 14C- and varve chronology in although these proxies are less straightforward this study has provided a valuable contribution to to interpret in this setting. constrain the age model for ongoing palynological-, paleomagnetic, DNA- and Stable isotope results suggest fjord-like, poorly compound specific isotope (δ2H, δ18O) analyses ventilated conditions during early deglaciation, also conducted within the framework of the with three clear phases: 1) an initial rapid, large CHASE- (Climate History of the Arctic Seaboard of freshening event; 2) subsequent slower, step- Eurasia) project. Put together, this continuous wise freshening (likely linked to the decay of the and unprecedented high resolution record SIS); 3) more marine, ventilated, saline effectively supplement previous attempts to conditions after ~15.6ka. These events may be reconstruct pre-Holocene environmental linked to regional and global climate changes changes based on fragmentary data from during this period of global climate changes, and moraines and exposed strata along river banks may help us evaluate the interplay between the and coastal cliffs around the Russian Arctic. SIS and climate in the North Atlantic and beyond.

ORAL

ORAL Relative sea-level data as a constraint New insights into the glacial and of Holocene ice sheet history in climate history of the Polar Urals, Finderup Land, NE Greenland

Arctic Russia Astrid Strunk1, Andreas Nilsson2, Marit-Solveig Seidenkrantz1, Benoir Lecavalier3, Glenn Milne4 Carl Regnéll1, John-Inge Svendsen1, Haflidi and Nicolaj K. Larsen1 Haflidason1 and Jan Mangerud1 1Department of Geoscience, Aarhus University, 1Department of Earth Science and Bjerknes Centre for Denmark, 2Department of Geology, Lund University, Climate Research, University of Bergen, Norway Sweden, 3Department of Physics and Physical

Oceanography, Memorial University, St. John's, Canada, 4Department of Earth and Environmental Sciences, Here we present new results and discoveries University of Ottawa, Canada from several field campaigns in the Polar Urals of

Arctic Russia. This talk focus on the late Weichselian and Holocene glacial and climate Here, we present a new relative sea level (RSL) history as inferred from a 24 m long, partly reconstruction for Finderup Land, NE Greenland, varved, high resolution and exceptionally well based on isolation basins to obtain more dated sediment core from a deep lake (Bolshoye knowledge about the Lateglacial and Holocene Schuchye) located in the interior of the mountain glaciation history. Existing RSL data is in general chain. The core, that is spanning the last 24,000 sparse in NE Greenland and the RSL curves years, provide a unique high resolution record of produced at nearby locations are based on very the climate and environmental changes since the limited data1,2. It is imperative to understand how Last Glacial Maximum (LGM). Our results infer the large ice sheets responded to a warming glacial influence on lake sedimentation including climate in the past, in order to make accurate annual rhythmites, i.e. varves, through the LGM predictions of future sea level change. until about 19 ka when the continuous sequence Reconstructions of past relative sea level changes of varves successively disappear and the is a key parameter in modeling global sea level sedimentation rate decrease. We conclude that all fluctuations under past climate changes1,3,4,5. local glaciers within the catchment had melted

162 We present a new dataset of isolation lakes Bølling warming (Gump et al. 2017, Mangerud et covering elevations from 8-62 m a.s.l. in which we al. 2017). The retreat was later interrupted by identify the marine to lacustrine environmental two re-advances that culminated ~14 ka (Older transition. We date this transition using Dryas) and during the end of Younger Dryas. We radiocarbon ages from foraminifera combined find 10Be- dating a very useful tool for making with paleomagnetic age correlation. Our new three-dimensional ice sheet reconstructions. The dataset will allow us to construct a RSL curve for front of the ice sheet seems to have been Finderup Land, which in turn reflects the surprisingly steep. In the Bergen area the ice Lateglacial and Holocene ice marginal surface appears to have reached an elevation of fluctuations in NE Greenland. Furthermore, we more than 700 m only some 15 km inside the compare our results with existing predictions of front. However, in low-lying areas radiocarbon past RSL in the area produced by the Huy2 (ref. 6) dating of basal lacustrine sediments provides and Huy3 (ref. 1) ice sheet models and discuss more precise and accurate dates of the possible improvements of the ice sheet models by deglaciation. incorporating our new data set.

ORAL ORAL

Deglaciation history of western The Mineral Assemblage of Gas- Norway inferred from 10Be- dating of charged sediments from Vestnesa erratics and 14C-dates from sediment Ridge, NW Svalbard – a tale of cores crystallization and dissolution

1 2 3 John Inge Svendsen1, Jan Mangerud1 and Jason P. Christoph Vogt , Simone Sauer , Aivo Lepland 4 Briner2 and Jochen Knies 1 1Dept. of Earth Science, University of Bergen and Crystallography, Geosciences, University of Bremen, 2 Bjerknes Centre for Climate Research, 2Dept.of Geology, Germany, CAGE – Centre for Arctic Gas Hydrate/UiT University at Buffalo, USA Tromsø & The Geological Survey of Norway, Trondheim, 3 Norway, CAGE/ UiT Tromsø & The Geological Survey of Norway, Trondheim, Norway & Uni Tallinn, Lettland, We report new results from an ongoing field 4CAGE/ UiT-Tromsø & The Geological Survey of Norway, Trondheim, Norway campaign in southern Norway aiming at reconstructing the glacial and climate history since the Last Glacial Maximum (LGM). The We present a full-pattern quantitative phase inferred ice sheet history is based on a large analysis of x-ray diffraction data (QXRD, Vogt et number of cosmogenic nuclide exposure ages al., 2002) from sediments taken within the active 10 ( Be) from glacially transported boulders as well methane seep sites of Vestnesa Ridge, NW as sediment records from lake basins. We find Svalbard. The 4 coring positions were controlled that all coastal mountains in the studied area by remotely operating vehicle (ÆGIR 6000) with were ice covered during the LGM, at which time three sites within the active seep sites and one the Scandinavian Ice Sheet was flowing reference site outside the main activity. Hence, a westward, independent of the underlying clear differentiation between active and inactive topography. Later, the fast flow of the Norwegian with respect to methane gas flux can be shown. Channel Ice Stream led to a lowering of the ice While the reference core can be related to well surface. The highest mountain peaks along the know sedimentary events in the vicinity of the W Hardangerfjorden became ice free as early as ~20 Spitsbergen shelf and Yermak Plateau – which are ka. Following the collapse of the Norwegian related to warm Atlantic water influx and/or Channel Ice Stream, the ice margin stabilized just deglaciation of the Svalbard ice sheets - gas- outside the outermost coast. A major withdrawal hydrate influenced cores contain particular took place ~15 ka, possibly in response to the carbonate mineral phases. Mg-rich calcites and

163 aragonites have been freshly precipitated in the atmosphere-sea-ice, precipitation-ice-masses, vicinity of a sulfide methane transition zone increased runoff from glaciers and solar forcing) (SMTZ) triggered by anaerobic methane of the different elements in the climate system in oxidation (AOM) and sulfate reduction due to that particular area. This will help to solve high methane flux through the sediments. questions as whether the Late Pleistocene-Early Holocene fjord temperatures increased first and The QXRD allows also for the investigation of Fe-, subsequently the glaciers on land retreated - or Mn-oxides and –sulfides probably precipitated in vice versa. Furthermore, we aim to identify if the the transition zones under changing redox- same climatic signals occur in both archives conditions. Combined with sediment and pore synchronously. Preliminary results from the water geochemistry, the authigenic mineral project will be presented. assemblage indicative for a gas-hydrate influenced sediment can be described in much detail. While geochemical processes can be quantitatively viewed, the high resolution POSTER determination of authigenic minerals also helps to understand the past history of methane Sea-ice in the Iceland-Norwegian Sea emissions in this Arctic gas hydrate system. . during the last 50-60000 years: first results from the IS-4C marine core

Erna Ósk Arnardóttir1, Esther Ruth POSTER Guðmundsdóttir1, Jón Eiríksson1, Ívar Örn Benediktsson1 and Yanguang Liu2 From fjord to land – Holocene climate 1Institute of Earth Sciences, University of Iceland, Askja, of the Femmilsjøen area, NE Sturlugata 7, IS-101 Reykjavík, Iceland, 2First Institute Spitsbergen of Oceanography (FIO), State Oceanic Administration, Qingdao, China Lis Allaart1, Anders Schomacker2, Matthias Forwick3, Michael Retelle4 and Lena Håkansson5 Sea ice coverage in the North Atlantic plays an 1UiT The Arctic University of Norway & University Centre in Svalbard, 2UiT The Arctic University of important role in the Arctic climate system. Norway & Natural History Museum of Denmark, 3UiT The aim of the study presented here is to The Arctic University of Norway, 4Bates College, ME, USA & University Centre in Svalbard, 5University Centre reconstruct and time sea ice coverage in the in Svalbard Iceland-Norwegian sea during the Weichselian with the purpose of increasing our understanding of climate and oceanographic changes. The area is The overall aim of the project is to reconstruct the highly affected by the cold southward flowing Holocene climate and glacial history of northeast East Greenland current and a branch of the Spitsbergen, based on a holistic approach warmer north-westward flowing Norwegian including collection and integration of marine, current, creating a complex zone of temperate terrestrial and lacustrine data. The area of main and cold waters. interest is the 8 km long lake Femmilsjøen in NE Spitsbergen, as well as its surroundings and the A 430 cm long marine sediment core, IS-4C, adjacent part of northern Wijdefjorden. Marine retrieved from 1598 m water depth in the sediment cores and swath bathymetry data were Iceland-Norwegian sea, northeast of Iceland has collected just off Femmilsjøen in the summer of been investigated with regard to quantity and 2017. Lacustrine cores are to be collected in source of ice rafted debris (IRD) as well as the 2018. We expect that data series from different abundance of planktonic foraminifera. These archives with restricted spatial distribution will proxies have been counted at every 2-3 cm reflect the various feedback mechanisms (e.g. the throughout the core. Radiocarbon dating indicate interaction between ocean-atmosphere, that the upper 251 cm of the core represent the

164 last 42000 years and the Vedde Ash is present in change from marine to lacustrine sediments the uppermost 30 cm. More precise chronology using a multiproxy approach including XRF core with radiocarbon dating, tephrochronology and scanning, magnetic susceptibility and diatom correlation of oxygen isotopic records from analysis. The marine-lacustrine isolations were Greenland ice cores and the North Atlantic deep dated using terrestrial macro fossils. Our new sea is in progress. results will be compared to existing RSL curves from the area and with the latest RSL-based ice IRD has been identified to three main sheet model of Greenland. components; crystals, rock fragments and ash/tephra. Planktonic foraminifera have been counted and identified to species. These proxies display high amplitude variations throughout the POSTER core indicating variable sea ice flux. A low sea ice flux is recorded between 184 cm (39500 yr. BP) Putorana ice sheet advance over and 294 cm indicating an interglacial period. The southern Taimyr, NW Siberia, during investigation is ongoing. the Late Saalian (MIS 6)

Ivar Benediktsson1 and Per Möller2 1Institute of Earth Sciences, University of Iceland, POSTER 2Department of Geology, Lund University

A new relative sea level curve from Mestersvig, NE Greenland based on Previous studies in NW Arctic Siberia suggest that isolation basins local ice caps around the Kara Sea shelf merged there repeatedly to form a Kara Sea Ice Sheet Frank Bauer1, Astrid Strunk1, Sarah Woodroffe2, (KSIS). When assembled to a large ice sheet, Anne Sophie Søndergaard1 and Nicolaj K. Larsen1 initial northward flow from the Byrranga 1Department of Geoscience, Aarhus University, Høegh Mountains on the Taimyr Peninsula reversed as Guldbergs Gade 2, 8000 Aarhus C, Denmark, the ice sheet further expanded southwards. The 2Environmental Research Centre, Department of most extensive glaciation over Taimyr occurred Geography, University of Durham, South Road, Durham, during the Taz/Late Saalian (MIS 6), during UK which the KSIS advanced from NW onto the Putorana Plateau south of Taimyr. However, stratigraphic sites along the Bol’shaya Balaknya Our ability to model the past response of the River (situated on southern Taimyr) suggest that Greenland ice sheet to climate change is the Taz/Late Saalian expansion of the KSIS from fundamentally dependent on the quality and NW was preceded by ice coming from the distribution of geological observations of ice Putorana Plateau to the south, a conclusion based margin history and relative sea level (RSL) on our site BBR 16. This site reveals a fining observations. In Greenland, the extensive ice-free upwards sequence from fluvial sands to shallow corridor provides an excellent opportunity to glaciomarine mud with shell fragments, dated develop a network of well constrained RSL with ESR to 171 ka BP. This sequence is observations that can provide powerful glacio- glaciotectonically deformed and unconformably isostatic adjustment (GIA) constraints over the overlain by subglacial traction till. The post-glacial period. In southern Greenland, the glaciotectonic deformation as well as clast fabrics RSL observations are in many places well in the overlying till, indicate stress application constrained in contrast to northern Greenland from southerly directions. Our preliminary model where the data quality and spatial resolution is suggests a marine transgression due to a growing poorer. In this study, we present a new RSL curve Putorana ice sheet, before it overrode southern from Mestersvig, Northeast Greenland. We used Taimyr during the Late Saalian (MIS 6). This sediment cores from seven isolation basins occurred at the same time as a KSIS advanced collected at different elevations to identify the

165 from the north beyond the Byrranga Mountains. (facies F) on ice-free land. Even if only a few of the The KSIS subsequently merged with the Putorana facies are actually found per sequence, it still ice sheet and eventually pushed the maximum implies a regional glaciation. At Kongsfjordhallet, extent of Late Saalian ice well south of the five cycles of glaciation and subsequent Putorana Plateau. deglaciation during high but falling relative sea levels are recognized. These are dated by luminescence to range in age from ~190 ka to the last deglaciation (Alexanderson et al., this POSTER volume). Facies model for a rebound cycle based on mid-late Quaternary sediments in the Kongsfjorden area, POSTER NW Svalbard The Weichselian Mona Henriksen1, Helena Alexanderson2, Heidi T. chronostratigraphical framework of Ryen3, Jon Y. Landvik1 and Gustaf Peterson4 the Kongsfjorden Trough Mouth Fan, 1Norwegian University of Life Sciences, 2Lund W-Spitsbergen University, 3Norwegian Water Resources and Energy Directorate, 4Geological Survey of Sweden Daniel Hesjedal Wiberg1, Haflidi Haflidason2 and Jan Sverre Laberg1 1Department of Geosciences, UiT – The Arctic University Raised marine deposits found in coastal areas of of Norway in Tromsø, N-9037 Tromsø, Norway., the Arctic have been instrumental in 2Department of Earth Science, University of Bergen, reconstructing past sea-level change and Bergen, Norway glaciations during the Quaternary. This is because the high relative sea level indicated by the marine sediments is largely due to isostatic The high-latitude Kongsfjorden Trough-Mouth loading and thus implies a preceding regional Fan (TMF), situated on the continental margin (ice-sheet scale) glaciation. Kongsfjordhallet is west of Svalbard was fed by the Kongsfjorden one of several sites in the Kongsfjorden area in paleo-ice stream system. A placement, which is NW Svalbard with such deposits, and where ideally suited for recording glacial advances to successions of Quaternary sediments are exposed the shelf break and thereby the development of in up to 40 m high coastal cliffs (Houmark-Nielsen the Svalbard Ice Sheet through time. During a & Funder 1999). Here, we present results from a survey in 2010, a regional seismic grid was more detailed sedimentological and established, consisting of 17 high-resolution stratigraphical investigation of the uppermost 15 seismic 2D lines (TOPAS). There were also m of Kongsfjordhallet. While subglacial tills are retrieved a 12.65 meter long sediment core from scarce, marine and littoral sediments are the southern part of the Kongsfjorden TMF at 846 volumetrically dominating, representing partial m water depth. Our preliminary conclusion fits shallowing-upward sequences. Interestingly, we well with the earlier proposed development also find alluvial and periglacial deposits, which models, which indicates that during the are not commonly recognized in this type of Weichselian glacial (117 – 11.6 ka), paleo-ice settings. streams from the west coast of Spitsbergen advanced to the continental shelf-break three Based on this record we have further developed times. The new data acquired allow us to study the facies model for rebound cycle by the last two advances in greater detail than Alexanderson et al. (2011). An idealized record, previously available. The upper half of the core representing glacial advance and overriding displays a very varied character, with layers (facies A), deglaciation with isostatic rebound comprising ice rafted debris (IRD) inter-bedded and successively shallower water (facies B-E) and with hemipelagic sediments, where the interval eventually fluvial and periglacial processes

166 between 2 – 5 m have been dated with AMS 14C. inversion modelling of glacier evolution of a An anomalous layer (at 270-335 cm) have been subset of ice caps enabling a forward simulation estimated to have an age between 23,3 – 25 ka, of future behavior. and is interpreted to comprise sediments from the last glacial maximum (LGM). The lower half of the core appears visually fairly homogenous, but have been interpreted to consist of alternating POSTER layers of GDFs and IRD related to the second advance during the mid-Weichselian, estimated Paleoceanographic ocean surface to have occurred from about 70 ka. conditions in Kongsfjorden, Svalbard over the last 400 years

POSTER Tiia Luostarinen1, Arto Miettinen2, Katrine Husum2, Dmitry Divine2, Seija Kultti1, Outi Evolution of Greenland’s glaciers and Hyttinen3 and Rahul Mohan4 ice caps in the 20th century 1Department of Geosciences and Geography, University of Helsinki, 2Norwegian Polar Institute, Tromsø, Niels J. Korsgaard1 and Miska Luoto1 Norway, 3Department of Geosciences and Geography, 1University of Helsinki, Department of Geosciences and University of Helsinki; Geological Survey of Finland, Geography Espoo, 4National Centre for Antarctic and Ocean Research, Ministry of Earth Sciences, Goa, India

About 20,000 glaciers and ice caps (GICs) surround the Greenland Ice Sheet. These GICs Marine subfossil diatom assemblages from cover 7% of the glaciated area in Greenland but Kongsfjorden are used to investigate sea surface store less than 1% of the total ice volume. It is temperatures (SST) and sea ice variability in high estimated that 14-20% of the total ice loss from temporal resolution. The oceanographic Greenland between 2003-2008 could be conditions in Kongsfjorden are strongly related attributed to the GICs, therefore they contribute to the characteristics of the West Spitsbergen far more to global mean sea level rise than their Current (WSC), transporting Atlantic Water (AW) size relative to the Greenland Ice Sheet would and therefore heat and salt into the Arctic Ocean suggest. They could make a significant (Svendsen et al., 2002). Changes in the AW inflow contribution in the 21st century, as they are more can have a major impact on the environment of sensitive climate indicators and adjust their size the Svalbard area (Ślubowska-Woldingen et al. in response to climate change more rapidly than 2007). ice sheets. Estimates for the 20th century that A 49 cm long marine sediment core was analyzed predates the modern age of remote sensing, use for diatoms and grainsize at 1.0 cm intervals. records from half a score of GICs to obtain Diatoms were abundant in the top 16 cm. The estimates of the mass loss for Greenland as a AMS 14C dates suggest the basal age of ca. 400 cal whole. This has implications for our yr. BP. The diatom-based SST reconstruction understanding of past glacier evolution and its based on the North Atlantic surface sediment coupling to climate, and hence also limits our sample calibration data set (Miettinen et al. 2015) ability to predict the future. This project aims to and WAPLS transfer function method (Ter Braak produce an improved observational data set for and Juggins 1993) indicates temperature physical and statistical modelling of ice loss with variation between 4.1 to 6.0 ˚C with a mean regional granularity. The record will extend back temperature of 4.8 ˚C. The qualitative sea ice to the Little Ice age, when the GICs began to reconstruction is based on the Marginal Ice Zone retreat from their maximum positions. Data and (MIZ) diatom assemblage. Factor analysis with models will be developed to facilitate an analysis the North Atlantic diatom factors based on of factors driving GIC evolution in the 20th. Andersen et al. 2004 was used to estimate the Finally, the data will be used as input for

167 variability of water masses. The preliminary fluctuations in the directional components of results show a cooling trend in both SST and sea energy supply and sediment delivery. ice since the Little Ice Age, and a very recent warming during the past decades. Grain size is The project is at an early stage of investigation dominated by fine fraction, but in the upper 15 and we present first insights into a new and cm coarse fraction increases up to 40 %, promising area of investigation. Work will be indicating change in depositional conditions. continued in summer 2018.

POSTER POSTER

Characteristics of wave-built Ice marginal fluctuations of local ice sedimentary archives in Buor Khaya caps in McCormick Fjord, NW Bay (71°N/130°E), Siberian Arctic, Greenland

Russia. Anne Sofie Søndergaard1, Nicolaj Krog Larsen1, Astrid Strunk1 and Jesper Olsen2 Lasse Sander1, Rune Michaelis1, Svenja 1Dept. for Geoscience, Aarhus University, Denmark, Papenmeier1, Sergey Pravkin2 and Karen H. 2Dept. for Physics and Astronomy, Aarhus University, 1 Wiltshire Denmark 1Alfred-Wegener-Institute, List/Sylt, Germany, 2Arctic and Antarctic Research Institute (AARI), St. Petersburg, Russia Knowledge about the glacial history of the Greenland Ice Sheet and its dynamic response to past climate variability is important to put the Prograded sequences of beach deposits preserve current changes into context. In southern and valuable paleoenvironmental information on the eastern Greenland, a number of recent studies long-term variability of the (wave-) climate have documented the ice marginal response to forcing driving centennial to millennial coastal Holocene climate variability (Lowell et al. 2013, evolution. Buor Khaya Bay, NE Siberian Arctic, is Larsen et al. 2016), but from northern Greenland located at the transition between the there are very few observations. Verkhoyansk mountain range and the Arctic Ocean and is one of the few places along the In this study, we use a multiproxy approach to try Russian arctic coast, where wide beach-ridge and constrain the Holocene glacial history in systems exist. Two field sites in Buor Khaya Bay McCormick Fjord in northwest Greenland. Due to were visited during an expedition in August 2017 the occurrence of moraines and the absence of in order to obtain baseline information to assess marine content in several retrieved lake cores, we the potential of the systems for the speculate that the area might has been subjected reconstruction of Holocene sea level and past sea- to an early Holocene ice advance that dammed ice extent. The inner parts of the bay are ice-free the area from the inflow of marine waters from for three to four months during the short boreal the fjord. summer. The wave forcing of the system is hence a function of the duration of ice-free conditions During the field season 2016 and 2017 we and fetch across the open sea surface. Both retrieved sediment cores from 5 lakes in different systems are composed of several sets of beach elevations, samples for cosmogenic exposure ridges composed of sand- to cobble-sized shales dating from two moraines, shell fragments and of local origin. The morphological arrangement of mosses from the margin of a nearby local ice cap. landforms and the characteristics of the beach Here we present C14 ages and XRF data of 6 deposits evidence (1) extensive periods of sediment cores and C14 dates of moss samples - continuous progradation, and (2) unconformities the rest of the samples are scheduled to be with changes in ridge orientation suggesting processed in early spring 2018.

168 With the collected data, we expect to obtain an streams are preserved in the glacial landform overview of the deglaciation history in record. This includes onset zones with reticulated McCormick Fjord. We will discuss the ages and ridges and hummocky topography, and trunk- data in relation to existing climate records from flow zones with elongate subglacial bedforms, the area and put the new results into context. rhombohedral ridge-networks and regularly- spaced transverse ridges. Reconnaissance fieldwork in 2017 indicates that elongate sedimentary bedforms consist of deformation till 8.2. Glacial processes, deposits and sorted sediments, and that rhombohedral and landforms and transverse ridges are mainly composed of till. Future excavations and GPR surveys aim at

revealing the internal structure of these ORAL landforms.

Palaeo-ice streams in NE-Iceland: a new project and the first findings ORAL

1 1 Ívar Benediktsson and Ólafur Ingólfsson Interpretation of glaciotectonic 1Institute of Earth Sciences, University of Iceland complexes from analysis of thin- skinned thrust-fault structures in Current understanding of the configuration, seismic sections, an example from the geomorphological imprint, dynamics and Jammerbugt in eastern North Sea. recessional history of palaeo-ice streams in Iceland is limited. A new project aims to advance Lars Ole Boldreel1 and Stig A.S. Pedersen2 our knowledge of palaeo-ice streams in NE 1IGN, KU, 2GEUS Iceland by investigating the glacial landform associations and sedimentary records in the Vopnafjörður, Bakkaflói, Þistilfjörður and During the last decade, a number of glaciotectonic Jökuldalsheiði areas, using multiple glacial complexes have been recognized in the North Sea geological, geomorphological, remote sensing, (Andersen 2005, Bendixen 2016, Larsen & geophysical/geotechnical and chronological Andersen 2005, Novak & Leth 2015, Pedersen & methods. The project is designed to elucidate the Boldreel 2017). The mapping of these complexes relative timing and spatial distribution of fast ice are merely depending on interpretation of flow, the absolute timing of ice-stream/ice-sheet qualified seismic data, which enables structural recession and thinning, and the mechanisms interpretation. This presentation demonstrates contributing to fast flow and the genesis of the complexity of seismic interpretation of streamlined subglacial bedforms. The project can glaciotectonic structures by the investigation of thereby provide insight into marine-ice sheet the Jammerbugt Glaciotectonic Complex. instability and the vulnerability of marine- terminating ice streams to sea-level rise, and The Jammerbugt Glaciotectonic Complex, eastern further our understanding of ice sheet part of the North Sea, occupies an area of more 2 deglaciation dynamics. An important benefit of than 300 km located about 10 km offshore the this project will be the value of its results for west coast of northern Denmark. The bedrock constraining numerical models aimed at included in the complex comprise the main part illuminating subglacial landform development of the Cretaceous Chalk Group in the North Sea. and the evolution of the Iceland ice sheet during The detachment surface in the proximal part of the last deglaciation. the complex occurs in Lower Cretaceous greensand about 400 m b.s.l. In the central part of Preliminary mapping suggests that the flow sets the complex the thrusting ramps the strong of several apparently cross-cutting former ice reflectors at the base of the Chalk Group and the

169 detachment surface continues in the lower part of Sheet a hanging-wall anticline is developed with the Upper Cretaceous chalk throughout the distal overturned limbs. This hanging-wall anticline can part. be followed for nearly 10km along the crest of the highest hills on Mors. A balanced cross section is The Eemian–Early Weichselian Skærumhede provided. The depth to the décollement zone is Group onlap the deformed beds at the boundary determined and the displaced along the shallow to the tectonic depression north of the complex dipping ramp and flat is calculated. indicating a Saalian age of the glaciotectonic deformation. The calculation of the displacement The Hanklit Thrust Fault Complex is a well- during balanced cross section construction documented thrust fault structure, and the model demonstrates that the thrust sheets in the tailing is a good illustration of the thin skinned thrust end of the complex had their source in the fault, and can also be compared to structures that Skagerrak Sea. Thus, we suggest that the hole occurs in mountain ranges like the Jura caused by displacement of thrust sheets mountains. contributed to formation of the Skagerrak depression.

ORAL

ORAL Diagnosing ice sheet grounding line stability from landform morphology Computer supported 3D modelling of the Hanklit glaciotectonic complex, Sarah Greenwood1, Lauren Simkins2 and John 2 Mors, Denmark Anderson 1Department of Geological Sciences, Stockholm University, 2Department of Earth Science, Rice Embla Galdal1 University 1University of Copenhagen

Marine-based ice sheet stability is largely The Hanklit coastal cliff is a glaciotectonic locality dictated by processes at or near the grounding where an excellent cross-section through a thrust line, where marine and glacial processes and the fault complex is exposed. The structural topographic setting govern the duration of architecture and structural features of the grounding line occupation and sensitivity to glaciotectonic complex is modelled in the 3D retreat. Landforms that are built at the grounding modelling software, Leapfrog Geo. line, such as grounding zone wedges and The structural elements in the Hanklit Complex recessional moraines, are inscribed extensively consist of thrust sheets interpreted to be the on formerly glaciated continental margins. These result of the Norwegian ice advance in a pro- landforms directly mark former grounding line glacial glaciotectonic deformation about 30- positions over a prolonged period of retreat 28,000 years ago. It consists of a 60m thick (thousands of years), represent the history of succession of Eocene diatomite overlain by 15m sedimentation during the occupation of each of glacial deposits. The Hanklit Thrust Sheet position, and offer high potential for extracting extends for more than 1km along the W-E strike information about grounding line dynamics. and is displaced for more than 300m to the south We characterise the morphological traits and (Klint & Pedersen, 1995). The Hanklit Thrust spatial distribution of thousands of grounding Sheet is thrusted across the foreland feature line landforms from the Ross Sea continental named Gullerup Thrust Sheet, whereas the shelf, which mark Antarctic Ice Sheet retreat Salgerhøj Thrust Sheet describes the since the Last Glacial Maximum. Recessional northernmost thrust element ramping up and moraines indicate a consistency of grounding line displaced upon the back of the Hanklit Thrust processes/setting and regularly forced retreat, Sheet. In the frontal part of the Salgerhøj Thrust

170 while grounding zone wedges are highly variable country. Here single or multiple generations of in size and shape, developing both asymmetry streamlined terrain with increasing size ranging and sinuosity during landform growth. We from tens of meters to tens of kilometres are attribute growth of sinuosity to lateral variability presented. Other subglacial features include in sediment delivery along the grounding line, eskers and tunnel-valleys. Examples are given on linked to basal meltwater drainage. This the combination of easily accessible on-land development of sinuosity over time is commonly features and obscured terrains partly buried on associated with larger-magnitude retreat events. the sea floor into a more whole appearance of A ‘stable’ grounding line position of relatively glacial landforms. In order to establish a long duration may thus be linked with an meaningful and modern model of the ice age ‘unstable’ retreat event. Landform construction is landscapes in Denmark, subglacial terrains are surprisingly insensitive to the local topographic but one of many pieces of the puzzle and they setting. We explore the processes controlling the must be seen in relation to other glacial production of contrasting grounding line landforms such as terminal moraines, dead-ice landform morphologies and, consequently, what land forms and features related to proglacial these morphologies reveal regarding the erosion and long time periglacial reshaping. (in)stability of a retreating ice sheet.

ORAL ORAL Mapping of glaciotectonic structures Details in glacial terrains detected and associated sedimentary from Digital Terrain Models brings deposition with ground penetrating new light upon the Danish glacial radar landscape Peter Roll Jakobsen1, Hans Lerche and Cecilie Michael Houmark-Nielsen1 Skovsø Andersen 1Centre for GeoGenetics, Natural History Museum, 1GEUS University of Copenhagen, Denmark

The analysis of glaciotectonic structures and geological setting is best done in outcrops, but as Previously unnoticed landforms of former they are limited both in occurrence and in lateral glaciated terrains in Denmark can now be extent, geophysical methods are often used to revealed from studies using Digital Terrain interpret the geology. Ground penetrating radar Models (DTMs) provided by the Danish Geo-data has proven to be an excellent method to Agency. The removal of buildings, vegetation etc. determine sedimentary structures as well as from DEMs with 25m, 10m and 1.6 m grids allow deformation structures. exposure of details in landforms not earlier subjected to investigation. GIS-based studies of Examples of structural analysis are given from hill shaded DTMs – on land as well as on the sea small composite ridges in the northwestern part floor –combined with Quaternary geological of Jylland created during the general retreat of mapping and data from open exposures as well as the Main Glacial Advance in the late Weichselian. the use of the rich literature on the Danish glacial Other examples are given from Northwest landscape and its origin, gives new insight into Sjælland where two georadar investigations were glacial landforms, that was formed along the carried out in the rim of the large end-moraines lowland fringes of the Scandinavian Ice Sheet from a re-advance of the Young Baltic Advance, during the last two glaciations. about 17.000 years ago.

In this lecture focus will be on subglacial The radar profiles are differentiated into radar landforms and their distribution around the facies with distinct reflection characteristics.

171 Glaciotectonic deformations such as thrusts and Murtoos are composed primarily of folds are interpreted from the GPR data. heterogeneous diamicton with minor amounts of Furthermore syn-tectonic and post-tectonic bedded sand. sedimentation is interpreted from the radar profiles. Murtoos are common in Finland and Sweden and we present a map of their distribution. They seem The examples show that the morphology of the to be most common where ice-retreat rates were ridges investigated is controlled by the high during deglaciation, and they are absent deformation structures, and that where extensive frozen-bed conditions were penecontemporaneous sedimentary processes present. have smoothened the morphology created by the deformations.

ORAL

ORAL The framework of glaciotectonic complexes and their position in the Geomorphology and distribution of glaciodynamic sequence stratigraphy subglacial triangular hummocks (murtoos) in Sweden and Finland Stig Schack Pedersen1 1GEUS

Mark D. Johnson1, Joni Mäkinen2, Gustaf Peterson3, The analysis of glaciotectonic complexes uses the Antti Ojala4, Jukka-Pekka Palmu4, Kari Kajuutti2, classification of architectural surfaces. These Christian Öhrling3 and Elina Ahokangas2 1University of Gothenburg, 2University of Turku, comprise four orders of surfaces (Pedersen 3Geological Survey of Sweden, 4Geological Survey of 2014). The first order includes the décollement Finland zone and the topographic surface, which define the bottom and the top of complexes. The second- order surfaces are the thrust-faults, which bound Triangular or V-shaped hummocks of subglacial the thrust sheets and duplexes that constitute the origin have been identified in Sweden and internal framework of tectonic complexes. The Finland due to the increased resolution provided third order comprises folded beds appearing in by LiDAR imagery. Their triangular shape is the internal structure of thrust sheets. The fourth distinctive and recognizable as a clearly order includes all small-scale structures like identifiable landform. These forms have been joints and faults with minor displacement, which previously mapped in some cases as dead-ice are important for the prediction of dynamic hummocks, but geomorphic relationships with development (Pedersen 2000). eskers, flutes and De Geer moraines show these to be subglacial. Good examples of these forms For the interpretation of the dynamic occur near Murtoojärvi, Finland, and we propose development, three macroscopic regimes are calling these new landforms ‘murtoos.’ Individual defined: the distal, the central and the proximal murtoos are diamond and triangular shaped with part of glaciotectonic complexes (Pedersen the axis of the triangle parallel to regional ice 2005). In the distal regime close to the foreland, flow. Murtoos have a longitudinal spacing on 50 flat-lying thrust-faults displace thin thrust sheets. to 200 m, and their widths are on the order of 50 In the central regime, steep dips of thrust faults to 100 m. They are asymmetric with a gentle up- occur together with hanging-wall anticlines. ice side and a steeper down-ice side. Often, they Towards the proximal part of complexes have a shingled appearance. In many cases, they superimposed deformation of duplexes occur, occur in patches in an ice-flow parallel path with which result in vertical orientation of surfaces. eskers defining corridors we believe to be of Glaciotectonic complexes may include subglacial meltwater origin. superimposed deformation related to

172 development in one event or superimposing of Three-dimensional microtomographic scanning several events. Glaciodynamic events are showed intervals of relatively stable till fabrics differentiated by application of glaciodynamic intervening with phases of fabric re-orientation sequence stratigraphy, which combines towards new equilibria. Shear stresses during the depositional and structural features (Pedersen deformation showed a distinct cyclicity possibly 2012). indicating formation and collapse of grain bridges.

Collectively, we interpret the ring-shear data as a ORAL signature of permanent and sometimes unsystematic evolution of till structure with a Subglacial till deformation: lessons general trend towards more ductile and less from laboratory experiments brittle deformation with increasing strain. These results bear on the reconstruction of past Jan A. Piotrowski1, Mia Bering Holdensen1, subglacial processes and we advocate extreme Włodzimierz Narloch2, Simon Carr3, Anders caution with interpreting the history of natural Damsgaard4 and Nicolaj Krog Larsen1 tills based on the micromorphological signatures 1Department of Geoscience, Aarhus University, DK-8000 alone. Aarhus C, Denmark, 2Department of Geology and Hydrogeology, Nicolaus Copernicus University, PL-87-

100 Toruń, Poland, 3School of Geography, Queen Mary 4 University of London, London E1 4NS, UK, Geophysical ORAL Fluid Dynamics Laboratory, Princeton University, Princeton, NJ 08540, USA Glacial landform evolution in

transitional cold – warm bed In a detailed study of mega-scale glacial lineations subglacial conditions in the central (MSGLs) left by a Weichselian palaeo-ice stream part of Scandinavian Ice Sheet, in in Poland, Spagnolo et al. (2016) analysed northern Finland multiple parameters of the land-forming till and concluded that it originated by a combination of Pertti Sarala1 lodgement and thin-skinned deformation whose 1Geological Survey of Finland, P.O. Box 77, 96101 cumulative effect was the formation of the MSGL Rovaniemi, Finland/Oulu Mining School, Univ. Oulu field.

To advance our understanding of till formation On-going glaciomorphological mapping in and deformation postulated by Spagnolo et al. Finland based on airborne LiDAR (Light (2016) we conducted a series of experiments on Detection And Ranging) interpretation has this till in a large ring-shear apparatus intended revealed new data that is useful for the to mimic subglacial shearing (Bering Holdensen glaciodynamic examination in the glaciated 2017). Undisturbed, oriented samples for terrain. One of the key study areas in Finland has micromorphological analyses were taken at been the Kuusamo Ice Lobe area close to the Late displacement increments of 0, 9, 18, 36, 72, 144, Weichselian ice-divide zone in Finnish Lapland. 288, 576 and 1152 cm. The glacial morphology of the ice lobe is composed mainly of moraine morphologies such Till microstructures mapped on thin sections as the glacial streamlined lineations of the across the zone of shearing gave intriguing and Kuusamo drumlin field in the eastern part and hitherto unmatched insights into the different hummocky and ribbed moraines in the development and evolution of till properties western part, i.e. at the core of the ice lobe. The during the shearing under controlled boundary drumlin field was formed under surging type conditions. The deformation signatures often glacial movement during Younger Dryas while varied non-systematically between the sampled the core part of the glacier remained cold-based. increments.

173 Glaciofluvial deposits (eskers and delta cliffs reveals a series of subaquatic moraines formations) occur in places representing last formed by a glacier emanating from deglaciation phase. Particularly, ribbed moraines Borgarfjörður to the north. The style of represent the depositional formations formed deformation demonstrates that these moraines under subglacial conditions at the transitional were primarily built up by ice- zone between the warm and cold based glacier. marginal/proglacial thrusting and folding of However, an erosional, subglacial meltwater marine sediments as well as deposition and channel network cutting the ribbed moraine subsequent deformation of ice-marginal formations before the deposition of glaciofluvial subaquatic fans. The southernmost and largest of deposits and smoothly lineated surface of the moraines is over 1.5 km wide and more than morainic terrains by glacier reworking gives new 30 m high and is interpreted to indicate the knowledge of the formation phases of subglacial maximum extent of the Borgarfjörður glacier. moraine formations in the core part of Generally, the other moraines become continental glacier. As the subglacial meltwater progressively younger towards the north, activity that formed the erosional channel system designating an advances or still-stands of the and later channel fills such as eskers was worked glacier as it oscillated during an overall retreat. after ribbed moraine formation, the origin of the Glaciomarine sediments rapidly accumulated in ribbed moraines must be earlier process, front of the glacier and filled in the depressions happened close to cold-based core part. between the moraines when the glacier finally receded from the area. Previously obtained radiocarbon dates from the deformed sequence suggest that these moraines were formed in the ORAL Younger Dryas. This study highlights the Active retreat of a Late Weichselian dynamics of marine-terminating glaciers and may have implications for the interpretation of marine-terminating glacier revealed their sedimentological and geomorphological by large-scale glaciotectonics in records. Melasveit, western Iceland

Thorbjörg Sigfúsdóttir1, Ívar Örn Benediktsson2 and Emrys Philliips3 ORAL 1Department of Geology, Lund University, Sweden & Institute of Earth Sciences, University of Iceland, Glaciotectonic analysis of the geology 2Institute of Earth Sciences, University of Iceland, in the NE part of Sjælland, Denmark, 3Birtish Geological Survey, Edinburgh, UK based on interpretation of vibro

seismic data along the west bank of Large and complete glaciotectonic sequences Esrum Sø formed by marine-terminating glaciers are rarely observed on land, hampering our understanding Line Winsløw1, Stig A. S. Pedersen2 and Lars O. of the behaviour of such glaciers and the Boldreel1 processes operating at their margins. During the 1Copenhagen University, 2GEUS Late Weichselian in West Iceland, marine- terminating glaciers deformed glaciomarine In the northeastern part of Sjælland, two sediments. These formations are now exposed in outstanding morphological elements are present: >5km long coastal cliffs in the Melasveit district, the composite hill ridges characterizing the recording past glacier dynamics and the terrain in Gribskov and the elongated depression interrelationship between glaciotectonic and lodging Esrum Sø. A simple glaciodynamic sedimentary processes under/in front of a interpretation of their formation is that they marine terminating glacier. The sedimentology represent a hill-and-hole pair with Esrum Sø and glaciotectonic architecture of the coastal representing the hole from where the material for

174 the composite hills in Gribskov derived. This the project will aim to produce a geological model interpretation satisfies the general N–S trend of with emphasis on a structural analysis of the morphological elements. deformed meltwater sediments. The ridges are parallel to the terminal moraine of the Vig- However, the northern part of Esrum Sø trends Hønsinge Arc formed by the Bælthav Readvance SE–NW parallel to the buried Esrum-Alnarp and are located on the proglacial meltwater plain valley suggesting a tectonic origin of the lake ahead of the terminal moraine. The ridges were morphology. For the investigation of this investigated by six 250 MHz GPR lines hypothesis, a 6.3 km vibro seismic profile was perpendicular to the ridges and one GPR line collected along the western bank of the lake. striking parallel to the ridges. The GPR lines were During the analysis of the seismic profile, a large successfully recorded and needed only very little glaciotectonic complex was recognized. The processing and patience with estimating the complex comprises five sections, which migration velocity, as diffractions were many. 8 characterize the distal to the proximal structural Facies have been determined from the radar development. The translation of the complex was stratigraphic analysis. Two facies of glacio-fluvial from a northerly to a southerly direction over a sand and gravel, which are folded and thrusted décollement surface, which stepwise rises from respectively indicating both ductile and brittle 95 m b.s.l. in the northern proximal region style deformation, with complex imbricate fans. shallowing toward the southern distal region. Additionally, deformed seasonal outwash, The glaciotectonic complex comprises ramps and channels, till, kames, landslides and cover sands flats with related hanging wall and footwall are interpreted as well. The GPR lines are structures. deformational shortened by 7 % on average. Two different scenarios are suggested to explain this The glaciotectonic complex developed during the deformation; A: A surge and sustained advance advance of the Scandinavian Ice sheet in the Late and B: Recession on an annual scale. Based on the Weichselian (30,000-20,000 B.P.). During the distribution of the radar stratigraphic facies is initial phase, glaciofluvial sediments accumulated scenario B interpreted to be the most likely one proglacially. These were later thrusted into to have happened. piggyback duplexes. Following the recession of the ice, a glaciolacustrine environment appeared.

In a final phase, a superimposed glaciotectonic deformation occurred concluding the POSTER development the glaciotectonic complex. New subglacial landforms detected from LiDAR data POSTER Kari Kajuutti1, Joni Mäkinen1, Elina Ahokangas1, 2 2 Subglacial or Pro-glacial Deformed Antti Ojala and Jukka-Pekka Palmu 1University of Turku, 2Geological Survey of Finland Middle-Late Weichselian Ridges in Jyderup Skov, Odsherred, Denmark High-resolution DEMs produced from LiDAR Cecilie Skovsø Andersen1 provide a revolutionary tool for the mapping and 1Former student at University of Copenhagen documentation of glacial landforms over wide areas (e.g. Johnson et al. 2015). The main resource for this study was the Maankamara map The aim of this study is to investigate the service (http://gtkdata.gtk.fi/maankamara/) of glaciotectonic deformation of the ice-push ridges the Geological Survey of Finland (GTK) where on the outer edge of the Vig-Hønsinge Arc in LiDAR data is supplemented with base maps and Jyderup Skov, Odsherred, Denmark. By maps of the Quaternary deposits as well as measurements of Ground Penetrating Radar bedrock, striation and the highest shoreline data. (GPR) reflections profiles across the structures,

175 Indeed, while studying the deglaciation of the solution to this, enabling the reconstruction of past Scandinavian ice sheet after the Salpausselkä relict networks over large areas. Such III stage in SW Finland (Kajuutti et al. 2016), our investigations have been facilitated by the release attention was drawn to formations being of freely available, high-resolution digital surprisingly regular triangles in shape. elevation models (e.g. ArcticDEM).

Even though the triangular landforms are clearly This study focuses on subglacial meltwater identifiable from LiDAR-based DEMs, they are corridors (SMCs), characterised as elongated almost impossible to detect from map contour- tracts of hummocky sediments often associated lines, other remote sensing images or even in the with eskers, glaciofluvial sediments and eroded field within forest covered areas. The triangles bedrock. Similar features have been recognised consist of till and are typically 100 – 200 m long before (e.g. Rampton et al., 2000; Utting et and 2 – 5 m high. Our hypothesis is that the al., 2009; Peterson et al., 2017) but their triangular landforms and related other features distribution over ice-sheet scales has yet to be belong to routed, large-scale subglacial drainage considered. This is an important consideration systems forming a continuum between for determining the formation of these features channelized (eskers) and more widely spread and confirming their link to subglacial meltwater small-scale distributed subglacial drainage i.e. identifying the source, magnitude and (Mäkinen et al. 2017). duration of flow required.

We have started co-operation with Swedish We use a large-scale mapping approach to researchers (cf. Peterson et al.) aiming to a joint understand the spatial pattern of palaeo- publication that will show the distribution of the subglacial flow beneath large parts of the former triangles in both countries and moreover expand Laurentide and Fennoscandian ice sheets. An our knowledge of their sedimentology and origin. automated method for identifying and mapping The name for the new landforms will be these features is developed based on the high published both in our forthcoming paper as well degree of roughness within these channels which as in the NGWM meeting. distinguishes them from the surrounding bed. The outputs of this approach are compared to traditional manual techniques and detailed morphological investigations to provide insights POSTER into the nature of the drainage system and to Using large-scale patterns and contextualise limited observations of contemporary subglacial meltwater drainage. morphology of subglacial meltwater corridors to gain insight into the spatial organisation, formation and POSTER evolution of meltwater drainage beneath ice sheets Sedimentology of the new subglacial landforms detected from LiDAR data Emma Lewington1, Stephen Livingstone1, Andrew Sole1, Chris Clark1 and Sarah Greenwood2 in SW Finland 1The University of Sheffield, 2Stockholm University Joni Mäkinen1, Kari Kajuutti1, Antti Ojala2, Jukka-

Pekka Palmu2 and Elina Ahokangas1 While spatio-temporal variations in the efficiency 1Department of Geography and geology, University of Turku, 2Geological Survey of Finland of the subglacial drainage system have been identified as a key control on ice sheet dynamics, the inaccessibility of the bed means its precise New triangular-shaped glacial landforms have character and evolution remains poorly been identified and described from LiDAR-based understood. Palaeo-bedforms provide one DEMs in SW Finland (Kajuutti et al. 2016;

176 Mäkinen et al. 2017). Our hypothesis is that they pointing down ice with an asymmetric vertical and related other features belong to routed, profile along its axis. The LiDAR DEM of Sweden large-scale subglacial drainage systems forming a has been surveyed for murtoos, and they continuum between channelized (eskers) and commonly throughout the country, most more widely spread small-scale distributed frequently north of the Younger Dryas ice margin subglacial drainage. and in areas deglaciated during Bølling-Allerød in the south. We have excavated murtoos at four We present the first sedimentological localities and have studied the internal structure description of the new triangular landform from through detailed sediment description. The SW Finland and tentatively discuss the distribution, geomorphology and depositional environment and related processes. sedimentological properties of murtoos collected The general sediment characteristics include here provide an opportunity to understand their stratified gravel-sand core covered by loose genesis. sandy/gravelly, massive/matrix-supported diamictons interbedded with disturbed, Murtoo sizes are roughly 10-100 meters wide, 5 laminated sand beds. The paleoflow pattern is to 50 m long, and 2-10 meters high. The lobe-shaped with boulder-rich margin. Maximum individual murtoos have an overlapping size of the boulders in the sediment is ca. 1 m and appearance and occur as fields. In places, the clasts are angular to edge-rounded. The elongated fields trend parallel to the overall ice sediment characteristics do not fit into current flow direction. Commonly, Murtoos occur in close conception of subglacial glaciofluvial deposits or relation to ribbed moraine and, in places, they are tills, but rather support the continuum between draped by eskers and overprinted by flutes, these as also indicated by the morphological indicating murtoos form subglacially. Murtoos characteristics. predominantly consist of a heterogeneous sandy gravelly diamicton, with angular to sub-angular Ongoing co-operation with Swedish researchers clasts. Lenses of sorted sediments are intermixed (cf. Peterson et al. 2017) will expand our in the diamicton and boulders are common on the knowledge on the sedimentology and genesis of surface. Further, their distribution in Sweden these new landforms. Their name will be suggests a formation during periods of rapid ice published both in our forthcoming paper as well retreat. We list multiple hypotheses, their pros as in the NGWM meeting. and cons, and discuss them to shed light on the formative process.

POSTER POSTER Sedimentological and morphological implications for the understanding of A new glacial deposits and features murtoo formation in Sweden database of Finland

Gustaf Peterson1, Mark D. Johnson2 and Christian Niko Putkinen1, Pertti Sarala1, Satu Putkinen1, Öhrling3 Jukka-Pekka Palmu1 and Antti E. K. Ojala1 1Department of Earth Sciences, Gothenburg University, 1Geological Survey of Finland Göteborg; Geological Survey of Sweden, Uppsala, 2Department of Earth Sciences, Gothenburg University, Göteborg, 3Geological Survey of Sweden, Göteborg Renewing of the glacial deposits and features database is going-on in the Geological Survey of Finland (GTK). It includes both a new definition During glacial landform mapping in southern of the landform categories and mapping work Sweden, a new distinct landform was detected, based on the 2-metre resolution LiDAR (Light which we refer to as murtoos. The landform Detection And Ranging) data interpretation with appearance is a V-shaped hummock, generally ArcGIS software. Preliminary sources for map

177 polygons and lines are: 1. LiDAR-DEM data provided by National Land Survey of Finland, 2. GTK’s Quaternary geological 1:20 000 and 1: 8.3. Open session Quarternary 200000 data, 3. aggregate, engineering geological geology and groundwater aquifer investigations. The multi-year project aims to produce 'the best mapping data for each location in Finland' with a ORAL cost-effective, minimal fieldwork approach. The mapping process combines both the main Repeated fluvial sedimentation geological unit (deposit) and a new, landsystems- during the late Pleistocene in Kitinen based glacial geomorphological feature information. Recent studies have shown that valley, Sodankylä previously detected large mega-scale glacial Annika Katarina Åberg1, Anu Kaakinen1 and Veli- features, such as mega flutings, drumlins, end Pekka Salonen1 moraine complexes and glacial melt water 1Department of Geosciences and Geography, University systems show up in LiDAR-based digital elevation of Helsinki, P.O. Box 64, 00014 Helsinki models (DEM) in greater detail than ever before (Putkinen et al., 2017). The new map database will significantly improve mineral exploration, New studies confirm (Sarala et al. 2015, 2016, groundwater studies, land use planning and Lunkka et al. 2015) that Weichselian glaciation in management. In the future, the database will be Central Lapland has been more complex than linked to the nationwide stratigraphical units and previously assumed. Three to four interstadials be extended to the national subsurface 3D have been suggested based on the existence of database. The glaciodynamic themes included in intertill sorted deposits and pollen assemblages the database are: Glacifluvial deposits, glacially of organic layers. In addition, subtill fluvial lineated terrains and various types of other deposits have now been discovered in test moraine types referred to much slower ice flow sections of Kärväsniemi, in Sodankylä, indicating velocities or different glacier margin landforms that the area was ice-free during Early and Middle (ribbed moraines, hummocky moraines, De Geer Weichselian. The Kärväsniemi site consists of moraines and end moraines). three till beds and four sorted sediment units. The OSL ages of the lower fluvial deposit vary between 67-79 ka, suggesting deposition during Odderade (MIS 5a). The upper sorted deposit,

interpreted as fluvial bar and channel lag deposit, may have deposited during Middle Weichselian interstadials (MIS 3). These two subtill sorted deposits, separated by a thin till unit, could be also correlated to Tärendö I and Tärendo II

(Hättestrand & Robertsson 2010) of the Riipiharju stratigraphy in northern Sweden. The sorted deposits in Kärväsniemi can be correlated with the lacustrine deposits of Sokli (Helmens et al. 2007).

A 3D model of surficial deposits was generated along with a GIS database and GPR interpretations to study sedimentation in the

Kärväsniemi area (Åberg et al. 2017). The sedimentation history in Kärväsniemi has at least three phases of fluvial deposition, disturbed by deposition of three till units. The non-destructive

178 contacts of the overlaying tills suggests that they were deposited from a stagnant frozen-bed ice ORAL sheet indicating an overall weak glacial erosion in Kärväsniemi. A bag of sand from the ice-concealed, 31 km large Hiawatha crater in

North-West Greenland: samples of ORAL the impact plume, ejecta blanket and crater floor from a recent meteorite An interglacial deposit from impact through the Greenland ice Copenhagen, Denmark: marine sheet isotope stage 7 Adam A. Garde1, Tod E. Waight2, Christian Ole Bennike1, Jens Galsgaard2, Joakim Stiel Weikusat3, Carsten Guvad1, Svend V. Funder4, Kurt Korshøj2, Geoffrey Lemdahl3, Kirsty Penkman4 and H. Kjær4, Iain McDonald5, Jette D. Møller6 and Richard Preece5 Gernot Nehrke3 1GEUS, 2GEO, 3Kalmar University, 4York University, 1Geological Survey of Denmark and Greenland, 5Cambridge University Denmark, 2Department of Geosciences and Natural Resource Management, University of Copenhagen, Denmark, 3Alfred Wegener Institute for Polar and During the construction of a new Metro station in Marine Research, Bremerhaven, Germany, 4Centre for Copenhagen, fossiliferous organic sediments GeoGenetics, Natural History Museum, University of were encountered. An investigation was Copenhagen, Denmark, 5School of Earth and Ocean undertaken on the organic sediments, which Sciences, Cardiff University, U.K., 6Natural History occurred beneath a succession of a lower till bed, Museum, University of Copenhagen, Denmark glaciofluvial sand and gravel, an upper till bed and glaciofluvial sand. The organic sediments were rich in plant fossils and the flora show that Hand-picked, sand-sized grains from a recent the region was forested but included some light- glaciofluvial sediment from the Hiawatha Glacier demanding species. The flora includes Najas draining the Hiawatha impact crater, Inglefield minor, which today has a northern geographical Land in North-West Greenland, provide rare new range limit in Germany. Shells of freshwater insight into melting and crystallisation processes molluscs were frequent, but the diversity was and unusual incorporation of organic carbon in rather low. Bithynia opercula were abundant, the uppermost parts of a large, young impact allowing the sediments to be put into an structure. aminostratigraphical framework. The amino acid The bulk sand composition mimicks the regional racemisation ratios indicate that the organic Palaeoproterozoic, granulite-facies paragneiss sediments formed during early MIS 5e or more bedrock. Predominating {10-13}, {10-12} likely during MIS 7. The older attribution is orientations of shock lamellae in quartz indicate consistent with OSL ages of 206 and 248 ka. The a threshold shock pressure of >16 GPa. Yellow, assemblages from Trianglen are similar to those green, brown and black, variably carbon-bearing reported from deposits recovered during the glass fragments have feldspar-, biotite- or garnet- construction of the free port (1.4 km away) in like compositions and high volatile contents Copenhagen in 1892, except that Corbicula was suggesting direct melting of these minerals and not found at Trianglen. The presence of Corbicula admixture of H2O and organic carbon. indicates a pre-Eemian age. AAR data from Microporphyritic to microcrystlline particles Bithynia opercula from the free port were almost have similar and occasionally crustal-melt-like identical to those from Trianglen, indicating that compositions. Microliths of euhedral, zoned the two sites are contemporary. We suggest the and/or skeletal feldspar, orthopyroxene, Trianglen interglacial be used as a local name for clinopyroxene, ilmenite and cordierite suggest the MIS 7 interglacial deposits. rapid crystallisation and partial quenching. An

179 ellipsoidal grain with radial crystallites may sediment units to be mapped out in some details. represent a melt droplet from the impact plume. Three regional seismic horizons have been Ejecta blanket? microbreccias with glassy or identified and correlated with the well dated 24 microcrystalline matrix contain abundant m long core retrieved from the lake. The detailed bedrock mineral splinters. time constrain available on the upper stratigraphic units in the lake offer also excellent Sand-sized carbonaceous grains and centimetre- possibility to calculate the development in sized charcoal fragments picked from glacier ice sediment fluxes in this Polar area from the Last preserve conifer cell structures; their highly Glacial Maximum (25 ka BP) to the present day. variable reflectance corresponds to 150-1200°C The detailed grid of seismic survey has also heating. Raman graphite-o-peak spectra of allowed the total sediment volume in the lake carbon in microbreccia matrix, glass and basin to be calculated and integrated with the microlith coatings likewise show a wide range of well dated core the age of the initial ordering without evidence of metamorphic sedimentation in the lake basin has been overprinting, unlike carbon in the Norwegian calculated to have started c. 55 ka BP, with a few Gardnos crater (Parnell & Lindgren 2006). The thousand years uncertainty. Identification of Hiawatha carbon was probably derived from submerged delta inside the lake basin suggest Pleistocene tree trunks buried under the ice; the that the lake level must have dried in and be ice sheet likely protected them from being blown lowered with at least 26 m below the present away during the initial impact phase. level during the LGM period. This finding offer a new insight into the climate condition in the Polar

Ural area, Arctic Russia, during the LGM and the ORAL early deglaciation period.

The Last Glacial and Holocene

Seismostratigraphy and ORAL sedimentation history of the Lake Bolshoye Schuchye, Polar Ural, Arctic Sandy deposits from a Preboreal Russia glacier lake outburst flood (Nedre Glomsjø), southeastern Norway Haflidi Haflidason1, Julie Lundekvam Zweidorff2, Richard Gyllencreuz3, John-Inge Svendsen2 and Louise Hansen1, Fredrik Høgås1, Lars Olsen1 and Slava Gladysh4 Georgios Tassis1 1Dept. of Earth Science and BCCR, University of Bergen, 1Geological Survey of Norway Allégt. 41, POBox 7803, N-5020 Bergen, Norge, 2Dept. of Earth Science and BCCR, University of Bergen, Allégt 41, POBox 7803, N-5020 Bergen, Norway, 3Department of The major outburst flood from glacier lake Nedre Geological Sciences, Stockholm University, 10691 Glomsjø in southeastern Norway, has been Stockholm, Sweden, 4I.S. Gramberg VNIIOkeangeologia, known for decades. Previously described Sonic Group, 190121, St.Petersburg, RUSSIA deposits include pronounced boulder accumulations upstream and vast fine-grained flood deposits far downstream. In addition, new The seismostratigraphic studies of the 11 km2 LiDAR data from the middle reaches of the and the 136 m deep Lake Bolshoya Schuchye, Glomma valley has revealed spectacular mega Polar Ural, Arctic Russia, have unrevealed that bars and erosional features related to the the lake is apparently preserving up to a 130-150 dramatic flood event (Høgaas & Longva 2016). m thick pile of seismostratigraphic laminated The LiDAR data provide a basis for further sediments. With aid of a Sparker array seismic investigation of the event and its impact on the and sub bottom profiling (SBP) surveys a dense landscape and the valley fill. Sedimentological grid of profiles have been collected allowing the investigation of a sandy dune field provides new sediment distribution and the geometry of the

180 insight into the variety of deposits from the At Pomlenakke and on Farø sections show a till outburst flood. The dunes were previously deposited by a glacier coming from NE, which is described as of aeolian origin. However, facies interpreted as the Midtdanske Till Formation analysis shows that the deposits were deposited (Late Weichselian 24 000–20 000 years ago). It is in association to the outburst flood. Beside the covered by two Baltic tills – Øst Jylland Till association with water-lain facies, such as e.g. Formation and Bælthav Till Formation (19 000– diffuse, climbing ripple lamination, a diagnostic 16 000 years ago). A characteristic boulder feature seems to be water-escape structures pavement is seen at the base of the lower unit. defined by numerous (sub)vertical tracks cutting The boulders are often more than 1 m in through the bedding including the foresets of diameter. mega-scale bedforms. The tracks are interpreted as a result of a significant drop in hydrostatic The most pronounced geomorphological element pressure as the flood levels were lowered and is the push moraine Væggerløse Arc, formed by triggered a release of excess pore pressure in the an advance from east. An esker stretches from the sediments. The study extends the understanding north-easternmost part of Falster and almost of the outburst flood as an extreme, landscape- down to Nykøbing Falster. A small meltwater defining event. In addition, the study has plain is associated with the esker. In the Northern important impact on the understanding of the part smooth ridges with a NW-SE trend are regions postglacial landscape as other, previously interpreted as older marginal moraines, defined aeolian fields may show to originate from subsequently overridden by glaciers. the flood, and comparable sedimentary features have been observed at Starmoen nature reserve. ORAL

A large young impact crater beneath ORAL the Ice in Northwest Greenland The Quaternary of the island of Kurt H. Kjær1, Nicolaj K. Larsen2, Svend Funder1, Falster, SW Denmark Michael Houmark-Nielsen1, Adam Garde3, Mark 4 5 6 Peter Roll Jakobsen1 and Knud Erik Klint2 Fahnestock , Ian McDonald , Olaf Eisen , Joseph 7 1 6 1GEUS, 2GEO MacGregor , Anders Bjørk , Veit Helm , Eske Willerslev1, Matheu Morlighem8, Jeremie Mouginot8, Henning Haack9, Kristian K. Kjeldsen10, The island of Falster is covered by the geological Horst Machguth11, Tobias Binder6, John Paden12 map sheets Geological map of Denmark 1:50.000 and Shfaqat Abbas Khan10 Stubbekøbing and Nykøbing Falster. During the 1Centre for Geogenetics, University of Copenhagen, geological mapping new data was collected 2Dept. of Geoscience, Aarhus University, 3Geological regarding Quaternary stratigraphy, morphology Survey of Denmark and Greenland, 4University of and the evolution of the landscape. Alaska Fairbanks, 5Cardiff University, 6Alfred Wegener Institute, 7NASA, 8University of California, 9Geobiology The pre-Quaternary deposits on Falster are and Minerals Section, University of Copenhagen, 10DTU Maastrichtien chalk and Paleogene Clay. The pre- Space, 11University of Zurich, 12University of Kansas Quaternary surface is influenced by NW–SE- striking faults that act as weakness zones, and During Earth’s history, cataclysmic impact events buried valleys are incised into the chalk surface. have been linked to major climate change and At Stubbekøbing, the course of the Fribrødreå mass extinctions. Here, we report on the valley is controlled by a fault. discovery of a large impact structure hidden The oldest till unit on Falster is seen in boreholes beneath Hiawatha Glacier in northwest and is interpreted as the Ristinge Klint Till Greenland. Beneath nearly a kilometre of ice lies Formation (c. 50 000 years ago). a 31-kilometre-wide, circular bedrock depression

181 with an elevated rim and a subdued central peak. westernmost mountains Kolla, Knutshøa and Outwash sediments from the largest river Blåhøe (Becker 2013), as well as Heidalsmuen draining from the glacier catchment contains (Tvedt 2013), also have material originating from shocked quartz and other unweathered impact source areas in the SW. The mountains grains. Geochemical analysis shows that the Storsølnkletten (Eidsvåg 2013) and Tron (Hult impactor was a Pt-rich iron asteroid that would 2011) located in the central part of the study area, have had a diameter of c. 1.5 km in order to and Søre Sølen (Kvamme 2012) in the eastern produce a crater of the observed size. part, have additional boulders transported from Radiostratigraphic, morphological and source areas in the S-SE. geochemical evidence suggest that the Hiawatha 10 impact took place between 38 and 11.7 kyr ago, In addition, we report Be surface exposure ages which would make it the largest known impact from 36 glacially transported boulders in the 10 experienced by modern humans. Our discovery study area. Be ages range from 7.7 ± 0.5 to 66.1 has potentially wide-ranging implications for our ± 1.9 ka, but cluster around 11 ka. The ages must understanding of the recent history of Earth. be considered minimum ages as they are not corrected for snow cover, weathering or isostatic rebound.

ORAL

Provenance and 10Be surface POSTER exposure age of Late Weichselian Mineralogical analysis of till by the glacial erratic boulders in southern Greenland Ice Sheet, Kangerlussuaq, Norway West Greenland Henriette Linge1, Lukas Becker1, Jenny Eidsvåg1 Karin Grodzinsky1, Eva-Lena Tullborg2, Johan and Derek Fabel2 Hogmalm1 and Ignasi Puigdomenech3 1Department of Earth Science, University of Bergen, 1Department of Earth Sciences, University of 2Scottish Universities Environmental Research Centre Gothenburg, Gothenburg, Sweden, 2Terralogica AB,

Gråbo, Sweden, 3Swedish Nuclear Fuel and Waste Management Company, Stockholm, Sweden Boulders and cobbles of non-local lithologies (i.e. erratics) are found on all types of substrates in east-central southern Norway. The only Till sampled from terminal moraines close to exception is surfaces formed after the last Kangerlussuaq at west Greenland are analyzed deglaciation. Hence, erratics are found in through mineralogical observations along with superimposed on surfaces of bare bedrock, chemical composition data including Sr-isotopes. blockfield, till, glaciofluvial and glaciolacustrine This study focus on the weathering processes and material. The erratics must have been glacially interaction between glacial meltwater and till. transported at some point, either as isolated Scanning Electron Microscope, XRD and leaching clasts or as till. Boulders resting on fragile experiments are, among other methods, used to substrates, such as sediments or weathered study chemical weathering and reactions. For bedrock, are characteristic for areas with past example, minerals such as pyrite and biotite show cold-based, low-erosive ice sheets. weathered edges with loss of sulfur and potassium, respectively. Some feldspars may We present a preliminary synthesis of five studies present caved surfaces which could indicate that used provenance analysis of erratic boulders weathering processes. Leaching experiments to reconstruct regional ice-flow direction east of indicate relatively fast interaction time between the present day main water divide. The water and till, and the data are compared to investigated mountains all have erratic material chemical compositions of moraine ponds and from source areas to the N and NNW. The pore water samples and even deep groundwater

182 from the same study area. These comparisons tsunami deposits from Norway but there are also increase our understanding of the course of differences such as absence of biogenic material events and reactions for the glacial meltwater on except for a few reworked foraminifers. The high its way from the glacier and further down the elevation of the inferred tsunami deposit at c. 75 bedrock and in the watershed. m a.s.l. precludes a relation to the Storegga tsunami and it must be older. As there is no The study has been carried out as a complement record of an older, regional tsunami, a local event to the Greenland Natural Analogue Project is suggested. A marine sparker survey in conducted by the Canadian Nuclear Management Leirfjorden reveals a major mass-wasting deposit Organisation, the Finnish Posiva Oy and the that accumulated in the fjord shortly after the last Swedish Nuclear Fuel and Waste Management Co. deglaciation. This mass-wasting could be a likely (Claesson Liljedahl, L. et al. 2016). The aim of the source for a local tsunami. Failure is explained by project was to investigate how glacial conditions high sedimentation rates and emergence would affect a deep repository for spent nuclear following glacier retreat, maybe combined with fuel during future glacial periods. seismicity.

POSTER POSTER

Sedimentary characteristics of a Late Glacial and Holocene possible tsunami deposit in the development within the source Leirfjorden area, North Norway depression of the Vejrhøj end-

Louise Hansen1, Reidulv Bøe1, Harald Sveian1 and moraine, NW Sjælland, Denmark Katrine Husum2 Peter Roll Jakobsen1, Ole Bennike1 and Jakob 1Geological Survey of Norway, 2Norwegian Polar Walløe Hansen2 Institute 1GEUS, 2UNESCO Global Geopark Odsherred

A material-extraction site near Leirfjorden in The prominent arcuate end-moraines in NW North Norway reveals a composite stratigraphy Sjælland are the backbone of the geology of of interbedded glacial and marine deposits. A Geopark Odsherred. The largest and coarse-grained, crudely stratified event bed is southernmost of the end-moraines, the Vejrhøj interpreted as a possible tsunami deposit. It is arc, is a glaciotectonic hill-hole pair landform. The underlain by marine deposits reflecting source depression makes up the innermost part reworking of glacial deposits by waves and of one of Europes largest reclaimed areas, the gravitational processes after glacier retreat. The Lammefjord. It constitutes a basin that has been event bed is divided into four main intervals filled with Late Glacial and Holocene deposits. As reflecting different stages of the sedimentation part of a large outreach programme the basin was process. From the base upwards, these are investigated in a drilling campaign and ground irregular, poorly sorted sand and gravel penetrating radar investigations was used in the interbedded with massive fine sand overlain by sandy areas. thin-bedded silt and sand with clasts. The succession of facies reflects flow processes of In the deepest recognized part of this basin, 25 m varied concentration alternating with suspension of sediment has been deposited. Macro fossils sedimentation of sand. Silty intraclasts and poor show that the basin initially was a Late Glacial sorting testifies to short and episodic lake, where sand and clay is deposited. The transportation and fast sedimentation. The bed is freshwater lake environment continued into the overlain by subtidal sediments. The Holocene, and peat was deposited at the shores of sedimentological characteristics of the bed show the lake. some similarities to previously described

183 During the Atlantic transgression the area was flood inundated basins more than 50 m above the flooded, and the present surface is now 3.8 m valley floor in our study area. below sea level. In the initial phase of the change of environment from freshwater to marine, brackish sediments are deposited in form of POSTER laminated gyttja deposits. In this phase some of the lake deposits where redeposited. Lateglacial – early Holocene Subsequently a full marine sequence deposited in geomorphology between Lake Vänern the basin as marine gyttja with numerous shells. and Lake Vättern, southern Sweden At the edge of the basin marine sand is deposited, and oyster banks developed at relative shallow Christian Öhrling1, Gustaf Peterson2 and Mark D. water depth. Johnson1 1Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden, 2Geological Survey of Sweden, Uppsala, Sweden POSTER

Lake sediment analysis of the Nedre The arrival of Light Detection and Ranging Glomsjø outburst flood event, derived elevation models enables efficient and accurate mapping of landforms. The region in Southeastern Norway central Sweden between Vänern and Vättern Helle Daling Nannestad1, Ivar Berthling1 and contains landforms created during two of the Fredrik Høgaas2 most important events during the late 11Department of Geography, Norwegian University of Quaternary of Sweden; the Younger Dryas cold Science and Technology, NO-7491 Trondheim, interval and drainage of the Baltic Ice Lake. NORWAY, 2Geological Survey of Norway, Postal Box 6315 Sluppen NO-7491Trondheim, NORWAY Here, we present a 1:220 000 scale geomorphic map of this region covering approximately 18 000 km2. Fifteen landform units have been Sediment cores from lake and mires can provide mapped; end moraines, De Geer moraines, geological archives of palaeofloods. By analysing drumlinoids, crag-and-tails, hummock tracts, the sediment we can better our understanding of irregular ridges, eskers, deltas/sandurs, outwash the nature and impact of large flood events. This complexes, meltwater channels, boulder study aims to constrain the run-up height and bars/sheets, the Timmersdala ridge, raised timing of the outburst flood from glacial lake shorelines, sand dunes and prominent landslide Nedre Glomsjø at the end of the last Ice Age. Cores scars. from four lake basins will be examined for grain size distribution, total organic carbon (TOC) and The mapped glacial geomorphology deepens the macrofossil content. In addition to this, we aim to understanding of the deglacial history by the provide a geochemical profile (using XRF) of the revelation of previously undetected geomorphic floodlayer and properly constrain the event in features and their relations, for example the time by radiocarbon dating macrofossils found abundant traces of meltwater erosion manifested above and below the flood sediment. as channels and hummock corridors, and Geochemical data will serve as a geomarker in previously unreported ice-marginal lines. order to identify the flood layer elsewhere. The Perhaps most striking is that all of these ice- probable flood layer stands out as a light, fine- margin positions are marked by distinct lobate grained layer in all of the retrieved cores. The moraines where they were formed above the upper boundary towards the organic gyttja as highest shoreline. sharp, which signals that sedimentation stopped abruptly. Preliminary results indicate that the

184 This map provides a ‘set table’ for future research of river Kitinen. During deglaciation, the study – e.g. glacier modeling, georesources, geologic area was first occupied by the Moskujärvi Ice history and geoheritage. Lake (207 m.a.s.l.) and later by the Ancylus Lake (186 m.a.s.l.) Stratigraphy and glacial deposits from the area were studied from six test pits and conducting fifteen kilometers of ground POSTER penetrating radar acquisition. Sediment logs Weichselian Stratigraphy and were made from test sections and fourteen sediment samples were analysed for their Deglacial Deposits from Kuusivaara, granulometric properties. Preliminary Sodankylä, Central Finnish Lapland observations suggest that weathered bedrock is covered by a probably Early Weichselian till with Markus T.O. Valkama1, Seija Kultti1, Annika K. sandy sediments and a distinct soil horizon on Åberg1, Emilia Koivisto1 and Veli-Pekka Salonen1 their top, which may represent an interstadial 1University of Helsinki deposit. The upper till is a stratified, loose sandy

melt-out deposits overlain by aeolian sands, Central Finnish Lapland exhibits limited glacial gravity flow or shoreline deposits. Stratigraphical erosion during the Weichselian. Therefore, the till evidence can be applied as a key to interpret units of Early and Middle Weichselian stadials are landscape evolution based on LiDAR images. preserved in many places (eg. Helmens et al.

2007, Lunkka et al. 2015). This study describes lithostratigraphy from Kuusivaara, which is situated 140 kilometres north of Rovaniemi, east

185 9. Economic geology 9.1. Circular economy Challenge 3: Estimation of the grades and in-situ ‘ore’-value, are critical for developing a ‘mining’ set-up and beneficiation flow charts.

ORAL Challenge 4: Estimation of the dynamic reserve tonnage. Turning anthropogenic stocks into economic viable ‘ore’ reserves – Challenge 5: Estimation of project viability: the major challenges for the Circular in-situ ‘ore’-value/’ore-concentrate’. Absence of Economy parameters characterizing the ‘ore’ and the ‘mineral concentrate’, as well as non-transparent Per Kalvig1, Rune J. Clausen2, Tonny B. Thomsen3 price schemes, prevents the development of and Jonas Nedenskov4 feasibility studies. 1Center for Minerals and Materials (MiMa), GEUS, 2Cent In conclusion; inadequate resource assessments for Minerals and Materials (MiMa), GEUS, 3Dep. Economic Geology, GEUS, 4Amager Resource Centre are major obstacles for addressing and closing (ARC) leakages in the circular economy.

Classical mineral exploration and resource assessment techniques are inadequate tools for ORAL assessment of the financial viability of Characterization of Raw Materials anthropogenic end-of-life stocks. In order to develop ample mining technologies and and Recycled Stone Wool Waste for beneficiation flow-sheets that provides for a Production of Stone Wool Melt viable exploitation of secondary raw materials 1 2 there is a fundamental need for characterizing the Vickie Schultz-Falk , Peter Arendt Jensen , Karsten 3 1 composition and properties of secondary raw Agersted and Mette Solvang 1 2 materials. ROCKWOOL International A/S, Department of Chemical and Biochemical Engineering, Technical Example; the Danish WtE plants produce c. University of Denmark, 3Department of Energy 600.000 tpa of bottom ashes that potentially Conversion and Storage, Technical University of Denmark constitute important secondary multi-element resources, which is generally considered as waste by plant-owners, and left to be utilized by Stone wool waste is generated either during entrepreneurs. The entrepreneurs apply a scrap- production, where edges are cut off in the shaping metal approach to extract some of the metals, and process, or during renovation or demolition of the remains are used e.g. in road construction. In buildings. Stone wool is produced by forming a order to reduce leakages, some challenges need melt that is spun into fibers. The raw materials to be targeted and overcome: include mineral raw materials as well as secondary raw materials i.e. waste from other Challenge 1: Physical and chemical industries. It is also possible to re-melt stone characterization of the heterogenic resource. wool waste and thus recycle the waste material Metals mainly occur as primary alloys and back into the production process. sedondary alloys developed in the incineration. This study investigates the differences in heat Challenge 2: Representative sampling of the response of a conventional stone wool raw heterogenic flow of the ‘ore’ material, coping with material mix and of stone wool waste. The study a wide range of particle sizes and shapes of the combined Differential Scanning Calorimetry ‘ore minerals'.

186 (DSC), X-ray Diffraction (XRD) and Hot Stage The tests aim at finding the best ways to improve Microscopy (HSM). The materials are compared cover material’s long-term durability and in terms of thermally induced processes stability, prevent erosion, and improve the occurring in the materials, melting temperature, sustainability of water management, carbon crystallinity and energy consumption associated balance and nutrient economy. Benefit of the use with heating and melting of the materials. of biochar is its’ local production which diminishes the transport and storage costs and DSC reveals that the raw material mix and stone opens new possibilities to develop local wool waste have fundamentally different heat entrepreneurship. Tailings are produced in large responses: the raw material mix decarbonizes quantities by the mining industry and it might be and the wool crystalizes before both melting. XRD more economical and beneficial to use the waste is used to investigate the crystallinity of the as a resource than treat it as a waste. Available mineral raw materials and the crystals formed in materials needed to improve tailings properties the stone wool waste upon heating. HSM reveals such as wood, fibre and bio sludge but also other that stone wool waste initiates melting at lower rest materials from other industries should be temperatures than the conventional raw material tested to enhance their valorisation. The project mix. is led by the Geological Survey of Finland and other research partners are the Natural Research Understanding the differences between the Institute Finland and the Oulu Mining School of conventional raw material mix and the recycled the University of Oulu. stone wool waste will ultimately help to optimize the production process towards recycling larger amounts of stone wool waste.

POSTER

Utilization of biochar as a cover material in mine waste areas

Pertti Sarala1 and Raija Pietilä2 1Geological Survey of Finland, P.O. Box 77, 96101 Rovaniemi, Finland/Oulu Mining School, Univ. Oulu, 2Geological Survey of Finland, P.O. Box 77, 96101 Rovaniemi, Finland

Good mineral waste coverages and landscaping solutions in northern mining industry will be developed and tested in the project ‘Utilization of biochar in dry cover material and landscaping of mine waste areas’ (Biopeitto) funded by the European Regional Development Fund. From the perspective of sustainable development and regional well-being, the solutions that will minimize the costs for environment and increase the local livelihoods should be developed in the northern region itself. Testing biochar, mine wastes and other rest materials as the component of mineral waste cover in tailings and waste rock pile solutions are environmentally important.

187 9.2. Mineral resources and deep-

sea mining in international and national seabed areas

ORAL

ORAL Exploration of seafloor massive Deep-sea mineral resources within sulfides: current status and National Jurisdiction perspectives.

1 Harald Brekke1, Georgy Cherkashov2 and Pedro Georgy Cherkashov 1VNIIOkeangeologia, St Petersburg, Russia Madureira3

1Norewegian Petroleum Directorate, 2VNIIOkeangeologia, University of St. Petersburg, Seafloor massive sulfide (SMS) deposits present 3EMEPC the third type of a short list of deep-sea minerals

after ferromanganese nodules and cobalt rich According to the UN Convention on the Law of the ferromanganese crusts. The discovery of Sea, the continental shelf is the area of seabed hydrothermal vents and associated massive that is under the jurisdiction of the coastal states, sulfides in the end of 1970s had not only which in some cases may extend beyond 200 fundamental but also economic importance due nautical miles. According to the Convention, the to extraordinary concentrations of metals being exploitation of any continental shelf resources discharged from hot vents to the sea bottom. The beyond 200 nautical miles is subject to a royalty major components of SMS are Cu, Zn, Pb, Au and to be paid through the International Seabed Ag. The high grades of such minor high/green- Authority. In most parts of the world, the tech components as Se, Te, Ge, Bi, As, Cd, Ga, Tl continental shelf consists of an inner, shallow and In are also detected in SMS deposits. part and an outer, deep-sea part. Oil and gas, Most of SMS deposits are localised in the area placers and aggregates are associated with the beyond the national jurisdiction which shallow parts of the continental shelf, while administrating by International Seabed Authority polymetallic mineral resources are found in the (ISA). Currently 6 contracts for exploration of deep-sea parts and likely to be relevant for SMS deposits are signed between States Parties royalty payments. In wide platform areas, like and ISA for the areas in the Atlantic and Indian those of the Atlantic, oil and gas may also be oceans. Different geological and geophysical subject to such payments. The polymetallic methods are used for the prospecting of active minerals are regarded as potential sources of and inactive SMS deposits. The first exploration nickel, copper, cobalt, manganese, zinc, lead, gold, contract should be completed in 2026. cobalt, tellurium, and possibly REEs. Estimates of the mineral resources of the deep sea and their SMS deposits localized within EEZ are the subject partition between the continental shelf and the for exploration study as well. Most of these international seabed are still very uncertain. deposits which distribute along the island arc Recently published studies indicate that, systems in the Pacific are well explored and even depending on the type of mineral, between 20% ready to be mined (e.g. Okinawa Trough, Bismark to 50% of the resource may be located within the Sea). The technologies for future mining are in continental shelf areas. Recent test mining by process of being designed and methods of metals Japan and the development of the Solwara 1 Mine extraction from SMS already exist being similar to in Papua New Guinea indicate that sulphides will that of land-based volcanogenic massive sulfide be the first deep sea mineral to be exploited, and deposits. that it will happen within the continental shelf.

188

ORAL ORAL

Sulfide mineralogy of the Loki’s Uncertainties in grade, tonnage, and Castle hydrothermal vent, Arctic Mid- distribution estimates for seafloor Ocean Ridge massive sulfide deposits

Kristian Drivenes1, Ben Snook1 and Kurt Aasly1 John W Jamieson1 and Rolf B Pedersen2 1Norwegian University of Science and Technology 1Memorial University of Newfoundland, Department of Earth Sciences, 2K.G. Jebsen Centre for Deep Sea Research, University of Bergen Samples from the active Loki’s Castle hydrothermal vent were collected from the seafloor by ROV during the MarMine cruise in The economic potential of deep sea mining is 2016. The hydrothermal vent sites consist of ultimately dependent on the size, grade, and black smoker systems, and as such have diverse distribution of ore deposits on the seafloor. For mineralogy with highly heterogeneous macro seafloor massive sulfide (SMS) deposits, there and micro textures. The samples currently under have been several studies that have reported investigation represent chimney collapse breccia quantitative estimates of the resource potential rather than massive sulphide from the core of the at both global and regional scales (including the deposit. Sulfide mineralization in the white North Atlantic), and these resource estimates are smoker material is limited with minor sphalerite, being utilized to drive policy decisions related to galena and pyrite. The less common black smoker the economic potential of SMS mining, and material is dominated by silica and sulfate associated exploitation and environmental gangue, with sulfides occurring as lenses and regulations. However, the geological uncertainty patches of fine-grained material and, locally, associated with these resource estimates is larger grains. significant. Development and regulatory decisions must ultimately be tied to not only the In the sulfide-rich areas, the sulfides occur in grade and tonnage estimates of individual mineralogically and metallogenically distinct deposits, but also an understanding of the zones on the cm scale. The Fe-rich zones associated uncertainty of these estimates. In this comprises intergrown pyrite and marcasite, the presentation, we will discuss the current state of Zn-rich zones comprises sphalerite, and the Cu- knowledge of the size, grade and distribution of rich zones comprises an isotropic Cu-Fe-S phase, SMS deposits. We will focus on how these likely isocubanite, with both sharp submicron estimates are determined, the evolving lamellae and larger exsolutions of chalcopyrite. uncertainties related to these estimates, and Minor pyrrhotite and galena was observed. There strategies that should be implemented to reduce is significant overlap between the zones, these uncertainties, including approaches to especially the Zn-rich and Cu-rich zones, where exploration, sampling and drilling. the isocubanite replaces sphalerite. The sphalerite is infected with chalcopyrite disease, but under the optical microscope several grains and zones appear to be inclusion-free. However, SEM investigations show lamellae in sphalerite less than 100 nm wide, oriented in the same crystallographic planes as chalcopyrite lamellae in neighboring isocubanite, indicating that not all lamellae in sphalerite may be visible in the optical microscope.

189 ORAL ORAL

Deep sea mineral resources in the The Seven Sisters Hydrothermal international seabed area System on the Arctic Mid-Ocean Ridge

Pedro Madureira1, Harald Brekke2 and Georgy AFA Marques1, RB Pedersen1, DL Roerdink1, T Cherkashov3 Baumberger2, CEJ de Ronde3, RG Ditchburn3, IH 1EMEPC, 2Norwegian Pteroleum Directorate, Thorseth1, I Okland1, MD Lilley4, M Whitehouse5 3VNIIOkeangeologia, University of St. Petersburg and A Denny1 1K.G. Jebsen Centre for Deep Sea Research University of Bergen, Norway, 2Pacific Marine Environmental According to the UN Convention on the Law of the Laboratory (PMEL), National Oceanic and Atmospheric Sea, the seabed and subsoil areas of the world Administration (NOA, 3GNS Science New Zealand, oceans are divided into two parts: the 4School of Oceanography, University of Washington US, international seabed under the jurisdiction of the 5Swedish Museum of Natural History, Stockholm International Seabed Authority (ISA), and the Sweden continental shelf under the jurisdiction of the coastal states. The resources of the international We present new findings on the shallow, hybrid, seabed area (termed “the Area”), are managed by seafloor hydrothermal system (known as the the ISA on behalf of the mankind. Today, there is Seven Sisters site) with epithermal-style an increasing interest for the mineral resources mineralization that is hosted by mafic of the deep ocean because of the demand for volcaniclasts on the slow spreading Northern certain metals needed in green technology. The Kolbeinsey ridge on the Arctic mid-ocean ridge. most promising mineral resources in the Area for The system lies on top of a flat-topped volcano at supplying global needs are polymetallic nodules, ~130 m depth from which relatively high polymetallic sulphides and ferromanganese temperature (up to 200°C) phase-separating crusts. They are regarded as potential sources of fluids vent from smoking craters and unique nickel, copper, cobalt and manganese (nodules), pinnacle-like edifices on top of mounds. The of copper, zinc, lead and gold (sulphides), and of hydrothermal mineralization at Seven Sisters cobalt, tellurium, manganese and possibly REEs manifests as replacement of mafic volcaniclasts, (crusts). Currently, the ISA have 28 Contractors direct precipitation from the hydrothermal fluid, carrying out exploration activities in the Area, and as vapor elemental sulfur sublimates. Barite rising from eight before 2011. Estimates of the is ubiquitous and is replaced by pyrite, which is mineral resources of the deep sea are still very the first sulfide to form, followed by Zn-Cu-Pb-Ag uncertain. However, exploration and scientific bearing sulfides, sulfosalts and silica. The studies in recent years indicate that the Co and Ni mineralized rocks at Seven Sisters contain resources of the deep sea exceeds those onshore appreciable amounts of ‘epithermal suite’ by ten and four times, respectively. In the case of elements with secondary alteration minerals. Mn and Mo, the resources of the deep ocean Vent fluids have a pH of ~5 and are Ba and metal- match those onshore. No one has so far started depleted. Sulfide and secondary alteration any commercial exploitation of these resources. mineralogy, fluid and gas chemistry, as well as The ISA is currently developing its regulations for d34S and 87Sr/86Sr isotope values indicate that exploitation, starting with the nodules. These mineralization at Seven Sisters is sustained by the regulations should be completed by 2020. input of magmatic derived fluids with seawater contribution. Radiometric dating of barite

suggests that this hydrothermal system has been active for at least 4670 ± 60 years.

190 ORAL pyrite, often with complex textures: chalcopyrite overgrowths on isocubanite; sub-micron Preliminary characterisation of laminations of chalcopyrite within isocubanite; potential seafloor massive sulphide micron scale chalcopyrite blebs within sphalerite. ore from the Loki’s Castle deposit, on the Arctic Mid-Ocean Ridge. ORAL Ben Snook1, Kristian Drivenes1, Kurt Aasly1 and Gavyn Rollinson2 CHARACTERISEING MINERAL 1 2 NTNU, University of Exeter REPLACEMENTS REACTIONS IN CU-

FE-ZN-S MINERALS FROM THE ARCTIC Ensuring efficient ore characterisation is MID-OCEAN RIDGE USING SEM, EBSD necessary for all stages of mine planning, thereby AND OPTICAL MICROSCOPY streamlining deposit identification, resource extraction, mineral processing and waste Bjørn Eske Sørensen1, Kristian Drivenes1 and Gert management. It provides information for Nolze2 compositional, chemical, textural and mineral 1NTNU, Department of Geoscience and Petroleum, liberation considerations, and tracks the 2Bundesanstalt für Materialforschung , effectiveness of mineral processing. As such, Berlin. Department of Materials Engineering defining the most effective assessment techniques for new ore types is of high Ore minerals in samples collected from black importance. smokers at Loki’s Castle at the Arctic Mid-Ocean In response to growing demand [1], potential ridge show complex intergrowth and exsolution new sources of copper and zinc have been textures. Cu-Fe-S mineral(s) appear in sphalerite identified in the deep sea, from seafloor massive as several µm size rounded inclusions, or as fine sulphides (SMS) [2,3]. One site under Norwegian lamellae parallel to {001}. Sphalerite (sph) jurisdiction demonstrating good possibilities for (Zn,Fe)S is replaced by a Cu-Fe-S phase SMS mineralisation is Loki’s Castle, where active (isocubanite), which itself has exsolutions of hydrothermal venting occurs at 2400 m depth on mostly submicron lamellae (chalcopyrite?). The the slow spreading Arctic Mid-Ocean Ridge [4]. matrix phase is isotropic, appears pinkish yellow, The site consists of two mounds, each and has a composition close to cubanite approximately 150 m across and 30 m high, (CuFe2S3). The lamellae are less pinkish, and capped by 5 active chimneys releasing 320° C have compositions close to chalcopyrite (CuFeS2, fluids [4]. During the 2016 MarMine cruise [5] tetragonal). In addition, a second set of boulders were collected from the mounds’ flanks, exsolutions appears as wavy laths. which represent collapsed chimney fragments Understanding the relations between the that have formed debris flows. The vent sites mineralizing phases are imperative to appear to consist of both white and black smoker understand the genesis of the deposits and hence systems, and as such have a diverse mineralogy also to make realistic models of the economic with highly heterogeneous macro and micro potential. textures. Further work will reveal more details on the We report initial approaches to determining relationship between the phases. After polishing analytical techniques to characterise SMS ore; with Ar-ions the pattern of isocubanite and petrography, geochemistry, and automated sphalerite were indexable, however because mineralogy. Preliminary results indicate that sphalerite and isocubanite have very similar typical sulphide mineral assemblages in samples structures they could only be differentiated using with elevated Cu and Zn grades comprise fine the combination of optical and backscattered grained chalcopyrite, isocubanite, sphalerite and electron imaging, EDS (energy-dispersive

191 spectroscopy) and EBSD. However, the EBSD 9.3. Open Session: Economic reveals topotaxial relations between sphalerite and isocubanite that preserves the orientation of Geology the host, reinforces the interpretation that isocubanite replaces sphalerite rather than growing together with sphalerite. Different ORAL methods of indexing the patterns and improved Paragenetic evolution of collection may enable us to distinguish also the chalcopyrite lamellae from the host isocubanite hydrothermal REE mineralisation in and sphalerite though the chalcopyrite structure the Olserum-Djupedal area, SE is very similar to the host phases. Sweden

Stefan S. Andersson1, Thomas Wagner2, Erik Jonsson3 and Radoslaw M. Michallik1

1Department of Geosciences and Geography, University 2 of Helsinki, Institute of Applied Mineralogy and Economic Geology, RWTH Aachen University, 3Geological Survey of Sweden, Department of Mineral Resources and Department of Earth Sciences, Uppsala University, Uppsala, Sweden

The REE mineralisation in the Olserum-Djupedal area is located at the border of the Palaeoproterozoic Västervik sedimentary

formation and c. 1.8 Ga granitoids belonging to the Transscandinavian Igneous Belt (TIB) in SE Sweden. The mineralisation is dominated by the phosphates monazite-(Ce), xenotime-(Y) and variably REE-bearing fluorapatite. These mostly formed, along with subordinate (Y,REE,U,Fe)- (Nb,Ta) oxides, during an initial hydrothermal

stage. During a subsequent stage, allanite-(Ce) formed locally, and secondary monazite-(Ce) and xenotime-(Y) also formed, mainly by leaching and remobilisation of REE from fluorapatite. Similar coupled dissolution-reprecipitation processes

subsequently also affected primary monazite- (Ce), xenotime-(Y), and minor (Y,REE,U,Fe)- (Nb,Ta) oxide phase(s). This mobilised REE, Th, U and Nb-Ta, and caused the formation of additional xenotime-(Y), monazite-(Ce), fluorapatite and variable amounts of allanite-(Ce) – ferriallanite-(Ce), uraninite, thorite and

columbite-(Fe) (Andersson et al., 2018). Bastnäsite-(Ce) and subordinate synchysite-(Ce) characterise the youngest REE mineralisation stage, and formed from the low-temperature alteration of allanite-(Ce) and ferriallanite-(Ce).

We interpret the paragenetic sequence to essentially be the result of decreasing

192 temperatures, from an initial high-temperature which account for the most important and hydrothermal stage (≥600°C) to a low- recently mined deposits, located in northwestern temperature stage (<<400°C). In addition, local Bergslagen. Elevated gallium and germanium differences in fluid chemistry, particularly the Ca contents are associated with rare earth elements content, as well as fluid oxidation state, facilitated (REE)-rich iron oxide skarn deposits in the dissolution-reprecipitation processes, and Bergslagen, and the potential for REE is relatively ultimately governed the stability of the REE good, in these and other types of mineralisations, minerals in the ore assemblages of the Olserum- as recently noted by Goodenough et al. (2016), in Djupedal area. several areas from southern Sweden (Norra Kärr and Olserum), via Bergslagen, to, a.o., the Kiruna type apatite-iron oxide ores of Norrbotten. The REEs in Sweden will be outlined in more detail in ORAL an upcoming SGU report, based on work done Critical metal mineralisation in within the EURARE project (www.eurare.eu).

Sweden: overview and highlights

Erik Jonsson1, Karin Högdahl2, Martiya Sadeghi1 ORAL and Nikolaos Arvanitidis1 1Geological Survey of Sweden (SGU) , Department of Towards Real-Time Ore Grade Mineral Resources, Box 670, SE-75128 Uppsala, Sweden Evaluation using Laser-Induced and Department of Earth Sciences, Uppsala University, Uppsala, Sweden, 2Department of Earth Sciences, Breakdown Spectroscopy Mineralogy, Petrology and Tectonics, Uppsala 1 1 University, Villavägen 1 Lasse Kangas , Roel van Toorenenburg and Jussi Leveinen1 1Department of Civil Engineering, Aalto University, Critical metals, as part of what is presently Espoo, Finland defined by the EU (https://ec.europa.eu/growth/sectors/ raw- On mining operations, Grade-control is based on materials/specific-interest/critical_en) as laboratory measurements from blast-hole Critical Raw Materials (CRM), are increasingly samples or appropriate type of well logging (e.g. sought for from both primary and secondary gamma logging) to characterize each block. The sources. The Swedish part of the Fennoscandian problems with these techniques are that they Shield, with its major ore provinces Bergslagen, slow, costly and the results are not immediately Skellefte district and Norrbotten, contains a available. To overcome these issues, it is essential significant number of primary sources, to develop new sensor technologies that can mineralisations with variably well-known provide elemental and mineralogical information potential for critical metal production. real-time and on-site. Traditional by-product critical metals such as antimony , cobalt and indium are variably known, Here, a case study using Laser-Induced the latter confined to some skarn-associated Breakdown Spectroscopy (LIBS) and samples of sulphide-oxide mineralisations in westernmost Parainen limestone quarry is presented. The aim Bergslagen, while the former mainly occurs of the research was to resolve, if LIBS hosted by accessory sulphosalts in polymetallic measurements can be used to characterize the sulphide deposits in several regions, chiefly in ore body during the blast-hole drilling. The Bergslagen and the Skellefte district. , Cobalt is quality parameters that are used in Parainen for represented by several different deposit types the ore grade evaluation are Ca/Si+Al and the including e.g. skarns and volcanosedimentary- magnesium content of the samples. The samples associated massive sulphides. While tungsten is consisted of drill cuttings samples from three known from a number of deposits, these are different blast-holes and four bulk samples of typified but not limited to skarn-hosted scheelite, different ore grades collected from the stockpiles.

193 The bulk samples were crushed, sieved and Raman offers a fast, non-invasive and non- resorted to get the same grain size distribution destructive alternative. with the drill cuttings. The cuttings and the crushed bulk samples were measured by free To test the ability of the Raman technology to falling them via funnel to mimic the moving classify wollastonite-bearing limestone rocks particles in the drill tube. into different quality categories, three samples were acquired from the Ihalainen deposit and The results from the LIBS measurements were these samples were scanned using a Raman validated using synchrotron X-ray diffraction and setup. Different data analysis methods were then gamma logging from the blast-holes. Our applied to map the spatial distribution and preliminary results suggest that LIBS can be used relative abundances of the minerals. The results as an on-line analyzing technique during the were validated using the scanning electron drilling process. The ore type and an microscopy (SEM) system of the Geological approximation of the ore grade can be detected Survey of Finland. from the spectral data. The preliminary results suggest that the relative quantity and the spatial distribution of wollastonite can be mapped using high spatial ORAL resolution Raman data. The ongoing study will next focus on acquiring more samples from the Non-invasive and non-destructive study area, and using these samples, to further quantification of wollastonite in test the potential of Raman for the detection of limestones using Raman the processing quality of rocks. spectroscopy

Kati Laakso1, Lasse Kangas1, Saara Kaski2, Heikki ORAL Häkkänen3 and Jussi Leveinen1 1 Department of Civil Engineering, Aalto University, Zn-Pb-Cu sulfide-bearing glacial Espoo, Finland, 2Department of Chemistry, University of Jyväskylä, Jyväskylä, Finland, 3Department of Biological sandstone erratics near Raahe on the and Environmental Science, University of Jyväskylä, western coast of Finland as indicators Jyväskylä, Finland of Paleozoic base metal

mineralization at the bottom of the Wollastonite is an economically important Bothnian Bay mineral that is used to manufacture plastics, ceramics and other products. Finland is currently Erik Nilsson1, Eero Hanski2, Hannu Huhma3, Yann among the top producers of wollastonite in the Lahaye3, Timo Mäki4, Hugh O'Brien3 and Kari world, and the largest in Europe. Finnish Strand2 wollastonite is sourced from the Ihalainen 1Geosciences and Environmental Engineering, Luleå deposit in Lappeenranta, southeastern Finland. University of Technology, Sweden, 2Oulu Mining School, University of Oulu, Finland, 3Geological Survey of Here, wollastonite is extracted from Finland, Espoo, Finland, 4First Quantum Minerals Ltd., Paleoproterozoic (1.9 Ga) limestones that also Pyhäsalmi, Finland host industrial-grade calcite. Processing of these rocks requires certain mineralogical compositions (e.g.: 21% of wollastonite) that Over the past tens of years, sandstone erratics determine the processing quality of the rock. variably enriched in Zn, Pb and Cu have been Currently, labor-intensive laboratory analytical collected from the coast south of Raahe, but their technology is commonly used for the source has remained unclear. In these non- mineralogical characterization of rocks. Laser- metamorphosed and non-deformed erratics, spectral methods have the potential to partially detrital grains of quartz and minor feldspar are replace such technologies, and for this end, cemented by calcium carbonate, which is partly

194 or wholly replaced by ore minerals, including and SE parts, which host many porphyry copper sphalerite, galena, pyrite, marcasite, and deposits (PCDs) and prospects. The Ahar-Jolfa chalcopyrite. Analyzed boulders have yielded metallogenic zone includes the Qaradagh and total base metals contents between 1 and 10 Sheyvardagh batholiths and many smaller wt%. The FeS content in sphalerite is low and intrusions and includes porphyry, skarn and variable, ranging commonly between 0.5-15 mol- vein-type mineralizations. This zone shares many %, which is in harmony with its coexistence with magmatic, geodynamic and mineralization pyrite. features with the neighboring South Armenian Block (SAB), where the Meghri-Ordubad Galena shows very radiogenic Pb isotope composite pluton of Eocene-Miocene age hosts 206 204 compositions, with Pb/ Pb falling in the many porphyry Cu-Mo deposits. By comparing 207 204 range of 20.55−21.06 and Pb/ Pb between the measured Re-Os and U-Pb ages of 15.90 and 15.94. These compositions are similar mineralizations in NW Iran [1,2,3,4,5], it can be to those measured for the Laisvall Pb-Zn MVT concluded that porphyry mineralizations have deposit in the Swedish Caledonides, being occurred in three epochs of late Eocene (~35 Ma), consistent with a similar Ordovician age of ore middle Oligocene (31-25 Ma) and early Miocene formation. However, S isotope analyses of pyrite (22-20 Ma). Mineralizations here coincide with 34 yielded mostly negative δ S values from −15.6 to the third epoch of such mineralizations in SAB, −7.6, which are distinctly different from the which are associated with Eocene to Miocene generally heavy sulfur isotope compositions (ave. intrusions, while the older middle Jurassic-early +24) reported from the Laisvall-type deposits. Cretaceous and upper Cretaceous epochs of SAB These results together with some mineralogical [6] have no reported counterparts in Iran. The differences (presence of chalcopyrite, absence of first epoch of NW Iran postdates all Eocene fluorite and barite) suggest that the boulders mineralizations in SAB. The second epoch is were not derived from the eastern front of the coeval with Paragachay and the first-stage of Caledonian orogen but their source occurs much Kadjaran PCDs. The third epoch is younger than closer, likely being a so-far-undiscovered base all mineralizations in SAB, except the second metal deposit under the Bothnia Bay. stage of Kadjaran PCD. These epochs are older than nearly all PCDs and prospects in Central and

SE Iran, revealing an old to young trend along the ORAL UDMA.

Cu-Mo mineralization epochs in NW

Iran and their temporal relationship ORAL with metallogenic zones of neighboring Lesser Caucasus and 2D elemental mapping of pyrite by Central Iran LA-ICP-MS: an application in visualizing Au enrichment process Vartan Simmonds1 1Research Institute for Fundamental Sciences, Lingli Zhou1, Balz Kamber1, Guotao Sun2 and University of Tabriz, Tabriz, Iran Qingdong Zeng2 1Irish Centre for Research in Applied Geology, Geology Department, Trinity College Dublin, 2Institute of The Tertiary Urumieh–Dokhtar magmatic arc Geology and Geophysics, Chinese Academy of Sciences (UDMA) in Iran represents the northeast-ward subduction of the Neo-Tethyan oceanic crust beneath the central Iranian domain during the Pyrite is commonly associated with late Mesozoic-early Cenozoic. It coincides with mineralization in deposits forming in different the porphyry copper metallogenic belt, including environments. The spatial distribution of trace 3 metallogenic zones in NW (Ahar-Jolfa), central metals in pyrite can be heterogeneous, and may

195 contain genetic information. With the of Earth Sciences, Uppsala University, Uppsala, Sweden development of 2D trace element mapping with Laser Ablation Inductively Coupled Plasma Mass In the Svecokarelian bedrock of south central Spectrometry (LA-ICP-MS) it is now possible to Sweden, and specifically, the Bergslagen ore reveal, in much greater detail, the interior province, hematite-dominated banded iron compositional textures of pyrite, and thus permit formations (BIF) constitute one of three major investigation of the mineralisation process that types of iron oxide deposits. Recently, due to the recorded in the crystallization history of pyrite. increased criticality of rare earth elements (REE) Here we report two cases of 2D elemental through their applications in modern industrial mapping of pyrite in investigating Au and low-carbon/energy saving technologies, mineralisation process. Pyrite samples were several projects have been undertaken to explore collected from a quartz pebble conglomerate of their potential distribution in previously the fluvial Mississagi Formation, Canada (the unknown deposits and deposit types. Among the basal part is Au abundant), and from the resulting discoveries were REE-mineralised BIFs Qingchengzi Pb-Zn-Au-Ag ore field, NE China, (e.g. Jonsson & Högdahl 2013). In the Högfors respectively. The trace element maps reveal a mines, silicate-dominated [e.g. cerite-(Ce) and Fe- common existence of core-rim structure for the analogue of västmanlandite-(Ce)] REE pyrite from Mississagi Fm. The detrital origin of mineralisation was interpreted to have formed pyrite is readily demonstrated from rounding of from epigenetic processes resulting in localised individual grains and cores and the revealed REE-enriched skarn replacing carbonate truncated texture of originally rounded detrital interlayers, i.e. a post-depositional hydrothermal fragments. Gold is finely dispersed in the detrital overprint. Subsequent sampling and analytical cores/grains, indicating a significant amount of work revealed REE-enrichment in other BIF Au was suspended in the river flows for the deposits in this part of Bergslagen, e.g. at the Nya enrichment. Two distinct episodes of gold Bastnäs field (8500 ppm REEtot), Storgruvan enrichment are distinguished from the element (1300 ppm REEtot), and Myrbacksfältet (8000 maps of pyrite from the Qingchengzi Pb-Zn-Au- ppm REEtot). The main REE hosts here are Ag deposits: an early syn-sedimentary stage allanite-(Ce), REE-enriched epidote, and cerite- when invisible gold is concentrated in diagenetic (Ce). These deposits are located in close vicinity pyrite, and maybe re-mobilized and re- to REE-rich skarn deposits in the REE-line concentrated later; and a later hydrothermal (Jonsson & Högdahl 2013), but REE-anomalous stage where gold forms as either free gold grains, BIFs have also been identified outside of this area. or as invisible gold in the pyrite. The BIF at Forsbo, located further to the north, has a REEtot of 1800 ppm, mainly hosted by monazite-(Ce). A post-depositional, epigenetic, yet pre-tectonic origin for the the REE- POSTER enrichment in the BIFs along the REE-line is suggested by geological, mineralogical and REE-enrichment in Palaeoproterozoic textural evidence. The phosphate-hosted REE banded iron formations, Bergslagen, mineralisation in the Forsbo BIF, on the other Sweden: primary precipitation or hand, appears to potentially having formed hydrothermal overprint? through primary precipitation.

Marcus Brismo-Ploetz1, Karin Högdahl2 and Erik Jonsson3 1Department of Earth Sciences, Uppsala University, Villavägen 16, SE-75236 Uppsala, Sweden, 2Dept. Earth

Sciences, Uppsala University Sweden and Geology and Mineralogy, Åbo Akademi University,, 3Geological

Survey of Sweden, Uppsala, Sweden and Dept. Earth Sciences, Uppsala University, Sweden and Department

196 POSTER

Characterisation of the Kivilompolo POSTER Molybdenum Mineralisation, Au-Ag-(Bi-Te-Se)-enriched Peräpohja Belt, Northern Finland polymetallic vein mineralisations in Matthew Goode1, Jukka-Pekka Ranta2, Holger SW Sweden: ore mineralogy and Paulick3 and Eero Hanski4 thermal evolution 1University of Oulu, MSc Student, 2University of Oulu, Doctoral Student, 3University of Oulu, Professor of Erik Jonsson1 4 Economic Geology, University of Oulu, Oulu Mining 1Geological Survey of Sweden, Department of Mineral School Dean of Education Resources, Uppsala, Sweden and Department of Earth Sciences, Uppsala University, Uppsala, Sweden

The Paleoproterozoic supracrustal Peräpohja Belt hosts several poorly studied metal occurrences. One of these includes the Polymetallic Au-Ag-(Te-Se)-bearing quartz (- Kivilompolo molybdenite mineralisation, initially carbonate) veins formed in association with discovered in the 1950´s. Mineralisation occurs in large-scale crustal deformation processes during boudinaged quartz veins within gneissic granites the c. 1 Ga Sveconorwegian orogeny and its adjactent to the 1.99Ga pre-orogenic Kierovaara aftermath are widespread in SW Sweden, chiefly granite (Ranta et al. 2015). The ore minerals in Dalsland and Värmland. Previously, ore consist of abundant, coarse grained molybdenite mineralogical data have been reported for some flakes, in addition to pyrite, pyrrhotite and Värmland veins (cf. Alm & Sundblad 1994, Alm chalcopyrite. Mineralisation occurs in a roughly 2000, and references therein), whereas 3km long zone and, based on drillholes, extends information on the Dalsland veins has been to a depth of at least 150m (Yletyinen 1967). overall lacking. The present study forms part of an attempt to increase the knowledge of the noble Preliminary single molybdenite Re-Os dating of and critical metals-rich deposits in this region; the mineralisation gives an age of 1.99Ga (Holly within this framework, new observations from Stein pers.comm), which is consistent with the the Värmskog veins were also supplied by Nysten adjacent Kierovaara granite. The precise age of (2013). the host granite is not known, but the close proximity of the Kierovaara granite would In most of the studied deposits, the occurrence of suggest a similar age. Discovery of high-grade Ag-Bi-Te-Se-rich minerals is interpreted to Palokas Au and Rompas Au-U mineralization in mainly represent unmixing during cooling of a the Peräpohja Belt has given impetus to study this higher-T sulphide phase carrying abundant trace occurrence. metals; mostly represented by bornite, but also galena, chalcocite and chalcopyrite. Observations, Combined outcrop and boulder mapping was including the presence of exsolved Bi-rich carried out in June of 2017 in order to determine minerals such as wittichenite (Cu3BiS3) and the extent of the mineralised zone. Detailed miharaite (Cu4FePbBiS6) suggest such high initial petrographical analysis of the host rock and temperatures; Bi-rich bornites able to exsolve mineralised zone will be carried out to better such phases have been termed “bismuth- understand the nature of the occurrence and the saturated” and form >400°C (cf. Cook et al. 2011). relationship between deformation and the The identification of accessory ore minerals (and mineralisation. Whole rock analysis of a number textures) such as altaite (Ag2Te), argentopyrite- of channel samples will be carried out to sternbergite (AgFe2S3), clausthalite (PbSe)- determine the presence or absence of a galena solid solutions, empressite (AgTe), hessite mineralised halo around the deposit. U-Pb dating (Ag2Te; both twinned and untwinned), Hg- of zircon from the host rock will provide a precise amalgams, jalpaite (Ag3CuS2)-galena control on the age of the mineralisation. intergrowths, matildite (AgBiS2) in galena,

197 mckinstryite [(Ag,Cu)2S], native tellurium, rocks and the shear zone activities, and shifting of naumannite (Ag2Se)-sulphide intergrowths, the spatial focus on the central and eastern part stibnite (Sb2S3), stromeyerite (AgCuS), petzite of the Häme Belt. Thematically, we will apply the

(AuAg3Te2) reaction rims, and uytenbogaardtite methods of prospectivity analysis to understand

(Ag3AuS2) combine to reveal an extensive the exploration potential for gold mineralisations evolution at decreasing temperatures, from within the area. above and around 300°C, to below 100°C.

POSTER POSTER Accessory minerals within the SAM – Crustal structure and hosting a preliminary case study lithology account for the spatial 1 2 distribution of gold mineralisation in Michal Ruszkowski and Janina Wiszniewska 1Department of Geology, University of Warsaw, Żwirki i SW Finland Wigury 93, 02-089 Warsaw, 2Polish Geological Institute -National Research Institute, Rakowiecka 4, 00-975 1 1 1 Jaakko Kara , Tuomas Leskelä , Iiro Pitkälä , Warsaw Janne Hokka2, Pietari Skyttä1, Markku Tiainen2, Hanna Leväniemi2 and Markku Väisänen1 1Department of Geography and Geology, University of Suwalki Anorthosite Massif (SAM) is a part of Turku, 2Geological Survey of Finland Mesoproterozoic, beltiform magmatic AMCG [anorthosite - mangerite - charnokite - granite rapakivi] suite known as a Mazury Complex New gold occurrences have been recently (Wiszniewska J., 2002). Fe-Ti-V large ore discovered in the Häme Belt, southwestern deposits were established within SAM. Finland (Grönholm and Kärkkäinen 2012, Nanoconcentrations of REE (La, Ce, Nd), PGE, Au Tiainen et al. 2017). The Geological Survey of and zircon minerals are often present in sulphide Finland and the University of Turku launched a Fe-Cu-Co-Ni dispersed mineralisation. Their size two-year collaborative project to investigate the ranges from 10-150 µm or in some cases up to link between the spatial distribution of the gold 250 µm. mineralisations, the regional-scale bedrock structure and the hosting lithologies. The project Hydrothermal concentrations of unusual also aims at training young geoscientists within zirconium elongated forms have been observed the field of economic geology. within the polymetallic SAM mineralization, suggesting their hydrothermal origin (Bin F., Two months of field work carried out in the 2009). Zircons form also dispersed grains, which western part of the study area in 2017 are of igneous origin and thin fillings, filaments concentrated on structural mapping to and rims around ore minerals. Thin zircon rims characterize the kinematics of the major N-S and are of 80-250 µm in length and 4-30 µm in width E-W trending shear zones, and structural and and they accurate imitate the shape of ore lithological mapping of the Uunimäki gold minerals. The biggest form was observed in mineralization (Kärkkäinen et al. 2016), located untypical zircon form of “blown candle flame” close to the intersection of the shear zones. structure. Enrichment of large quantities of Hf Moreover, conducted mapping and sampling of (0,5-0,8 mass %) were measured by SEM-EDS mafic intrusive rocks provides material to study method. Wider parts of thin zircon rims around the geochemical signatures and fertilities of mafic ore minerals were prepared for age rocks which seem to host several known gold determinations and isotopic analyses by SHRIMP mineralizations in the target area. IIe machine at PGI in Warsaw. The next stage of the project involves U-Pb age determinations to date the gold-hosting intrusive

198 Numerous small inclusions of Te (0,4-0,7 mass wall of the same fault. The writer will investigate %) were measured in hydrothermal sulphides, the distribution and chemistry of the PGM to gain especially in millerite. They are grouped in small a better understanding into the ore forming forms, which are directed along flow of hot processes. Scanning electron microscopy (SEM) solutions. 2-4 µm in size of single inclusions were and electron probe micro analyzer (EPMA) will observed. be utilized, as well as transmitted-and reflected light microscopy for studying base metal New results of accessory minerals in sulfides. Thermodynamic software such as polymetallic mineralisation may increase our Perpl_x and MELTS may be used to model knowledge of the evolution of documented SAM. stability of silicates and sulfides.

POSTER

Platinum Group Element Mineralization of the RF-4 drill core,

Reinfjord Ultramafic Complex, Troms, Norway

Lars Tollefsrud1 1Norwegian University of Science and Technology (NTNU)

The Reinfjord Ultramafic Complex (RUC) is a part of the Seiland Igneous Province (SIP). The SIP is given an age of 560-570 Ma (Roberts et al. 2006), and is a part of the Kalak Nappe Complex. Thus, the SIP is a part of the Middle Allochton of the Caledonian thrust nappe. The RUC comprises rocks that of dunitic, wehrlitic and olivine- clinopyroxenitic composition and is surrounded by metasediments and gabbro. Chemical data of four drill cores from the RUC (RF-1, RF-2, RF-3 and RF-4) display platinum group element (PGE) anomalies in the upper third part of the drill cores.

Detailed work on the PGE mineralization in the

RF-1 drill core of the was performed Even Nikolaisen (2016). Nikolaisen discovered that majority of the platinum group minerals (PGM) were present as tellurides hosted by base metal sulfides (BMS).

The writer desires to continue the work by

Nikolaisen by investigating the PGM in the RF-4 drill core. The RF-4 drill core is located on the footwall of what is likely to be a normal fault, while the RF-1 drill ore is taken from the hanging

199 10. Engineering and enviromental geology 10.1. Geohazards in the Nordic There are a series of challenges related to “helping nature” in terms of artificial triggering of and Arctic regions landslides. This includes the media attention and communication issues related to evacuated people, municipality and other ORAL

Artificially supply of water for release of the Veslemannen instability at ORAL Mannen in Romsdalen, western An automatic watch of a slope, Lac à Norway l’Eau-Claire, Nunavik Lars Harald Blikra1, Lene Kristensen1 and Gustav Armelle Decaulne1 and Najat Bhiry2 Pless1 1CNRS, LETG UMR6554, Nantes, France, 2Université 1The Norwegian Water Resources and Energy Laval, Centre d'études nordiques, Quebec city, Canada Directorate

The slope topography and talus morphometry in Permanent monitoring and early warning Lac à l’Eau-Claire (56°20’N; 76°17’W) indicate systems were established at the unstable rock inherited and active gravity processes. Evidence slope Mannen in 2009. The instrumentation of recent activity has been observed during field includes a comprehensive surface network in investigations. However, the identification of addition to 120 m deep instrumentation in two gravity processes on slopes remains difficult, as boreholes. A periodic ground-based InSAR no event has ever been reported and no witness campaign in 2014 identified large displacements is able to relate any event in this remote area. in a small portion of Mannen (Veslemannen Nevertheless, Lac à l’Eau-Claire is traversed by instability). The volume is between 120.000 and Cree and Inuit hunters and fishermen all year- 180.000 m3. The possible runout area includes round, and a well-known place for trap. Lac à some few houses, a farm and the railway. Stages l’Eau-Claire is also part of the Tursujuq National of increased velocities in 2014, 2015 and 2016 Park, and welcomes tens of tourists each year. led to evacuation of people, animals and closing Gravity processes thus become not only physical of the railway. These events have attracted a processes, but raise hazard and risk issues. massive media interest. This has shown to be a challenging situation for the evacuated people, In an attempt to better know the year-round the municipality and for NVE having the gravity processes acting on Caribou slope, we responsibility for the monitoring. installed in August 2016 an automatic camera. This slope has been selected because it presents NVE decided to artificially add water in order to fresh scattered boulders indicative of recent reduce the stability and possibly release a part or slope activity; furthermore, the apical rockwall is the entire Veslemannen instability, and was heavily affected by frost weathering and deep performed two times in October 2017 during cracks are opening on the uppermost of the periods were people were evacuated (red hazard rockwall. From the collection of 2855 pictures, level). The displacements before the experiment we are able to survey gravity movements and was already significant and the additional water snow cover evolution on the slope. supply had an effect in terms of increased displacements. However, the area stabilized The camera at Caribou slope, and three other on again when temperatures lowered below zero different slopes, is now operating. Additional and the precipitation came as snow. cameras surveying slopes and slope processes have also been installed in other places

200 encountering gravity processes in Nunavik: in ORAL Tasiapik valley, south-east of Umiujaq; and over the road leading to the airport in Continuously monitoring of Kangiqsualujjuaq. Gámanjunni 3, 26 Mm3 unstable rockslide, Kåfjord, northern Norway.

Gudrun Dreiås Majala1, Lars Harald Blikra1, Lene ORAL Kristensen1 and Ingrid Skrede1 1 Artificially triggering of Rock Fall in NVE

Norway. Methods, consequences and lessons learned. Gàmanjunni 3 is classified as a high-risk object based on the movement, structures and the Ulrik Domaas1 and Trond Vernang1 consequences of the rockslide. As a high-risk 1Norwegian Geotechnical Institute object, the unstable rockslide need continuously monitoring.

Securing roads, housing areas, construction sites The section for rockslide management in NVE are and protective work from rock fall may involve in charge of all unstable rock slopes (7 in present) artificially blasting, scaling and other means in that are classified as high-risk objects and some addition to ordinary protective work with rock objects that needs periodic monitoring. NGU is bolts, wire rope nets, wire rope fences and dams. responsible for the mapping and classification of Foreseeing the consequences of artificially large rock-slope failures. release of rock fall for human activities below are difficult to evaluate due to the complexity of such Gámanjunni 3 is a 26 Mm3 large unstable activity. Making evacuation plans without rockslide located in Kåfjord, northern Norway, knowing the exact outcome of rock fall release is and is the third monitored site in the necessary to do before executing the rock fall municipality. Gàmanjunni 3 has a movement of 2- release. Improved planning, hazard zoning, 6 cm/year towards W-SW and has a fully involvement of local authorities, police and developed wedge with a 150 m vertical rescue team can give a successful outcome. Close displacement. A large rockslide from Gámanjunni cooperation with entrepreneurs and decision 3 will cross the valley and dam the river. makers during the work is vital. Information in Since October 2016 NVE have established 10 peoples meeting and in local newspapers is GPS-antennas, 3 different web cameras, 4 necessary. Triggering of loose rock with platforms for helicopter and a weather station moderate volumes may cause larger rock fall that forms the monitoring network. A ground- volume than expected, producing dust cloud and based radar in the valley further monitor the rock fragment splashing far beyond known rockslide. In order to improve the signal from the runout. Rock fall material may also trigger debris satellite radar (InSAR), corner reflectors are flow days after the event itself. Removing loose placed in the unstable area. Investigations in rocks with water or free hanging iron ball under terms of resistivity and seismic surveys have helicopter is efficient to clear an unstable area. been performed in order to build a better Use of air pillow or rubber mats may be efficient geological model. Run-out modelling, dam- to release single blocs but can be difficult in steep breach analysis and flood modelling are mountainsides. Systematic assembled knowledge completed. of methods, cases, and unforeseen consequences from artificially triggered rock falls is needed and will be beneficial to all sides of the industry.

201 ORAL ORAL

Permafrost rock walls in norway - Artificial trigger of the large-scale Thermal regime and Chapf rock instability by two geomorphological processes in time blastings in 2001/2002, Bernese and space Oberland, Switzerland.

Bernd Etzelmüller1, Florence Magnin1, Kristin S. Ueli Gruner1 Myhra2, Benjamin Jacobs3, Michael Krautblatter3 1Kellerhals + Haefeli AG, Bern, Switzerland and Sebastian Westermann1 1University of Oslo, 2Western Norway University of 3 Applied Sciences, 3Technical University Munich, A large unstable rock mass of about 250’000 m Germany called Chapf near Innertkirchen (Bernese Oberland, Siwtzerland) was continuously monitored during 50 years. The Grimsel Pass The role of the ground thermal regime on road is situated about 1‘000 m below and was geomorphological processes in settings thus endangered. The movement was associated to steep slopes has received accelerating from about 1 cm/year up to 0.6 considerable attention in the past. It is evident cm/day during the years 1999 to 2001. Therefore from recent studies that e.g. rock walls have a the Canton of Bern decided to take emergency profound effect on the thermal regime in measures. First, the collapse was intended to be mountain sides, a.o. influencing rock wall triggered by infiltrating water into the open stability, weathering regimes and glacier- joints, as the movements reacted strongly to permafrost interaction in space and time. This precipitation. The watering had to be stopped presentation discusses the importance of the due to the seasonal decrease of the available thermal regime in space and time on water. Finally, the unstable rock mass was geomorphological processes in steep slopes. We removed by two big blastings. combine direct observations of air, ground and rock wall temperatures with numerical The removal was carried out in two steps from simulations. We present results from both the top to the bottom. In a first step, 156 thermal (2D transient thermal model - CryoGRID boreholes up to 95 m deep were drilled in the 2D) and thermo-mechanical modelling along upper half of the about 150 m high rock wall. With with Electrical Resistivity Tomography (ERT) a digital elevation model based on aerial validation of different sites dominated by photographs and laser scanning a 3D-model of unstable rock slopes in Norway. We analyse how the joints was elaborated in order to determine thermal gradients in rock walls may influence the explosive charge. The blasting in October important geomorphological processes related to 2001 with a total of 19'000 kg of explosiv weathering, talus developments, material denudated about 150’000 m3 of rock. accumulation and ice aggregation in coarse The second blasting in August 2002 was planned material. On longer time scales we hypothesise with a similar approach as 2001 (21’000 kg of that permafrost dynamics associated with blasting charge). About 110’000 m3 of rock were glaciation and deglaciation phases may have blasted. Both blastings were very successful: The influenced the development and stability of large- stable rock wall of the Chapf was not affected and scale valley systems. consequently this area does not endanger the Grimsel Pass road anymore.

202 ORAL ORAL

Geological observations of the Cosmogenic nuclide dating of rock- landslide of June 17, 2017 in Karrat slope failure deposits and rock slope Fjord (central West Greenland) deformation in Troms county, northern Norway Pierpaolo Guarnieri1 and Erik Vest Sørensen1 1GEUS-Geological Survey of Denmark and Greenland Reginald L. Hermanns1, Martina Bøhme1, John Gossse2 and Samuel Niedermann3 1Norges geologiske undersøkelse, 2Dalhousie university, On June 17, 2017 a landslide occurred along the 3GeoForschungsZentrum Potsdam southern slope of the 2180 m-high Umiamakku

Auffaa in the Karrat Fjord, central West Greenland (Lat. 71º 38’). The rock mass slid into Systematic mapping for unstable rock slopes has the Kangilleq Fjord generating a tsunami that been carried out in Troms county since 2007 and severely damaged the village of Nuugaatsiaq 129 unstable rock slopes were recognized (more located 35 km to the south-west. The Karrat Fjord than one third of all known in Norway). Despite region is part of a geological mapping project in this large number, the 1810 Pollfjellet rock the Uummaanak region between the Geological avalanche is the only historic event in the county. Survey of Denmark and Greenland (GEUS) and We dated deposits of rock-slope failures and rock the Government of Greenland. During field slope deformation by cosmogenic nuclide (CN) operations conducted in 2015-2017 a large dating. Most of the deposits of rock-slope failures number of oblique, high-resolution stereo- date to shortly after deglaciation in this region. images were acquired for photogrammetric However, ages also span the entire Holocene. studies coupled with geological observation covering the entire region. This allows us to study Four sliding surfaces that dissect high altitude flat the geology and structure of the region in three surfaces have been sampled for CN dating. Two of dimensions and in great detail. Detailed oblique these top surfaces have been dated to be older photos along the southern flank of Umiamakku than LGM, while for the remaining two results are Auffaa were collected in 2015, two years before expected soon. Two of those surfaces are the rockslide event, and again in July 2017, one dissected by deep-seated gravitational slope month after the disastrous event. This gives us deformations (DSGSDs). Both topmost sliding unique control of the geological and structural surfaces have ages in the upper part that predate setting before and after the landslide event and LGM. Both DSGSDs have collapse deposits along furthermore allows us to estimate the size of the their foot that date shortly after deglaciation. The landslide precisely. The geology of that particular other two top surfaces are dissected by area is represented by quartzites, amphibolites rockslides. Both became active within or at the and meta-pelites belonging to the end of the thermal maximum within the Palaeoproterozoic Qeqertarssuaq Formation. 3D- Holocene. None of those are related to any rock- photogeology in the GEUS Photogrammetry-Lab slope failure deposit. Our data thus suggest that and field data shows strongly foliated meta- rock-slope deformation in Troms county is a volcanic and meta-sandstone rocks dipping 20° process that has been active from before the LGM to the SW. The downslope setting toward the and DSGSDs can survive glacial cycles in cold- fjord and the tectonic layering suggest a based ice environments, while rock slides rather lithological and structural control for the seem to be phenomena that started and peaked landslide mechanism. after deglaciation and maintain on a low constant rate within the Holocene.

203 ORAL 600 m a.s.l. seem to be dissociated from continuous permafrost. The different timing of Destabilisation and temporal the initial failure at the two adjacent instabilities deformation patterns of rock-slope demonstrates the structural complexity of the instabilities in Northern and Western sites and importance of local settings.

Norway

1 2 Paula Hilger , Reginald L. Hermanns , Kristin S. ORAL Myhra3, Bernd Etzelmüller4 and John C. Gosse5 1Geological Survey of Norway; University of Oslo, Monitoring active rock fall and 2Geological Survey of Norway; Technical Univeristy avalanche events Trondheim, 3Høyskole på Vestlandet, Sogndal; University of Oslo, 4University of Olso, 5Dalhousie Lene Kristensen1, Ingrid Skrede1 and Lars Harald University, Halifax, Canada Blikra1

1NVE More than 300 active rock slopes demonstrating post glacial deformation are mapped in Norway, Movements in release areas have been measured whereof seven are classified as high-risk objects prior to both rock fall events and snow because of their sliding rates and potential impact avalanches in Western and Northern Norway. on infrastructure. In addition to post-glacial Our results indicates that both prior movement stress increase, we expect water pressure and and acceleration phases can be identified rock altitudinal permafrost dynamics to significantly falls and avalanches and may potentially be used impact these gravity driven slope processes along as early warning. However – in several instances complex pre-existing bedrock structures. we have measured large movements and To improve understanding of the potential accelerations that stopped due to changed influence of post-glacial permafrost dynamics on conditions (meteorology etc.). rock-slope failures, we use terrestrial cosmogenic The movements have been measured primarily nuclide (TCN) dating along three sliding surfaces using ground based InSAR systems (LiSALab), to derive the timing of initial failure and potential while change detection and analysis has been sliding patterns since the onset of deformation. aided using point clouds from terrestrial laser Preliminary TCN ages of the Mannen and scans. In combination the datasets allows for Revdalsfjellet 2 instabilities in western and detailed detection of how movement relates to northern Norway respectively, suggest that rock structures. sliding started close to the Holocene Thermal Maximum, when mountain permafrost presence The examples presented are a part of a research was at a minimum. This indicates that permafrost project, aiming to obtaining acceleration curves thawing may have contributed to the timing of of different types of slide events. NVE is these rock-slope instabilities. The preliminary responsible for all types of geohazard relating to results of Revdalsfjellet 1, which is an adjacent slides (rock, clay, avalanches etc.) as well as but independently moving rock body to flooding in Norway. The Section for Rockslide Revdalsfjellet 2, suggest a movement onset Managements primary responsibility is during strong temperature fluctuations in the monitoring of seven high risk rock slides in mid Holocene. Norway, and periodic monitoring of less risky objects. We base the monitoring on the Recent acceleration of deformation at the assumption that large rock slopes develop over Mannen site could be connected to late stage time and accelerates prior to failure. In the permafrost thawing at the lower boundary of project we extend the methodology and altitudinal permafrost, whereas relatively slow equipment to study other types of slides. displacement rates at the Revdalsfjellet instabilities connected to their low elevation of

204 Measurements of movement in source areas can These features, and more information, are shown greatly aid a visual inspection of stability and in a map viewer: provide a basis for handling crisis situations after https://apps.sgu.se/kartvisare/kartvisare- slides to buildings or infrastructure. Furthermore skanestrand.html is increases NVEs preparedness to handle various types of geohazards. The information can be used for e.g. coastal physical and marine spatial planning and for study of sediments and sedimentary processes in coastal environments. ORAL

Sensitivity to coastal erosion in southern Sweden shown in a map ORAL viewer Integrated analysis of past, and

Kärstin Malmberg Persson1 potential future rock slope failures of 1Geological Survey of Sweden various size from Rombakstøtta, Norway

A rising sea level is expected to cause increased Odd André Morken1, Reginald Hermanns2 and coastal erosion in southernmost Sweden where Paula Hilger1 the postglacial isostatic uplift is negligible. To 1NGU, 2NGU, NTNU predict where coastal erosion will be most intense and which areas are most sensible to erosion, detailed geological data are necessary. Catastrophic failure of large rock slopes has led to The coast of Skåne displays great variation in fatalities in Norway several times per century. geology and topography and while some parts are The Geological Survey of Norway (NGU) carry out highly sensible to erosion, other parts are very systematic mapping of potentially unstable rock resistant. slopes in Norway. In this context, a hazard analysis and preliminary consequence The Geological Survey of Sweden has carried out assessment of the unstable rock slope at combined land- and sea-based geological Rombakstøtta, has been carried out. Additionally, mapping along the coastline of Skåne. The a fragmentation cycle analysis, used to assess the collected data on land include beach sediment fragmentation of the rock mass during a failure, composition, beach morphology, sediment and to separate rock fall deposits from rock stratigraphy, signs of active erosion and avalanche deposits, has been developed and constructions for coastal protection. Information tested. collected on the sea floor includes surface sediment composition, detailed bathymetry and The study area is in a north facing slope along a patterns of erosion and deposition caused by fjord, within the arctic circle and close to the city waves and currents. of Narvik. Based on delimiting lineaments observed in the field, aerial photos, photo The information has been used to classify the shoreline into different coastal types with panoramas and digital elevation models, eight different sensitivity to erosion (Malmberg failure scenarios are defined. Application of Persson et al. 2016). An attempt to estimate the NGU´s hazard analysis as well as volume erosion conditions after a one-metre rise of the estimation and run-out analysis were done for all sea level has also been made. The most common scenarios. Four of the scenarios have modelled coastal type today is sandy beaches with run-out reaching vital infrastructure and the alternating erosion/accumulation but in balance fjord. over an extended time (31 % of the coast). 12 % of the coast is subject to net erosion.

205 The fragmentation cycle analysis has been thawing of ground ice could have played an developed and applied inspired by Charrière et al. important role as a triggering factor. Ice- (2016). Results suggest that the rock avalanche cemented blocks of debris have been observed in deposits at Rombakstøtta underwent 0-3 the deposits of two other recent landslides in fragmentation cycles during failure and northern Iceland, in the Torfufell Mountain and transport. And that rock fall deposits generally the Árnesfjall Mountain. This suggests that experienced more than 4 fragmentation cycles discontinuous permafrost is degrading in Iceland, during failure and transport. due to climate change. This study highlights that ground ice thaw could represent a new source of hazard in Iceland. The knowledge of the detailed distribution of mountain permafrost on the island ORAL is poorly constrained and should be a priority for The triggering factors of the future research.

Móafellshyrna debris slide in northern Iceland: intense precipitation, earthquake activity ORAL and thawing of mountain permafrost Geomorphologic Evidence and

Þorsteinn Sæmundsson1, Costanza Morino2, Jón Timeline Reconstruction of Holocene Kristinn Helgason3, Conway Susan4 and Halldór G. Jökulhlaups along the Hvítá River and Pétursson5 Gullfoss, Iceland 1Department of Geography and Tourism, University of Iceland, Askja, Sturlugata 7, 101 Reykjavík, Icel, 2School Greta Wells1 of Environment, Earth & Ecosystems, The Open 1University of Texas at Austin University, Milton Keynes MK7 6AA, UK, 3Icelandic Meteorological Office, Avalanche Centre, Suðurgata 12, 400 Ísafjörður, Iceland, 4Laboratoire de Planétologie et Gullfoss is one of Iceland’s most visited tourist Géodynamique de Nantes UMR-CNRS 6112, 2, rue de la sites, a two-tiered waterfall where the Hvítá River Houssinière, BP 92, 5Icelandic Institute of Natural plunges 32 meters into the Hvítárgljúfur canyon. History. Borgum við Norðurslóð, 602 Akureyri, Iceland This system is one line of evidence for paleofloods that surged across the region ~9500 years BP. Over a span of 100-200 years, a series of floods On the 20th of September 2012, a large debris drained the ice-dammed glacial lake Kjölur in the slide occurred in the Móafellshyrna Mountain in southwestern highlands. The largest events the Tröllaskagi peninsula, central north Iceland. reached an estimated maximum peak discharge The slide initiated after an unusual warm and dry of 3 x 105 m3 s-1, ranking them among the largest summer followed by a month of heavy known floods in Iceland and on earth. Most precipitation. Furthermore, the slide originated research on Icelandic jökulhlaups has focused on after a seismic sequence. The main source of floods generated by volcanic and geothermal material was ice-rich talus deposits perched on a activity beneath the southernmost ice caps; but topographic bench. Blocks of ice-cemented the little-studied Kjölur floods, not triggered by deposits broke off the frontal part of the talus volcanogenic processes, may provide a better cone and fell onto the talus slope below. Further analog for most global glacial lake outburst downslope, the landslide material became over- floods. A pioneering study by Tómasson (1993) saturated, causing it to evolve into a debris slide. reconstructed the Kjölur paleofloods based on We estimate that the total volume of the debris geomorphologic evidence and paleolake slide is around 500,000 m3 and that its primary strandlines. This project builds on previous cause was intense precipitation. We cannot research by employing new methods to better exclude the influence of the seismic sequence as a constrain flood timing, magnitude, and routing. contributing factor. The presence of ice- This presentation has three main goals: 1) cemented blocks in the slide deposits shows that

206 present new and synthesized geomorphologic Ground-Based InSAR revealed displacement field evidence; 2) outline a sampling strategy for estimates at rates of mm/day, indicating that geochronological analyses; and 3) situate the seasonal changes related to water and ice Kjölur jökulhlaups in the broader context of influences the stability of the unstable rock slope. catastrophic flood geomorphology in Iceland. This research will yield insight into drainage Based on structural measurements and dynamics of ice-dammed proglacial lakes, which displacement patterns detected by InSAR, the pose an increasing hazard worldwide due to deformation in Oksfjellet is interpreted to be rapid climate-driven glacial lake expansion. It has controlled by a complex interaction between excellent potential to bridge the gap between ductile and brittle structures, following a academic research and public outreach through common deep seated sliding surface between communication to a high number of international foliation/thrust and fractures. The combination visitors. of InSAR data and field mapping proved valuable in order to assess displacement patterns at different temporal and spatial scales. This contributed to an improved understanding of the POSTER evolution of the unstable rock slope in Oksfjellet.

A structural and InSAR study of the unstable rock slope in Oksfjellet, POSTER Troms The Kassen and Håkåneset rock slope Marie Bredal1, Steffen G. Bergh2, Lars Harald Blikra3 and Tom Rune Lauknes4 instabilities along fjord lakes in 1Geological Survey of Norway (NGU), 2UiT The Arctic Telemark show large postglacial University of Norway, 3Norwegian Water and Energy gravitational strain but no present Directorate (NVE), UiT The Arctic University of Norway, 4Norut Northern Research Institute day deformation, Southern NorwayThe Kassen and Håkåneset rock slope instabilities along fjord Oksfjellet is one of many unstable rock slopes in Troms, Norway. Due to the hazard and risk posed lakes in Telemark show large by potential slope failures, it is important to postglacial gravitational strain but no obtain precise deformation measurements. In present day deformation, Southern this study, a combination of field observations Norway and InSAR data was analyzed to better understand the geological structures susceptible Kaja Krogh1, Reginald L. Hermanns2, Trond for sliding in Oksfjellet. Eiken3, John Gosse4, Martina Bøhme2 and Ivana Penna2 Field mapping in Oksfjellet revealed a ductile 1Norwegian University of Science and technology, shear zone/thrust that is interpreted to have Norway, 2Geological Survey of Norway, Trondheim, formed during the Caledonian nappe Norway, 3University of Oslo, Oslo, Norway, 4Dalhousie emplacement. Mapped fractures, trending NE-SW University, Halifax, Canada and NW-SE, coincides with regional Mesozoic brittle structures. The Kassen and Håkåneset rock slope Satellite InSAR data (TerraSAR-X and Radarsat-2) instabilities lie along fjord lakes. The Kassen revealed subsidence of the unstable slope at a instability lies at the tip of a plateau dipping rate of 4 ‒ 5 mm/year. Additionally, satellite steeply towards Bandak lake. The instability InSAR data detected subsidence of a larger area, stretches 2,5 km E-W. Its up to 100-m-high steep at a rate of less than 1 mm/year, that is thought back scarp separates undeformed crystalline to relate to active down-faulting. Results from bedrock from strongly desintegrated rock mass

207 breaking the slope in various compartments. In Preikestolen is included as one of the main the central part a depression exists, that has investigation objects. The master thesis “Stability descended an additional 25-50 m. Below that, analysis of Preikestolen" is a part of this project, bathymetric data reveal a 13.4-million-m3 large and will be based on data collected by NGU in rock-avalanche deposit on the bottom of lake addition to student work. Bandak. Preliminary cosmogenic nuclide ages indicate that the top of the mountain melted out of the ice at 14.1 ka and was mainly active in the In September 2017, the rock formation was early part of the Holocene. Differently the top of scanned from four different angles with a ground the Håkåneset rock slope instability lies mid based LiDAR scanner. These scans will be put slope but similarly the up to 75-m-high back together to create a detailed 3D model of scarp separates strongly deformed and cracked Preikestolen. In addition, two 3D models will be rock mass from stable rock mass. Bathymetric created using photogrammetry. One model will data of Tinnsjø lake reveal that the instability be based on photos taken from helicopter and the extends down to ~330 m below lake level. At the other one from drone photos. These models will foot both a 40-m-high pressure ridge within a be compared to field data in order to test which terrace and several generations of slide scars remote sensing data give the closest results and within this terrace suggest that the instability can be used best as a standard method. Further, reaches down to the lake bottom. the 3D-models will be investigated in Coltop-3D Kinematic feasibility tests at both locations show to gather structural data measurements. These that simple failure modes are possible in the measurements will be used in combination with steepest slope parts but bi-planar sliding is structural data from fieldwork to do a kinematic feasible at both locations for larger feasibility test. Further, the stress distribution in compartments. Displacement rates determined the rock formation will be modelled with RS2. To by dGNSS show velocities below significance level gather input data, several test are planned in the (< 2mm/yr) for the past years suggesting that rock mechanics laboratory at NTNU. Eventually, both rock slopes stabilized in comparison to the all data will be discussed to give a final evaluation pronounced postglacial deformation. of the stability.

POSTER POSTER

Stability Analysis of Preikestolen Assessment of risk posed by slope (Rogaland county, Norway) failures at a coastal cliff in Hyllestad municipality (Sogn og Fjordane, Katrine Mo1, Reginald Hermanns2, Martina Norway) Böhme3 and Pierrick Nicolet3 1Norwegian University of Science and Technology, Vegard Nes1, Reginald Hermanns2, Ivanna Penna2 2Norwegian University of Science and Technology, and Jon Runar Drotninghaug1 Geological Survey of Norway, 3Geological Survey of 1NTNU, 2NGU Norway

In the last years, the Norwegian Geological The hike to Preikestolen is one of the most Survey has been mapping unstable rock slopes in popular trails in Norway, with more than a Sogn og Fjordane county. Several of them hundred thousand visits each year. Despite the developed on fjord slopes, which implies that in popularity, the stability of the rock formation is addition to the direct impacts, the consequences not yet determined. The Geological Survey of related to displacement waves need to be Norway (NGU) is now mapping potential addressed. In this context, slope instabilities unstable rock slopes in Rogaland County. Hence, along a 6 km coastal cliff in Aafjorden has been

208 identified, and two of them are currently being post-glacial rock avalanches that have been monitored (NGU, 2017). The aim of this work is deposited in Innfjordalen (Scheiler et al. 2016). At to give a complete overview of the unstable this site, in addition to the rock avalanche slopes present along the coastal cliff of Aafjorden, deposits, a large colluvial fan can be observed as well as their main controlling factors by (Skei 2016). The objectives of this work are to including the results of a recent survey. describe the source of sediments and the surface processes contributing to the development of the The mapping was completed through field work, fan. This study takes advantage of permanent and interpretation of photogrammetric models monitoring equipment (3 cameras and 1 and a 1m resolution DEM. The mechanism of meteorological station) and periodic failures is based on site measurements as well as measurements (LiDAR, photogrammetry, structure detection with COLTOP3D. Volume gigapixel pictures) to study the slope processes estimates of the unstable blocks were calculated that are active nowadays. An area of intensively using CloudCompare. fractures rocks, that remains in the headscarp, is shown to be the main source of sediments. Our analysis shows that there are 8 unstable Indeed, 93 negative differences (e.g. missing blocks with volumes up to 170 000 m3 along the blocs) have been observed between 2014 and coastal cliff of Aafjorden that can lead to 2016 on the gigapixel pictures in this area. In considerable displacement waves, as already addition, 63 positive or composite differences occurred in 1992 (Harbitz, 2001). The (e.g. deposited bloc or sediments transported on detachments are controlled by steep N-S and E-W a short distance) have been identified in the same striking joint sets in the western domain, and area, which suggest that the sediments are often joint set dipping 70 degrees towards east in the transported only on a short distance. eastern domain. The kinematics of the unstable Furthermore, the permanent camera placed in blocks have exposed both potential toppling- the valley permits to identify several snow failures and planar failures. Future work includes avalanches that remobilize sediments down to the risk assessment of all the potential scenarios, the lower parts of the fan. During snow melt using the methodology developed by NGU season or precipitation events, materials are (Hermanns, et al., 2013). transported in form of debris flows along two main channels. Further work is needed to better relate the observed events with the POSTER meteorological conditions.

Monitoring of surface processes in Gråfonnfjellet, Rauma municipality,

Norway

Pierrick Nicolet1, Ivanna Penna1, Reginald Hermanns2, Odd Are Jensen3, Lena Rubensdotter1 and Silje Øren Skei4

1Norges Geologiske Undersøkelse, Trondheim, 2Norges Geologiske Undersøkelse, Trondheim; Norges Teknisk-

Naturvitenskapelige Universitet (NTNU), 3Norges 4 vassdrags- og energidirektorat, Norges Teknisk- Naturvitenskapelige Universitet (NTNU), Trondheim

Loose rock masses remain on the headscarps and after historic and prehistoric rock avalanches on Gråfonnfjellet mountain, Innfjorddalen, Norway. This material is remaining after at least three

209 10.2. Open session Engineering type of model can be integrated with the overall geology of an area fairly easy in contrast to a site and enviromental geology specific voxel model.

ORAL ORAL The modelling of ice-marginal complexes and salt structures using Geochemistry of deposited mine 3D layer models tailings in Repparfjorden, northern Norway, and their effect on bottom Thomas Breum Andersen1 fauna. 1GEO, Geodata and Subsurface models, Maglebjergvej 1, 2800 Kgs. Lyngby Malin Andersson1, Tor Erik Finne1, Hilde Trannum2, Kristine Pedersen3, Anita Evenset3 and Paul Renaud3 Among the most challenging geological 1Geological Survey of Norway, 2The Norwegian Institute structures to interpret and model in the Danish for Water Research, 3Akvaplan-niva area are the ice marginal complexes with complex stacked internal structures and areas with salt domes intruding Neogene and Quaternary strata. Submarine tailing disposal (STD) involves the The geology will reflect complex tectonics that discharge of mine tailings below the sea surface must be interpreted and turned into a sequence as an alternative to on-land deposits. Norway, a of tectonic events in order to represent this in a country with deep, sheltered fjords, is one of the 3D model. few countries in the world where these disposal operations are in use. This study investigated a The development of a reliable conceptual model four decade old mine tailing deposit in is essential in this work and this Repparfjorden, originating from copper ore conceptualization must encompass a thorough processing in the 1970's. Bathymetry from this analysis of all data sources available including project revealed that the deposit is still presently drillings, geophysics, geomorphology, previous almost intact. The issue is of interest as the mine investigations ect. representing a cross-discipline is likely to reopen in 2019. investigation. The mine tailings are, in relation to the natural The development of a geological 3D model that materials lying under the tailings and on top, reflects the conceptual geology and tectonic clearly enriched in the elements Au, Ba, Bi, Cr, Cu, structures requires special techniques when Hf, Ni, Re and Zr, but also depleted in the using layer models including sophisticated elements: Be, Cd, Cs, In, Li, Nb, P, Pb, Rb, S, Sc, V positioning of digitalization-points, interpolation and Zn, therefore establishing the chemical and adjustment procedures in order to develop signature of the tailing material. To be able to steeply dipping or vertical strata, faultlines or compare geochemical results and execute fauna saltdomes that may be developed as true dome experiments, newly fabricated flotation tailings structures or horst structures. were produced. The old tailing deposit differs considerably from these, which could be due to Examples will be shown from well-known differences in ore material or flotation process, or geological Danish geological sites as the Røsnæs chemical changes during deposition. These Icemarginal complex, Thyborøn (Rønland differences make chemical predictions for a Saltdiapir) and Suldrup Saltdiapir where these future deposit difficult. methods have been used in connection with ground water modelling projects and for The bottom fauna study revealed differences in geotechnical purposes. The modelling technique the number of species and individuals present in takes the layer-model method to its limits but this the surface sediments depending on the influence

210 of the tailings. Depending on the depth of tailings has been demonstrated on 28 samples from three on top of surface sediments, a decrease in granitic rocks of different textures and biomass amount was evident during a re- structures. The strength of the methodology is colonisation experiment. the increase in knowledge of critical parameters affecting cracking processes in rock materials and how these are related to the rock micro- and mesostructure. ORAL

Development of a direct tensile test method for microtextural fracture ORAL studies Construction geological map of Karin Appelquist1, Mathias Flansbjer2, Linus Stockholm- and example of geo-data Brander1, Lovise Sjöqvist1, Jan Erik Lindqvist1 and recycling. Camilla Lindström1 1RISE CBI, 2RISE Mechanics Research Phil Curtis1 and Claes Mellqvist1 1SGU

Traditional macroscale rock strength tests generally aim at characterizing and comparing The original construction geological map of different rock types in a standardized way. Stockholm was produced during the 1970s and is However, these methods rarely shed light on the still widely used today in the early planning crack development in relation to the material stages of new infrastructure projects. Although it structure. Often the loading situation and was digitized in 1997 it has not been updated specimen geometries are complex, resulting in since its original publication. The Geological difficulties identifying the contribution of Survey of Sweden (SGU) has been working on different synchronous deformation processes. such an update that includes the incorporation of Examples are compressive loading tests, in which geological data from existing infrastructure a combination of compression and shearing projects from external sources such as (Swedish occur, and Los Angeles tests, in which crushing, Transport Administration) Trafikverket and the abrasion, tension and shearing occur construction industry. The new map is to be simultaneous. Due to this shortcoming, a new issued on the web in a 2D format for ease of use, methodology which combine detailed cracking however, much of the visualization and monitoring techniques with mechanical rock interpretation process has been performed in 3D tests – allowing the examination of different and the results will be available for viewing on a isolated deformation mechanisms – is presented. separate website.

The methodology combines tensile stage testing of a rock specimen with continuous monitoring of the cracking processes by Digital Image ORAL Correlation and Acoustic Emission. After completion of tensile test, examination of Weakness Zones in the Bedrock - microcracks and fractures by fluorescent Geophysical Studies in City Area transmission microscopy is conducted. This Taija Huotari1 and Marit Wennerström1 methodology enables the spatial and temporal 1Geological Survey of Finland visualization of the cracking processes within a rock sample, on micro- and mesoscale, linking the cracking processes (e.g. initiation, reactivation, As the amount of underground building in city propagation and bridging of microcracks, and the areas grows the need for information of bedrock final development of the open fracture) to rock under the ground surface is increasing. texture and microstructure. The methodology

211 Problematic features for underground ORAL construction might be weakness zones in the bedrock. Information on the location, orientation Digital archive for strong ground and properties of weakness zones before starting motions recorded in earthquake construction will improve the schedule and cost sequences estimates of the project, as well as usually reduces the construction costs. The potential of Evangelos Katsanos1 and Victor Ambo Boserup1 different geophysical methods were tested to 1Department of Civil Engineering, Technical University detect weakness zones in the bedrock in the of Denmark project called ‘Intrageo’ (Huotari & Wennerström, 2017). Further, the geophysical Numerous structures and infrastructures results were integrated with structural geological systems have been recorded to encounter interpretation of weaknesses in the bedrock. extensive damages or total collapse due to successive earthquake ground motions occurred in short time spans. A list of recent earthquake The investigations were carried out at sequences, found to be detrimental for both Hannusjärvi and Finnoo in Espoo on the planned humans and the building stock, comprises of route for the 2nd phase of the West Metro, as well seismic events from Amatrice-Italy (2016) and as in the area of the new underground Kumamoto-Japan (2016), Gorhka-Nepal (2015) wastewater treatment plant of HSY (Helsinki and Tōhoku-Japan (2011). Nevertheless, the Region Environmental Services Authority) water current seismic codes prescribe the structural services at Blominmäki, Espoo. Both design on the basis of a single “design” investigation areas are located in the Helsinki earthquake waiving the sequential seismic events metropolitan area in Finland. In 2nd phase West that may increase the seismic vulnerability of Metro targets the measurements were structures. It is, thus, important to focus on this concentrated on tests of ground geophysical hazardous phenomenon in order, eventually, to methods. The aim was to test different methods mitigate its consequences. Over the last 15 years, along the same survey profiles to perform the effects of earthquake sequences on the integrated interpretation and to evaluate the structural performance have been elucidated [1- usability of different methods. In Blominmäki 3]. However, the use of real strong motions from tests concentrated on geophysical drill hole successive ground shakings is commonly measurements and magnetic measurements with restricted to a single earthquake sequence event dense line spacing in the most fractured rock that may dominate (or bias) the structural area. Petrophysical properties, as well as the rock response results [4]. Additionally, the artificially- type and structural features, were studied from developed earthquake sequences may derive drill core samples for the sake of comparison and questionable seismic demand [5]. Hence, this verification. study is dedicated to compile a dataset including almost 7000 suitably selected strong ground motions, which were recorded worldwide during earthquake sequences and found of interest for

studies addressing the structural response imposed by multiple earthquakes. The dataset compiled provides metadata related to seismological characteristics and strong ground motion parameters while, when necessary, the

records were processed (i.e., base-line correction and frequency-based filtering). Finally, systematic analysis of the selected motions revealed trends on the basis of the several

212 parameters associated with the successive ORAL earthquakes. Risks of arsenic exposure through agriculture

ORAL Kirsti Loukola-Ruskeeniemi1, Juha Kaija1, Timo Tarvainen1, Tarja Hatakka1, Riitta Keiski2, Auli The quaternary history at the Horns Turkki2, Jana Pinka3, Isabel Jordan3, Fabienne Rev 3 site. Battaglia4, Marina le-Guedard5, Celia Jones6, Prosun Bhattacharya7, Sirpa Kurppa8, Ingo Joakim Stiel Korshøj1 Müller9, Grzegorz Siebielec10 and Jose Solis Veliz11 1Geo 1Geological Survey of Finland, 2University of Oulu,

Finland, 3GEOS Ingenieurgesellschaft mbH, Germany, 4BRGM, France, 5LEB Aquitaine Transfert, France, In 2013 Geo was contracted to carry out pre 6Kemakta, Sweden, 7Kungliga Tekniska Högskolan, investigations for Energinet, for the offshore Sweden, 8Natural Resources Institute Finland, 9LfULG, windfarm Horns Rev 3. The pre investigations Germany, 10Institute of Soil Science and Plant revealed a buried landscape, with dislocated floes Cultivation, Poland, 11National University of of Miocene clays. Engineering, Peru

The Horns Rev 3 bank is composed of a rather complex sequence of Postglacial and glacial Arsenic is a toxic and carcinogenic semi-metal sediments, including glacial floes of Tertiary which can enter into agricultural soil and water sediments. The area was not covered by ice due to human activities or from natural deposits. during the Weichsel glaciation. The sea-level was AgriAs Water JPI project started 1st April 2017 approximately 120 m below current sea-level. and evaluates arsenic contamination in Europe The only deposits from Weichsel that is observed focusing in two study areas with intense in the area is from meltwater rivers flowing in the anthropogenic pollution. Research institutes, lower lying areas. Two Postglacial units have universities and companies from five EU been deposited during the Flandrian countries participate in the project. AgriAs transgression. Deposits consist of non graded summarizes national and European databases sand and organic clayey silt and clay. The (e.g., Tarvainen et al. 2013) and develops deposits are generally loose/soft, locally the recommendations and guidelines for sustainable organic content is high, here they are described management of arsenic risks in agricultural as organic clay (gyttja). Some smaller deposits of areas. The French study site is a historical area of peat have been observed, one of which was dated destruction of WWI chemical weapons located in by C14 determination. The peat layer was found a sensitive zone for agriculture and groundwater. in the bottom of the Postglacial sequence and was The German site is characterized by 800 years of dated to between 8211 and 7791 years BC. In- mining. Arsenic removal technologies will be between the meltwater deposits smaller till developed and demonstrated in both areas. layers are seen, as well as floes of Tertiary Biological tools will be applied to manage sediments. ecological, environmental and human risks. Dissemination activities will follow the Tertiary deposits have been found as floes procedures of the successful LIFE + project interbedded in the meltwater deposits and two ASROCKS which developed guidelines for rock borings stopped in Tertiary deposits. Since aggregate production in arsenic-rich areas (e.g., drilling stopped in these layers, it is not possible Parviainen et al. 2015). In the first stakeholder to say if they are parts of folded Tertiary sediment workshop organized in Freiberg in September by Saalian or earlier glaciations, floes or if the 2017, interaction and discussions between Tertiary sediments are in situ. farmers, authorities and researchers were active.

213 The authors thank EU and the Academy of The model is fast in coarsely determining Finland, Agence Nationale de la Recherche, aggregate volume. It is highly suitable for Bundesministerium für Ernährung und focusing expert fieldwork. Land use in the area Landwirtschaft and Forskningsrådet FORMAS for continues to sterilize new locations. To avoid funding, in the frame of the economic and ecological damage, a plan should AgriAs Consortium financed under the ERA-NET be implemented for securing this resource. This WaterWorks2015 Cofunded Call. This ERA-NET may include the reserving of locations, reducing is an integral part of the 2016 Joint Activities use, checking legislation on production and developed by the Water Challenges for a recycling used aggregates. Changing World Joint Programme Initiative.

ORAL ORAL Developing of Geothermal District 2,5D Open Source Modeling of Rock Heating solutions for 4 towns in Aggregate Resources in the Helsinki Poland Metropolitan Area Kirsti Midttømme1, Beata Kępińska2, Leszek Samppa Mäkelä1 Pająk3, Baldur Pétursson4, Jan Kocbach5, Ingvar 1University of Helsinki Henne5, Usman Dar6, Jørgen. B Skauge6, Óskar P. Einarsson7 and Friðfinnur K Daníelsson8 1Christian Michelsen Research (CMR), 2Mineral and The objective of this study is to develop a method Energy Economy Research Institute, Polish Academy of of appraising rock aggregate resources, using Sciences (MEERI PAS), 3MEERI PAS, 4Orkustofnun, open data and open source tools. The availability 5CMR, 6Sweco Norge, 7Verkis, 8Alvarr of aggregates in Finland is mostly determined by competing land use and restrictions on extraction. Therefore, it is important to Poland possesses proper geothermal energy to determine the extent of available resources, supply low-emission thermal energy. Polish, especially near areas of high demand. Icelandic and Norwegian experts collaborate to develop geothermal district heating solutions for The study area consists of the 14 municipalities four towns in Poland. Three of the towns, in the Helsinki metropolitan area, a total of 3841 Konstantynów Łódzki, Sochaczew, and km2. The data used are open access, provided by Poddębice, are located in sedimentary rocks GSF and NLS. These are combined in a GIS to central Poland in the Permian-Mesozoic Szczein – identify locations where extraction of aggregates Lodz Miechow. The last town, Lądek Zdrój is is possible. Geology, limitations and the highest situated in crystalline rocks in Sudet Mountains and lowest point of possible extraction are close to the boundary to Czech Republic. The detrmined. These are used to estimate the town is one of the oldest Polish health resorts available resources and locate the economically using thermal water. feasible sites. Data used include a digital elevation model and layers on geology and land use. A 10 MWth geothermal district heating plant was established in Poddebice in 2013, substituting The results show that competing land use has fossil energy. The geothermal well of 2101 m sterilized most aggregate locations in the area. depth is extracting water of 70 °C from Lower Remaining locations are concentrated on the Cretaceous sandstones. Maximum flow rate is edges. However, some potential sites remain. 252m3/h. The water is discharged into the Ner Field evaluations and comparison to previous river and it is a challenge to satisfy the studies show that the method is sound and able requirement of a maximum temperature of 35°C to locate possible localities. on the water discharged. There is also a need for

214 better understanding of the effect of long-term useful information for further detailed geothermal exploitation engineering geological surveys.

A new geothermal well of 2800m depth The FinEst link project examines the technical extracting water of 70 C from Lower Jurassic is and economic feasibility of the undersea tunnel planned as an additional energy source for and the logistic solutions in addition to its cost- Konstantynów Łódzki incooperated in the effectiveness and economic, environmental and existing Łódź district heating system. social impacts. Results are to be expected during the present year 2018. The viability of planning The authorities in Sochaczew plans a geothermal the tunnel can be assessed only after receiving district heat pump solutions utilizing water of these results. 40°C from Lower Cretaceous sandstone. The research work on the feasibility of the tunnel A new geothermal well of 2500 m depth is project was enabled by EU funding under the planned in Lądek Zdrój producing water of 70°C Interreg Central Baltic programm. The project is from fracture zones. led by the Helsinki-Uusimaa Regional Council in cooperation with the City of Helsinki, the Finnish The joint Polish/Icelandic/Norwegian project Transport Agency, the City of Tallinn, the was funded by EEA Grant. Estonian Ministry of Economic Affairs and Communications and the Harju County Government ORAL

Geological studies of the possible ORAL Helsinki–Tallinn undersea tunnel route Nyt borearkiv ser dagens lys - Øget adgang til private borearkiver Keijo Nenonen1 and Ossi Ikävalko1 1Geological Survey of Finland Mikkel Wendelboe Toft1

1Cand.scient Geological Survey of Finland (GTK) and Estonian geological Survey (EGS) conducted geological Geo har skabt en ny online adgang til viden om studies and acoustic-seismic surveys of the undergrunden. Formålet er at sikre at fagfolk på possible linings for an undersea railway tunnel tværs af organisationer kan arbejde med bedst between Helsinki and Tallinn. muligt udgangspunkt så projekterne bliver løst The surveys provided a detailed overview of the mest effektivt og med mindst risiko. I dette oplæg geological structure of the sea floor basement and vil vi fortælle om strategien bag frigivelsen af deposits between Finland and Estonia. A new virksomhedens data, samt om de tekniske finding was that the crystalline Proterozoic problemstillinger som vi bliver mødt af under basement sea floor continues all the way to udviklingen af et sæt helt nye services. Desuden Naissaar and to the shallows near the Estonian perspektiveres der mod potentialet ved af coast. A thick layer (100-150 m) of soft tilgængeliggøre andre virksomheders data. sedimentary rocks from Cambrian - Ordovician Initiativet er blandt andet motiveret af Statens age (sandstones, claystone and limestones) beslutning om at stille sit kortgrundlag gratis til covers the hard granitic bedrock on the city of rådighed, hvilket har skabt helt nye Tallinn area. Presently ongoing FinEst Link forudsætninger i markedet. Vi har udviklet en project between Finland and Estonia examines række værktøjer som, via bagvedliggende 3D the possibilities of building a 100 km long railway modeller af undergrunden, kan lave virtuelle tunnel. The geological findings provides new and boringer, udstille 3D jordartskort i fladesnit, samt gøre det muligt at lave hurtige og brugervenlige

215 profilsnit af høj kvalitet. Ved at udstille developed National Database for Ground værktøjerne online, søger vi at skabe maksimal investigations (NADAG) is a potential source for tilgængelighed, og mulighed for høj valuable stratigraphic information from e.g. brugervenlighed. Et interessant potentiale i linked drill reports. Well organized and tendensen med åbning af adgangen til data i de standardized stratigraphic information in a private virksomheder, er værdien ved digital format is needed for extending the present sammenstilling af data fra andre kilder. En day geological map products into the subsurface, sammenstilling gør det muligt eksempelvis at se and for further analyses and modeling. Possible relationen mellem registreret jordforurening, web solutions are presented. arealanvendelse eller befæstelsesgrad, og den overfladenære geologi. Mulighederne for anvendelse er utallige, og når først brugeren i POSTER særlige fagdomæner får adgang, så vurderer vi at anvendelsesmulighederne vil spire frem. Provenance and Contamination

History of the Paraná Delta, Argentina POSTER Jane Ihrfors1, Matilda Schütz1, Rodney Stevens1, Development of a database for Juan Pablo Milana2 and Claudio Parcia3 stratigraphic information on 1University of Gothenburg, 2Universidad Nacional de Quaternary deposits at the Geological San Juan, 3Universidad Nacional de San Martin

Survey of Norway (NGU) This is a sedimentological and geochemical study 1 1 1 Louise Hansen , Bo Nordahl , Alexandra Jarna documenting sediment provenance and 1 and Inger-Lise Solberg contamination of the Paraná Delta front during 1Geological Survey of Norway the last 150 years. The Paraná river system is a

pristine landscape home to several endangered A National database for superficial deposits have species and South Americas second largest existed in Norway for decades and is developed drainage basin containing some of the world’s and hosted by the Geological Survey of Norway. largest wetlands. The basin has been cultivated The database is the basis for web services for a long time but with an expanded human presenting Quaternary map information at activity during the last century with increased different scales and associated products and deforestation and industrialisation. Therefore, services (www.ngu.no). The maps are used in studies in the Paraná could give an indication on society for various purposes from research to how the Amazons will be affected by increased public planning. Stratigraphic information has human impact. Previous studies of the delta front previously only been presented as a somewhat have mapped and dated beach ridges (Medina et complicated text strings locally on analogue al, 2013). A transect sampled perpendicular to Quaternary maps, or in associated these provides a historical record of the delta reports/articles. There has, till now, not been any progression and development. The aim is to see database to receive stratigraphic information in a how the change of climate and human activity in structured way. As there is a growing need in the the catchment area have affected the sediment Norwegian society for subsurface geological provenance at the delta front. The samples are information there is also a need for the analysed using methods to identify the mineral development of a stratigraphic database. A composition in the clay and sand fractions to prototype of a stratigraphic database is reveal their provenance and roughly estimating presented. An important aspect of the database is each sub-basin’s sediment supply to the delta that it can host varied types of stratigraphic front. Sediment geochemical trends over the information from different sources. The newly sampled timeline, with a particular emphasis on

216 heavy metal contents, are interpreted in terms of The Geological Survey of Denmark and Greenland provenance and contamination, which in turn are has until 2011 been responsible for the geological linked to human impact through deforestation, studies of near-surface areas (100-200 meter afforestation, population growth, urbanisation depth) for the repository. The task has been to and industrial activity. In general, the delta- locate and recognize non-fractured clays or forming processes themselves need to be re- Precambrian bedrocks with low permeability evaluated on the Paraná Delta since these are also which can isolate the radioactive waste from the affected by changing climate and increasing surroundings. Six potential areas have been human impact. located based on the most favorable conditions in relation to geology, hydrogeology, nature protection and climate change conditions.

POSTER Five of the six localities Paleogene and Neogene clays are considered as suitable as the last barrier Investigations of clay deposits as in the repository based at these criteria: 1.The barrier for a final repository for clay layer shall be at least 50-100 m thick, 2. Denmark's low- and intermediate The clay layers shall have a continuous level radioactive waste in subsurface horizontal distribution in the selected area. 3. The clay layers shall be low permeable without to 500 m depth. fractures and with very low groundwater Bertel Nilsson1, Peter Gravesen1, Stig A. Schack content. 4. The selected area shall be without Petersen1 and Merete Binderup1 groundwater and drinking water interests. The 1Geological Survey of Denmark and Greenland (GEUS), last locality was located in Precambrian Øster Voldgade 10, 1350 Copenhagen, Denmark basement rocks.

In 2018 new technical studies will be carried out The Danish radioactive waste from the research to determine possible future locations for a deep station Risø must be stored on Danish land geological final repository at ~500 meter depth. territory (exclusive Greenland). The radioactive As the existing data and previous studies do not waste is consisting of the waste from the make it possible to conclude where a deep decommissioning of the nuclear facilities at Risø, repository can be placed. and the radioactive waste produced in Denmark from hospitals, universities and industry.

217 11. Hydrogeology 11.1. Groundwater transport in validate the model of infiltration and thawing. The model was successful in reproducing the cold, changing climates: theory, thawing and soil moisture patterns observed in experiments, models the soil, and hence looks like a promising tool for predicting snowmelt infiltration and melting of ground frost in a sandy unsaturated soil. ORAL

Modelling snowmelt infiltration in a ORAL seasonally-frozen soil monitored by electrical resistivity measurements Numerical simulations of temperature-dependent transport in Helen Kristine French1, Andrew Binley2 and Cliff Voss3 waste rock piles in permafrost- 1Norwegian University of Life Sciences, 2Lancaster dominated environments Environment Centre, Lancaster University, UK, 3U.S. Geological Survey, Menlo Park, CA 94025 USA Daniele Pedretti1 and Leslie Smith2 1Geological Survey of Finland (GTK), 2University of British Columbia (UBC) Infiltration during snowmelt can be highly heterogeneous due to the formation of ice on the ground surface below the snow cover. In Waste rock piles (WRPs) contain unsaturated situations where snow is contaminated, such as materials that can yield water with elevated along highways and airports due to de-icing solute concentrations as a consequence of agents, the area that takes part in the early sulphide mineral oxidation. Tracer tests can be infiltration will determine the retention time and used to provide insight to transport properties potential for degradation in the unsaturated that affect the evolution of the effluent water zone. In 2001, French and Binley (2004) quality over time. In cold environments, flow and observed a highly variable snowmelt infiltration transport are also affected by variably freezing over a small area at Gardermoen, Norway, conditions within the pile, a process that monitored with time-lapse electrical resistivity complicates the interpretation of tracer tests. measurements. In this study, we want to test the This contribution describes a numerical model suitability of a newly developed numerical model simulating conservative solute transport in a for water and heat transport including phase homogeneous WRP with temperature-dependent change (modified version of SUTRA_ICE, boundary conditions and variably freezing cycles described in McKenzie et al.,2007) in a variably within the pile. The conceptual model is based on saturated soil against field observations. the experimental waste rock piles at the Diavik Monitored weather and snow melt data defined Diamond Mine in northern Canada, located in an the boundary conditions of a simulated area of continuous permafrost. unsaturated profile with seasonal freezing. The dependency of capillary pressure and The results illustrate the key role of an explicit permeability on water saturation is taken from solution of temperature-dependent flow the van Genuchten equation. Soil physical data conditions to evaluate the seasonal and annual and heterogeneity was based on local soil release of solute loads. The model illustrates the measurements. Different infiltration scenarios annual drainage cycles in the core of the pile, were tested. Soil temperatures, TDR which were hypothesized to be characterized by measurements of soil moisture, a tracer distinct spring flushes and steady decline in flow experiment conducted at an adjacent site and prior to freeze-up. Solutes move within the changes in electrical resistivity were used to

218 unfrozen core of the pile even when the external investigations and environmental monitoring. portion of the pile starts to freeze. The Data (e.g. gw-levels) will be collected in the field temperature boundary conditions affect the in real-time using an innovative sensor (transient) flow geometry within the piles, and technique. The project will develop visualization can complicate the interpretation of tracer tests. capability for this data and interpolation routines In particular, an apparent dual-porosity-like will be added, allowing analysis of trends across effect is produced on solute breakthrough curves monitoring sites. Connections to GTK corporate even when the pile is physically simulated as a databases will be established, making data hydraulically and geochemically homogeneous exploration simple and intuitive for GTK single porosity domain. geoscientists and the supervising authority. Sharing real time groundwater data in Groundhog Desktop, and visualizing interactively in maps, logs and cross-sections, will significantly ORAL help environmental agencies to monitor and Groundwater levels real time control the sustainable use of water. monitoring and visualization software demonstrated for Precambrian valley sediment POSTER aquifers in Ostrobothnia, W Finland Subpermafrost Groundwater and

Niko Putkinen1, Holger Kessler2, Ben Wood2, Elina Pingos in Adventdalen - Evaluating the Lindsberg1, Harri Issakainen1, Tero Rönkkö1, Esa Implication of Holocene Permafrost Kauniskangas1 and Miikka Paalijärvi1 Formation in Near Coastal Areas 1Geological Survey of Finland, 2Brittish Geological Survey Mikkel Toft Hornum1, Peter Engesgaard2, Søren Jessen3 and Andy Hodson Professor at UNIS 1Master student at UCPH, guest master student at UNIS, Old buried Precambrian valleys in Ostrobothnia, 2Professor at UCPH, 3Associate professor at UCPH Kurikka, W Finland play a major role in the groundwater system and will ensure the future municipal drinking water supply for over 150000 In previously glaciated areas of the Arctic, people. Several year’s of intensive substantial isostatic rebound and associated hydrogeological studies include 70 boreholes to relative sea-level fall have lead to Holocene the bedrock, ~200 km gravity measurements, permafrost formation in former shallow marine numerous seismic profiles in the 100km2 study areas. The study area for this work is area. According to the reported results, it is Adventdalen in Svalbard, a glacial valley for possible to conclude the bedrock structures which an extensive amount of research on promote the most conductive hydrogeological geological and permafrost-related subjects exists. units interlinks between faults, fractures and The implications of this landscape’s history for other structures, the topography of the glacially subpermafrost groundwater is investigated in eroded bedrock surface and the overlying three ways: 1) Electrical Resistivity Tomography weathered bedrock surface and 50-100m thick (ERT) surveys around a pingo enable location of highly variable glacial deposits include several intrapermafrost groundwater flow paths. 2) A confined - semi confined sand and gravel decoupled 1D/2D heat and groundwater flow sediment aquifers and clayey till and marine silt model provides quantitative estimates of the aquitards. potential discharge from the subpermafrost groundwater system as permafrost aggrades. 3) In this project GTK and BGS are working together Artesian springs at three pingos facilitate for water companies on developing free–to-use hydrogeochemical interpretation of controlling geological software for use in hydrogeological processes along groundwater flow paths. Results

219 from the flow and heat transport models suggest 11.2. Groundwater – surface that the permafrost thickness has not yet reached equilibrium, and so frozen ground might still be water interaction; chemical and developing in the lowest part of the permafrost. quantitative impacts on rivers, This implies that groundwater discharge from the lakes, wetlands, fjords and subpermafrost aquifer could be driven by coastal areas. permafrost aggradation, leading to the artesian springs seen at the pingos. However, the spring water analyses show complex hydrogeochemistry probably due to freeze and ORAL thaw processes, although a common source is Groundwater discharge and recharge probable and a subpermafrost origin seems most likely. On the basis of the model results and the patterns in complex aquifer system in ERT, a new conceptual model of open-system a mine exploration area in Northern pingo formation will therefore be presented. Finland

Susanne Charlotta Åberg1, Kirsti Korkka-Niemi1 and Veli-Pekka Salonen1

1Department of Geosciences and Geography, University of Helsinki, P.O. Box 64, 00014 Helsinki

A prominent Cu-Ni showing named to as Sakatti has been discovered in Sodankylä (Brownscombe et al. 2015), close to Kitinen river and below the Natura 2000 protected Viiankiaapa mire. Understanding of the interaction of surface and

groundwater is essential for sustainable ore exploration and development. However, the complexity of the sedimentation history of the surficial deposits makes the groundwater occurrences scattered and elusive. The mire hydrology and its relationship with groundwater recharge–discharge patterns is also crucial for

mire vegetation, but has seldom been studied in Finland (Laitinen et al. 2005). Understanding groundwater-surface water interaction areas is also important when protecting habitats of groundwater dependent ecosystems (GDE).

MODFLOW-NWT model was utilized for defining

the groundwater recharge and discharge patterns and to relate them with GDEs in the area. Hydrostratigraphic units of the model based on the previously created conceptual sedimentary model (Åberg et al. 2017). At the same time annual groundwater table fluctuation was studied from monitoring wells for definition to

initial recharge rates. The recharge parameters were calibrated with parameter estimation. Hydraulic conductivities were manually

220 calibrated with interpolation from previous k- parameters were measured at six occasions, and value calculations. The model results indicated data loggers were installed in 10 wells. that major flow direction is towards the Kitinen river. The model underestimated the distribution Studies dealing with saltwater intrusion in of the discharge zone within mire area. It also fractured (bedrock) aquifers are rare. The slightly overestimated the recharge rates. The hydrogeological assessment on Koster thus fluxes from the bedrock are needed in order to reveals interesting new insights into coastal get more reliable results. Flow modelling was groundwater in crystalline rock formations. found to be effective tool for evaluating the However, the dominating management problem conceptual sedimentary model. on Koster appears to be rather a combination of a lack of national regulations and an overly complex framework of responsibilities. This contribution attempts to combine ORAL hydrogeological and societal aspects and draws some wider-ranging conclusions on the relation Coastal groundwater in Western between hydrogeological research and its Sweden: Hydrogeological and societal application in decision making processes. challenges

Roland Barthel1, Markus Giese1, Ezra Haaf1, Ingmar Geuze1 and Michelle Nygren1 ORAL 1Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden Spatial variability of water and nutrient fluxes in groundwater discharging to Ringkøbing Fjord Groundwater at the Swedish coast occurs in fractured bedrock or in isolated, shallow Carlos Duque1, Joel Tirado-Conde2, Sachin Karan3, quaternary sedimentary formations. Those Janja Svetina1, Søren Jesen2 and Peter resources are of limited interest for public water Engesgaard2 supply. However, a large and growing number of 1Aarhus University, 2University of Copenhagen, poorly regulated private wells create an 3Geological Survey of Denmark and Greenland (GEUS) increasing pressure on groundwater in attractive coastal areas and on islands. River and groundwater discharge to coastal The “Koster” archipelago forms a microcosm of waters bring nutrients that may cause coastal groundwater problems in Sweden. eutrophication, algal blooms or hypoxic events. Koster's geology is dominated by fractured, The quantification of nutrient discharge to crystalline bedrock, occasionally overlain by coastal waters is essential for the management quaternary deposits. With around 300 these areas and it is especially relevant in permanent residents, and up to 6,000 summer estuaries with a limited flushing by seawater. The guests in peak holiday season, the existing water quantification of the groundwater component is supply based on 800 private wells reaches a limit. challenging since it takes places in the subsurface Water availability forms an obstacle to future and under the water. Often it is estimated development and the current situation is indirectly based on water budgets or regional regarded as being unsustainable. numerical models on the scale of the estuary or study area. Likewise, the quantification of Groundwater on Koster was monitored over a nutrient loading is usually carried out by period of 1.5 years. All observations were made assuming an average concentration. in about 220 private, pumped wells. 350 samples Nevertheless, it is well known that groundwater were analysed for major ions and metals. discharge, as well as nutrient concentrations are Groundwater levels and in situ physicochemical highly variable over short distances. This introduces uncertainties in the quantification of

221 coastal nutrient exports. In this work, the spatial Conductivity (EC) and 18O) was also used to variability of the groundwater discharge and the better constrain the analysis under the groundwater nitrate and phosphorus assumption that EC behaved as a conservative concentration to Ringkøbing Fjord is measured tracer. directly at the horizontal and vertical meter scale 18 to assess the range of variability that can be The 4 ha lake is located in sandy deposits. O and considered at these environments. The data are EC were measured in 30 wells (depth of 1.25 m) compared with the hydraulic conductivity around and close to the lake. End member measurements to investigate the potential concentrations and uncertainty were determined correlations between fluxes, nutrient by sampling groundwater in wells on the concentration level, and hydraulic conductivity at discharge side, as well as lake water and rainfall. variable distances from shore and depths below 18O and EC were robust tracers able to identify the seafloor. discharge (South) and recharge (West, North) zones. On the Eastern shore the analysis showed

a mixture of discharge/recharge explained by the ORAL proximity to a water divide and/or a more complex geology with near-surface clay and Use of Water Stable Isotopes and End chalk. The identified seepage zones agree with an Member Mixing Analysis to Map and iso-potential map and spot measurements of Quantify Groundwater Exchange with seepage.

Lakes

Peter Engesgaard1, Ingeborg Solvang2 and Emil ORAL Kristensen3 1Department of Geosciences and Natural Resource An integrated and coupled Management, University of Copenhagen, Denmark, surface/subsurface water model to 2Multiconsult Norge AS, avd. Bergen, Norway, 3Freshwater Biological Laboratory, Department of estimate lake hydrologic and Biology, University of Copenhagen, Denmark biogeochemical budgets over Northern lake-rich regions Groundwater-lake exchanges are important in Zachary Hanson1, Jacob Zwart1, Alan Hamlet1, order to establish water budgets for lakes. Stuart Jones1 and Diogo Bolster1 1University of Notre Dame We used water stable isotopes (18O) to map discharge and recharge zones. In groundwater downstream of lake recharge zones (lake water Lakes are intense biogeochemical processors and seeping to groundwater) one expects to find a play key roles in the global carbon cycle. signal similar to that of the lake (typically However, to date large-scale models rely on 18 enriched in O compared to groundwater) and in multiplying a mean observed areal rates by groundwater discharge zones, one expects to find regional or global lake surface area, treating all a groundwater signal. lakes as the same. This ignores the heterogeneous nature of these systems and their static nature However, concentrations are ‘noisy’ due to renders them incapable of predicting how lake rainfall-evaporation processes, groundwater carbon cycling will change under future global flow, changes in residence time etc. An End change scenarios. To rectify this, we developed a Member Mixing Analysis accounting for end process-based model incorporating surface and member uncertainty (rainwater, groundwater groundwater hydrology, physics, and ecology. and lake water) was used to map seepage zones The model can be applied over large geographic at Lake Tvorup Hul in National Park Thy, regions to hindcast and forecast lake hydrologic Denmark. A two-component analysis (Electrical

222 and carbon fluxes. We applied our model to materials as clays. Groundwater inputs, or simulate lake levels and daily carbon fluxes and exchanges with lakes in such hydro-geological pools for 3675 lakes in the Northern Highlands settings are generally believed to be small and Lake District (NHLD), Wisconsin, USA from 1980- therefore often ignored in water balance 2010. The model produces patterns consistent calculations. with observations. We show that variability in lake carbon fluxes are related to some simple The presented study investigates the hydrologic metrics, such as the fraction of groundwater component in the water balance for hydrologic export as evaporation. This can then a lake located on the island of Funen, Denmark. predict important carbon processes and fluxes The lake rests upon 20 meter of low permeable for the region. Hydrologic characteristics were till moraine clay which overlays an artesian evenly distributed across lake sizes; therefore, aquifer, as indicated by piezometric heads and median areal lake carbon emissions and burial the occurrence of a spring located on a small across the lake size gradient were similar, which island on the lake. Evaluation of the water meant that large lakes constitute an balance combines results from continuous water overwhelmingly large proportion of the total lake quantitative and qualitative measurements at 11 carbon flux for the region. Preliminary results surface inlets, 1 outlet and at the spring. forecasting behaviors over the next 50 years Furthermore, in order to understand the under climate change suggest dramatic changes physiography of the lake–aquifer system, in hydrologic and biogeochemical characteristics geophysical surveys are conducted. The in the region. measured water fluxes shows an important discharge of groundwater to the lake, supported by isotopic analysis. Groundwater modelling is used to validate the measured water balance of ORAL the lake.

Investigating groundwater contribution to lakes in clay ORAL dominated catchments Geo-hydro-ecological factors affecting Jacob Kidmose1, David Lajer Juul Kristensen2, Catharina Simone Nisbeth2 and Søren Jessen2 the distribution of endangered 1Geological Survey of Denmark and Greenland, species of Viiankiaapa mire, in ore 2University of Copenhagen prospecting site

Kirsti Korkka-Niemi1, Anne Rautio1, Paula Bigler1 Groundwater discharge to lakes is normally and Susanne Åberg1 investigated in geological environments 1University of Helsinki, Department of geosciences and dominated by permeable, high hydraulically geography conductive sediments, which can facilitate the groundwater-surface water interaction. This includes, for example, lakes set in glacial Potential impacts of ore prospecting, as well as meltwater outwash planes comprising coarse- mining development activities, are often related grained sandy aquifers. In other investigations, a to surface and groundwater resources and their sand, chalk, or other water baring interactions. A prominent Cu-Ni-PGE sulphide hydrogeological units, are in contract with some discovery named Sakatti has been discovered parts of the lake, either in a bathymetrical deeper below the Natura 2000 protected Viiankiaapa part, or in a horizontal zone of the lake. Few mire, in Northern Finland. It is important to studies has been carried out in hydrogeological understand the possible association of the mire settings where the upper 10-20 meters near vegetation with groundwater–surface water surface geology are dominated by low permeable

223 interactions, as well as the geochemical features nutrient import pathways need to be precisely of the local bedrock. quantified. Nutrient loading via some pathways, for example streams, can be easily quantified This study aims to answer the question of how quite accurately. The estimation of nutrient much the hydrological and hydrogeochemical import to lakes by lacustrine groundwater factors control the patterns of endangered discharge (LGD) is usually much more difficult. vegetation in Viiankiaapa mire. Especially in the We discuss some reasons why LGD has often been areas rich in Hamatocaulis vernicosus, underestimated and disregarded in lake nutrient groundwater recharge-discharge patterns have budgets. We give a brief overview of been compiled on the basis of data collected by measurement techniques, and present volumes, field studies, thermal infrared (TIR) remote concentrations and loads reported in literature sensing and laboratory analyses. Groundwater for LGD. Most measurement techniques are based flow patterns have been determined by on separate determinations of seepage volume measuring water tables in observation wells and and nutrient concentration of exfiltrating peat layers. Water samples (N=137) have been groundwater, and then multiplying both values. taken from groundwater and from peat layer, in Concentrations of groundwater compounds vary order to determine the variations in water along the flow path from the catchment to the chemistry including stable isotopes, dissolved lake. Especially the aquifer-lake interface is often silica, main ions, pH, EC, DOC and trace elements. considered a reactive zone. We describe the fate TIR survey using unmanned aerial vehicle has of nitrogen and phosphorus on their subsurface been used in order to observe groundwater pathway from the catchment through the reactive discharge locations in the mire and to assess if interface into the surface water body. As a case endangered species prefer groundwater study we present results from Lake Arendsee influenced habitats. (Germany) where LGD is the major driver of intense eutrophication in the lake. More than 50 Temperature anomalies were detected, % of the total P load is of groundwater-borne indicating cold groundwater discharging into the origin in this case. soil surface at some locations in the studied mire. Groundwater and surface water chemistry revealed significant vertical and horizontal variation. Geochemical stratification in peat ORAL layers could be observed in pH, EC, stable isotopes and some dissolved elements. "Translating" a density-independent groundwater model into a SEAWAT

model ORAL Thomas Ljungberg1 Lacustrine groundwater discharge 1Department of Geoscience, Aarhus University. and its relevance for eutrophication In coastal regions, the higher density of the saline Jörg Lewandowski1, Karin Meinikmann1, Gunnar groundwater influences the flow pattern of the Nützmann1 and Donald O. Rosenberry2 lighter fresh/brackish groundwater as it makes 1Leibniz-Institute of Freshwater Ecology and Inland its way to the sea. In order to get the best possible Fischeries and Humboldt University Berlin, 2US understanding of the flow patterns when Geological Survey, Denver, Colorado, United States modelling such coastal aquifers it is necessary to take the density difference into account, e.g. by Eutrophication is still a major threat to lakes. setting up a SEAWAT model. However, SEAWAT Typical anthropogenic nutrient sources include can easily become unstable if the cell volumes fertilizers, manure and sewage. As a first step across the model are not uniform, and it does best towards an effective lake management all if several model layers represent each geological

224 unit [Guo & Langevin, 2002]. These requirements The Geological Survey of Denmark and Greenland make it difficult to assign values of hydraulic has in collaboration with Aarhus University parameters to the model, as the geological units recently started developing methods to assess rarely are uniformly distributed across the the chemical and quantitative interaction modelled area. Besides this, when considering between groundwater bodies, rivers, lakes, density differences and solute transport, the coastal water and GWDTE. The task is to review complexity of the calculations means that the national monitoring programs in terms of how runtime of such a model is much longer than for a well the data collection on hydrological and density-independent model of the same system. chemical data capture the potential interaction In my Master's thesis I set up a 5-layer density- between the around 400 Danish groundwater independent MODFLOW model with non- bodies and surface water bodies. The hydraulic uniform cell volumes, and calibrated it from contact between the groundwater, rivers, lakes measurements of hydraulic head. Subsequently, and coastal water will be quantified using a this model was "translated" into a 10-layer national hydrological model for Denmark. Results density-independent model with uniform cell and experiences obtained on the various parts of volumes, and then further developed into a the hydrological cycle will be presented. The SEAWAT model, and it was shown that these work is funded by the Danish EPA. three models produced very similar results, as far as hydraulic heads go. In this talk I will present the technique that was used for translating the ORAL model, and show that the models do indeed produce similar results. Using the stable oxygen isotope of

phosphate as a tracer for various phosphorus sources to Lake Nørresø, ORAL Denmark.

Developing methods to assess Catharina S. Nisbeth1, David W O’Connell2 and quantitative and chemical contact Søren Jessen1 between groundwater and the 1University of Copenhagen, Dept. of Geosciences and various surface water bodies in Natural Resource Management, Copenhagen, Denmark, 2Department of Civil and Environmental Engineering, relation to update of river basin Trinity College Dublin, College Green, Museum Bui management plans in Denmark

Bertel Nilsson1, Lars Troldborg2 and Lærke Eutrophication of freshwater ecosystems is in Thorling3 particular sensitive to phosphorus input. Thus, 1Geological Survey of Denmark and Greenland (GEUS), identifying the different phosphorus sources and Øster Voldgade 10, 1350 Copenhagen, Denmark., their relative fraction of the total phosphorus 2Geological Survey of Denmark and Greenland (GEUS), load is essential for restoration and improvement C.F. Møllers Allé 8, Bygning 1110, , Denmark., of eutrophic aquatic ecosystems. Analyzing the 3Geological Survey of Denmark and Greenland oxygen isotopes of phosphate (δ18Op) of (GEUS),C.F. Møllers Allé 8, Bygning 1110, 8000, phosphate in the various PO fractions could Denmark. 4 provide the necessary knowledge for tracing the

origin of the different phosphorus sources. The European Water Frame Directive (WFD) sets Furthermore, δ18Op could also be used to identify out objectives for the water environment. These which sources are most significant in the include the protection of, enhancement and degradation of the associated freshwater restoration of surface water, groundwater and ecosystems at a local scale. The method utilizes groundwater dependent terrestrial ecosystems that the P-O bond in the orthophosphate, is (GWDTE). resistant to inorganic hydrolysis at temperatures

225 and pH levels found in natural abiotic aquatic Understanding P cycling in the terrestrial ecosystems. Subsequently, the δ18Op will reflect hydrosphere is important to manage ecosystems. the isotopic signature of the sources 1. However, We conduct a cross-disciplinary study of biological activity alters the source δ18Op groundwater P cycling by comparing the current signatures, which leads to an isotopic equilibrium water and P balance of a 70 ha lake (Nørresø, Fyn, between the ambient water and the phosphate 2. Denmark) in a clayey till dominated landscape to the lake’s Holocene trophic history, as retrieved This method is contingent upon an extended from sediment cores. The diatom and pigment 18 knowledge of the δ Op signatures from different records of core samples with 14C ages predating phosphate sources. Nonetheless, the various human influence (>6000 yr BP) indicate that the source signatures have not yet been entirely lake was never P-poor but rather meso- to evolved and more research has to be conducted eutrophic. The current lake water balance in order to constrain these signatures further. indicates a ~35% groundwater contribution, while ~65% comes from about ten ditch streams This study focuses on identification of the δ18Op and direct precipitation. A groundwater-fed signatures for the main phosphate sources to the spring at 1 m elevation above lake level exists on eutrophic lake, Nørresø, in Denmark. The aim was a small island and shows that there is an artesian to i) identify which of the phosphate sources aquifer beneath the confining till. Furthermore, constituted the largest fraction of the total metre-scale circular ice holes during the winter phosphate input to the lake, and ii) investigate if supports groundwater discharge to the lake from some of the sources in fact came from the same an artesian aquifer via discrete discharge zones in place of origin. the lake bed. The spring water is anoxic, ferrous, and contains 130 µg P/L. Similar water quality and total-P contents of 150-390 µg/L are ORAL observed in artesian glaciofluvial sand probed by water supply wells distanced 0.5 to 2.7 km from Trophic state control of groundwater- the lake. If the P concentration of the spring is fed ecosystems by groundwater- representative for the artesian aquifer, the borne phosphorus aquifer’s groundwater discharge constitutes ~90% of the external source of P to the lake. The Catharina Simone Nisbeth1, Jacob Kidmose2, combined data suggest that geogenic P may be Kaarina Weckström3, Kasper Reitzel4, Bent Vad mobilized within and transported through Odgaard5, Aia Aistrup Eriksen5, Ole Bennike6, aquifers and may ultimately control the trophic Bertel Nilsson2, Lærke Thorling7, Suzanne state of groundwater dependent ecosystems. McGowan8, Anders Schomacker9, Marie-Louise Siggaard-Andersen9, David Lajer Juul Kristensen1 and Søren Jessen1 ORAL 1Department of Geosciences and Natural Resource Management, University of Copenhagen, 2Department of Hydrology, Geological Survey of Denmark and Transport and transformation of Greenland, 3Department of Environmental Sciences, nitrate in a riparian wetland University of Helsinki, 4Department of Biology, University of Southern Denmark, 5Department of Rasmus Jes Petersen1, Christian Prinds1, Bo Geoscience, Aarhus University, 6Department of Marine Vangsø Iversen1, Charlotte Kjærgaard2, Søren Geology, Geological Survey of Denmark and Greenland, Jessen3 and Peter Engesgaard3 7Groundwater and Quaternary Geology Mapping, 1Department of Agroecology, Aarhus University, Geological Survey of Denmark and Greenland, 8School 2SEGES, 3Department of Geosciences, Copenhagen of Geography, University of Nottingham, 9Natural University History Museum of Denmark, University of Copenhagen

Even though riparian wetlands have been intensively studied during the past 30 years these

226 areas still function as a “black box” with regards study, we used the method for locating discharge to removal of nitrogen input from surrounding from tile drains into lowlands and water bodies areas. To comply with regulations of the (lakes, streams, ditches etc.). Tile drains are one European Water Framework Directive, Danish of the main end points for nutrients applied to the agriculture is to reduce the load of nitrogen from agricultural fields and a fast conduit. When agricultural fields to fresh water bodies. One studying the function of riparian lowlands and initiative is moving from a uniform regulation of wetlands as nutrient buffer zones, it is essential nitrogen application to a spatially differentiated to know 1) the location of drainage input into the regulation where less fertilizer should be applied buffer system and 2) the flow path of the water. to vulnerable areas. This leads to the The TIR imagery was collected by a UAV (eBee identification of vulnerable and robust areas, in from SenseFly) with a thermal camera which riparian wetlands plays an important role. (ThermoMap from SenseFly) at early spring in 2016 and 2017. The surveys are conducted in The present case study investigates the transport cold periods where discharging drainage water and transformation of nitrate entering a riparian (and groundwater) are warm anomalies wetland via drain water from surrounding compared to the cold soil. We hereby obtain maps agricultural areas. The drain pipes are cut off at of the area’s thermal signature at the time of the hillslope and drain water irrigates the flight. The drainage outlets are easily observed as wetland. Depending on the saturation state of the sharp point sources of warm water and surface wetland soils and the amount of water entering flows are also remarkably clear making TIR a during precipitation events, a part of the water usable approach for mapping of flow direction in infiltrates into the wetland sediments and travels low-gradient areas such as riparian lowlands and towards the stream. Some of the infiltrated water wetlands. The flow systems can be compared to may be caught by drains within the wetland soils topographically modelled surface flow using and transported directly to the stream. The high-resolution DEMs and flow direction remaining water can be either evapotranspired algorithms. or transported directly to the stream via overland flow. Preliminary results show an efficient denitrification of nitrate infiltrating into the studied wetland soils. The nitrogen removal ORAL efficiency at different drain outlets seems then to be largely controlled by the amount of drain Using land-based and waterborne water input relative to the infiltration capacity of hydrogeophysical methods to infer the wetland soil. geological controls on groundwater discharge to a lake

Eva Sebok1, Sachin Karan2 and Peter Engesgaard3 ORAL 1Department of Geosciences and Natural Resource Management, University of Copenhagen; COWI A/S, Mapping surface flow in low-gradient 2Geological Survey of Denmark and Greenland (GEUS), areas with thermal remote sensing Department of Geochemistry, 3Department of Geosciences and Natural Resource Management, Christian Prinds1, Rasmus Jes Petersen1, Rene University of Copenhagen Larsen1, Mogens Greve1 and Bo Vangsø Iversen1 1Aarhus University, Dept. of Agroecology The geological heterogeneity of stream and lake sediments can lead to spatially heterogeneous Thermal infrared (TIR) imagery has long been groundwater discharge to surface waters, which used for mapping groundwater-surface water can be detected by Distributed Temperature interactions and mainly for locating areas of Sensing (DTS). The heterogeneity of underwater groundwater seepage in lakes and shorelines sediments can also be mapped by waterborne (Rundquist et al. 1985, Banks et al. 1996). In this geophysical surveys such as floating electrode

227 Electrical Resistivity Tomography (ERT). lakebed, as well as the drastic changes of the lake However, ERT and DTS measurements are rarely stage throughout the year (160 cm), may combined to detect the spatial variability in influence LBF efficiency. Several field methods groundwater discharge to surface waters. The were applied to understand the temporal aim of this study was therefore to: (1) test the use behavior of the transient seepage patterns and to of DTS in a deeper lake environment up to 4 m of investigate the (in)filtration potential of the near- water depth and (2) assess if sediment lake area. Based on data (hydraulic conductivity heterogeneity indicated by waterborne values, borehole information, resistivity profiles, geophysical surveys can result in potential sediment samples) about the geological setting of discharge patterns detected by DTS. the area, a conceptual 2D/3D geological model was developed in GeoScene3D. In addition to Lake Tissø is the fourth largest lake in Denmark hydraulic field and tracer data the geological with a surface area of 12.3 km², maximal depth of model was used to develop a 2D/3D 13 m and a present surface water extraction of 5 hydrogeological conceptual model to examine the million m³/year. At the Eastern lakeshore groundwater-lake interaction. Finally, a 3D flow- potential locations of groundwater discharge in and multiple tracer transport model was the near-shore region were mapped by DTS. developed in MODFLOW and MT3D to explore the Sediment properties were surveyed with both impacts of a pumping test carried out at the field on-land and waterborne ERT and the resulting site for assessing the potential for LBF. resistivity data were used as input to a 2D flow model aimed to test the potential discharge locations interpreted from the DTS survey. Our results show that potential patterns of POSTER groundwater discharge agree well with the location of a higher resistivity/coarser material An evaluation of tools to standardise zone detected 60-140 m offshore. The numerical groundwater resource assessment flow model also confirmed that the surveyed for coastal areas in Sweden sediment distribution can result in discharge patterns detected by DTS measurements. Ingmar Geuze1 and Roland Barthel1 1Department of Earth Sciences, University of Gothenburg, Sweden

POSTER Groundwater problems in coastal regions are Potential for Lake Bank Filtration at usually not associated with the sparsely Lake Tissoe, Denmark populated shores of water-rich Scandinavia. However, the combination of local geology and Franciska Amalie Køhn1, Eva Sebok2 and Peter the specific conditions of water usage create Engesgaard1 challenges even there. Along the Swedish coast, 1Department of Geosciences and Natural Resource much of the groundwater occurs in fractured Management, University of Copenhagen, 2Department bedrock or in relatively small, shallow, and of Geosciences and Natural Resource Management, isolated Quaternary sedimentary formations. University of Copenhagen; COWI A/S Those aquifers are usually not considered

relevant as water resources and have thus In collaboration with Kalundborg Forsyning previously not received much attention from (KALFOR), COWI is currently investigating the water authorities or researchers. Nevertheless, a potential of Lake Bank Filtration (LBF) at Lake possible long-term solution to the increasing Tissø, Denmark. Challenges associated with pressure on water resources could be found pumping up groundwater in close vicinity to the within the utilisation of these groundwater lake are the temporal variability in the systems. groundwater-lake seepage, where clogging of the

228 No attempt has been made to review and evaluate foreland likely under permafrost conditions the results of individual investigations carried during LGM and experiencing a relative rise in sea out by different municipalities in coastal areas. level during the Holocene. Airborne Thus the status of coastal groundwater systems electromagnetic surveys indicate saltwater up to in Sweden remains unclear and a standard 20 km inland. Reclaimed from the Wadden Sea, methodology that could be applied for these low-lying areas have been protected from groundwater resource assessment in Swedish flooding by dikes for the last 200 years and have coastal areas does not exist. Hydrogeological been heavily drained. In order to identify the investigations involve high costs, meaning that origin and dynamics of the saltwater and the role performed investigations should yield reliable of heterogeneous geology, a 3D regional-scale results that fill multiple uses. With the project density-driven flow-and-transport model was presented here, an attempt is made to develop a used. The formation of saltwater intrusions was standard methodology for the specific simulated during the Holocene taking into hydrogeological conditions on the Swedish account changing conditions caused by flooding coastline. and dike construction. The results reveal that the saltwater originate from a combination of We present firstly the results of an online survey remnant (pre-Holocene) seawater, Holocene carried out among Swedish coastal transgression and recent drainage. Main features municipalities, illustrating the various types of controlling the progression of the modern problems, methods of investigation used and seawater into the coastal aquifers are buried measures taken. We secondly review various valleys providing preferential flow path for methods commonly applied, in conjunction with saltwater in combination with an extensive a proposal for a standard methodology that may Miocene clay layer hindering saltwater intrusion be applicable on a national level. and land management with dike construction transforming the shallow aquifer from being salt

saturated during flooding to being refreshed after POSTER the dike was built.

Formation of saltwater intrusions in the low-lying coastal areas during the POSTER Holocene in Southern Jutland Temperature profiles to measure Rena Meyer1, Peter Engesgaard1 and Torben O. groundwater discharge to Ringkøbing Sonnenborg2 Fjord. 1Department of Geosciences and Natural Resource Management University of Copenhagen, Denmark, Joel Tirado-Conde1, Carlos Duque2, Sachin Karan3 2Geological survey of Denmark and Greenland (GEUS), and Peter Engesgaard1 Copenhagen, Denmark 1Department of Geosciences and Natural Resource

Management. University of Copenhagen, 2Department 3 Aquifers in low-lying coastal areas are threatened of Geoscience. Aarhus University, Department of Geochemistry. Geological Survey of Denmark and by saltwater intrusions, as a result of low head Greenland (GEUS) gradients, high abstraction rates and land management, and climate change. Understanding the evolution and driving mechanisms of Groundwater discharge or upwelling plays an saltwater intrusions can help to adapt water important role in the ecological and hydrological management strategies to mitigate the impact. dynamics in coastal areas, bringing fresh water The 1700 km2-large study area in the border inputs to saline water systems. However, locating region between Denmark and Germany, adjacent it both in space and time as well as quantifying to the Wadden Sea, has undergone a complex how much groundwater flows upward to coastal (hydro-)geological evolution; lying in the glacial areas requires a big effort since these are very

229 heterogeneous systems. Seasonal changes in 11.3. Integrated Hydrological rainfall, temperature and water level lead to temporal variability, while variations in the Modeling hydraulic properties and hydrological processes can generate spatial heterogeneity, making the process of measuring those fluxes complicated ORAL and requiring multiple measurements to obtain Assessing the impact of model accurate results. Furthermore, the non-steady position of the fresh water-salt water interface structure on uncertainty in increases the uncertainty surrounding these integrated hydrological modelling processes. Using temperature as a tracer, the groundwater inputs to a surface water body can Michael Butts1, Sílvia Leirião1, Douglas Graham1 be calculated by means of solving analytically the and Jeremy Kobor2 1 2 conduction-convection equation, shortening DHI, Agern Alle 5, DK 2970 Denmark, Now at O’Connor Environmental, Inc., PO Box 794, Healdsburg, considerably the amount of field work needed to CA 95448,USA obtain groundwater upwelling fluxes. In this work groundwater upwelling in the Ringkøbing Fjord coastal area was obtained using two Understanding and quantifying model methods: direct upward flow measurements and uncertainty is essential for decision-making in indirect flow calculations with shallow fjord bed water resources management. Model uncertainty temperature profiles. These two different sets of comes from the forcing data (rainfall, data are compared in order to assess their evapotranspiration), the boundary conditions feasibility to map and quantify upwelling. and the parameters. It also arises from the model Addressing the strengths and weaknesses of each structure, including the process descriptions, method, we aim to better constrain the reliability numerical approximations, and geological of them in order to improve the quality of the data models. In practice, we trade-off the complexity collection process. of the model required to capture the relevant catchment processes against the accuracy needed

to make reliable decisions.

In this paper, we examine the impact of model structure on model calibration and prediction uncertainty in three case studies. The first study assesses the impact of land use change in the Napa Valley, USA. We present a model framework that allows for a range of model structures, which we used to calibrate in separate steps the surface

water and then the groundwater. In the second case, we systematically explored different models and model structures for rainfall-runoff processes in the Blue River, USA. In this case, the uncertainties in the predicted flows due to model

structure were larger than uncertainties from both the rainfall and the model parameters. Finally, we are currently using the same modelling framework to investigate the impact on model structure and calibration on an

integrated hydrological model of the Hinds catchment, New Zealand where changes in water allocation and land use may result in unacceptable flow reductions in an extensive

230 coastal spring system. The aim is to explore (Kjærgaard et al., 2011-2015) are used for different facets of risk calculation based on Bayes evaluating any gain of the implementation of the equation to determine whether the proposed drain concepts on dynamics and quantity. changes lead to unacceptable flow reductions

ORAL ORAL Integrated hydrology in the Can new drain concepts improve local COHERENT project drain flow performance in catchment 1 1 scale modelling (MIKE SHE)? Morten Andreas Dahl Larsen , Kirsten Halsnæs and Martin Drews1 Ida Bjørnholt Karlsson1, Anker Lajer Højberg1 and 1Technical University of Denmark Bo Vangsø Iversen2 1Geological Survey of Denmark and Greenland (GEUS), The COHERENT project, funded by Innovation 2Institut for Agroøkologi, Aarhus Universitet Fund Denmark, was instigated on Nov. 1 and

addresses risks in the coastal zone of both natural Nitrate leaching to groundwater, surface water and anthropogenic origin and the interplay and oceans are an increasing issue for areas with between them. The presentation will present intensive agriculture. The drainage flow system is work led by the presenting author which important for the transportation of water but also specifically addresses the impact of works as a potential fast track with limited inland/watershed hydrology on natural hazards reduction for nitrate pollutants. As the need for in the coastal zone, most often flooding events on catchment models that can simulate and predict coastal cities, and the interactions with nitrate transport and degradation grows, so does adaptation practices, urban development and the necessity for models able to adequately management. The topic is highly relevant due to represent drainage flow on local scale. projected increases in frequencies and magnitudes of natural hazards in the coastal zone In this study (TReNDS, Højberg et al. 2016-2018) under current climate change potentially the aim is to test whether or not knowledge about resulting in high social and economic costs. the mechanisms controlling drain flow creation can be used to develop new drain concepts; that The physical impact of coastal flooding is made can improve local scale performance. The up of mainly the impact of the storm surge itself concepts must be founded in data obtainable on as well as waves, tides and a general increase in catchment scale; as they potentially should be sea level and the assessment of potential incorporated into national modelling schemes. adaptation measures can be complex. The vulnerability can however increase for the fluvial A fully distributed hydrological MIKE SHE model part with higher stream flow and groundwater for the 101 km2 Norsminde catchment, Denmark level, with temporal scales in the order of days to is used (Hansen et al., 2014; He et al., 2015). The seasons. Another influence comes from the catchment is dominated by agriculture and an pluvial side when rainfall events occur extensive drainage network. The concepts are simultaneously, with temporal scales in the order built on theses of differentiated occurrence and of minutes to days. A key objective of the work is parameterization for different drain types (tile, therefore to assess the influence of inland- natural and urban drain); and important watershed hydrology on the risk hazards for variables (such as TWI and clay content in the current and future conditions within the three soil, (Iversen, 2016)) controlling the generation cases of the project; Skive, Ringkøbing and of drain flow that can be accounted for within the Aabenraa municipalities. A key objective is close limitations in the MIKE SHE model concept. interaction with municipalities and stakeholders Measured drainage from eight drain flow stations

231 to reflect applied conditions and assess true POSTER projected urban development goals. Estimated variation in pesticide leaching through greens and fairways

ORAL based on detailed fate-descriptions in 12-cm soil profiles A watershed scale approach to model iron concentration in river Sachin Karan1, Nora Badawi1, Anne M. D. Jensen2 and Annette E. Rosenbom1 Markus Saari1, Hannu Marttila1, Pekka Rossi1 and 1Geological Survey of Denmark and Greenland (GEUS), 2 Heini Postila2 Department of Geochemistry, University of Copenhagen, Department of Geosciences and Natural 1Water resources and environmental engineering Resource Management research unit, University of Oulu, 2Water resources and environmental engineering research unit, University of Oulu Leaching resulting from treating golf courses

with pesticides is presently not well known. Numerous studies have reported increases in Although studies have shown that 90-100% of iron concentrations in freshwaters especially in applied pesticides can be microbially removed in boreal regions. The significant role of iron in turfs with a surface near thatch layer, this is not biochemical processes and element cycles makes ubiquitous. The retardation of pesticides in soils this matter of concern among research is compound specific, but also controlled by the community. With infrequent sampling (weekly hydrogeological setting that for fairways can interval) in main rivers we have limited process include the presence of wormholes. Thus, understanding to evaluate main drivers behind potential rapid preferential flow and transport the iron transport in watershed scale. To enhance may make fairways more vulnerable in regards to this, we used watershed scale SWAT model for leaching. typical clayey soiled and agriculture dominated Based on both detailed fate (degradation and river basin in Southern Finland. In this type of sorption) and hydrogeological descriptions of the watershed, the mobility of iron is dominated by upper 12-cm soil profile of golf courses, the the erosion and transportation of suspended leaching potential of tebuconazole (TBZ) through solids, especially clay particles. The strong linear six greens (three USGA and three push-up correlation between TSS, turbidity and iron greens) and of MCPA through three fairways concentration was utilized to model iron (low, medium and highly fertilized) were transportation in watershed scale. Successful estimated numerically using COMSOL model calibration and validation allowed us to Multiphysics. All the golf courses were located in study main sources for iron transport and areas characterized as macro porous clay till seasonal dynamics. Based on the modelling settings. The impact of fate processes on the results the most crucial times for iron transport leaching potential of: are late autumn rainfalls which cause significant erosion on agricultural lands. We further used the · TBZ as: model to predict future land use and climate change scenarios and possibilities to mitigate - an analytical grade compound, their joint effects to iron transport. - a commercial formulation,

- a commercial formulation in combination with a surfactant product

· MCPA as:

- an analytical grade compound

232 - a commercial formulation 11.4. Open session was evaluated numerically for greens and Hydrogeology preferential transport for fairways given the presence of a wormhole. The preliminary simulation results indicate that ORAL

- TBZ has a high potential for leaching through Skåningshave - a new major well-field the greens in high concentration on the island of Lolland (S.Denmark). - MCPA has a low potential for leaching through Development and hydrogeology. the fairways given a high degree of degradation in Kristian Bitsch1, Karl Jørgensen2 and Mikael the upper 12 cm. Jørgensen3 1Rambøll, Hannemanns Allé 53, DK-2350 Copenhagen S, 2Municipality of Lolland, Jernbanegade 7, DK-4930 Maribo, 3NIRAS, Sortemosevej 19, DK-3450 Allerød

The Island of Lolland lies in the southern part of Denmark and comprises 1242 km². The Island is very flat having an average of 7 m in altitude and

a maximum of 30 m above sea level. The surface of the Island is dominated by glacigene sediments of late Weichselian age, clayey tills and glaciofluviatile outwash sediments forming discontinuous basins. The prequaternary are

Maasthrictian-Campanian chalks in the north and Paleocene clays to the south. Non-saline groundwater forms a shallow lens with a maximum depth of 50 m in the northern 2/3 of the island. The water supply structure is based on 4 municipal and 25 community waterworks, delivering a total of 2 + 1 million m3 per year. A

new infrastructure project demands up to 450 000 m3/year. 100 000 m3/year can be delivered by the existing waterworks. In the central part of the island a widespread layer of outwash sands was recognized. The area had just been subjected

to an intensive geological and geophysical mapping using all existing well data, seismic profiling and extensive SkyTem mapping, which had been used to make a new regional geological and hydrological model of the area. This model was used as the basis for producing a detailed well field model later improved with additional

data from MRS soundings and 6 new wells including a major testpumping. This led to a new model and an abstraction strategy minimizing the impact on the surrounding wetlands including the large NATURA 2000 area, the Maribo Lakes.

233

ORAL POSTER

Investigating controls on Sustainable Water Resources in groundwater drought hazard in Iranian Qanats Scandinavia Fataneh Hajatpour Birgani1 and Rodney Stevens1 1Department of Earth Sciences, University of Ezra Haaf1, Pekka M. Rossi2, Bjørn Kløve2 and Gothenburg Roland Barthel1

1Department of Earth Sciences, University of Gothenburg, Gothenburg, Sweden, 2Water Resources Qanats are water-transport tunnels with a lower and Environmental Engineering Research Unit, slope than the groundwater surface they University of Oulu, Finland intersect, typically in arid regions with alluvial-

fan geomorphology. Since the traditional qanat Drought has historically been a minor issue in technique (Persian origin in 1st millennium) Sweden and Finland, countries of high water relies solely on gravitational drainage to assess abundancy. However, since late 2015 into 2017 deep groundwater resources, they are suitable in large parts of Sweden and Finland have been rural areas, and the over 50,000 active qanats in classified with medium to high risk for drought the Middle East are a crucial supply for drinking impact according to the drought monitor of the and agricultural water for numerous population JRC of the European Commission. In Sweden, the centers. Qanat sustainability is related to changes Swedish Geological Survey (SGU) has reported in climate, population and land-use. Importantly, falling groundwater levels through their groundwater lowering by excessive pumping monitoring program, particularly during the decreases or stops qanat discharge. We have summer in Southeastern Sweden. By spring of considered the qanat sensitivity to these 2017, this problem had intensified and influences by characterizing the geomorphologic, groundwater drought had been registered in geologic, climatic and resource-management large parts of the country. Impacts on society associations in selected case studies. Debris-flow have been rules on water use, irrigation ban and alluvial fans can be expected to have steeper private drinking water wells running dry in groundwater gradients than do stream-flood certain regions. In Finland, groundwater levels fans. This is due to the greater surface slope and have been periodically reported to be low during the lower hydraulic conductivity associated with the 2000s based on the monitoring network by fine-grained, debris-flow deposits. The internal Finnish Environmental Institute, which has stratigraphy can further reflect the fan evolution caused worries in water usage. Although some of over time and further influence reservoir the Swedish aquifers are recovering as of autumn character. This poster presents a problem 2017, the drought is still persisting in many analysis of qanat resources, their future potential systems. The current understanding of severity and vulnerability. The study is a part of the and persistence as well as propagation of drought KERMIT project (Knowledge Exchange for into groundwater for Swedish and Finnish Resource Management and International Trust, groundwater systems is very limited. Here, we see separate abstract by Stevens et al., this investigate patterns of groundwater droughts volume), which uses the endemic knowledge of historically and geographically. Furthermore, we refugees in Sweden to develop case studies and explain the sensitivity and persistence based on cooperation networks both within Sweden and geologic and environmental controls for different abroad. types of groundwater systems with decision tree learning.

234 POSTER

Fracture minerals investigations at POSTER Kyläniemi, Southern Finland: Stable water isotopes in snow: Paleohydrogeological implications Changes throughout the season in Minja Seitsamo-Ryynänen1 Finse, Norway 1Department of Geosciences and Geography, University of Helsinki, Finland Evelien van Dijk1 1University of Oslo

In crystalline bedrock environments, a bulk of groundwater flow occurs in channels provided by Here we present changes of stable water isotopes fracture networks. Isotopic compositions of within the snow pack throughout one season precipitated fracture minerals can be utilized to from the Finse area in southern Norway. gain information about the origin, age and Stable water isotopes have become a key element compositional evolution of the deep in hydrological and atmospheric research topics. groundwaters in crystalline bedrock. They can be used to get an understanding about The aim of this study is to investigate the the changes in the snow pack throughout the hydrogeochemical evolution of groundwaters in snow season. For this study, 215 samples from the crystalline bedrock at Kyläniemi, located in several snow pits were analyzed for stable water Southern Finland near Salpausselkä end- isotopes throughout the snow season 2016-2017. moraines. Fracture mineral samples containing Sites were selected by looking at the snow drift calcite and/or pyrite were collected from water- patterns and snow accumulation to get an conducting fractures at the upper ∼500 m of the undisturbed stratigraphy. The Lagrangian bedrock. These fracture filling calcites occur as particle model Flexpart will be used to model the thin ∼200–350 μm crusts on open fracture moisture sources for this snow pack to get a fuller surfaces, and the pyrites as small euhedral understanding of the snow processes and the crystals. atmospheric part of the hydrological cycle. As snow is a water storage it is important to In addition to optical microscopy and chemical understand which processes play a role within composition analyses, the calcite fillings are the snow pack during accumulation and melt and analyzed for the isotopic composition on carbon how these processes influence the deformation and oxygen, and the pyrites for the isotopic and melting. By understanding how the snow composition on sulfur. The δ18O values of the melt phases change, better predictions about the latest calcite generations are expected to show spring floods can be estimated. Modeling the values indicating the influence of glacial melt moisture sources is important to give a better waters. The δ13C values of calcite and δ34S values understanding of the atmospheric part of the of pyrite should demonstrate the evolution of hydrological cycle. The atmospheric part of the redox environment fronts. cycle is not yet fully understood, and by using the isotopic composition of snow to track air parcels The results of this study are compared to those of back in time a better understanding can be previous studies conducted at Olkiluoto accomplished. (Sahlstedt et al. 2010, 2013, 2016) which is the chosen geological repository site for spent nuclear fuel. Unlike Olkiluoto, the Kyläniemi site rose above the sea-level in early Holocene. Thus, late-stage groundwater evolution is unaffected by brackish water intrusions related to Yoldia Sea and Littorina Sea stages.

235 12. Geophysics 12.1. Open session in Geophysics stations could greatly increase our understanding of this activity.

ORAL ORAL Data acquisition in the North and e- infrastructure by the EPOS-Norway Very deep structural contrasts across team the Northern Tornquist Zone

Kuvvet Atakan1, Valérie Maupin2 and the EPOS- Niels Balling1 Norway Consortium3 1Department of Geoscience, Aarhus University, Aarhus, 1Department of Earth Science, University of Bergen, Denmark Norway, 2Department of Geosciences, University of Oslo, Norway, 3see https://epos-no.uib.no The Tornquist Zone defines a major tectonic lineament across Europe. It extends from the Integrating multidisciplinary transnational Black Sea to the North Sea and separates old infrastructures is a key challenge for solid Earth Precambrian cratonic units to the east and Science. EPOS (European Plate Observatory northeast from younger Phanerozoic tectonic System) is a European project to integrate units in Central and Western Europe. In its existing research infrastructures within the fields northern part, this tectonic zone splits into two of seismology, geodesy, geophysics, geology, rock main elements, the Sorgenfrei-Tornquist Zone physics and volcanology in Europe. Within this (STZ), trending northwest from around the island framework, the EPOS-Norway project is working of Bornholm to the Skagerrak Sea, and, further in several directions, from developing new e- south, the Thor Suture between palaeo- infrastructure to integrate Norwegian Solid Earth continents, Baltica and Avalonia. data to improving the monitoring capacity in the Arctic, including Northern Norway and the Arctic This presentation is focused on the STZ. Here, a islands of Jan Mayen, Bear Island and Svalbard. wide range of geophysical studies reveal marked Two main recent developments will be differences in crustal and upper-mantle presented. structure. From shield units in southern Sweden to deep basins in Danish areas, we observe A prototype of the e-infrastructure to visualize pronounced crustal thinning, increased surface and analyze geophysical and geological data will and upper-mantle heat flow and different gravity be demonstrated, and we will also present how and magnetic field anomalies. From traveltime we are working to implicate the scientific (Medhus et al. 2012; Hejrani et al. 2015) and community in the development of the software. surface wave (Köhler et al. 2015) tomography, very deep structural contrasts, down to 250-300 We will also report on the results from the survey km, are recently revealed along the STZ as well as conducted in August-September 2017 to further north. A marked, narrow lithosphere determine the exact locations of the six planned transition zone is outlined with high upper- co-located seismological and geodetic stations on mantle P- and S-wave velocity below Swedish Svalbard. The survey was conducted with the shield areas and low velocities below Danish vessel Ulla Rinman who set out from Basin and most of southern Norway. Despite Longyearbyen with a crew of scientists and markedly different crustal structure between technicians from UiB, Kartverket and UNIS. Denmark (deep basins) and southern Norway Svalbard is currently experiencing increased (Scandinavian Mountains), similar low upper- seismic activity in Storfjorden and continued mantle velocities are observed. These results seismic activity in Nordaustlandet, and the new emphasize the significance of the STZ and the

236 importance of including deep structural magnetic components and use them for dating information in understanding different tectonic Quaternary tectonic episodes e.g. at Albæk Hoved evolution and associated contrasting geological where Eocene sediments were tilted by the ice. environments.

ORAL ORAL Crustal structure across coastal Magnetic characteristica of Paleogene Nordland (Norway) from teleseismic sediments in Jutland, Denmark. receiver functions

Claus Beyer1, Per Nørnberg2 and Claus Heilmann- Anne Drottning1, Christian Schiffer2, Stéphane Clausen2 Rondenay1 and Lars Ottemöller1 1CB-Magneto, 2Institute of Geoscience, Århus University 1University of Bergen, 2Durham University

During the last decades we have carried out The uplift and erosional history of the coastal palaeomagnetic work on the Cenozoic sediments Nordland region, in northwestern Norway, is of in Denmark. Eocene sediments investigated are: great scientific interest as it may have caused The Ølst Formation, including the basal Eocene hydrocarbons to accumulate differently than Stolle Klint Clay, Røsnæs Clay and Lillebælt Clay expected across the area (Nyland et al. 1992). Formations, and two upper Eocene members of Elucidating this history requires a solid the Søvind Marl Formation: the Moesgård and understanding of crustal structure in the region. Kysing members. The magnetic properties vary To help address this need, 26 broadband seismic according to the geochemic environment, stations were deployed across coastal Nordland biogenic factors and mineralogy, particularly from 2013 to 2016, as part of the broader concentration of magnetite. NEONOR2 project. Here, we present preliminary results of an inversion of teleseismic receiver The Stolle Klint Clay has a weak remanent functions computed at these stations, with the magnetisation due to the anoxic depositional aim to map the crustal velocity structure and environment, with its organic content causing Moho depth beneath the region. We employ an degradation iron oxides. The overlying Ølst automated workflow based on the methods of Formation has a stronger, well defined remanent Schiffer (2015) and Svenningsen and Jacobsen magnetisation due to its favourable environment (2007), which inverts simultaneously receiver for preservation of iron oxides. In both units the function waveforms and Ps polarizations at remanent magnetisation is sitting in discrete frequencies to obtain S velocity structure multidomaine grains. A change to high-intensity in the crust and uppermost mantle. The data magnetisation occurs in the Røsnæs Formation quality is highly variable from one station to the due to that the magnetic grain fractions are other. Some stations yield a very clear Moho pulse dominated by single domaine grains (>90%) at relatively shallow depths (~20-30 km). throughout the rest of the Eocene up till the base Conversely, other stations return ringy receiver of the Moesgaard Member. Separation of the functions that are either associated with complex magnetic phase and subsequent analysis by crustal layering or, more likely, with strong near- translucent scanning electron microscoping station noise and scattering. The robustness of (TEM) identified magnetite grains smaller than the method and the results is tested with 50 nanometers, similar to the ones produced by synthetic datasets. The most robust results from magnetotactic bacteria. Their occurrence in this high signal to noise ratio stations are integrated stratigraphic interval may be due to the warm into regional maps of seismic velocities and Moho clima and/or the marine sedimentary facies. The depth. result is an excellent palaeomagnetic recording which makes it possible to define secondary

237 ORAL

ORAL Relative relocation of earthquakes along the northern North Atlantic The 3D stress field of Nordland, ridge using Rayleigh waves northern Norway - insights from numerical modelling Christian Grude Kolstad1, Valérie Maupin1, Tormod Kværna2, Steven Gibbons2 and Asbjørn Sofie Gradmann1, M Keiding1, O Olesen1 and Y Breivik1 Maystrenko 1Department of Geosciences, University of Oslo, Norway, 1Geological Survey of Norway, Trondheim, Norway 2NORSAR, Norway

The Nordland area in NW Norway is one of the Earthquake activity along mid-oceanic ridges is tectonically most active areas in Fennoscandia. It particularly difficult to monitor due to the lack of exhibits patterns of extension, which are in nearby stations. Precise location of earthquakes contradiction to the first-order regional stress is however required in order to reach a better pattern that reflects compression from ridge- understanding of the relation between the push. The regional stress field stems from the seismic activity and the tectonic mechanisms at interaction of ridge push and GIA (glacial isostatic play during the geological history of the mid- adjustment); the local stress field mainly results oceanic ridges. from gravitational stresses, as well as the flexural effects of sediment erosion and re-deposition. We present the results from the relative relocation of 153 shallow moderate-size We develop 3D finite element numerical models earthquakes along the North Atlantic Mid- of crustal scale, using existing geometric Oceanic ridge from Iceland to Svalbard. Rayleigh constraints from previous geophysical studies. waves are usually a major and well-recorded Internal body forces, induced by variations in seismic phase for mid-oceanic earthquakes. density, topography or Moho depth, already yield Nearby earthquakes produce very similar significant deviatoric stresses, which are often Rayleigh waveforms even when recorded at omitted in stress models. We show that these can rather distant seismological stations, and cross- strongly influence the near-surface stress regime. correlation provides a good measurement of their Similarly, existing weakness zones (such as time delays. Injected in a double-difference faults) control the local stress field. algorithm, this can be used to relocate the earthquakes relative to each other. The mean We apply the far-field stress fields (GIA, ridge- distance shift is found to be about 8km. Visual push, sediment redistribution) as effective force inspection shows a better alignment of the boundary conditions to the sides or base of the seismicity after relocation and plotting on a high- model. This way, we can account for all stress resolution sea-bed map shows that the sources at once, but can also vary them separately earthquakes locations are better consistent with in order to examine their relative contributions to tectonic features after relocation. The relocation the observed stress and strain rate fields. is also compared with an independent study We compare our models to the stress and strain made in the same area that uses a Bayesian observations derived from different recent approach to relocate the seismic activity based on seismological and geodetic data sets. a large set of recordings of regional Pn and Sn arrivals.

238 ORAL The data are currently being processed and the first results will be presented at the conference. High-resolution seismic investigations of the Caledonian

Lower Allochthon and basement ORAL transition in Jämtland, Sweden Seismological observations of Peter Hedin1, Christopher Juhlin1, Henning Landslide and Tsunami in Karrat Lorenz1 and Alireza Malehmir1 Fjord, Greenland, June 17 2017 1Dept. of Earth Science, Uppsala University, Uppsala, Sweden Tine B. Larsen1, Trine Dahl-Jensen1, Peter Voss1,

John Clinton2 and Meredith Nettles3 During August-September 2017 we acquired 1GEUS, Copenhagen, 2ETH Zürich, 3Columbia University, high-resolution reflection seismic data in the New York

Jämtland region of west-central Sweden to increase our understanding and knowledge On June 17, 2017, a large landslide occurred in regarding mountain building processes. Of NW Greenland, around 20 km from the small particular importance is the nature and extent of village of Nuugaatsiaq, population 100 in Karrat deformation within and across the lowermost Fjord. The slide slipped into the fjord, inducing a allochthonous units of the Caledonides, the main large tsunami, which inundated much of the orogenic décollement and underlying village, producing widespread destruction – 11 Precambrian basement of the Fennoscandian houses were swept out to sea, and four people Shield. The Lower Allochthon host structures that lost their lives. strike parallel with the orogenic compression in this region. Therefore, deformation zones, faults The slide generated seismic energy equivalent to and fracture systems in the near surface are also a magnitude 4.1 earthquake, visible across the of interest since they may be important in globe. Careful examination of the seismic controlling the current hydrogeological waveforms indicates no triggering tectonic event. environment and influence ground water The landslide lit up all 30 GLISN stations circulation and the transportation of pollutants. (http://glisn.info). One station, NUUG, is located The study area is in close connection with a in the village of Nuugaatsiaq and recorded the planned 2.5 km deep borehole of the Collisional seismic energy generated by the slide and Orogeny in the Scandinavian Caledonides (COSC) responded to the ground tilt induced by the project (Gee et al., 2010) and previous regional fluctuating water levels from the resultant seismic (Juhlin et al., 2016) and magnetotelluric tsunami. (Yan et al., 2017) studies, which will allow interpretation in a regional context. The time series from NUUG clearly records both the slide and the resulting inundation events. In addition to these more scientific objectives, the Seismic waves from the landslide reaching the current project presents an opportunity to town had a duration of about 5 minutes. This long evaluate and develop equipment and duration and the relatively monochromatic, long- methodology for efficient and versatile period part of the signal that slowly increases in acquisition of high-quality multi-purpose amplitude are indicative of complex landslide reflection seismic data. We used a 500 kg Bobcat- signals. The long-period, large-amplitude mounted drop-hammer as the seismic source. tsunami waves are seen in the seismograms as Recording was done along two perpendicular signals with a period of 3 min, lasting for over 3 profiles simultaneously, using 1C and 3C wireless hours. units (20 m separation) and a high-resolution seismic landstreamer comprising 100 fully digital The long-period signals observed across the 3C MEMS sensors (2-4 m separation). GLISN network, and around the globe, are

239 consistent with a landslide source. The long- polarisations into the inversion workflow, period signal suggests failure occurred in two or something that should yield important new more stages. constraint on the composition of the crust and uppermost mantle.

ORAL ORAL Towards a new global crustal model derived from rapid receiver function Late Mesoproterozoic, inversion of GLImER data Sveconorwegian orogenic mantle preserved beneath SW Fennoscandia, 1 2 Christian Schiffer , Stéphane Rondenay , Anne reflected in seismic tomography and Drottning2 and Lars Ottemöller2 1Department of Earth Sciences, Durham University, assessed by thermal modelling 2Department of Earth Science, University of Bergen Trond Slagstad1, Yuriy Maystrenko1, Valerie

Maupin2 and Sofie Gradmann1 Teleseismic receiver functions provide a 1Geological Survey of Norway, Trondheim, Norway, relatively easy way to image structure in the 2Centre for Earth Evolution and Dynamics, University of Oslo, Oslo, Norway Earth’s subsurface. Despite its general ease of use, the method often requires substantial user input to yield stable and robust results. This is The Late Mesoproterozoic Sveconorwegian also the case for the inverse modelling of receiver orogeny in SW Fennoscandia comprised a series functions, which can yield highly variable results of geographically and tectonically discrete events depending on the choice of independent between 1140 and 920 Ma, involving accretion constraints and model parameterisation used in and partial subduction of continental fragments the inversion workflow. As a consequence, large- behind an active continental margin (Slagstad et scale applications to global datasets have been al., 2017). Today, this region is characterised by limited. We developed a generalised receiver low seismic velocities compared to other parts of function inversion approach to obtain robust Fennoscandia (Medhus et al., 2012; Gradmann et estimates of the crustal and uppermost mantle al., 2013). A channel-like zone with particularly shear-wave velocity structure. The automated low velocities in the lithospheric mantle beneath and rapid inversion technique uses the SW Norway coincides spatially with the inferred polarisation of incident P-waves in conjunction Sveconorwegian continental-margin arc. Based with the original receiver function waveforms to on results from thermal modelling, we argue that constrain the S-wave structure beneath seismic the channel-like, low-velocity zone, at least in stations. We apply it to a global receiver function part, reflects the thermal (radioactive) effects of database, GLImER (Global Lithospheric the refertilised mantle wedge of this continental Imagining using Earthquake Recordings), with magmatic arc. Similarly, the generally low seismic the aim to construct a new global crustal model velocities in the interior of the orogen are consisting of thousands of individual 1D crustal interpreted to reflect refertilisation due to models. We use previous global estimates of subduction of continental material (cf. Moho depth and intra-crustal structure as Hieronymus & Goes, 2010). Thermal effects from starting models and refine these during the younger tectonic events, such as Permo-Triassic inversion. The greatest improvement of our rifting or late Palaeozoic Caledonian orogenesis approach over existing ones will be the additional can be all but ruled out. In contrast, hot mantle information it provides about layering and material derived from the Iceland plume may absolute S-wave velocity in the upper mantle. have an effect on temperatures beneath SW Future work includes the integration of absolute Norway, but is unlikely to produce the observed P-wave velocity from teleseismic S-wave tomographic variations. The geological record in

240 SW Fennoscandia suggests that active-margin POSTER magmatism terminated as a result of rapid slab roll-back and trench retreat starting at ca. 1 Ga. 3D geomodelling workflow using high The rapid shift from active- to passive-margin performance computing – the vuonos processes was probably critical to preserve the and keretti deposits in Outokumpu mantle wedge, and their identification can Mining area, eastern Finland therefore shed light on how active-margin processes terminated in ancient orogens. Eevaliisa Laine1, Heidi Laxtröm1, Jan Westerholm2 and Johan Ersfolk2

1Geological Survey of Finland, 2Åbo Akademi University, Faculty of Science and Engineering POSTER

Geological characterization of clayey The Outokumpu district hosting a number of ore till using cross-borehole ground bodies is located within the Palaeoproterozoic penetrating radar. North Karelia Schist Belt. Mining activity started 1913 and several mines have already been closed Espen Bing Svendsen1, Majken C. Looms Zibar1, (e.g. Keretti/Outokumpu and Vuonos) but serve Kurt Kjær2, Lars Nielsen1 and Bertel Nilsson3 as valuable data sources for ore exploration. 1University of Copenhagen, 2Natural History Museum of Project GECCO combines expertise in high Denmark, University of Copenhagen, 3GEUS performance computing and geomodelling, and

aims to develop tools for faster geological Approximately 40% of Denmark is covered by common earth model (CEM) modelling in a clayey till. Knowledge of the water flow and powerful computing environment. transport pathways through these glacial This paper demonstrates the GECCO workflow deposits is necessary in order to sustainably for the area containing historical Keretti and exploit and protect our water resources. In clayey Vuonos massive Cu-Zn-Co and disseminated Ni till, the presence of macropores dominates the sulphide ore deposits hosted by a distinct transport pathways as they create a three- lithological assemblage, the Outokumpu dimensional network of pathways that enable a assemblage, consisting of peridotite and much faster water and contaminant transport serpentinite enveloped by Cr-bearing carbonate- than through the surrounding fine-grained quartz rocks. Geological structures and diffusion-limited clay matrix. These macropores lithological heterogeneity of the Outokumpu exist as fractures, biopores from burrows and assemblage were modeled by using geostatistical roots, as well as sand lenses. The macropores are simulations constrained by drill core data, non-trivial to map and at present, a low-cost non- geological cross sections and fault zones. invasive technique for mapping such networks Hundreds of simulated realizations were does not exist. We aim to use existing ground summarized as stochastic geological 3D models, penetrating radar (GPR) tools to develop such a i.e., 3D voxets populated by probabilities for each technique for geological characterization of rock type. The calculated gravity and magnetic clayey till. This study will present preliminary responses were used to validate the alternative results from Havdrup, Eastern Zealand, first of geological 3D voxel models and compared with four field sites, and will focus on correlation the Vuonos-Keretti 3D model built by traditional between cross-hole GPR data and XRF core- 3D modelling. High performance computing scanner acquired major and minor element using GPU for simulation and visualization made variation. it possible to make gravity and magnetic forward modelling in real time. The suggested approach

gives a possibility to analyze uncertainties associated with geological 3D models spaced on sparse data sets.

241 POSTER

POSTER Why the mantle transition zone does not appear to be thinned at plume Geophysical modelling of the Leka sites Ophiolite Complex Thorsten Nagel1, Erik Duesterhoeft2 and Christian Alexander MIchels1, Suzanne McEnroe1 and Schiffer3 1 Christine Fichler 1Department of Geoscience, Aarhus University, 1 Norwegian University Of Science and Technology Denmark, 2Department of Geoscience, Christian- Albrechts University, Kiel, Germany, 3Department of Earth Sciences, Durham University, Durham, UK The ~497 Ma Leka Ophiolite Complex (LOC) on the island of Leka in central Norway is one of northern Europe’s most complete ophiolites Deep mantle plumes and associated high thermal complexes. The LOC is comprised of oceanic gradients are expected to cause an upward lithosphere that formed near the margin of deflection of phase transitions defining the Laurentia in a subduction-initiated setting, was lower-upper mantle boundary and an overall obducted on to Laurentia in the early Ordovician, thinning of the mantle transition zone in receiver and later transferred to Baltica as part of the function data. We use forward calculation of upper allochthon in the Scandian Orogen. The mineral assemblages, seismic velocities, and LOC has excellent exposures of partially receiver functions to explain the common serpentinized mantle rocks, crustal cumulate absence of these observations by means of large dunites and wehrlites, the petrologic and temperature-dependent variations of seismic geophysical paleo-Moho, gabbro, sheeted dykes velocities in the lower mantle transition zone. At and pillow basalts. Here we present a model for high thermal gradients, primitive mantle the structure of the LOC based on its geophysical compositions display assemblages dominated by and petrophysical properties. This is the first majoritic garnet and periclase. Associated seismic geophysical study of the LOC that utilizes both velocities would be 5-10 percent lower than for gravity and magnetic data. New ground-magnetic wadsleyite- or ringwoodite-rich assemblages surveys combined with a recent aeromagnetic characteristic for undisturbed thermal survey by NGU are use to model the LOC, and conditions. The identified low-velocity zone at investigate the enhanced magnetization upwelling sites could cause a miscalculation of associated with the major faults. The Bouguer the lower-upper-mantle boundary in the order of gravity high near the center of the island is 50.5 20 kilometers. Our results also confirm and mGal with a magnetic high 2800 nT. Using gravity explain existing propositions of low velocities in surveys, new aeromagnetic data and the the lower mantle transition zone at plume sites, petrophysical properties of 564 rock samples, which are based on the observation of negative three model sections that transect the island conversions in receiver function data in 500-600 northwest to southeast were created. Depth of kilometers depth. the base of the model was constrained by the gravity data while magnetic data was used to constrain contacts and structures within the LOC.

The new models suggest the depth of the complex is near 2 km and the ultramafic part of the LOC has a synclinal structure.

242 POSTER

The seismic signature of the Mantle POSTER Transition Zone in different Towards a Finnish Seismic Database – geodynamic scenarios Taming the National Seismological Christian Schiffer1, Kenni Petersen2, Thorsten DDSS Nagel2 and Erik Duesterhoeft3 1Department of Earth Sciences, Durham University, Tommi Vuorinen1, Aleksi Aalto1 and Ilmo 2Department of Geoscience, Aarhus University, 3Insitute Salmenperä1 of Geosciences, Kiel University 1Institute of Seismology, University of Helsinki

The Mantle Transition Zone (MTZ) is defined by a Institute of Seismology, University of Helsinki series of phase transitions that form the (ISUH) is responsible for maintaining the Finnish transition between upper and lower mantle. At national seismological network (HE). In addition about 410 km, olivine transforms into wadsleyite, to HE network, ISUH actively collects and at 510 km into ringwoodite and at about 660 km, employs continuous waveform data from other ringwoodite and garnet decompose into seismic networks across the Nordic-Baltic region. bridgemanite and periclase. These phase changes In addition, data is also gathered and managed cause high-amplitude seismic discontinuities as from various temporary network installations they represent abrupt density and associated and active seismic sounding projects. These data seismic velocity steps. The exact pressure and and the accompanying metadata streams are depth at which these occur are dependent of combined, analysed and processed, and later temperature and composition. Therefore, combined with the results of the neigbouring deflections of the phase transitions are to be countries (where applicable), to provide data, expected when cold, depleted subducted data products and services which can be utilized lithosphere or a warm, possibly enriched mantle by researchers, various agencies and the public. upwelling are crossing the MTZ. ISUH is actively participating in the pan- These depth-changes for different geodynamic European solid-earth Research Infrastructure scenarios is one of the most common ways to EPOS which will set data management, licensing study lower-upper mantle mass exchange, and distribution standards for the provided commonly interpreted from receiver function DDSS. In order to address the requirements set by images. We explore the imaging capability of EPOS and the practical necessities of managing receiver functions of the MTZ for different big data, ISUH is developing a database-driven subduction and upwelling scenarios using an SeisComP3-compatible solution that will integrated petrological-modelling-seismological facilitate more diverse, standard-based access to approach to create realistic receiver function available data and data products. images of the MTZ phase transitions. In particular, we develop self-consistent numerical The database will also enable the development of models coupled to the most advanced new services and software, which will help not thermodynamic databases to derive realistic only in data management and curation but also in densities and seismic velocities. The generated processing raw data streams into usable snapshots are the base for full-waveform seismic products. Indeed, quality of certain data & data modelling and subsequent receiver function products have already been improved and new processing. Using this synthetic modelling software has entered testing during the approach, we will explore the effect of different development and implementation phase of the station layouts, noise and dimensions of project. anomalies.

243 13. High and low temperature geochemistry, cosmochemistry and geochronology: 13.1. Geomicrobiology of the Ma). The lower part of the Arena Fm consists of black shales deposited under locally euxinic past and present conditions as evidenced by high proportions of highly reactive iron and pyrite. These black shales display muted Mo enrichments, low Mo/TOC ORAL compared to overlying shales and Phanerozoic euxinic sediments. The δ98Mo values are Ocean redox conditions between the consistent with other Cryogenic euxinic basins Snowballs – geochemical constraints and well below that of the modern oceans. The from Arena Formation, East combination of low [Mo] and δ98Mo suggests that Greenland widespread anoxia prevailed in the oceans at this time. These results are consistent with most Tais W. Dahl1, Eva L. Scheller2, Alexander J. other studies from this time suggesting that Dickson3, Donald E. Canfield4, Christoph Korte5 ocean oxygenation was not linked to Snowball and Kasper K Kristiansen5 Earth deglaciation, but was delayed until animals 1Natural History Museum of Denmark, University of effectively entered the scene. Copenhagen, Denmark, 2Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, USA, 3Department of Earth Sciences, University of Oxford, United Kingdom, 4University of ORAL Southern Denmark, Odense M, Denmark, 5Institute of Geology and Natural Resources, University of Primordial cellular oxygen sensing key to Copenhagen, Denmark animal evolution in the oxic realm

Emma Hammarlund1 The emergence of animal ecosystems is largely 1Lund University believed to have occurred in increasingly oxygenated oceans after the termination of the Sturtian and Marinoan glaciations. This transition Microbes sense environmental oxygen through has led to several hypotheses for the mechanism mechanisms that since have been inherited driving ocean oxygenation and animal evolution. through evolution all the way to vertebrate One hypothesis is that enhanced weathering animals[1]. The inherited and modified increased oceanic nutrient levels, primary mechanisms in animals now couple to cell productivity and organic carbon burial, and responses that are crucial for the maintenance of ultimately oxygenated the atmosphere and tissue. However, to what extent an evolution of oceans. Another hypothesis suggests that an the oxygen sensing mechanisms mattered for the animal-driven reorganization of the marine evolution animals remains largely unexplored. biogeochemical cycles might have oxygenated the Oxygen sensing mechanisms have primarily been oceans. Through molybdenum (Mo), carbon, explored in the field of tumor biology, since they sulfur isotopes and iron speciation results from associate with tissue hypoxia[2] and the the Arena Fm, East Greenland, this study maintenance of cancer stem cells. Cancer stem constrains ocean redox conditions after the cells possess the capacity to form new tissue. In Sturtian deglaciation and before the major these studies, the hypoxia-inducible radiation of animals. Carbon and sulfur isotope transcription factors (HIFs) are central, by how stratigraphy is used to correlate the Arena Fm they are guided by ambient tissue oxygenation with other formations worldwide between the and how they associate to stem cell-like features Sturtian and Marinoan glaciations (~720–635 (stemness)[3]. Insights from tumor biology, on

244 how HIFs regulate tissue formation, emphasize The pollution of oceans through plastic debris has that refined control of primordial oxygen sensing emerged as a new global challenge. The mechanisms must play a role for large life in the introduction of these synthetic particles to oxic environment. Indeed, by acknowledging a aquatic systems raises environmental health few observations from the fields of stem cells concerns, but these particles may also alter the science and tumor biology, it appears a paradox transport and burial of microbial organic matter that animals renew tissue in the oxic and influence global biogeochemical cycles. Both environment at all. in the water column and sediment, bacteria are found as free-living cells or surface-oriented Based on transdisciplinary observations biofilms. While biofilm found on marine plastic regarding the role of the oxygen sensing implies a new ecological niche, named the mechanisms – inherited from microbes – I Plastisphere, our knowledge of marine plastic- present a model of evolving stemness control that microbe interaction is still nascent. Plastic acts as may have facilitated animals to enter and a vector for microbial communities, offers a diversify in the oxic environment. The model surface for abiotic and biotic element cycling, and challenges the view that an increased extent of may even be a microbial carbon source. Indeed, oxic niches resulted in the Cambrian explosion. microorganisms may play a key role in degrading, Implications of the model is compared to transporting and incorporating (micro)plastic observations in the geological record. into biogeochemical cycles. In this new study, we combine microbial community profiles,

bioimaging, isotope, and elemental analysis to ORAL elucidate plastic-associated element cycling. Focus on the interaction between microbes, the Microbial element cycling and plastic surface and their environment, as well as transport: from ancient sedimentary the effect of transport and diagenesis will inform the influence of these particles on element basins to the Plastisphere cycling. Nicole R. Posth1, Serguei Chiriaev2, Elena

Gorokhova3, Thomas R. Neu4 and Jakob Strand5 1 Geology, Dept of Geosciences & Natural Resource ORAL Management, University of Copenhagen, DK, 2SDU NanoSYD, IRCA, Mads Clausen Institute, SDU, Mechanistic insight into microbial Sønderborg, 3Dept of Environmental Science & Analytical Chemistry- ACES, Stockholm University, formation of iron oxides: implications 4Microbiology of Interfaces, Helmholtz Centre for for development of banded iron Environmental Research (UFZ) Magdeburg, 5Dept of formations and our atmosphere Bioscience, Aarhus University Karina K. sand1, Stanislav Jelavić1 and James J. DeYoreo2 Microorganisms play a key role in 1Department of Chemistry, University of Copenhagen, biogeochemical processes in aquatic Denmark, 2Physical Sciences Division, Pacific Northwest environments, closing all major element cycles National, Laboratory, Richland, WA, USA. and influencing element transport and burial. Experiments with modern, model organisms have been used to constrain the role of microbes Microbial control over mineralization is a in ancient aqueous environments. Both the widespread phenomena that has shaped the acquired knowledge and the analytical methods near-surface mineralogy and chemistry of the used in these studies of the Earth´s past are also earth, oceans and atmosphere. However, the useful to clarify the role of microorganisms in mechanistic understanding of these interactions contemporary and future evolving environments. is poorly constrained. We quantitively addressed the mechanisms behind the controls that

245 microbial extracellular polymeric substances porosity of host rocks surrounding nuclear waste (EPS) exert in directing mineral formation and repositories in order to control or prevent transformation. We captured the collective bond radionuclide transport. To determine a suitable behavior of model and natural EPS during field injection approach, a series of bench scale interaction with the two common iron oxides, experiments were undertaken in the laboratory. hematite and ferrihydrite. Subsequently, we First, batch experiments focused on the kinetics applied nucleation theories to the measurements of calcite precipitation as a function of bacterial and obtained information on the mechanistic mass, urea and Ca2+ concentration and anaerobic controls for iron oxide formation on the vs aerobic conditions. Results showed that the polymers. One of the main findings is that EPS, as ureolytic bacteria performed equally well under well as less complex polysaccharides, strongly both oxygen poor and oxygen rich conditions. In bind iron species and iron oxides to such an the next stage, flow-through experiments in extent that they modulate the interfacial free various media (sand columns, rock cores) were energy of the iron oxide-polymer system, thus carried out to examine the homogeneity and promoting nucleation on the polymer matrix by extent of the pore space fill along the column / decreasing the nucleation barriers. These core as a function of injection strategies. It findings have implications for mineral formation emerged that a staged injection strategy, where in both oxic and anoxic conditions and may we alternate between bacterial and reactant explain the mechanisms behind the development injection, yields the most homogeneous calcite of banded iron formations (Lalonde et al., 2012) fill, reducing overall porosity by up to 45 %. and oxygen buildup during the Great Oxidation Ultimately, this approach was tested at the field Event (Canfield, 1998). scale, led by University of Birmingham, to seal a fractured rock (dacite) at ~28 m depth, in a quarry in Leicestershire, UK. Within few injection cycles, the single fracture was substantially ORAL plugged by calcite, yielding a significant Pore space sealing using microbially transmissivity decrease over several meters. mediated calcite precipitation: a lab to field scale study

Dominique J. Tobler1, Mark O. Cuthbert2, Michael

S. Riley3, Stephanie Handley-Sidhu4 and Vernon R. 5 Phoenix 1Nano-Science Center, Department of Chemistry, University of Copenhagen, Denmark, 2School of Earth and Ocean Sciences, Cardiff University, United Kingdom, 3School of Geography, Earth and Environmental Sciences, University of Birmingham, United Kingdom, 4School of Geography, Earth and EnvironmentalSciences, University of Birmingham, United Kingdom., 5Civil and Environmental Engineering, University of Strathclyde, United Kingdom

Microbially driven calcite precipitation (via ureolysis) has shown great potential in a wide range of applications, including solid-phase capture, concrete crack remediation, soil stabilisation and carbon sequestration. Here, this process is investigated as a means of reducing the primary porosity and/or secondary fracture

246 13.2. Bio-mineral interactions ORAL In, on or in between: tracking the persistence of proteins in the past ORAL

1 Crystallization kinetics of apatite Matthew Collins 1University of Copenhagen model systems

Henrik Birkedal1 It is a time of great change in the use of 1Department of Chemistry & iNANO, Aarhus University, biomolecules in archaeology and geology. As a Denmark young lecture at the Fossil Fuels and

Environmental Geochemistry Institute in The formation of biominerals remains shrouded Newcastle, I was used to thinking that it was small in mystery. A plethora of mechanisms have been robust molecules which typified organic proposed [1,2]. To obtain detailed insights into geochemistry. Today leading Scandinavia the formation of such minerals, we have present Archaeologist Kristian Kristiansen (Gothenburg) is arguing that his discipline is undergoing a third results of studies of apatite formation. science revolution, in which genetics allied to We use in situ X-ray diffraction to map isotope geochemistry and data modelling is crystallization kinetics [2-5] and found that at casting aside postmodern notions and returning high pH apatite forms from amorphous calcium to older concepts of cultural change. Of these phosphate precursors. Choices of pH and three pillars, both bigger geochemical datasets counterions have significant impacts on and better modelling strategies were foreseen, crystallization kinetics and the shape of the the explosion in genetic data was not. Genetics resulting nanocrystals. and proteomics are now potential tools for archaeologists and geoscientists because We show that using dense organic gels afford extraordinary technological advances, driven by chemical garden type formation of hollow tubes the biosciences, are luckily well suited to the with apatitic (and other minerals depending on fragmented remains which accumulate over choice of conditions) walls [6] while coupling time. Using new genomic methods, the last sedimentation and particle aggregation results in decade has revealed how remarkably well large large transparent nanocrystal aggregates [7]. fragile organic molecules persist and can be Organic additives change crystallization kinetics recovered and interrogated. and crystal size/shape [3,4,7] and may even dramatically alter the crystallization pathway by Proteins survive longer than DNA - therefore if introducing metastable mesoscopic states prior genomics has revolutionised archaeology will to nucleation [8]. These results illustrate the proteomics revolutionise geosciences...? Er, no, complex nature of (bio)mineral formation. probably not. Nevertheless in this presentation I will explore what we know about protein survival. How long do proteins survive into geological time, where and how does they

survive, and what use might they be upon recovery? As I am speaking in the bio-mineral interactions session, it probably comes as no surprise that it is minerals which seem to key to answering these questions.

247 ORAL crystallization towards fabrication of bio inspired composite materials. Biomimetic approach to material design

Anne Rath Nielsen1, Daniel J. Murray2, Behzad ORAL Rad2, Susan L.S. Stipp3, Ronald N Zuckermann2 Sub-micron resolution diffraction and and Karina K. Sand4 1University of Copenhagen, Department of Chemistry, fluorescence tomography reveals Materials Chemistry Section, 2Molecular Foundry, bone microstructure Lawrence Berkeley National Lab, California, USA, 3Materials Chemistry, Nano-Science Center, Department Nina Wittig1, Simon Frølich1, Mie Birkbak1, Jonas of Chemistry, University of Copenhagen, Denmark, Palle1, Maja Østergaard1, Kathryn Spiers2, Jan 4 Geography & Earth Sciences, Aberystwyth University, Garrevoet2 and Henrik Birkedal1 UK 1Department of Chemistry & iNANO, Aarhus University, Denmark, 2DESY Photon Science, Hamburg, Germany

Biomineralising organisms are experts in controlling the interplay between polymers and The structures of many materials including minerals to obtain strong and functional biominerals are highly complex. Understanding materials. The use of bio inspired polymers to their structure is challenging and calls for control and direct growth of calcium carbonate, methods with sensitivity across several length could provide a pathway towards the fabrication scales in 3D. Multimodal X-ray tomographies are of novel tough and strong composite materials. such techniques [1]. Here, we apply diffraction An important step in this direction is to gain scattering computed tomography (DSCT) to control of the calcium carbonate nucleation and reveal the crystalline properties and fluorescence growth processes, which requires thorough tomography (FT) to probe element distributions characterization of the organic/inorganic in bone using a 400 nm X-ray beam. interactions. Bone displays essential structural features Bio inspired peptoid polymers (N-substituted ranging from the nano- to macro-scale. The links glycines) can be synthesized with precision between bone structure and function remain sequence control and are known to form ultrathin poorly understood. The osteon is a building block two-dimensional nanosheets [1]. A recent study in human long bones. In osteons, mineralized has shown that nanosheets with surface exposed collagen fibrils are arranged in a twisted plywood acidic chains can template formation of stable structure surrounding a Haversian canal. While it amorphous CaCO3 (ACC) [2]. This has inspired us has been shown that the indentation modulus to investigate the CaCO3 nucleation rates and varies periodically with the osteon lamellae and growth on functionalised substrates as a function that this is positively correlated with the mineral of time using a custom build flow cell system. We content [2], it remains uncear how the mineral used model systems of chosen self-assembled phase’s properties varies across the osteon. The monolayers (SAMs) to map the effect of specific same holds for oligo elements such as Sr. To functional groups as well as studied direct unravel the structure of osteons, we nucleation and growth on immobilized peptoid combine DSCT and FT with sub-micron polymers. resolution. This experiment combines the capabilities of diffraction and fluorescence with This study provides insight into the different those of computed tomography to allow for energy barriers provided by the different reconstruction of a diffractogram and a surfaces. Knowledge of the kinetics and fluorescence spectrum in each volume element thermodynamics of the crystallisation process is within the sample [1]. The resulting >1.5 million an important first step for guiding the diffractograms were Rietveld refined using MultiRef [3] to obtain typical crystallographic

248 parameters, including unit cell parameters, polymers. Our results highlight the strength of profile parameters etc. This revealed distinct DFS as a tool of investigating the determining variations in mineral properties and element mechanisms behind mineral-organic distributions with distance from the osteon interactions. center.

POSTER POSTER Using LA-ICPMS to investigate Quantification of molecular bonding: seasonality in Cod otolith Implications for origin of life and the microchemistry iron cycle Kristian Nielsen1, Simon Hansen2, Tonny Stanislav Jelavić1 and Karina K Sand2 Thomsen2 and Karin Hüssy1 1University of Copenhagen, Nano-Science Center, 1Technical University of Denmark, National Institute of Department of Chemistry, Copenhagen, Denmark, Aquatic Resources, 2Geological Survey of Denmark and 2Aberystwyth University, Geography & Earth Sciences, Greenland, Department of Petrology and Economic Aberystwyth, United Kingdom. Geology

Mineral-polymer interactions are vital for many Fish ages are traditionally determined by visually life forms have probably played a significant role inspecting the ring structures in fish ear stones in the origin of life through polymerization of (otoliths). These ages are important in fish stock nucleotides. To form functional biopolymers, the management, e.g. when assessing fishing preexisting monomers had to be preconcentrated pressure, growth patterns or stock conditions. from dilute prebiotic solutions and the For the eastern Baltic cod the methods of visual thermodynamic barrier to polymer formation age determination has always been problematic, had to be surpassed. Both these processes has and in recent years this has worsened, causing been found to be encouraged by mineral problems for the stock management. In this adsorption. Element cycles of carbon and iron are project we aim to develop an alternative age also strongly impacted by mineral-polymer determination method using the chemical interactions. E.g. microbial production of iron composition of otoliths. We have analysed 132 oxides occurs on such a vast scale that it impacts otoliths using LA-ICPMS line transects which the global iron cycle and has been responsible for provide a chronological record of the fish’s entire major biogeochemical events such as the creation life from hatch to catch. The elements analysed of an oxygen-rich atmosphere. Despite the were Mg, P, Ca, Mn, Cu, Zn, Sr and Ba, which are significance of the polymer-mineral interaction, the most abundant elements in otoliths. The little insight into the thermodynamic and kinetic otoliths are recaptures from a mark-recapture properties of the polymer-mineral bond is experiment, where cod were tagged with an available at a mechanistic level. external tag and an internal chemical marker by injecting SrCl2, which incorporates into the Dynamic force spectroscopy (DFS) can directly otolith during growth. During LA-ICPMS analysis, capture the bond behavior of interacting bonds the Sr marker was detected by screening with a 3 between molecules and mineral surfaces. We µm laser spot size, whereas the analyses were have used this atomic force microscopy performed using a beam size of 40 µm at 5 µm/s technique to investigate the thermodynamic and progressing rates. The Sr marker acts as a time kinetic bond parameters describing bond stamp that allows evaluation of the LA-ICPMS behavior and energetics of nucleotide adsorption elemental analysis in time. The aim is to and RNA polymerisation on clay mineral surfaces investigate if some of the analyzed elements vary as well as the mechanism behind the observed on a seasonal basis, and how well this can be used enhanced iron oxide formation on bacterial for age determination. The presentation will

249 include method details and preliminary results of uncleaned foraminifera generally has Mn-oxide- this on-going project. type spectra (removable via cleaning methods). μXRF maps show that in many species, Mn is fairly evenly distributed at low-moderate concentration throughout the test, potentially POSTER suggesting stable oxygenation conditions. Manganese speciation and However, other species have specific high-Mn chambers, perhaps suggesting intervals of distribution in foraminiferal calcite greater oxygen stress or a response to under varying environmental foraminiferal processes that alter the conditions microenvironment.

Nadine Quintana Krupinski1, Sam Webb2, Per Persson1, Marit-Solveig Seidenkrantz3, Takashi Toyofuku4 and Helena Filipsson1 1Lund University, 2Stanford Synchrotron Radiation

Lightsource, 3Aarhus University, 4JAMSTEC

Benthic foraminiferal Mn/Ca, though often referred to as an indicator of authigenic contamination, has recently been suggested as a bottom water oxygen proxy. However, our understanding of Mn incorporation into benthic foraminifera is incomplete, and roles of potential contaminant phases need to be clarified. To evaluate whether Mn can indicate past hypoxia, we need to understand where/how Mn occurs in benthic foraminifera: is it incorporated into the calcite as a Mn-bearing carbonate species, and are other forms of Mn present? We also study how/whether changing environmental conditions and vital processes may affect Mn speciation and distribution.

We use synchrotron methods (X-ray absorption spectroscopy (XAS)) and micro-X-ray fluorescence (μXRF) mapping) to evaluate how Mn is incorporated into the benthic foraminifera calcite lattice (its distribution and speciation). We complement this with solution ICP-MS to determine mean Mn/Ca values for pooled foraminifera from the same samples. We use field-collected samples of living benthic foraminifera (to avoid diagenetic effects) from two oxygen conditions to evaluate whether differing environmental conditions affect Mn distribution and coordination.

Spectral data (XAS) indicate that Mn in the foraminiferal tests occurs as a Mn-carbonate, while small external debris with high Mn in these

250 13.3. Inorganic Geochemistry ORAL Turbostratic disorder: Lessons learned from Fe-bearing Layered ORAL Double Hydroxides. Microscopic view of hydrogen motion Knud Dideriksen1, Laura Voigt2, Marco in Clay minerals from neutron Mangayayam1, Case van Genuchten3, Cathrine scattering Frandsen4, Kristen M. Ø. Jensen1, S. L. S. Stipp1 and Dominique J. Tobler1 Heloisa Bordallo1 1Nano-Science Center, Department of Chemistry, 1Niels Bohr Institute - University of Copenhagen University of Copenhagen, Denmark, 2Department of

Chemistry, Technical University of Denmark, Denmark, 3Dept. of Earth Sciences-Geochemistry, Utrecht Neutron science is the science of everyday life, University, Utrecht 3508TA, The Netherlands, providing a microscopic view of the materials we 4Department of Physics, Technical University of rely on for modern life. Neutrons, similarly to X- Denmark, Denmark rays, penetrate matter. However, unlike X-rays, neutrons interact with matter in a different manner, thus allowing the identification of Turbostratic disorder exists in ordered materials elements with very low molecular weight, with highly anisotropic bond strength (e.g., clays) including hydrogen. For this reason, neutron and affects their properties (e.g., stability and ion spectroscopy brings unique information about exchange). It arises when sheets of strongly hydrogen mobility and can contribute for better bonded atoms, stacked along the direction of understanding the mechanisms that govern weaker bonding, are displaced so that atomic processes in clay dominated environments. alignment across sheets is lost. Layered double hydroxides (LDH) are composed of MeII-MeIII In this talk I will discuss on this promising hydroxide sheets separated by interlayers with approach by presenting a couple of specific water and weakly held anions. To probe short examples of quasi-elastic neutron scattering range order (1-40 Å) in synthetic LDHs in the experiments. The first is related to the sulphate green rust (FeIII) - nikischerite (AlIII) investigation of how the transport mechanisms series, we performed pair distribution function (of water or ions) are affected by an applied (PDF) analysis of high energy X-ray scattering electric field. To shed light into this question, we data. Results show that structural coherence have focused specifically on the dynamics of along the c axis decreases with increasing Al water in clays through investigating the origin of content, although Bragg peaks are clear for basal changes observed in water resistance under in- planes. The PDF for synthetic nikischerite is best situ electric field stimuli. The second focus on in- matched by the calculated pattern for coherent situ measurements performed during controlled scattering domains composed of a single metal exposure to water vapour and how the dynamics hydroxide sheet. Parallel to the decrease in the of adsorbed water change over a large range of structural coherence between layers, the unsaturated conditions. Using this approach we coherence within layers also decreases markedly were able to confirm that true material to ~6 nm for synthetic nikischerite. Thus, this equilibrium at intermediate hydration states is a material does not simply have unaligned, but time dependent phenomenon. The overall otherwise structurally developed sheets. Instead, knowledge acquired using neutron spectroscopy crystals are mosaic with coherent scattering opens new possibilities in the mitigation of soil domains that decrease in all directions. In fact, contamination and geo-environmental the aspect ratio of the large green rust sulphate engineering, where the role played by water crystals is comparable to that of the small controls the system properties. coherent scattering domains in synthetic nikischerite. Given that the structure of

251 disordered material is very complicated to characterise with traditional techniques, we speculate to what degree silicate clay minerals have mosaic crystals rather than only turbostratic disorder.

ORAL

CaCO3 scaling: Nucleation and growth inhibition of aragonite by MgSO4

Mia Rohde Nielsen1, Juan Diego Rodriguez- 2 1 1 Blanco , Karina Sand and Susan Stipp 1Nano-Science Center, Department of Chemistry, University of Copenhagen, Denmark, 2Department of Geology, Trinity College Dublin, Dublin, Ireland

2+ 2- Mg and SO4 are abundant in seawater and in hydrothermal fluids and are hence naturally present where calcium carbonate minerals form. Both ions are known to influence nucleation and growth of CaCO3 polymorphs but reports of 2+ 2- aragonite growth inhibition by Mg (±SO4 ) are contradictory. We used UV-vis spectroscopy to 2+ 2- explore the influence of Mg and SO4 on nucleation and growth rates of crystalline CaCO3 phases and we examined the solids using scanning electron microscopy (SEM) and powder 2- X-ray diffraction (PXRD). SO4 promoted formation of vaterite, extended the induction time for nucleation and decreased growth rate. 2+ 2- Mg (±SO4 ) promoted formation of aragonite in preference to calcite. Aragonite nucleation and growth was inhibited by Mg2+ alone and in 2- 2+ combination with SO4 . Mg clearly prolonged induction time and inhibited aragonite growth proportional to Mg2+ concentration. The results suggest an environmentally friendly method to inhibit aragonite scale formation, for example in desalination plants.

252 14. Hydrocarbon geology and energy 14.1. Geothermal energy and CO2 storage ORAL Seismic interpretation of a slopping offshore potential CO2 aquifer; the ORAL Gassum Formation in Skagerrak

Assessing European geological CO2 between Norway and Denmark storage capacity Ulrik Gregersen1, Irfan Baig2, Anja Sundal2, Lars Karen L. Anthonsen1 and Niels E. Poulsen1 Henrik Nielsen1, Mette Olivarius1 and Rikke 1Geological Survey of Denmark and Greenland Weibel1 1GEUS, 2University of Oslo

Deployment of large scale CCS in Europe is depending on knowledge about location and The first phase of the project “Optimized CO2 storage capacity of the most attractive storage storage in sloping aquifers – CO2Upslope” is areas and thus a reliable CO2 storage atlas is a key seismic stratigraphic interpretation of the tool for planning future CCS operations. siliciclastic Upper Triassic–Lower Jurassic Gassum Formation in Skagerrak between Since the beginning of 1990ties, several studies Norway and Denmark. The wells Felicia-1, J-1 and have attempted to map and estimate the 13/1-U-1 provide seismic-well ties for selected European storage capacity for CO2. Among the lines from eight 2D seismic surveys constituting most prominent are the Joule II project (Holloway the database. The work resulted in a detailed et al. 1996), the GESTCO project from 2004 interpretation of the top and base of the (Christensen & Holloway, 2004), the CASTOR formation and three sequence stratigraphic project (2006), the EU GeoCapacity project horizons within the aquifer (SB5, TS9 and TS10). (Vangkilde-Pedersen et al. 2009) and the CO2 The formation is mostly less than 100 m thick in StoP project (Poulsen et al. 2013). the study area, with its thickest parts located in/near the Felicia-1 well (230 m). The formation These projects more or less build on one another, thins towards east and north and shallows to the but there are differences between the projects north where it is truncated in places. The three with respect to number of countries included, internal horizons approach the base of the screening parameters, classification of storage formation towards north and only TS10 sites and assessment methodology. It is continues into the northernmost part of the study important to recognise the evolution of European area where it ties near the base of the 13/1-U-1 CO2 assessments and the challenges related to well. Some minor trough-shaped seismic features the methodology (static or probabilistic) for within the formation may indicate channel mapping and estimating storage capacities in incision. The formation is succeeded by Europe. mudstones of the Fjerritslev Formation divided by two internal horizons. Fourteen assigned Apart from the European EU co-funded projects, Norway has published an atlas for the Norwegian faults and additional minor faults are interpreted. continental shelf (Halland et al. 2014) and the Most faults are normal faults trending SW–NE NORDICCS project made an assessment for the and some are associated with ridges/structures Nordic countries (Anthonsen et al. 2013) and formed by regional tectonic events. Most faults released a joint Nordic CO2 storage web-atlas in slightly offset the Top Gassum horizon and parts 2015. Both United Kingdom and Spain have of the Fjerritslev mudstones. Succeeding phases prepared a national CO2 storage atlas. of the project involve establishment of a 3D geological model forming the basis for numerical

253 modelling of CO2 injection, movement and ORAL trapping. Shallow subsurface thermal structure for onshore Denmark

ORAL Ingelise Møller1, Niels Balling2 and Claus Ditlefsen1 A numerical investigation of 1Geological Survey of Danmark and Greenland, combined heat storage and extraction Denmark, 2Department of Geoscience, Aarhus in deep geothermal reservoirs University, Denmark

Marton Major1, Søren Erbs Poulsen2 and Niels Balling1 Information of shallow subsurface geothermal 1Aarhus University, Denmark, 2VIA University College, conditions is important for number applications Campus Horsens, Denmark including exploitation of shallow geothermal energy, heat storage and cooling as well as of general geoscience interest. Available measured Heat storage capabilities of deep sedimentary temperatures and thermal conductivities geothermal reservoirs are evaluated through covering Danish onshore areas to a depth of numerical model simulations. We combine about 300 m have been compiled and storage with heat extraction in a doublet well analysed. Temperature data from about 50 system when storage phases are restricted to boreholes, 100-300 m deep and thermal summer months. The effects of stored volume conductivities measured on samples collected at and annual repetition on energy recovery are 31 well-characterized outcrops and on core investigated. Recovery factors are evaluated for material from 20 boreholes are included. several different model setups and we find that Temperature gradients and thermal storing 90 °C water at 2500 m depth is capable of conductivities were grouped according to details reproducing, on average, 67% of the stored of lithology over which they were measured. energy. In addition, ambient reservoir temperature of 75 °C is slightly elevated leading Significant thermal variations are observed. At a to increased efficiency. Additional simulations depth of 100 m, temperatures vary between 7.5 concerning pressure build up in the reservoir are and 12 °C and at 200 m, between 9 and 15 °C. carried out to show that safety levels may not be Characteristic temperature gradients are in a reached. Reservoir characteristics are inspired by range of 1 - 4 °C/100 m. Following Fourier’s law Danish geothermal conditions, but results are of heat conduction (heat flow = thermal assumed to have more general validity. Thus, conductivity x temperature gradient) a deep sedimentary reservoirs of suitable correlation is observed between temperature properties are found to be viable options for gradients and thermal conductivities of different storing access energy for high demand periods. lithologies, and a regional estimate of characteristic shallow heat flow in Denmark is obtained. Quartz-rich sand deposits (high thermal conductivity) show low temperature

gradients, chalk and limestone intermediate gradients and almost pure clay (low thermal

conductivity) high gradients. Mean thermal conductivities range between 0.6 and 6 W/mK. An estimated regional heat flow of about 37 mW/m2 is in good agreement with local, classically determined heat-flow values from

shallow borehole data. Due to long-term palaeoclimatic effect, this value is significantly below deep background heat flow.

254 POSTER

ORAL Regional evaluation of structural collapse in sandstone reservoirs and Understanding nature's secrets and impact on reservoir quality, a case using the new knowledge to solve study from the Entrada Sandstone, society's challenges: insights for CO2 Utah, USA sequestration Nikoline Bromander1, Sigrid Østmo da Costa1, Elin S. L. Svane Stipp1 and and the Members of the Skurtveit2, James Evans3, Ivar Midtkandal1, Alvar NanoGeoScience Research Section1 Braathen1, Valentin Zuchuat1 and Anja Sundal1 1Nano-Science Center, Department of Chemistry, 1University of Oslo, Norway, 2Norges Geotekniske University of Copenhagen Institutt (NGI), Norway, 3Dept. of Geology, Utah State University, Logan, Utah, USA

The electronics revolution has given us tools that can "see" at molecular scale, providing whole new In this study we examine exhumed paleo- insight into the physical and chemical processes reservoirs showing evidence of past CO2-charged that control the interface between natural solids fluid accumulation to better understand and fluids (anything that flows, water, oil, CO2, processes related to geological sequestration of gases). By understanding how nature works, we CO2 in subsurface siliciclastic reservoirs. Field find clues to solve some of the challenges that data was collected from the wet aeolian dune society faces. An important issue is to reduce the system in the Jurassic Entrada Sandstone in Utah, CO2 available in the atmosphere and oceans by USA, and in particular the reservoir converting it to mineral form, where it will be characteristics of the light-coloured fluvial and stable for millennia. By understanding the aeolian dune interlayers have been evaluated. processes that take place at the surfaces of Bleaching in red rocks is interpreted to have minerals, we can tailor underground gas storage developed in response to reduction and/or facilities to be more effective and we can build dissolution of iron oxides as CO2-charged fluids models to predict their safety. What we have from underlying reservoirs escaped through the learned about CO2 injection into the basaltic rocks sedimentary succession. Some light-coloured, of Iceland has also inspired investigations with highly porous layers contain extensive amounts mineral fibre insulation and the design of of deformation bands, which may be associated nanoparticles for in situ remediation of with structural collapse. contaminated groundwater. Our work is very fundamental and also very applied. We combine The working hypothesis is that observed experiment with theory, in the lab, the field and reservoir collapse structures (deformation at synchrotron radiation facilities. bands) in specific layers is a regional feature related to sedimentary facies. Deformation band distributions and orientations are used to document reservoir collapse. Deformation bands

occur in different structural settings; clusters connected to faults cutting the stratigraphy, single deformation bands exclusively in fluvial and aeolian dune interlayers dying out in the over/underlaying facies forming small scale faults in the reservoir, as well as in major meter- scale circular collapse structures. Deformation

bands were present in some specific layers throughout the field area, with frequencies from 0 to 18 per meter and the degree of structural

255 collapse increased towards zones of high permeability (~500 to 1500mD) cause spreading deformation, e.g. faults. Preliminary results show of a CO2 plume. Smaller grains yield larger that collapse structures are regional features reactive surfaces, accelerating the dissolution of exclusively occurring in two types of facies, with framework minerals (e.g. chlorite, feldspars, the degree of collapse locally determined by pyrite), and thus reactivity is facies dependent. structural parameters. Relatively low temperature (~50 ºC) and pressures (120 - 160 bar) in Smeaheia will affect mineral dissolution kinetics and the potential for

POSTER subsequent CO2 trapping through carbonate precipitation (e.g. siderite, ankerite). Mass estimation of CO2 trapping in the Smeaheia reservoir

Tatiana Sacco1, Anja Sundal2 and Helge POSTER Hellevang3 1UiO - University of Oslo, Master student, 2UiO - Geological constraints on the University of Oslo, Postdoctoral Fellow - Section of immobilization potential for CO2 in 3 Geology and Geophysics, UiO - University of Oslo, the Upper Triassic – Lower Jurassic Associate Professor - Section of Physical Geography and Hydrology Gassum Formation (Skagerrak, Norway)

CO2 storage in saline aquifers is an important Anja Sundal1, Helge Hellevang1, Mette Olivarius2, measure to reduce anthropogenic greenhouse Rohaldin Miri1, Lars Henrik Nielsen2, Ulrik gas emissions. The Smeaheia reservoir (located Gregersen2, Odd Andersen3, Halvor Møll-Nilsen3, east of the Troll field, 50 km offshore) has been Rikke Weibel2 and Per Aagaard1 proposed by Gassnova and Statoil as a suitable 1University of Oslo, 2GEUS, 3Sintef

CO2 sequestration site due to low leakage risk and large storage capacity. The aim of this work is to determine and quantify the temporal distribution In the CLIMIT-funded “CO2-Upslope” project, the main objective is to improve reservoir of CO2 in i) mineral phase; ii) dissolved in the formation water; and iii) free phase for specific characterization schemes to optimize geological layers and facies in the Smeaheia reservoir storage of CO2. Coupled modelling is applied to candidate. estimate trapping efficiency and migration distances in order to ensure safe storage in open- The reservoir interval (1.2 to 1.6 km depth) boundary, sloping aquifer type reservoirs. The comprises deposits from Middle to Upper Jurassic Gassum Formation comprises fluvial to marginal ages; named Sognefjord, Fensfjord and marine sandy and muddy deposits. The Krossfjord formations. These are heterogeneous prospective reservoir is located in Skagerrak near shallow marine and deltaic sandstones. The industrial, onshore CO2 emission sources. Our

Draupne Formation consists of marine estimates of the reaction potential for CO2 in mudstones and serves as a sealing unit. The these sub-arkosic sandstones indicate significant Heather Formation comprises silty-claystones capacity for immobilization of injected gas into with low permeability, interfingering with sandy fluid and solid phases. The salinity of the units. formation water is high, and thus the dissolution potential is limited (~0.65 mol/kg), but may be In addition to the porosity and permeability catalyzed by solid carbonate precipitation - distribution, the geochemical trapping potential driving further dissolution of CO2. PHREEQ-C for CO2 in Smeaheia is considered in this study. simulations in a reservoir setting with 20 % The low salinity (TDS~5.6g/l) provides porosity show dissolution of oligoclase and dissolution potential for CO2, and favor mineral chlorite, providing cations and facilitating dissolution. High porosity (~30%) and precipitation of magnesite, siderite and calcite,

256 trapping more than 5 mol/l carbon after 1000 years. Petrography and geochronology results indicate immature sand with relatively high contents of reactive phases (i.e. feldspar, rock fragments) in the upper part of the Gassum Formation, which dominates on the Norwegian shelf, caused by a shift in provenance area towards the south during the later phases of deposition. Ongoing research activities in “CO2-

Upslope” will further improve the sedimentological, structural and diagenetic model as basis for reservoir simulations. Ultimately, a complete storage scheme tailored to the Gassum Formation and representative of migration assisted CO2 storage in sloping aquifers will be provided.

257 15. Marine geology 15.1. Tectonic, geodynamic, between the Arctic and the North Atlantic Oceans, and the development of the AAG to a deep-water oceanographic, and cryospheric connection and its influence on the global climate evolution of the Arctic Ocean system. from Mesozoic to present day Getting a continuous record of the Cenozoic sedimentary succession that recorded the evolution of the Arctic-North Atlantic horizontal ORAL and vertical motions, and land and water connections will also help better understanding The Opening of the Arctic-Atlantic the post-breakup evolution of the NE Atlantic Gateway: Tectonic, Oceanographic conjugate margins and associated sedimentary and Climatic Dynamics – Status of the basins. IODP Initiative

Wolfram Geissler1 and Jochen Knies2 1Alfred Wegener Institute Helmholtz Centre for Polar ORAL and Marine Research, 27568 Bremerhaven, Germany, 2Geological Survey of Norway, 7491 Trondheim, Depositional history of the western Norway/CAGE, University of Tromsø, 9037 Tromsø, Amundsen Basin, Arctic Ocean Norway John R. Hopper1, Carlos Castro2, Paul Knutz1 and Thomas Funck1 The modern polar cryosphere reflects an extreme 1Geological Survey of Denmark and Greenland, 2Niels climate state with profound temperature Bohr Institute gradients towards high-latitudes. It developed in association with step-wise Cenozoic cooling, beginning with ephemeral glaciations and the Seismic reflection data collected in the western appearance of sea ice in the late middle Eocene. Amundsen Basin show a uniform and continuous The polar ocean gateways played a pivotal role in cover of sediments over oceanic basement. An changing the polar and global climate, along with interpretation of seismic facies units shows that declining greenhouse gas levels. The Arctic Ocean the depositional history of the basin reflects was an isolated basin until the early Miocene changing tectonic, climatic, and oceanographic when rifting and subsequent sea-floor spreading conditions throughout the Cenozoic. The early started between Greenland and Svalbard, history of the basin shows a tectonically initiating the opening of the Fram Strait / Arctic- influenced restricted basin that gave way in the Atlantic Gateway (AAG). Although this gateway is early to mid-Miocene to a bottom current known to be important in Earth’s past and dominated environment indicated by a buildup of modern climate, little is known about its Cenozoic contourite deposits. It is suggested that this is a development. The opening history and AAG’s response to the opening of the Fram Strait and the consecutive widening and deepening must have establishment of geostrophic bottom currents had a strong impact on circulation and water that flowed from the Laptev Sea towards mass exchange between the Arctic and the North Greenland. These deposits are overlain by a Atlantic Oceans. To study the AAG’s complete seismic facies unit characterized by buried history, ocean drilling sites in the Boreas Basin channels and erosional features. These include and along the East Greenland continental margin prominent basinward levee systems that suggest are proposed. These sites will provide a channel morphology maintained by overbank unprecedented sedimentary records that will deposition of muddy sediments carried by unveil the history of shallow-water exchange suspension currents periodically spilling over the channel pathway. These deposits indicate a

258 change to a much higher energy environment that is proposed to be a response to brine formation associated with the onset of perennial sea ice ORAL cover in the Arctic Ocean. This interpretation implies that the development of significant sea Greenland Ice Sheet evolution and cover results in a significant change in the energy dynamics seen from the perspective environment of the ocean that is reflected in the of a large glacial fan system, depositional and erosional patterns observed. northeast Baffin Bay The lack of similar high energy erosional features and the presence of contourite deposits Paul C Knutz1, Andrew M W Newton2, John R throughout most of the Miocene may indicate the Hopper1, Mads Huuse3, Ulrik Gregersen1, Emma Arctic Ocean was relatively ice-free until the very Sheldon1 and Karen Dybkær1 latest Miocene. 1Geological Survey of Denmark and Greenland, Øster Vold Gade 10, 1350 Copenhagen, Denmark, 2School of Earth and Environmental Sciences, University of Manchester, M13 9PL, UK, 3Cryosphere Research at ORAL Manchester (CRAM), University of Manchester, M13 9PL, UK Arctic Climate Perturbations during the Early Triassic Biotic Crisis The Greenland Ice Sheet (GrIS) is a major Jochen Knies1 freshwater reservoir and a key component of the 1Geological Survey of Norway global climate system so understanding its past dynamic behaviour is crucial for underpinning climate model predictions. The long-term history Fractured and kaolinite weathered basement of the GrIS is mainly deduced from deep ocean rocks have been discovered in various wells off drilling sites while relatively little information the Norwegian coast and inferences on timing, exists from its dynamic glacial margins. Here we source to sink relationships, and environmental present mapping results, based on a dense 2D implications have been widely discussed. The reflection-seismic grid tied to industry well data, reason for the kaolitinization has often been which illuminates the stratigraphy and spatial related to intensive chemical weathering during evolution of the Melville Bugt - Upernavik trough- late Triassic to early Jurassic times. Chronological mouth fan system. The fan depocentres, formed control has primarily been inferred from the by sediments eroded and transported by the overlying late Jurassic/early Cretaceous marine northern GrIS, are constructed by sequentially transgression and poorly constrained K-Ar organized prograding depositional units, datings from weathered basement onshore as bounded by glacial erosion surfaces that extend well as climate conditions favourable for into steeply dipping clinoforms on the outer kaolinite formation. margin. South of the main trough, the erosion surfaces are commonly onlapped by laterally In this study, I present evidence that the deeply continuous strata attributed to sea-level weathered basement off the mid-Norwegian transgressions. The study reveals eleven phases coast represent a complete paleosol profile of ice stream advance over the northwest formed ca 250 million years ago. The timing Greenland continental margin since the onset of corroborates with the Early Triassic biotic crisis shelf-based glaciation at around 2.8 Ma. The GrIS and suggest a causal relationship between advance phases were interrupted by glacial intense chemical weathering, high atmospheric retreats and sea-level rises that appear to CO concentration, extreme ocean warming, 2 correlate with super-interglacial periods delayed biotic recovery, increased riverine flux of identified in the Siberian Arctic region. Moreover, nutrients and widespread anoxia/euxinia in the a change in ice flow configuration from uniform high northern latitudes during a time of rapid glacial advances to distinct trough-based global climate perturbations.

259 drainage points to a major change in GrIS represent the pre-Cenozoic continental slope dynamics through the Mid-Pleistocene transition. north of Svalbard.

ORAL ORAL

On the origin of the marginal plateaus Late Cenozoic paleoenvironment and north of Svalbard and Greenland erosion estimates for the northeastern Svalbard/northern Yngve Kristoffersen1, Yoshihide Ohta2, John K. Hall3 and Geir B. Larsen4 Barents Sea continental margin, 1University of Bergen/Nansen Environmental and Norwegian Arctic Remote Sensing Centre, 2(retired) Norwegian Polar Insititute, 3(retired) Geol. Survey of Israel, 4Lundin- Amando Lasabuda1, Wolfram Geissler2, Jan Sverre Norway Laberg3, Stig-Morten Knutsen4, Tom Arne Rydningen3 and Kai Berglar5 1Research Centre for Arctic Petroleum Exploration The marginal plateaus north of Svalbard and (ARCEx), IG, University of Tromsø, Norway, 2Alfred- Greenland are conjugate features with respect to Wegener-Institut Helmholtz-Zentrum für Polar- und the Gakkel Ridge and likely to share a geologic Meeresforschung (AWI), Bremerhaven, Germany, history. 3Department of Geosciences, University of Tromsø – the Arctic University of Norway, Tromsø, Norway, Dredge hauls from three sites on the Yermak 4Norwegian Petroleum Directorate (NPD), Harstad, Plateau have recovered an abundance of Norway, 5Federal Institute for Geosciences and Natural metasediments and gneisses with strong Resources (BGR), Hannover, Germany affinities to known lithologies from northwest Spitsbergen. The results support the earlier idea The upper Cenozoic sedimentary succession of of the plateau being a continental outlier except the northeastern Svalbard/northern Barents Sea for its northeasternmost tip. The outlier rifted off continental margin is analyzed using available 2D the margin north of Svalbard and moved with the seismic data. The primary focus is to better Greenland plate which implies significant understand the glacial paleoenvironments and Paleogene dextral shear motion close to the coast sedimentary processes as well as to estimate the of Spitsbergen. Past coast-parallel shear is glacial erosion of the inferred source areas. supported by observed seismic velocity Seismic facies analysis shows three main facies; anomalies in the crust characteristic of parallel to oblique parallel, contorted, and chaotic continental transform boundaries. seismic patterns. These observations suggest an A seismic reflection transect across Morris Jesup interplay between contour current and glacial- Rise show an eastern flat-topped spur of related mass-wasting processes. The seismic undeformed west-dipping layers and a western mapping shows abundant contourite deposition dome-structure cored by deformed sediments, since the Miocene, interpreted to be related to the possibly an imbricate stack of thrust sheets. High establishment of an ocean circulation system amplitude rough seismic reflections interpreted following the opening of the Fram Strait, similar as lava flows are present at depth in the 40 km to present conditions. The glacigenic debrites and wide depression between these two structures. its associated mass-transport deposits are interpreted to characterize the area in front of the The shared geologic history of the marginal troughs. This is likely related to extensive plateaus involve Yermak Plateau rifting off north glaciations in the Plio-Pleistocene during which of Svalbard at Chron 24 and the eastern Morris ice sheets repeatedly advanced to the shelf break Jesup Spur rifting off the Yermak Plateau at about during the full-glacial conditions. The inter Chron 15. The Morris Jesup Spur is likely to trough-mouth fan areas appear to be dominated by contouritic deposits characterized by a series

260 of sediment waves and sheeted drifts. In the deglaciation. Depending on future warming of studied margin, there is an increasing trend of bottom waters in the Barents Sea, the gas mass-wasting processes eastwards, while along- hydrates underlying the GHPs on southeastern slope processes dominate to the west. Isopach Storbanken could dissociate rapidly, forming new maps of the glacial strata will be presented along craters and sending large quantities of methane with the erosion estimates using a mass-balance to the sea surface and atmosphere. Such events approach. Major sediment source areas will be have important implications for both seabed discussed in relation to the late Cenozoic history geohazard mapping and for climate change of this studied margin. This contribution will be models, which must take into account all sources useful to better understand the dynamics of uplift and sinks of methane, a powerful greenhouse gas. and erosion events in the greater Barents Sea area.

POSTER

ORAL An automated cryogenic magnetometer at the Geological Enigmatic craters and giant gas flares Survey of Norway for natural in the central Barents Sea remanent magnetization and rock Francis Chantel Nixon1, Shyam Chand1 and Terje magnetism: A case study of North- Thorsnes1 East Atlantic continental margin 1Norges geologiske undersøkelse sediments

Martin Klug1, Karl Fabian2, Jochen Knies2 and Recent analyses of high-resolution multibeam Simone Sauer3 swath bathymetry and water column data 1Geological Survey of Norway, Trondheim, Norway, collected from the central Barents Sea resulted in 2Geological Survey of Norway, Trondheim, Norway; over 300 new observations of active gas flares CAGE - UiT The Arctic University of Norway, Tromsø, emanating from southeast Storbanken (~100- 3CAGE - Centre for Arctic Gas Hydrate, Environment and 200 m below modern sea level; mbsl). Seabed Climate; UiT The Arctic University of Norway fluid escape features, including pockmarks, craters, and mounds (tentatively interpreted as A new, automatically operating cryogenic gas hydrate pingos; GHPs) were also mapped in magnetometer system at the Geological Survey of this area. Interestingly, mapped fluid escape Norway is used to acquire natural remanent features do not coincide with the locations of the magnetization (NRM) and rock magnetic active gas flares, which is in contrast to hundreds parameters from two locations, West Barents Sea of similar craters, GHPs, and co-located gas flares (~71.6°N,16.2°E) and Vestnesa Ridge, NW ~300 km southwest, at depths of 310-370 mbsl Svalbard (~79.0°N, 6.9°E). The magnetometer lab (Andreassen et al., 2017). The GHPs and craters setup comprises an automated robot sample observed on southeast Storbanken occur outside feeding, dynamic measurement operation and of the methane hydrate stability limit, indicating monitoring, and customised output-to-database that the gas hydrates underlying the GHPs data handling. The setup is designed to constitute a mix of methane and heavier natural dynamically enable a variety of parallel gases, which remain stable at shallower water measurements with several coupled devices (e.g. depths and/or warmer temperatures. The balance, MS2B) to effectively use dead-time in craters, most of which are immediately adjacent between the otherwise time-consuming to the GHPs, indicate that methane hydrates measurements with the cryogen magnetometer. (≥99.9% methane) were formerly present, but Web-based access allows remote quality control became unstable and dissociated from the and interaction 24/7 and enables high sample seabed, likely between ~12 - 15 ka BP following throughput.

261 In the studied cores the magnetic properties are area that has been rarely accessed due to mostly combined with geophysical, geochemical perennial sea-ice cover prior to 2017. measurements and optical imaging, both radiographic and colour images, from high- The data cover a wide range of different resolution core-logging. The multidisciplinary geological provinces across the NE Greenland approach enables determination and shelf, but can roughly be subdivided into deep interpretation of content and formation of the troughs (formed by glacial erosion) and magnetic fraction, and its development during basement highs, which also appear to be affected diagenetic processes. Besides palaeomagnetic by glaciers. In nearly all areas, a thin cover (1-3 age determination the results offer the m) of most likely Holocene mud drapes the opportunity to study sediment transformation varying structures. Sedimentary basins (with processes that have implications for the burial estimated mud/clay thickness up to ca. 15-20 m) and degradation of organic matter. The results were only encountered in a few places on the also help to understand long and short-term shelf, primarily linked to glacier outlet troughs. variability of sediment accumulation. Chemical Varying seafloor morphologies can be recognized sediment stability is directly linked to such as blocky and faulted seafloor, rugged environmental and climate variability in the polar seafloor possibly related to slope failures, marine environment during the recent past. potential iceberg plough-marks, basement outcrops and flat seafloor related to minor

sedimentary basins. Similarly, the reflections POSTER below the seafloor show varying characteristics such as parallel high-amplitude continuous The general seafloor morphology of reflections and low-amplitude discontinuous the NE Greenland shelf - Insights from chaotic reflections indicative of changing new marine shallow seismic and core subsurface. data collected during the NorthGreen2017 expedition POSTER Lasse Nygaard Eriksen1, Katrine Juul Andresen1, Tove Nielsen2, Christof Pearce1, Tine Lander Active fault systems and submarine Rasmussen3, Hans Røy4 and Marit-Solveig landslides along the Eastern Sakhalin Seidenkrantz1 slope, the Okhotsk Sea 1Department of Geoscience – SeisLab and Centre for Past Climate Studies, Aarhus University, 2Department of D.D. Rukavishnikova1, K. A. Dozorova1 and B.V. geophysics, Geological Survey of Denmark and Baranov1 Greenland, 3Department of Geosciences, UiT, The Arctic 1Shirshov Institute of Oceanology, Russian Academy of University of Norway, 4Department of Bioscience - Sciences, Moscow, Russia Center for Geomicrobiology, Aarhus University

Continuous sub-bottom profiling and detailed We present preliminary observations from bathymetry maps obtained during international seismic data supported by marine sediment cores projects in 1998-2015 has first revealed areas of from the NE Greenland shelf between 80°N and active tectonics and associated submarine 74°N. The data were acquired in nearly ice-free landslides within central and northern areas of conditions and consist of ~2200 km of shallow Sakhalin Island slope, the Okhotsk Sea. Active seismic subbottom profiler data as well as faults form two local systems within limited sediment cores from 15 different sites. The data areas. Within the northern area the fault system were acquired during the NorthGreen2017 contains NE and NW striking normal and strike- expedition in September 2017, and represent an slip faults. In this area tectonic deformation caused displacement and destruction of a

262 sediment block with approximate volume of 16 15.2. Paleo-landscape analysis km3. NW striking normal faults form steep instable tectonic scarps up to 120 m high. Seismic based on high-resolution survey reveals mass transport deposits with marine data 3 estimated total volume of 3 km at the base of the largest scarp Within the central slope segment the active fault system contains NE and NS ORAL striking normal and strike-slip faults. Vertical displacements along the NE normal faults result The impact of a buried shear margin in subsidence of sediments and form closed moraine and thermokarst landscapes depressions with steep walls. Failure of one of on ice-stream dynamics of the SW such steep walls formed a landslide with volume Barents Sea revealed by high- of about 4 km3. The presented data show that the active tectonics creates favorable conditions for resolution 3D seismic data landslides generation in the study area. Benjamin Bellwald1, Sverre Planke1, Nina Lebedova-Ivanova1, Emilia Daria Piasecka2, Mohamed Ali Matar3, Karin Andreassen2 and Reidun Myklebust4 1Volcanic Basin Petroleum Research (VBPR), 2UiT The Arctic University of Norway, 3Nordic Geo-Consult, 4TGS

Meter-scale glacial landforms and layers, not

resolvable by conventional seismic data, comprise new information about glacier dynamics and fluid flow, which are valuable for the development of offshore infrastructure and geohazard assessments. The goal of this study is to characterize the paleo-landscape of the SW Barents Sea on a meter-scale, to correlate these

structures with the sub-surface geology and to study their implications on ice-stream dynamics. The database consists of c. 200 km2 of high- resolution P-Cable 3D seismic data and 37 gravity cores in the SW Barents Sea. The grids of the

picked seabed and Upper Regional Unconformity (URU) horizons, which define the top and base of the Quaternary sediment sequence, are compared with interpretations obtained from conventional 3D seismic and multibeam echosounder data. Seabed images interpreted in P-Cable 3D seismic data show an increased

resolution and sharpness compared to surfaces derived from multibeam echosounder and conventinal 3D seismic data. Hill-hole pairs and rhombohedral ridges at URU are interpreted as geological structures formed by subglacial

thermokarstic processes, indicating the presence of permafrost. Reflections within the intraglacial sediment package are not visible in conventional

263 seismic data, and include a shear margin moraine, carried out in connection with the Geocenter mass tranport deposits and soft beds. This study Denmark project SEDI-TRAPS. shows that high-resolution seismic data can be used to identify geological structures in Correlation of the coring results and the seismic multibeam echosounder quality of both the data show that the Anholt Lock is linked closely seabed and the shallow sub-surface. Identified to the structural development of the Tornquist thermokarst landscapes, a submarine braided Zone strike-slip fault system and synsedimentary river and a shear margin moraine have led to the Late- and Postglacial depositional patterns development of a revised ice-stream model of the document that reactivation has taken place. SW Barents Sea.

ORAL ORAL Postglacial paleo-landscape evolution Geological setting of Anholt Loch (Site of Aalborg Bay-Læsø Rende, M0060) IODP Expedition 347 northwestern Kattegat – results of a regional aggregate raw material Jørn B. Jensen1, Ole Bennike2, Katrine J. Andresen3 mapping campaign and Ole Rønø3 1Department of Marine Geology, Geological Survey of Niels Nørgaard-Pedersen1, Jørgen O. Leth1, Ole Denmark and Greenland (GEUS), 2Department of Bennike1 and Steen Lomholt1 Marine Geology, Geological Survey of Denmark and 1Geological Survey of Denmark and Greenland Greenland (GEUS)., 3Deparment of Geoscience, Aarhus University

In 2016 a regional shallow seismic mapping IODP Expedition 347 Site M0060 is situated in the campaign for aggregate raw materials took place 2 southern Kattegat at a water depth of 34m. The in an 1800 km area in Aalborg Bay in background selection of the coring position was a northwestern Kattegat. The main purpose of the rather coarse grid of seismic lines, that indicates study, performed for the Danish Environmental an erosional valley southeast of Anholt Island in Agency, was to assess the distribution and quality the Kattegat Sea. The valley was originally of aggregate material as well as monitoring the interpreted as infilled by a sequence from MIS 6, habitat conditions in the area. Mapping of basis of MIS 5e, and MIS 3 (Lykke-Andersen et al. 1993). the Holocene deposits in the area, representing Later boomer profiles and shallow cores show, the low stand period at about 12.000-10.000 yrs. that the younger parts of the infill is late glacial BP, reveals a network of valley/channel systems and Holocene age (MIS 2–MIS 1; Jensen et al. which appear to be connected to the major 2002). drainage systems connected to inlets of eastern Jutland. Rapidly increasing relative sea level from In 2013 the IODP program core M0060 reached a about 10.000-7.000 yrs. BP enhanced marine total depth of 232.5m of which 0 to 9 mbsf is transport of very large volumes of sandy material Marine Holocene and the range 9 to 82 mbsf from the northwestern Kattegat in to the covers the most recent deglaciation 14 – 18 ka BP northern part of the study area. Elongated sand i.e. (Bokhari 2015). On greater depths alternating bars tens of kilometers long formed in Læsø sandy and silty sequences are recorded, while the Rende. In the mid-Holocene at about 5000-4000 lowermost 84 m consists of diamict. yrs. BP relative sea level culminated at about 4-5 m above present sea level. Due to the continued Parallel to Expedition 347 a local Danish – isostatic uplift of the northern part of Kattegat Swedish project DAN-IODP-SEIS carried out High relative sea level fell after c. 4000 yrs BP. The Resolution 2D seismics (Nørmark et al. 2014) and large sand bar and intervening channel systems in spring 2017 a 3D high resolution survey was were selectively eroded and large amounts of

264 sandy material were transported southward to tens of meters of glaciolacustrine deposit. the central deeper part of Aalborg Bay. The Variations in the appearance of unit D,0 and development of a geological model encompassing lithological variations in the lacustrine deposits the present distribution of specific stratigraphic results in variations in thrust style. units and the related paleo-landscape evolution in relation to sea level changes, is an important prerequisite for predicting aggregate raw POSTER material distribution and quality variability. Paleo-river valleys near the Dogger

Bank in the Danish and German ORAL sectors of the North Sea – an Glaciotectonic thrust complex undiscovered tributary system to the offshore Holmsland, the Danish North Paleo Elbe Valley Sea - New Results. Trine Andreasen1, Katrine Juul Andresen1, Daniel A. Hepp2 and Hanno Keil3 Bernhard Novak1 and Henrique Duarte2 1SeisLab Aarhus, Department of Geoscience, Aarhus 1 2 Independent, Geosurveys Ed University, Høegh-Guldbergs Gade 2, 8000 Aarhus C, 2Centre for Marine Environmental Sciences, MARUM, Bremen, 3Faculty of Geosciences, University of Bremen Geological structures and seismic stratigraphy of a large-scale glaciotectonic thrust complex has been investigated in an area 5 km offshore along This study presents a new system of paleo-river the coastline off the Holmsland Dunes area, west valleys southeast of the Dogger Bank which has Denmark. A dense grid of seismic data combined been mapped using high-resolution subbottom with surface samples and boreholes information profiler data and sediment cores acquired during have been analyzed in a 6 by 15 km area. The base a RV Heincke expedition to the German and of the Quaternary (D,b) constitutes an Danish sectors of the North Sea in May 2016. unconformity interface to Neogene. A smooth seismic horizon (D,d) that outline ramps and flats The paleo-river system covers an area of approx. constitutes a decollement surface beneath the 200 km2 and is found below a thin succession of thrust complex. New analysis (and data) yield marine sediments, which indicates that the river evidences that the base Quaternary unconformity system formed prior to the marine transgression is unaffected by the deformation and that near 8000 years ago. The river system is characterised horizontal parallel seismic facies onlaps D,b. The by a central, 5 km wide and up to 6 m deep NE- seismic unit D,0 between the horizons D,b and D,d SW striking valley that intersects six older and shows medium to high amplitude parallel smaller NW-SE striking channels. (onlap), mound, channel, oblique and chaotic The course of the wider central valley roughly seismic facies. This 0 to 30 meter thick seismic follows the contours of the submerged Dogger unit is interpreted to represent glaciolacustrine Bank and the infill of the valley is characterised laminated sediments (parallel facies) deposited by well-defined subparallel and continuous over a proglacial outwash plain environment. reflections. This suggest a steady infilling of the Analysis of thrust block dip variations above D,0 valley, which may have occurred within an suggests a correlation to the thickness of unit D,0 estuary environment prior to the marine and the thrust style. In areas where the unit is transgression. absent a fold/dome deformation style at the base of the complex is accompanied by steep thrust The six older and smaller channels have higher style and maximum space between thrust ridges sinuosity and follows a course perpendicular to above the folds. Our model suggests that unit D,0 the Dogger Bank. These channels are interpreted function as a hydro conductive agent beneath to constitute an older meandering river system

265 dewatering the Doggerland and terminating in WesternLimfjord-expedition in May 2017. Our the Paleo-Elbe Valley east of the study area. preliminary results show that the Quaternary paleolandscape from the seismic data as expected The six older meandering rivers can be readily is very dynamic, and most likely have recorded linked to other similar systems mapped further the history from an ice-covered to shallow-water southeast (Hepp et al., 2017) and there is environment. The seismic data typically show a generally a very good agreement of our new distinct transition from high-amplitude chaotic findings with the existing theories on the reflections interpreted as Weichselian till, to development of the Doggerland landscape since lower amplitude, semi-parallel, continuous the Weichselian lowstand. reflections interpreted as the Holocene succession. A few places, we observe a third unit

in between the glacial and Holocene units, which POSTER we tentatively suggest could represent late glacial deposits. Sediment descriptions and age Late glacial to Holocene geological dating from two gravity cores in Visby Bredning development of the western Limfjord are included to address the Holocene development in more detail and unravel the – reconstruction of a dynamic changing influence of fresh, brackish and marine paleolandscape waters in Visby Bredning.

Katrine Juul Andresen1, Anders Dahlin2, Kasper U.

Kjeldsen3, Hans Røy3 and Marit-Solveig Seidenkrantz4 POSTER 1SeisLab Aarhus, Department of Geoscience, Aarhus University, Høegh-Guldbergs Gade 2, 8000 Aarhus C, The Young Sound fjord system, NE 2SeisLab Aarhus, Department of Geoscience, Aarhus Greenland – Insights from new University, 3Centre for Geomicrobiology, Department of Bioscience, Aarhus University, 4Centre for Past Climate marine shallow seismic and core data Studies, Department of Geoscience, Aarhus University collected during the NorthGreen2017 expedition The western Limfjord in northern Denmark Lasse Nygaard Eriksen1, Katrine Juul Andresen1, comprises wider water-areas such as Løgstør and Tove Nielsen2, Christof Pearce1, Tine Lander Thisted Brednings, narrow straits, small islands Rasmussen3, Sofia Ribeiro2, Søren Rysgaard4, Hans and some larger islands with spectacular Røy5 and Marit-Solveig Seidenkrantz1 landscapes such as Mors and Fur. The Quaternary 1Department of Geoscience – SeisLab and Centre for development of the fjord has been highly Past Climate Studies, Aarhus University, 2Department of governed by surface processes related to geophysics, Geological Survey of Denmark and changing ice-covers which has carved-out the Greenland, 3Department of Geosciences, UiT, The Arctic fjord, deformed the Cenozoic succession University of Norway, 4Department of Bioscience - including the Eocene Mo-clay by thrusting and Arctic Research Centre, Aarhus University, 5Department folding, and generated sea-level fluctuations due of Bioscience - Center for Geomicrobiology, Aarhus University to ice-melting and isostatic glacial rebound. At the same time, deep geological subsurface processes such as rising salt diapirs, tectonic faulting and The Young Sound fjord system in NE Greenland fluid migration have also controlled the generally consists of an outer, up to 7 km wide, formation of the landscape. shallow water (<200 m) part and an inner narrow (2 km wide) and deeper water (300-400 m) part In this study, we present a detailed subsurface known as the Young Sound Deep. The fjord investigation of Visby Bredning in the western system have been extensively surveyed for Limfjord based on high-resolution seismic data marine, terrestrial and meteorological data since and sediment cores acquired during the 1994 (Bendtsen 2014 et al.), but the underlying

266 seafloor and the subsurface sediments have to deeper geological structures could have our knowledge only been mapped superficially. controlled and effected the configuration of the In this study, we present preliminary pre-Vejle Fjord landscape and in turn the focus of observations from seismic mapping and the Quaternary glacial processes. sediment coring within the Young Sound. The data that consist of 400 km of shallow seismic In this study, we interpret newly acquired high- subbottom-profiler data and four sediment cores resolution 2D seismic data and sediment cores were acquired during the NorthGreen2017 from Vejle Fjord with the aim of mapping and expedition in September 2017 and represent the investigating the deeper geological structures first detailed marine seismic study of the and their potential influence on the formation of geological development of the fjord system. the fjord. Our seismic data show a number of faults, which in the southern part of Vejle Fjord We show that the central basin in Young Sound offset Eocene sediments presently at the seafloor. Deep is filled with a fairly thick sediment package The faults can be followed down to ca. 70 m below (at least 40-50 m where thickest). There was the seafloor, with a few faults continuing even furthermore a clear distinction in both the deeper. Three hypotheses for the formation of the seafloor morphology and the subsurface geology faults are suggested: Quaternary glacial tectonic from the inner part of the fjord towards the outer deformation, slope failure deformation, and part of the fjord, which is most likely a direct polygonal faulting. Which of the hypotheses that representation of the similar marked changes in are applicable have a great importance for the topography at the fjord sides. Thus, our understanding of the early origin of Vejle Fjord observations from the high-resolution shallow- and for fjord formation in sedimentary basins in seismic data suggest that we can track first-order general. To understand the faults, our erosion and depositional processes within the interpretation is focused on constraining their 3D fjord back in time. geometries and in turn their timing, activity and controlling factors.

POSTER

Deep geology at Vejle Fjord – Paleogene structural control of a Quaternary fjord system

Jakob Roued1, Marit-Solveig Seidenkrantz1, Lars Ole Boldreel2 and Katrine Juul Andresen1 1SeisLab Aarhus and Centre for Past Climate Studies, Department of Geoscience, Aarhus University, 2Department of Geosciences and Natural Resource Management, University of Copenhagen

Vejle Fjord in Denmark is believed to have formed as a tunnel valley initially carved-out during the Elsterian glaciation and later reused and expanded during succeeding glaciations and inter-glaciations. Folds and thrust faults in the present-day coast-profiles of the fjord bear evidence of glacial deformation while outcrops of

Paleogene and Neogene sediments have aided the reconstruction of the paleolandscape. It has however not been investigated in detail, how

267 15.3. The Quaternary geology of perspective. Examples of high-resolution data will be shown from site surveys in the Norwegian the North Sea Basin [co- sector and in areas crossing the UK-Norway organized with Quaternary border. Geology]

ORAL ORAL The Norwegian Strandflat - an The Quaternary Stratigraphy in the offshore perspective Norwegian Sector of the Central North Sea – A Site Survey Perspective Helge Løseth1 1Statoil ASA, R&D Trondheim Björn Bohling1 1Fugro The strandflat is the picturesque world-heritage topographic low-land, island and sounds on the Quaternary deposits of the North Sea are of coast of Norway. The age and processes of particular interest for geohazard and site forming the strandflat have been debated since characterisation studies ensuring the save first described by Hans Reusch in 1900. The emplacement of offshore installations (IOGP objective of this work is set constrains to the age 2013 & 2015). A coherent (litho-)stratigraphic and formation processes of the strandflat by framework is required in order to perform a linking it to the offshore geological evolution. reliable interpretation of geophysical and Seismic and well data are used to interpret the geotechnical site survey data and in order to Cenozoic geological evolution of the margin while ensure the comparability of results. the strandflat is studied through literature and field observations. The British sector of the North Sea has been systematically mapped by the British Geological The non-parallel tilts of the strandflat relative to Survey. Reports and maps presenting seabed offshore Cenozoic surfaces show that the sediments and the Quaternary geology have been strandflat was formed during the Quaternary. published (e.g. Johnson et al. 1993, Gatliff et al. 1994). Such systematic mapping has not been The strandflat is widest, up to 50 km, on the mid undertaken in the Norwegian sector of the Norwegian coast. The combined effect of glacial southern and central North Sea. Therefore, the erosion (volume-vice most important) and wave interpretation of site survey data in the erosion formed the strandflat. Wave erosion cut Norwegian sector is often based on the leveled platforms into the glacial-segmented extrapolation of the British stratigraphic model, coast. This occurred most efficiently during leading to a considerable degree of uncertainty glacial periods when the coast was ice-free and inconsistency. Recent research has improved simultaneously as the land was depressed under the understanding of Quaternary deposits (e.g. the weight of the inland ice. During repeated Buckley 2014, Ottesen et al. 2014). However, glacial and intra-glacial events the platform grew many studies focus on the early Quaternary wider and deeper simultaneously as the coast sequence or make use of conventional 3D gradually rose and tilted westward under exploration seismic data that have a relatively isostatic adjustments form onshore erosion and low resolution and do not image the complexity offshore deposition. Outside Møre and Troms the of middle and late Quaternary deposits. strandflat is isostaticly forced below the sea level under the weight of the two glacial depocenters, This presentation will highlight issues and the North Sea Fan and the Bjørnøya Fan. The challenges regarding the Quaternary stratigraphy absence of the strandflats in Finnmark and SE in the central North Sea as seen from a site survey

268 Norway I explain by offshore glacial erosion and ORAL no flexural down-bending of the coast. The tunnel valleys of the central and northern North Sea (56°N – 62°N):

ORAL Distribution, Characteristics and Generations The geological history of the North Sea Basin during the Quaternary Dag Ottesen1, Margaret Stewart2 and Marco Brønner1 Dag Ottesen1, Christine Batchelor2, Julian 1Geological Survey of Norway, 2British Geological Dowdeswell2 and Helge Løseth3 Survey 1Geological Survey of Norway, 2Scott Polar Research Institute, University of Cambridge, 3Statoil ASA Tunnel valleys are km-scale linear landforms

formed subglacially beneath large ice sheets. In The Quaternary sediments of the central and the British and Norwegian sectors of the North northern North Sea have been mapped based on Sea, offshore tunnel valleys are associated with a large 2D and 3D seismic database. The multiple Quaternary glaciations. In this study, we Quaternary North Sea basin is a N-S-trending use 2D and 3D seismic reflection data, and basin, 100-200 km wide and up to 1000 m deep. magnetic data, to map more than a thousand The infill pattern of the basin is outlined and the buried tunnel valleys in the central and northern depositional setting has been studied based on North Sea. The tunnel valleys are generally buried surfaces in 3D seismic cubes. The central present from the seabed to depths of around 400 basin is filled in by a thick, deltaic sequence metres, in a study area of 180 000 km2 from 56°N deposited from the E-SE, whereas the northern to around 62°N. Buried tunnel valleys are well- basin is filled in by prograding glacigenic debris imaged in seismic reflection data, particularly in flows deposited from the east. horizontal timeslices in 3D seismic data. In magnetic data, the tunnel valleys appear as small On top of the sediments mapped in the northern scale magnetic lows, likely due to their infill being basin, west of the Norwegian Channel, an upper less compacted and potentially more porous than regional unconformity (URU) is present. This the surroundings. unconformity is defined by a shift from westward (below) to eastward (above) dipping reflectors, This work provides the most extensive study of recording a major change in sedimentation tunnel valleys in the region to date, with more (before and after the onset of the formation of the than 20% of the study area containing buried Norwegian Channel). The age of the URU is tunnel valleys, and also finds the longest tunnel uncertain, but a timing of around 0.8 million valley recorded worldwide, with large years is suggested. Parts of the sedimentary meandering tunnel valleys extending for more sequence have been linked to the seismic than 160 km. We also find tunnel valleys further stratigraphy on the Dutch shelf, which is dated north than previously reported, as well as a based on palaeo-magnetic and biostratigraphic number of isolated tunnel valleys extending data (Kuhlmann and Wong, 2008). towards and into the Norwegian Channel. As reported by other studies in the region, the apparently extensive networks of buried valleys are found to be comprised of cross-cutting generations. In four study areas, we find between 3 and 6 generations, and relate them to potential

ice sheet configurations.

269 ORAL POSTER

Quaternary depositional Near-shore seafloor depressions in environments and glacial history of the Western Limfjord, Denmark – the North Sea constrained by potential geohazards? aminostratigraphy Anders Dahlin1, Katrine Juul Andresen1, Kasper U. Benedict Reinardy1, Hans Petter Sejrup2 and Berit Kjeldsen2, Hans Røy2 and Marit-Solveig Hjelstuen2 Seidenkrantz3 1Stockholm University, 2University of Bergen 1SeisLab Aarhus, Department of Geoscience, Aarhus University, 2Centre for Geomicrobiology, Department of Bioscience, Aarhus University, 3Centre for Past Climate The aminostratigraphy of up to 1000 m of glacial Studies, Department of Geoscience, Aarhus University and interglacial sediments in the North Sea Basin is compiled from multiple boreholes sites and Pockmarks which are circular to semi-circular dated using strontium isotope (Sr) analysis to seafloor depressions formed due to fluid venting, provide a chronological framework extending is a well-known geological phenomenon that in throughout the Quaternary. The new relative and several cases have proven to represent absolute chronology also ties to regional geohazards particular in relation to safety and seismostratigraphy. Increasing sediment cost implications for the integrity of seafloor deposition rate during the Early Pleistocene constructions and pipelines. During the venting, reflects glacier ice advancing to the Norwegian fine-grained sediment is removed from the coast. The earliest evidence of grounded ice in the venting site leading to an excavation of the investigated area comes from mega scale glacial seafloor. lineations formed during the Mid Pleistocene Transition. At least one episode of diminished In this study, we present preliminary coarse clasts and increased foraminiferal observations of 7 large-scale seafloor diversity during the Mid Pleistocene suggests a depressions in the shallow waters (<20m) of the progression from ice proximal to warmer, western Limfjord, Denmark. The depressions are possibly interglacial conditions. Furthermore, the tentatively interpreted as pockmarks and have stratigraphically deepest generation of tunnel been mapped using a new multibeam and high- valleys may have formed during the Mid resolution 2D seismic subbottom profiler survey Pleistocene. Amino acid ratios indicate that a high and sediment cores acquired during the shear strength till containing chalk clasts WesternLimfjord research expedition in May transported from the west and/or south of the 2017. The depressions are characterized by a study area was likely deposited during MIS6. The complex circular to elongated map view Late Pleistocene stratigraphy is dominated by morphology, a width of 40-500 m, and typical glacimarine sediments and tills that are depths of ca. 3 m with very steep sides (11°) and chronologically well constrained with amino acid flat to rugged bottom morphologies. In total, the data. A sand layer recovered at core top in part of depressions cover an area of roughly 425.000 m2 the study area is interpreted to correspond to the and can be associated with the removal of ca. drainage of an ice-dammed lake in the southern 850.000 m3 of sediment, which may have taken North Sea during the last deglaciation (MIS2). place through violent fluid expulsions or slow This study shows that much of the Quaternary seepage. age sediments within the northern North Sea were deposited relatively rapidly during short If the depressions are indeed pockmarks they periods of time probably leaving significant would represent a rare case of near-shore hiatuses within the stratigraphic record. pockmarks which is very important to study in order to constrain their formation, timing, duration and present-day activity and to understand their potential geohazard risk;

270 particularly whether similar structures may form have significant implications for seabed habitats, in the future. the carbon and sulphur cycle, as well as the region’s glacial history, palaeoclimate and oceanography.

POSTER POSTER Morphology of the southeast Skagerrak (Denmark) from a new Buried Valleys in the Danish Central geophysical dataset Graben

Matthew Owen1, Zyad Al-Hamdani1, Jørn Jensen1, Lasse Krogsgaard Prins1, Katrine Juul Andresen1 Jørgen Leth1, Katrine Andresen2 and Lasse and Ole Rønø Clausen1 Eriksen2 1SeisLab Aarhus, Department of Geoscience, Aarhus 1Department of Marine Geology, Geological Survey of University Denmark and Greenland, 2Deparment of Geoscience, Aarhus University The Danish Central Graben has been subject to extensive seismic surveying (both 2D and 3D) As part of the Danish marine habitat mapping during the past four decades. The 3D seismic data programme an extensive geophysical dataset has mainly been used for oil and gas exploration, including multibeam bathymetry, side scan sonar but in the last decade, these data sets have proven and Innomar sub-bottom profiler has been very useful for investigating the Quaternary acquired in the Danish Skagerrak. Approximately sediments and especially erosional channels. 2200 line km of data were acquired in an area of Geotechnical data such as CPTu logs have approximately 2600 km2, extending between furthermore proven very successful in Skagen in the east and Hirtshals in the west and determining sediment types and by from 4 m water to 190 m in the deeper Skagerrak incorporating geotechnical data we can optimize some 50 km north of the Danish coast. This new our geological models and create a geotechnical dataset allows the first detailed morphological stratigraphy. In this study, we have utilized both analysis of this area and the first major study 3D and 2D high-resolution seismic data sets since the mid-1990s. A number of morphological together with geotechnical borehole data to features are noted that both confirm previous interpret the Quaternary landscape evolution in observations and provide new insights. In deeper the Danish North Sea. The emphasis is on the water these include: outcropping strata in the morphology, infill and relative age of buried west, where the Jutland current erodes the Quaternary valleys. We describe the differences seabed; sub-parallel wavy Innomar reflectors between the seismic expressions of buried river indicating contourite deposition; grooves eroded valleys and tunnel valleys. The present study into Holocene sequences, showing bottom combines extensive mapping of these channels current pathways; a variety of depression from 3D seismic data with detailed seismic morphologies coupled with a strong gas front analyses of high-resolution 2D seismic site indicating gas release and pockmark formation. surveys in order to validate the mapping from 3D Where the gas is absent the Innomar signal time-slice analyses. This gives us a better provides evidence of vertical chimneys and understanding of the sediment distribution in the images reflectors previously associated with late different channels and their relative age. This Pleistocene ice-proximal glacimarine deposition: study is part of the DHRTC (Danish Hydrocarbon below a Holocene sequence tens of metres in Research and Technology Centre)-funded project thickness. In shallower waters a large variety of “Seismic Acoustic Methods: A tool for refining the bedforms, from ripples to 4 m high sand waves, 3D geotechnical models in a mature hydrocarbon are present giving strong evidence of the across- producing area” in which the goal is to create a shelf sediment transport. These observations

271 geotechnical stratigraphy for the Danish Central 15.4. Open session Graben.

ORAL

EMODnet Seabed Habitat, an ambitious project for mapping benthic habitats in European waters. The Danish contribution.

Zyad Al-Hamdani1, Nicky Witt1 and Matthew

Owen 1GEUS

EMODnet (The European Marine Observation and Data Network) is funded by DG-MARE and in its third phase is composed of eight thematic “Portals” aiming at producing a multi-resolution seabed digital map for the whole European

waters that include bathymetry, geology, chemistry, biology, physics, human activities, seabed habitat mapping and the recently added Data Ingestion Portal.

The aim of the Seabed Habitat is to produce a broad scale seabed habitat map of all European waters. A cost effective method to obtain full spatial coverage seabed habitat maps uses

environmental layers such as sediment types, bathymetry, photic depth etc., as proxy to model the seabed habitat was adopted.

In the Phase I seabed habitat maps were produced with 1km resolution, in Phase II the resolution was increased to 250m and in the

current Phase III the aim is to produce 100m resolution broad-scale habitat maps for all European waters. Additionally, individual habitat maps from national surveys and point datasets from national monitoring programs will be

collated and standardised (INSPIRE), also habitat distribution models. The final habitat map is

converted into EUNIS classification as the common classifier for European waters habitats.

To achieve this member states need to provide available information gathered through mapping endeavours and point sampling.

272 Denmark has contributed in all EMODnet Phases. POSTER We present the latest habitat mapping project performed by GEUS/Orbicon in the North Sea. EMODnet Geology – a gateway to marine data in Europe

Jørgen O. Leth1, Bjarni Pjetursson1, Matthew J. ORAL Owen1 and Zyad Al-Hamdani1 1GEUS When did the Danish/German/Swedish straits form? Rapid access to reliable and accurate information is vital in addressing threats to the marine Ole Bennike1, Jørn Bo Jensen1 and Niels Nørgaard- environment, for developing policies and Pedersen1 legislation to protect vulnerable marine areas 1GEUS and in understanding trends and forecasting future changes such as the effects of climate change. The access to an effective pan-European The timing of the formation of the marine data infrastructure will also enable Danish/German/Swedish straits and the first effective and efficient marine spatial planning marine influence in the Baltic Basin has been and legislation for environment, fisheries, much debated. Here we present new radiocarbon transport and defence. ages from sediment cores retrieved from Danish waters. Most ages are based on shells of marine The European Marine Observation and Data molluscs, which means that the ages are Network (EMODnet) is a network of more than uncertain because we do not know the reservoir 160 organisations assembling marine data, age in the past. We use a reservoir age of 400 products and metadata to make the fragmented years, which is based on dating of museum resources more available to public and private specimens collected before testing of nuclear users relying on quality-assured, standardised bombs starter. It is clear from the ages that the and harmonised marine data, which are Great Belt (Storebælt) was inundated before the interoperable and free of restrictions on use. All Sound (Øresund). The oldest ages from the marine data users including marine industries, northern part of Great Belt are about 8700 cal. decision-making bodies, scientific research and years BP. From the central part of the Great Belt the public in general, benefit from the overall the oldest ages are about 8100 cal. years BP and philosophy of the EMODnet data infrastructure in the south-western Baltic Basin ages varies “collect once and use many times”. GEUS has from 7200 to 7600 cal. years BP. Sediments been involved in EMODnet-Geology since the deposited prior to the occurrence of marine start in 2009. EMODnet-Geology has successfully molluscs contain brackish-water ostracodes compiled harmonised offshore data across the (Cyprideis torosa and Cytheromorpha fuscata); European seas including: sea-floor geology, the sediments are usually laminated and non- seabed substrates, rates of coastline migration, bioturbated. The brackish-water phase may have geological events and probabilities and mineral lasted 500 to 1000 years. resources. The products are available via the EMODnet Geology Portal. In its third phase (2017-2020), the existing data products is further developed with higher resolution (1:100.000)

including more thematic themes such as, seabed geomorphology and Quaternary and submerged landscapes. New services are being built, so users now can investigate and search for borehole data and seismic survey data using interactive maps and tools.

273 16. Geomorphology 16.1. Remote Sensing - Digital acquisitions, we have been able to follow the eruption with high-temporal resolution. In mapping, remote sensing and particular, we have been able to reconstruct time 3d models in Earth Science series of gas and lava emissions, and ground deformation. We have also been able to document variation in activity at the lava lake itself, ORAL monitoring lava level and tracking individual overflows on time scales of tens of minutes. The 2017 eruption of Erta ‘Ale Integrating observations of both the lava lake and volcano, Ethiopia: a case study in vent, which represent two windows into the monitoring remote volcanoes with magmatic system, provides an unusual satellites. opportunity to contains the behaviour of a magmatic system during an eruption. Talfan Barnie1, Ashley Davies2, Gezahegn Yirgu3,

Moore Chris4, Simon Carn5, David Pieri2, Clive 6 7 4 Oppenheimer , Juliet Biggs , Tim Wright and ORAL Andy Hooper4 1Nordic Volcanological Center, Institute of Earth A 10-year series of surface Sciences, Reykjavik, Iceland, 2Jet Propulsion Laboratory- kinematics of periglacial sorted California Institute of Technology, Pasadena, USA, 3School of Earth Sciences, Addis Ababa University, Addis circles from SfM close-range Ababa, Ethiopia, 4School of Earth and Environment, photogrammetry University of Leeds, Leeds, LS2 9JT, UK, 5Department of Geological and Mining Engineering and Sciences, Ivar Berthling1, Luc Girod2, Andreas Kääb2 and Michigan Tech, USA, 6Department of Geography, Radmil Popovic1 University of Cambridge, Downing Place, Cambridge, 1Department of Geography, Norwegian University of 7 CB2 3EN, UK, School of Earth Sciences, University of Science and Technology, 2Department of Geosciences, Bristol, Wills Memorial Building, Queens Road, Bristol, University of Oslo UK

Sorted circles are one type of periglacial Most volcanoes on Earth are not monitored by patterned ground, created by large-scale local sensor networks, but we can potentially cryoturbation due to freezing and thawing of the track all subaerial eruptions using spaceborne active layer. It is one of the most conspicuous sensors. Here we investigate the prolonged types of patterns created by geomorphic fissure eruption of Erta ‘Ale volcano in northern processes on the earth surface, and widely used Afar, Ethiopia, which began in January 2017. We as an example of emergence in complex systems. are unaware of any local installations of monitoring equipment despite the longevity of Since 2007 we have attempted to document the the eruption and the geodynamic significance of spatial pattern of displacements going on in the volcano, which lies on an axial volcanic range sorted circles at 79°N on Kvadehuksletta, Ny- of the Red Sea rift system. The volcano is of Ålesund, Svalbard using Structure-from-Motion particular importance, as over the past 15 years (SfM) photogrammetry and feature-tracking. or so the behaviour of the lava lake(s) in the Published results (Kääb et al. 2014) show the summit caldera have apparently tracked or even applicability of this method in terms of gaining heralded volcanic and tectonic activity witnessed high-resolution information on vertical and across the broader Afar-Red Sea region since the horizontal displacements within the sorted circle early 2000s. Using a suite of routinely-, manually- system. This presentation will document a and automatically-commissioned satellite image decade of displacements within these sorted

274 circles, but also comment on challenges and ancillary information sources, software tools for possible solutions for long-term SfM monitoring advanced co-visualisation, interpretation and of sorted circles. data sharing are non-standard and rely on custom solutions for different applications. As a During 2007 and 2010 campaigns, we acquired means of addressing this imbalance, the current the images from a portable ladder. In 2015, 2016 contribution presents LIME, a lightweight, high and 2017, images were shot from a camera performance software package for viewing and attached to a long pole via a wifi connection to the interacting with 3D models and related spatial camera. The design was set up to yield a and non-spatial data sources. The software theoretical resolution of the digital elevation focuses on the novel integration of a variety of model of around 1 mm. geospatial and field data, such as 3D models, georeferenced images and maps, logs,

interpretation panels, and hyperspectral images. ORAL In addition, measurement and interpretation can be carried out by digitising in the 3D scene. A key Combined visualisation of 3D outcrop component is the generation of high quality and related geoscientific data using visual products, such as by projecting image and LIME 3D data onto photorealistic models to generate novel overlay layers. These features are Simon J. Buckley, Kari Ringdal, Bowei Tong, exemplified through case studies in Benjamin Dolva, Nicole Naumann, Tobias H. hyperspectral imaging, geophysical data Kurz integration and digital outcrop mapping.

Uni Research CIPR, N-5020 Bergen, Norway

Digital representation of the earth’s surface topography, using techniques such as digital ORAL photogrammetry, laser scanning and publicly available digital elevation models, is now Crystal-scale magnetic anomalies commonplace in geology and other areas of the geosciences. High resolution and accurate surface revealed by scanning magnetic models aid quantitative mapping, interpretation microscopy and analysis, acting as a framework for compiling Nathan Church1 and Suzanne McEnroe1 project data. In addition to 3D modelling, 1NTNU, Trondheim, Norway complementary imaging techniques (e.g. multispectral, hyperspectral and thermal imaging) add colour and spectral information Scanning magnetic microscopy (SMM) maps the that can be used for interpretation of patterns, magnetic field generated by petrologic thin texture, object material properties and sections or polished rock surfaces at the sub-mm distributions. Integrated 2D–3D analysis can scale, creating the possibility to resolve the provide powerful synergy when applied to contribution of individual grains and mineral problems in geoscience. Furthermore, compiling phases to bulk magnetic signal. The instrument 3D spatial datasets with supplementary spatial developed at NTNU has the capability to measure and non-spatial information in a single graphical both remanence properties and, uniquely, the environment aids interpretation and magnetic response in a field of known magnitude communication of study data to students, and direction. A series of case studies are collaborators and other stakeholders. presented to examine the capabilities of the microscope and to describe applications to the Despite the current ease of acquiring digital 3D study of crustal magnetism. The use of well- models, the increasing access to publicly characterized samples allows signals in magnetic available data, and the wealth of disparate scans to be attributed to grains of known

275 composition, including the discrimination of models, volume calculations and mapped signal associated with discrete oxides and volumes, contour maps (depth to layer/volume) assemblages of exsolved oxides in silicates, which and volume thickness. These products contribute can be observed to have differing directions of to a better understanding of the geology, a more magnetisation. The ability of this instrument to effective running of the deposits and, not least, image in fields mimicking those experienced in are attractive products for financial contributors the crust allows the observation of the induced and decision makers. This project is regarded as magnetic response, both qualitatively in the form a development project where we have created the of changes in magnetization direction, and workflow required from initial drone flight quantitatively by varying experimental planning, drone flying, point cloud management conditions. This capability gives SMM the ability to model integration in 3D MOVE. This project is to map both remanent response and generate a an initiative of the Mineral Resources Division at map of susceptibility, and provides a powerful the Geological Survey of Norway in collaboration new tool for the examination of bulk magnetic with several Norwegian Mining companies and is response in the Earth’s crust. partly financed by Mineralklyngen Norge.

ORAL ORAL

3D modelling and visualising of ASPECT spectral imaging CubeSat for resource deposits in Norway with planetary studies UAV technology and 3D MOVE Tomas Kohout1, Antti Näsilä2, Tuomas Tikka3, Iain Henderson1, Morgan Ganerød1, Espen Mikael Granvik4, Antti Kestilä5, Antti Penttilä4, Torgersen1 and Tom Heldal1 Janne Kuhno3, Karri Muinonen4, Kai Viherkanto2, 1Geological Survey of Norway Esa Kallio5 and Jaan Praks5 1Department of Physics, University of Helsinki / Institute of Geology, The Czech Academy of Sciences, This study combines detailed terrain models and 2VTT Technical Research Centre of Finland, 3Reaktor orthophotos of resource deposits in Norway with Space Lab Ltd, Finland, 4Department of Physics, geological information underground. The terrain University of Helsinki, 5Department of Electronics and Nanoengineering, Aalto University, Finland models are constructed using photogrammetry from a DJI Phantom4 drone and Litchi Mission Hub software. Individual flight plans are ASPECT (Asteroid Spectral Imaging Mission) is a uploaded to the autonomously flying drone 3U (30 x 10 x 10 cm) CubeSat concept designed leading to better model construction and more for deep space exploration of small Solar System efficient use of drone battery time. Point cloud bodies. The payload of ASPECT is a miniaturized data is uploaded to the Agisoft Photoscan visible - near infrared (500-2500 nm) spectral Professional software, where the 3D mesh imager. The primary scientific task of ASPECT is representing the ground surface is created and orbital high resolution compositional mapping of control points are added. The resultant the target surface with a meter resolution. The georeferenced mesh is exported to 3D MOVE and obtained compositional maps can be used to integrated with underground geological data, study space weathering and impact processes, as producing a fully integrated terrain-geological 3D well as in evaluation of areas for subsequent model. We have constructed several, widely sampling or in-space resource utilization (ISRU). different models: the Høgtuva Be-deposit i ASPECT is proposed to be part of European HERA Nordland, the Kleivan slate mine in Oppdal, and mission to asteroid Didymos or Japanese MMX the marble deposit at Fauske in collaboration mission to martian moon Phobos. with Norwegian Rose AS. A number of valuable products have beeen developed: Full digital 3D-

276 natural and man-made landscape changes that Iceland is exposed to.

An open-access benchmark repository providing high-resolution LIDAR topography and hyperspectral data for land-cover and landform

classification is under construction. Furthermore, a multi-temporal archive stretching back to 1945 allows a decadal evaluation of landscape changes by the development of automated change detection techniques.

The development of pattern recognition and ORAL machine learning-based approaches to image Environmental mapping and classification and change detection is one of the main tasks of the EMMIRS project, aiming to monitoring of Iceland by remote extract and compute earth observation variables sensing (EMMIRS) as automatically as possible. Ground reference data collected through a field campaign will be Gro B. M. Pedersen1, Olga K. Vilmundardóttir2, used to validate the implemented methods, which Fadi Kizel3, Nicola Falco4, Joaquin M. C. Belart1, outputs are then inferred with geological and Friðþór S. Sigurmundsson5, Gudrun Gisladóttir5 vegetation models. Here, preliminary results of and Jón Atli Benediktsson3 an automatic land-cover classification based on 1Institute of Earth Sciences, University of Iceland, hyperspectral image analysis are reported. Sturlugata 7, 101 Reykjavík, Iceland, 2Institute of Life and Environmental sciences, University of Iceland,

3Faculty of Electrical and Computer Engineering, University of Iceland, 4Lawrence Berkeley National POSTER Laboratory, CA, USA, 52Institute of Life and Environmental sciences, University of Iceland Safeguarding long records of

geomorphological measurements Iceland is exposed to rapid landscape changes using Structure-from-Motion from caused by natural processes and man-made ground-based images activities, which impact and challenge the country. Fast and reliable mapping and Ivar Berthling1, Bernard Hallet2 and Radmil monitoring techniques are needed on a big spatial Popovic1 scale. However, currently there is lack of 1Department of Geography, Norwegian University of operational advanced information processing Science and Technology, 2Earth and Space Sciences techniques, which are needed for end-users to Department, University of Washington incorporate remote sensing (RS) data from multiple data sources. Hence, the full potential of Modelling of the Earth System response to the recent RS data explosion is not being fully climate change benefits from records exploited. documenting sub-system response across The project Environmental Mapping and climatic perturbations. For many of the processes Monitoring of Iceland by Remote Sensing that today are incorporated within an ESM, we do (EMMIRS) bridges the gap between advanced not have this advantage. One example is information processing capabilities and end-user cryoturbation, the overturning of soil in mapping of the Icelandic environment. This is permafrost areas, suggested highly relevant for done by a multidisciplinary assessment of the the carbon budget. The process itself leaves no Hekla area, which encompass many of the rapid proxy records, except a mixture of soil organic carbon of variable age beneath the ground

277 surface, so recorded values of soil surface to quantify sand transport volume along the displacements through time is needed for this slipface of the dune. The model comprises 2500 purpose. images with a resulting ground-sampling distance of 1.67 cm/pixel over an area of 550 x During the 1980’ies, before the onset of 530 m. Special attention is given to the accelerated climate warming in the Arctic, identification of artifacts caused by the less Bernard Hallet initiated measurements on the structured, uniform sand areas. stone circles on Kvadehuksletta, Svalbard. The stone circles are a remarkable example of the effects of large-scale cryoturbation. Although these measurements are not continuous, the installations are partly still in place. They were POSTER re-measured in 2010, 2015, 2016 and again in September 2017. The purpose of this UAV photogrammetry to monitor presentation is to document our work on stability of rock climbing sites safeguarding the remains of these installations, and to transform the methodology using Axel Hellman1, Mark D. Johnson1 and Anne Structure-from-Motion from ground-based Hormes2 images, to enable continuing these 1Department of Earth Sciences, University of measurements into the future. Our goal is to Gothenburg, 2Institute of Geology, The Arctic University document how ground surface movements and of Norway, Tromsø cryoturbation have responded to the amplified effects of global warming at high latitudes, and to understand this response. Monitoring of steep rock faces and documenting their geostructural character to evaluate stability is a difficult task from the bottom of a steep rock face. Unmanned aerial vehicle (UAV) sensors and POSTER technology have seen a rapid development over the last five years. They can enable surveying and UAV topographic survey of a monitoring of rock-slope failures and detached migrating dune – pitfalls and first blocks in areas previously inaccessible and results (Sylt, southern North Sea) hazardous (Boccali et al., 2017). For this project, we study two frequently visited rock-climbing Benjamin Eberhardt1 and Sebastian Lindhorst1 crags in Sweden and Austria, both with 1University of Hamburg, Institute for Geology, documented rock-fall activity. In Sweden, a Bundesstr. 55, 20146 Hamburg, Germany recent rock-fall destroyed a well-known climbing

route in Fjällbo, Gothenburg. In Austria, High resolution topographic information is Engelswand is a very popular climbing crag in instrumental in analyzing sand transport Ötztal, where we counted 70 climbers on one processes on active coastal dunes. Unmanned Saturday, with reoccurring smaller rock-falls and aerial vehicles (UAV) greatly facilitate the on-site occasionally larger blocks occurring in the spring collection of aerial images and structure-from- during the melting period. motion (SfM) algorithms allow producing Our study explores the accuracy of UAV detailed topographic models from UAV-based photogrammetry for the analysis of rock-fall photogrammetric surveys. First results from a hazards. In Austria, we tested a rough acquisition SfM case study from an active (but partly workflow deploying handhold GPS points as vegetated) migrating dune (dune height up to 30 ground control points together with aerial m) are presented including survey design, imagery and telemetry data. We aim to compare georeferencing issues and applied data the accuracy of this quick method with the more processing steps. Aim of this study is to test the resource and cost-inefficient method of using a applicability of UAV-based topographic surveys

278 differential GPS and triangulation points to evaluate pros and cons of the different acquire a high precision of ground control points. algorithms.

The UAV imagery is processed in different software packages for compilation and comparison of accuracy. 3D models, digital terrain models (DTMs) and point clouds are produced and will be used for kinematic analysis.

Preliminary 3D model results suggest that the rough workflow provide accurate and detailed outputs.

16.2. Holocene coastal morpho- POSTER sedimentary systems: Archives, Classification of block fields in processes and forcing Norway using Machine Learning mechanisms

Mads Nedergaard Paulsen1 and David Lundbek Egholm2 ORAL 1Aarhus universitet, 2Aarhus Universitet

Did cuspate foreland formation The origin of Scandinavia’s extensive block fields trigger large-scale barrier coast has been a subject of debate for some time. One retreat? hypothesis suggests that the block fields mainly formed by pre-Quaternary warm-climate Mikkel Fruergaard1, Lasse Sander2, Jérôme chemical weathering (Paasche et al 2006), while Goslin1, Thorbjørn Joest Andersen1, Peter another hypothesis uses Late-Cenozoic cold- Johannessen3, Lars Henrik Nielsen4 and Morten climate physical weathering mechanisms to Pejrup1 explain the block fields through long-term 1Department of Geosciences and Natural Resource periglacial landscape evolution (Goodfellow et al. Management, University of Copenhagen, 2Alfred- 3 2014, Egholm et al. 2015). Several field studies Wegener-Institute, Geological Survey of Denmark and Greenland, 4Geological Survey of Denmark and have mapped the extent of selected block fields in Greenland (GEUS) Scandinavia, but the full distribution of block fields has not yet been studied. The stratigraphic evolution of barrier systems is In this master-degree study, we aim to use controlled by the ratio between rate of sea-level Machine Learning to map the distribution of rise and rate of sediment supply from external block fields in Scandinavia. The vast amount of sources. Because of increasing coastal erosion public available LIDAR data provides us with the and flood risk caused by the global rising sea opportunity to study distributions of landforms, level, many studies on barrier system evolution e.g. along climatic gradients set by latitude or are focused on understanding the impacts of sea- elevation. However, the shear data volume and level changes despite changes in sediment supply the need for consistent objective mapping call for are equally important controlling coastal automatic classification methods based on evolution. In this study we investigate how topographic features such as elevation, surface changes in sediment supply influenced the large- slope, curvature, and roughness. We discuss the scale coastal evolution of the Danish Wadden Sea applicability of selected Machine Learning barrier coast. This coast is wave-dominated and algorithms, such as k-means clustering, SVM, angular wave approach generates a large boosting gradient and Neural Networks, we southward-directed littoral drift. The Wadden

279 Sea is bounded towards the north by the cuspate storminess over the North Sea reconstructed foreland of Blåvands Huk and the shallow marine from a coastal lake of Western Denmark. Past shoal of Ulven. Based on detailed aeolian activity and storminess are reconstructed sedimentological and chronological using aeolian sand inputs preserved within the investigations of ~60 km barrier coast we organic-rich lake sediments. present several stratigraphic evidences that the coast experienced region-wide flooding and Our data demonstrate high-frequency variations coastal erosion between 4500 and 1400 years of aeolian sand influx between ca. 5000 and 2200 ago. New chronological data suggest that yrs B.P. that we believe adequately reflect the coinciding with the flooding and erosion, changes in past wind-climate and storminess. sediment accumulation and accretion took place Impressively cyclic pluridecadal-scale “breathing in the area directly north of the Danish Wadden patterns” in storminess activity are observed Sea. We suggest that the retreat of the coast was between ca. 5000 and 4300 years B.P. A massive related to the construction of cuspate foreland of sand invasion is then observed around 4300 yrs Blåvands Huk that largely trapped the littoral B.P., in accordance with the first period of dune drift from the north, preventing the sand reaching building obsreved along the west coasts of the Wadden Sea coast and thus shifted the Denmark (Clemmensen et al., 2001; 2009) and depositional locus northward from the Wadden simultaneousl to a period of climate deterioration Sea. The study indicates how sediment supply widely recognized elsewhere in Europe and and large-scale morphology of the coast can globally. The signal then progressively slowly control coastal evolution. fades-out, most probably reflecting coastal progradation and dune fixation.

These results will allow us to discuss potential ORAL internal and external climate forcing mechanisms, as well as to question the High-resolution Holocene windiness interdependencies between aeolian activity, and storminess over the North Sea: sedimentary dynamics and relative sea-level. insights from Filsø lake, Western

Denmark. ORAL Jérôme Goslin1, Lars B. Clemmensen1, Mikkel Fruergaard1 and Lasse Sander2 Detailed dynamic development and 1Institute for Geosciences and Natural Resources sedimentary architecture of a Management - University Of Copenhagen, 2Alfred Wegener Institute - Sylt Holocene to Recent micro-tidal barrier-island, Danish Wadden Sea.

Possessing long and accurate archives of past storm events is one key towards a better understanding of the atmospheric patterns Peter Niels Johannessen1, Mikkel Fruergaard2, driving these latter and of how coastal systems Lars Henrik Nielsen1, Lars Nielsen2, Ingelise reacted in the past to changing forcing Møller1, Thorbjørn Joest Andersen2, Stefan mechanisms. During the last decade, several Piasecki1 and Morten Pejrup2 Holocene storminess chronologies have been 1Geological Survey of Denmark and Greenland (GEUS), based on aeolian influxes within coastal lakes and 2Department of Geosciences and Natural Resource mires (e.g. Björck and Clemmensen, 2004; De Management

Jong et al., 2006; Nielsen et al.; 2016; Orme et al.,2016). The Rømø barrier-island is 14 km long, 4 km wide and the Holocene deposits c. 15 m thick. It is a This study presents a high-resolution (pluri- very sand-rich system as it receives coastal drift annual) history of Holocene past windiness and

280 sand from north and south along the shoreface. It Water levels of freshwater lakes can lower during is separated from the mainland by a 8 km wide the course of an interglacial and sedimentation lagoon. Average tidal range is around 1.8 m. can infill basins. Besides, wave actions develop During strong westerly storms, the water level spit systems in larger lakes by longshore increases considerably, up to 5 m above mean sediment transport that may cuts of smaller sea-level. basins. Here, we show combined effects of spit development, wave actions, antecedent The barrier-island formation started for c. 8000 topography and lake level changes on the years ago and is still active, which allows detailed Holocene development of the present-day Danish studies on recent sedimentary processes. lake, Mossø. A variety of methods were used: Stacking geometries of different sand units have coring, intensive profile digging and remote been unraveled based on: Seven c. 25 m long sensing, geophysical mapping by seismic sediment cores, 35 km ground penetrating radar reflection and electromagnetic induction, and (GPR) reflection profiles, and dating of 70 core dating by radiocarbon and optically stimulated samples using optically stimulated luminescence luminescence. We find that Mossø has undergone (OSL) providing a unique stratigraphic water level changes of perhaps 6 m and shore framework. erosion has varied accordingly. The sediment supply for spit formation depended of the vigor of Due to the detailed knowledge of the erosion, on wind direction and strength and on stratigraphic framework, depositional building up of the platform in front of the spits. environments and precise ages, a detailed palaeo- Strong spit activity was identified during three geographic reconstruction of the Rømø barrier- periods: c. 10 ka, 4.2 ka and 2.5-2.0 ka. The island has been carried out. The barrier-island location of spit formation was determined by initiated as a short and narrow island. The first changes in lake level and also local bathymetry 5000 years the barrier island sand aggraded and sediment transport patterns. Two spits because sedimentation kept pace with the connected and were reinforced by a beach barrier relative sea-level rise. The last 3000 years the by 2.5 ka, today constituting the eastern shoreline barrier-island prograded seawards, as the rate of of present-day Lake Mossø. The data suggests relative sea level rise decreased. This presence of an early Holocene large palaeo-lake aggradational-progradational development has Mossø with a 25 km east-west extent from the resulted in a thick and broad reservoir sand body. present-day lakes Skanderborg Sø to Salten This study shows that if there is a surplus of sand, Langsø. Confirmation of this paleo-lake requires a barrier island can aggrade and even prograde more investigations, as later erosions at the during a sea-level rise, creating thick barrier- thresholds that connects Mossø to the adjacent island deposits. lakes, and to river Gudenå, remains uncertain.

ORAL ORAL

Was the 4th largest Danish Lake The occurrence and formation of (Mossø) once much larger? wash-over deposits along the shores of the inner Danish Waters Søren M. Kristiansen1, Niels Emil Søe1, Aart Kroon2, Anders Vest Christiansen1 and Bent Vad Aart Kroon1, Lars Clemmensen1 and Verner B. Odgaard1 Ernstsen1 1Department of Geoscience, Aarhus University, 1Department of Geosciences and Natural Resource Denmark, 2University of Copenhagen, Department of Management University of Copenhagen, Denmark Geosciences and Natural Resource Management, Denmark

281 Wash-over deposits occur along many beaches seaward-dipping strata of the strand plain. fringing the inner Danish Waters. They are often Whereas strand-plain progradation is located on the Holocene barrier islands and spits interpreted to result from swash sedimentation and they are important accumulative features at the beach face under enduring calm conditions, with a relatively high preservation potential. The ridge construction reflects enhanced wave action barrier islands and spits are formed by at the beach due to elevated storminess or alongshore driven wave-induced currents and reduced nearshore sea ice. The internal they partly get their sediments from adjacent sedimentary architecture of individual beach eroding glacial cliffs. Wash-over fans are often ridges is interpreted to reflect maximum wave- present at the landward side of the barrier or spit runup height during the time of ridge crest and they are formed during storms under a construction. Ridges at sheltered parts of the combination of high water levels and onshore coast exhibit either seaward-dipping beds, directed high waves. The high water levels are interpreted to result from swash deposition, or however not always caused by wind set-up an aggradational stacking pattern being the result during storms in the inner Danish waters. The of wave overtopping. At exposed beaches, larger joint probability of water levels and waves shows ridges develop composed of seaward- as well as that under 30% of the high water levels have landward-dipping beds. Development of large waves. This means that the frequency of individual beach ridges is seen to result from occurrence of wash-over fan events is far less multiple storms rather than single events. than extreme water level statistics would suggest. In the present paper, we will address the spatial The number of individual ridges which are occurrence of different types of recent wash-over preserved from a given time interval varies along fans in east Denmark using satellite images and the coast depending on the morphodynamic lidar observations. We will also show the driving setting: Sheltered coasts are characterized by forces behind wash-over fan formation and show numerous small ridges, whereas fewer but larger the frequency of occurrence of these driving ridges develop on exposed beaches. forces. Data show that even ridges at higher elevation can be subject to later reactivation and

reworking. This questions sea-level ORAL reconstructions based solely on morphology and dating of polar beach ridges and advise careful Polar gravel beach-ridge systems – investigation of the stratigraphic architecture sedimentary architecture and use as prior to sampling for dating purposes. climate archive (South Shetland

Islands, Antarctica) POSTER Sebastian Lindhorst1 1University of Hamburg, Institute for Geology, Stratigraphy and sedimentary Bundesstr. 55, 20146 Hamburg, Germany architecture of polder fills along the

North Frisian Wadden Sea (southern The sedimentary architecture of polar gravel- North Sea) – potential archives of sea- beach ridges is presented and it is shown that level and climate variability (project ridge internal geometries reflect past wave- SEASTORM) climate conditions. Amalie Cordua1, Sebastian Lindhorst1 and Ground-penetrating radar (GPR) data obtained Christian Betzler1 along the coasts of King George Island (South 1University of Hamburg, Institute for Geology, Shetland Islands, Western Antarctic Peninsula) Bundesstr. 55, 20146 Hamburg, Germany show that beach ridges unconformably overlie

282 During the past millennium the North Sea coast Caleta de los Loros is a coupled beach ridge and was altered by sea-level and climate fluctuations tidal lagoon system located on the northern shore as well as by the onset of human land of San Matías Gulf, Patagonia, Argentina. The reclamation. Polders, areas embanked along the study is based on remotely sensed data, sediment coast during the last millennium, bear unique cores and a comprehensive dataset of ages sedimentary archives of coastal evolution during determined using optically stimulated different time intervals. These archives are so far luminescence (OSL). We present observations on unread. the geomorphology, sedimentology and chronology of the field site and propose As a first result of the ongoing project SEASTORM, inferences on the drivers behind its late Holocene stratigraphy and sedimentary architecture of evolution. Caleta de los Loros is located in a selected polders on the German Eiderstedt topographical depression within a cliffed peninsula are presented. The peninsula has been shoreline composed of friable sand and gravel th shaped by land reclamation since the 10 stones. The oldest marine deposits of Holocene century, and since the 12th century the history of age formed in the inner part of the depression polder embankment is documented. The around 2300 yr ago. Between 1000 and 500 yr sedimentary successions were investigated on ago, an up to 4 km wide strandplain formed in the the basis of a sedimentological dataset (grain size, exposed southern part of the system. The tidal XRF, core description, X-radiographic images, lagoon subsequently experienced a period of and radiocarbon ages); depositional geometries increased sedimentation between 500 and 100 yr were imaged by means of ground-penetrating ago. The system is hence much younger than radar. A LIDAR-based high-resolution digital similar coastal environments in Patagonia and terrain model allows for geomorphological shows no apparent relation to changes in the investigations. rates of mid- to late Holocene sea level change (Schellmann & Radtke, 2010). However, stages in The sedimentary succession preserved in the the morphosedimentary evolution of Caleta de polders documents the complex geological los Loros are concurrent with proposed changes evolution of the area comprising multiple phases in humidity and wind regime for northern of salt-marsh growth, re-flooding and erosion. Patagonia as well as with changes in human Correlation of sedimentary successions in occupation and subsistence strategy (Favier- different polders aims on overcoming local-scale Dubois and Kokot, 2011; Marcos et al., 2012). effects to reconstruct changes in sea level and Caleta de los Loros presents a new example of the climate oscillations. potential importance of sensible environmental changes for the rapid and non-linear development of coastal systems. POSTER

Chronology and late Holocene evolution of Caleta de los Loros, NE Patagonia, Argentina

Lasse Sander1, Morten Pejrup2, Andrew Sean Murray3, Gerardo M. E. Perillo4, Luís Ariél Raniolo4 and Mikkel Fruergaard2 1 Alfred-Wegener-Institute, List/Sylt, Germany, 2University of Copenhagen, Copenhagen, Denmark, 3Nordic Laboratory for Luminescence Dating, University of Aarhus, Denma, 4Instituto Argentino de Oceanografia, Bahía Blanca, Argentina

283 very low detail. The aim of the study was to 1) develop a procedure for processing topobathymetric lidar data and generating Digital Elevation Models (DEMs) in coastal zones, 2)

automatically classify morphological units, and 3) investigate the potential of mapping shallow water vegetation. We show results from two locations with different environmental settings: the Knudedyb tidal inlet system in the Danish

Wadden Sea and Rødsand lagune in the inner Danish waters.

16.3. Lidar in Geomorphology

ORAL ORAL Morphologic mapping and Mapping morphology and vegetation monitoring of sediment transport in shallow water using using high resolution topobathymetric lidar topobathymetric Lidar in manifold

Mikkel S. Andersen1, Zyad Al-Hamdani2, Laurids R. geomorphic settings: Examples from Larsen3, Frank Steinbacher4, Ramona Baran4, Isar river in Munich and Wadden Sea Bjørn M. Torsvik5 and Verner B. Ernstsen5 in Denmark 1NIRAS A/S, Denmark & Dept. of Geosciences and Natural Resource Management, Uni. of Copenhagen, Ramona Baran1, Frank Steinbacher1, Wolfgang DK, 2Geological Survey of Denmark and Greenland Dobler1, Mikkel S. Andersen2, Laurids R. Larsen2 (GEUS), Denmark, 3NIRAS A/S, 4Airborne Hydro and Verner B. Ernstsen3 Mapping GmbH, Austria, 5Department of Geosciences 1AirborneHydroMapping GmbH, Innsbruck, Austria, and Natural Resource Management, University of 2NIRAS, Allerød, Denmark, 3Department of Geosciences Copenhagen, Denmark and Natural Resource Management, University of Copenhagen, Denmark

The coastal zone is under pressure from human exploitation and climate change, which leads to a Fluvial and coastal/tidal environments are need for sustainable coastal zone management – valuable ecosystems under pressure due to a challenge which requires high resolution globalization and/or climate change. Their mapping and monitoring. Historically, there has detailed mapping is required to manage river been a gap of information in shallow water, courses and coastal zones in a sustainable way. however, the emerging technology of airborne Traditionally, the transition zones between land topobathymetric lidar has proven capable of and water were difficult or impossible to map and simultaneously capturing topographic and investigate in high spatial resolution due to bathymetric elevation information, resulting in a challenging environmental conditions. The new seamless coverage of the land-water transition generation of airborne topobathymetric LiDAR zone. The new technology also provides a potentially enables full-coverage and high- potential for detailed identification and resolution mapping of land-water transition classification of shallow water morphological zones. Repeated surveys provide the opportunity units and vegetation – which was previously for geomorphologic mapping, monitoring and impossible to map, or at best it was mapped in quantifying fluvial and coastal sediment-

284 transport. We first present results from two We have now surveyed one of these rock glaciers, repeated topobathymetric surveys along the Isar situated in Ivarsfjord, by repeated drone imagery river in Munich, Germany, to quantify and map (2016-2017) and Terrestrial Laser Scanning river-bed changes related to a large flood (June (2017). Digital elevation models (DEMs) were 2013). We evaluated river-bed elevation compiled from aerial photos from 1975, 1982 and differences between the survey before (October 1992, and a network of miniature data loggers 2011) and after (July 2013) the flood yielding was employed over the rock glacier surface to elevation differences of several decimeters to evaluate near surface temperatures. Two short meters due to erosion and sedimentation of bed- ERT (Electrical Resistivity Tomography) profiles material. The detailed analysis provides new were established from the top to the front slope possibilities to better manage inner-city river of the rock glacier. structures and support future planning on restoration along the Isar river. In a second study, Our first results indicate both thermokarst we performed a topobathymetric LiDAR survey development and front position advances since in the Knudedyb tidal inlet-system in the Danish 1975. This implies that the rock glacier is active, Wadden Sea (April-May 2014). This dataset was but currently degrading. The ground surface used for detailed geomorphic analysis on the temperature network indicates above 0˚C intertidal drainage-network and bedforms, and temperatures as an annual mean. We therefore was further compared to a topographic LiDAR believe that permafrost can be present even at survey (2011) to evaluate and quantify coastal sites in Finnmark in special settings, morphodynamics, e.g. sediment-transport indicating sporadic (palsas) to more wide-spread directions. Our results demonstrate that high (rock glaciers) permafrost, but in a state of resolution topobathymetric LiDAR is an efficient, degradation at present. widely applicable tool to monitor and measure With large-scale permafrost thaw occurring in fluvial and coastal sediment-transport and the Arctic at present, this area could serve as a geomorphic processes. time-space substitute of High-Arctic landscapes like Svalbard or Siberia in a changing climate.

ORAL

Active rock glaciers at sea level in ORAL Finnmark, Northern Norway? Better Visualisation of Air-borne

Karianne Lilleøren1, Vetle Aune1, Bernd Laser Scanning for geomorphological Etzelmüller1 and Trond Eiken1 and archaeological interpretation 1Department of Geosciences, University of Oslo 1 2 Thomas Ljungberg , David Stott and Søren Munch Kristiansen1 Rock glaciers are geomorphological expressions 1Institut for Geoscience, Aarhus Universitet., 2Institut of permafrost presence. Their state of activity for Geoscience, Aarhus Universitet; Arkæologisk IT, indicates occurrence of current or former Moesgaard Museum. permafrost. A series of rock glaciers emerging at sea level have been identified in Digital elevation models derived from high- Nordkinnhalvøya, Northern Norway, and have precision Air-borne Laser Scanning (ALS or earlier been classified as relict landforms LiDAR) point clouds are becoming increasingly (Lilleøren & Etzelmüller, 2011). However, a available throughout the world. These elevation recently published permafrost model of the models presents a very valuable tool for locating Nordic countries (Gisnås et al., 2016) simulates and interpreting geomorphological as well as permafrost at similar elevations elsewhere in archaeological features in the landscape. The Finnmark, but mainly in mires as palsas. elevation models are, however, not always

285 directly useable, because the variations in and will continue for three years. The project is elevation in the models often are orders of part of the BONUS Programme, co-funded by magnitude larger than the features of interest, national research funding agencies of the three which makes these hard to see. It is therefore project partner countries Germany, Poland and usually necessary, and always advisable, to Denmark. . enhance (transform, improve, manipulate) the visual appearance of the elevation model, so that the features of interest are more clearly shown. In this paper, we discuss the usefulness of several advanced visualisation techniques for locating and interpreting a.o. fossil beach ridges, paleo- lake shorelines, sub-glacial meltwater courses, Iron Age Celtic field boundaries, and various other geological and archaeological phenomena under Danish conditions. 16.4. Open session in Geomorphology

POSTER

EcoMap Project: Baltic Sea POSTER environmental assessments by Landslides in northwest Iran: a case innovative opto-acoustic remote study on the landslide hazard sensing, mapping, and monitoring. zonation in Baleghluchai watershed

Signe Schilling1, Zyad Al-Hamdani2, Verner in Ardabil using AHP Fuzzy method Ernstsen1, Jørn Bo Jensen2, Aart Kroon1 and Jens Keristineh Jananeh1 and Shahram Roostai1 Schneider von Deimling3 1Geography Department, University of Tabriz, Tabriz, 1IGN/KU, 2GEUS, 3University of Kiel Iran

Remote sensing and classification of the seafloor Landslides and slope instabilities are among the are required to obtain a comprehensive view on important natural hazards, which cause human the marine environment. It allows for analysing and financial casualties and loss of economic spatio-temporal dynamics, monitoring of natural resources every year. The northwest of Iran is seabed variations, and evaluating possible prone to the occurrence of landslides due to its anthropogenic impacts, all being crucial in mainly mountainous topography, complex implementing marine spatial planning for geology, abundance of tectonic activities and sustainable use of the sea that leads to the earthquakes and variable climate. These hazards economic growth of the region. mostly occur in natural slopes or those The EcoMap project will develop a remote manipulated by human. This contribution sensing catalogue documenting the feasibility of includes a case study on the landslide potential latest opto-acoustic methods for improved Baltic zonation within the Baleghluchai watershed in Sea habitat monitoring. This catalogue will be NW Iran. First, the main factors including the developed in close co-operation with authorities slope and its direction, geology, soil, climate, to meet their requirements and will allow distance from the road and river and land usage stakeholders with different interests to quickly were determined. The method of current judge which remote sensing method is ideally investigation was Fuzzy AHP in the GIS suited for respective monitoring tasks of specific environment, based on which, after preparing habitats. EcoMap commenced in September 2017 data layers using the above-mentioned parameters and giving weights to them in the GIS

286 environment, the landslide potential map, as well as classification was carried out by Fuzzy AHP method.

According to the final zonation map, the watershed was divided into 5 classes. Results showed that the largest part of the watershed (32.21%) has low landslide potential, while about 13.5% of it has very high potential. Areas with very high and high landslide potential (327.39 km2 area) are mainly located in the northwest of the watershed, with some small areas distributed in the south and east, while areas with very low and low potential (504.06 km2) are mainly found in the central to northwestern and southern parts of the watershed.

17. Education, preservation and outreach 17.1. Education, Geology Day is a Swedish non-profit organization. Our aim is to spark curiosity among the public communication, preservation and to highlight the benefits of basic knowledge and Geoheritage of geology and earth sciences to society. Every year since 2001 our organizers invite the public to take part in a nationwide celebration of ORAL geology in September. At the 17 year mark we ask ourselves; what have we learned, what are our Geology Day in Sweden, lessons from challenges and how do we continue working to 17 years promote earth sciences throughout the year?

Nelly Aroka1 1Geological Survey of Sweden ORAL

287 Challanges in conveying geology to - Do we really want to share them with the society. - Examples from Danish rest of the world? landscapes traced by a Norwegian - How can local community benefit the site? geologist, in order to create curiosity - How may we plan for massive traffic in a for geology and explain geological sustainable way? processes. The presentation will show examples from Thorbjørn Kaland1 Danish landscapes, with the objectives to create 1 University of Bergen curiosity for geology and geological processes.

Though schools at all levels are teaching geology and science, we are facing frequent lacks of knowledge leading to misunderstanding of basic geology.

Teachers, journalists, bureaucrats and politicians may need to upgrade knowledge in geology. ORAL

Geologists need to meet the challenge and share What do we actually teach students in their interests for earth science. the field?

But how? Rie Hjørnegaard Malm1 1University of Oslo The best way of making people search for the answers of everything’s genesis, is to take them out of their rooms, and rediscover nature. Fieldwork has a central position in the geosciences and is typically an integrated part of Scandinavian and German tourists drive through the study programme, where it is considered by Denmark to see everything, - but geology. They many as a crucial part of the learning process and disregard the most beautiful jewels of Denmark. linked to the process of becoming a professional Most sites have got a geological story to tell. geoscientist (King, 2008; Raab & Frodeman, 2002). Fieldwork is suggested to be an effective How may we make the local society understand learning arena to teach the scientific method and their local landscape? New visual tools may bring reasoning (Mogk & Goodwin, 2012). Educational back the ice cap with its drain and movement. research shows great opportunities for learning, but how do we know what the students learn? How may social media tell more than any And how does our teaching in the field affect the geologist? students’ opportunities to learn?

Trolltunga is a cliff in Western Norway, lying In this piece of research I follow students closely lonely for 10.000 years. in the field and explore how and what they learn. By seeing teaching from the students’ perspective After a few foreign hikers dropped into the site I am able to show in detail how the organization and posted their picture on Facebook, Trolltunga of teaching has an influence on the learning = Norway. Yearly more than 100.000 hikers walk potentials for the students. the 9 hour mountain walk to take their selfie at Trolltunga. When the students are given the freedom to explore and collect data on their own they This story reveals some interesting challenges: experience a learning situation that simulates an - Where do we find “Trolltungs”? authentic research situation. In this process it proves to be crucial that the students are allowed

288 to make mistakes and are given enough time to The idea in these was that individual teacher discuss their data collection. If we only show could use the one, or ones, containing students how to work in the field great learning information about the bedrock in his/her area. opportunities are lost. I present results from my The produced material is naturally highly usable research on students working in the field in in popularising geology to any non-professional mainland Norway, Svalbard, the Orkney Islands, target group. and the Spanish Pyrenees and discuss how we can construct teaching in the field that promotes learning.

ORAL ORAL

Generalized bedrock map of Finland Rock Fossils on Tour – Zoological and related material nomenclature at its coolest! Perttu Mikkola1 Jesper Milàn1, Mats E. Eriksson2, Achim G. 1Geological Survey of Finland Reisdorf3, Esben Horn4 and Rune Fjord5

1Geomuseum Faxe, Denmark, 2Department of Geology, 3 In most countries the laymen’s typically have Lund University, Lund, Sweden, University of Basel, Switzerland, 410Tons APS, Denmark, 5Rune Fjord limited understanding of geological concepts and Studio, Denmark processes. Reasons behind this are multiple, but one recognised factor, at least in Finland, is the lack of suitable teaching material that could be Zoological nomenclature, the science of naming used in elementary and high schools. To answer extant and extinct organisms can seem like a dull this need Geological Survey of Finland (GTK) field with little public appeal. However, a new produced in 2016 a generalised 1:1 000 000 scale travelling exhibition “Rock Fossils on Tour”, bedrock map (Mikkola et al. 2016), which is dealing with just that theme, has managed to based on the same database as the ”professional” attract a wide international audience and reach version compiled by Nironen et al. (2016). The far beyond the normal palaeontological circles, generalisation was done in association with and straight into the heart of rock fans! geography teachers to ensure that for example terminology used is understood by the target The exhibition portrays fossils that are named group. Although the map is available as a print after rock, punk, pop, jazz and heavy metal stars, ready pdf-file, the most important distribution and features exclusive lifelike sculptural channel is an online map service. In this service reconstructions of the animals. In addition, the user can open short information boxes by clicking musicians who lent their names to science are on the map objects. These include for example the presented alongside amusing anecdotes from the age of the formation, its distribution in Finland, in scientists responsible for this unusual etymology. what kind of environment it was generated and Many of the items have been signed by the rock one or two photos of representative outcrops or stars. The exhibition has gained extensive samples. Readymade slide packages on the larger attention in the media and news groups geological entities, e.g. the Archean in Finland, worldwide, and has been very well received by were also distributed to the geography teachers. both music and fossil fans in the six European museums it has visited so far.

289 This is the story of how the exhibition came to be, Cooperative projects and educational activities from a spontaneous capricious idea, its rise to with partner institutes in stressed regions are the success, and the plans for its future expansion. distinctive profile of the KERMIT project. These activities build upon our international networks and the multidisciplinary research from the cooperative projects, utilizing earlier results and

emphasizing the exchange activities for knowledge transfer in all directions. One on- going case study deals with water-management strategies for Aleppo, Syria, and considers the increased pollution loading on agricultural areas along the river due to continued irrigation during the war while the water-treatment plant has not

functioned. In addition, urban pollution sources, transport pathways, and recipients are modeled using system structural analysis and relative risk ORAL ranking methods.

Knowledge Exchange for Resource Management and International Trust POSTER – Aleppo case study GIS - an appropriate tool for Rodney Stevens1, Mohamed Alkridi1 and Michael Kouro1 undergraduate field mapping? 1Department of Earth Sciences, University of 1 1 Gothenburg Morten Aanvik , Sigmund Slang , Amund Bråten 1 1 Rian and Monika Oftedal Voll 1University of Oslo The KERMIT project deals with research and capacity-building targeted at two, related groups Geographic information systems, GIS, are key with academic backgrounds: 1) refugees in tools in the industry and geological surveys, Europe and 2) local populations in the stressed increasing the efficiency of mapping and data regions from which people are fleeing. Although collection in the field. Though GIS usage is the long-term focus is aimed at raising the widespread, there is little focus on GIS in the field competence and capacity for sustainable parts of the geology program at the University of resource management in stressed regions, the Oslo. The focus lies on learning basic field skills refugees with academic backgrounds involve and traditional mapping methods. We are often both new challenges and opportunities with met with the argument that we need to hold a related objectives. These refugees need basic knowledge of traditional methods before complementary study to adapt their educational advancing to more complex digital systems. Here background to European conditions, and at the we report use of Arcmap Desktop to digitally map same time they can provide valuable expertise an area in the inner Oslofjord as part of our and knowledge of specific regions and general bachelor capstone course. To implement ArcMap conditions where resource conflicts and management have increased migration. Utilizing data files were created to record mapping the connections to the local academic community observations, together with DEM/DSM files and the existing infrastructure, project activities constructed from laser data. Computer files were explore the dual and complementary goals to interpreted and analysed during fieldwork to find increase human capacity, thereby strengthening areas where more observations were needed. the hope for positive, short-term and long-term This resulted in a high learning outcome in use of developments for both groups. ArcMap. Comparing traditional mapping to GIS

290 mapping highlights advantages of using digital geologists' and archaeologists' eyes; ii) An tools. Data collection increases greatly in speed, engaging level - we hosted exhibitions and a quantity and quality. Potential downsides include public event with the purpose of showing battery life of devices and vulnerability to different possibilities of making a living out of weather. Both objections are easily mitigated by soapstone as well as communicating this message using water proof cases and power banks. Digital through the press; iii) A teaching level - we have mapping greatly improved the quality and communicated the results of the project through precision of our map and geological talks, a film and a website about the project. By understanding of the field area. We conclude that mixing traditional scientific outreach with GIS is a teaching aid that should be utilized in field elements of involving communication and a focus work, having the potential to improve the on direct relevance, we reached new types of geological understanding of students and prepare audience. By focusing on direct relevance and by them for the work life. involving several stakeholders representing authorities (municipality level), business (business council and business support), art (museums and artists) and tourism (tourism POSTER organisation and operators), we have created a Soapstone from Nuuk: better understanding of how to use our research among locals. Communicating scientific and commercial value of a local resource

Rebekka Knudsen1, Nynke Keulen2, Majken D. POSTER Poulsen3, Kisser Thorsøe4 and Morten Meldgaard Ilisimatusarfik, Nuuk, Greenland & Natural Stevns Klint, Denmark – UNESCO History Museum of Denmark, Copenhagen World Heritage Site and how to University, Denmark conduct geological research at the 1 Greenland Perspective, Natural History Museum of site in the future. Denmark, Copenhagen University, Denmark, 2Geological Survey of Denmark and Greenland, Nuuk Jesper Milàn1 and Tove Damholt2 Greenland & Copenhagen Denmark, 3Geological Survey 1Geomuseum Faxe/Østsjællands Museum, Denmark, of Denmark and Greenland, Nuuk Greenland & 2Verdensarv Stevns, Store Heddinge, Denmark Copenhagen University, Denmark, 4Geological Survey of

Denmark and Greenland, Nuuk Greenland

The UNESCO World Heritage Site, Stevns Klint, in The Soapstone from Nuuk project bridges the gap the eastern Denmark represents the best exposed between scientists and people by anchoring Cretaceous−Tertiary boundary section in the research into society and showing its relevance to world. The boundary clay layer is easily daily life. Our goal is to inform the citizens of recognizable beneath a pronounced topographic towns and villages in Greenland about the overhang, which separates the soft Cretaceous potential for small-scale mining of soapstone and chalk from the overlying, harder Paleogene to engage local community in using the limestone. This makes the boundary layer visible opportunities soapstone holds; for small-scale even to the inexperienced eye. Furthermore the mining, geo-tourism and local rock collectors and exceptional complete marine fossil record for archaeological investigations. In order to present at Stevns Klint makes the site among the engage a broad spectrum of the population in the best localities worldwide for studying marine project we decided to work on 3 communicative biotic turnover across the K-Pg boundary, and the levels: i) A practical level - we hosted an in situ discovery of the iridium anomaly in the boundary citizen science workshop to teach the clay layer in 1978 made the site a key locality in participants how to see the landscape and the the scientific debate about an impact vs. rock formations in the Nuuk area through the volcanism related cause for the End Cretaceous

291 extinction. The management of Stevns Klint as as shared cultural and historical identity. Better UNESCO World Heritage Site is developed in environmental management, better and new order to secure protection of the site in a manner products for the tourism industry, better tourist that encompasses the opportunity for sampling experiences, development of new tourist sites for scientific purposes and encourages continued and better education in the region. research activity. According to the agreed guidelines sampling in the cliff face for scientific In the interreg project GEARS (2017-2019) ,are purposes may be permitted by the local SGU project owners and NGU have project geological museum, Østsjællands Museum. Who management. In addition, several other regional will help, ensure that the sampling are institutions and companies from Norway and constructed in a manner that both ensures the Sweden participate in the project. scientific purpose of the sampling, and minimizes Interreg project Sweden and Norway (2017- the impact on the protected cliff site. 2019): SGU is project owner, NGU is project Østsjællands Museum invites all interested manager In addition, several other regional researchers to contact the museum to obtain institutions and companies from Norway and permits for sampling, and also to participate in Sweden participate in the project. the effort to communicate the scientific importance of the site to the general public. POSTER

Detailed mapping of the POSTER polydeformed Gressholmen and GEARS: Geological heritage in inner Rambergøya islands, Oslo Rift - a Scandinavia capstone course project at Oslo University Terje Motrøen1, Rolv Dahl2 and Gunnel Ransed3 1Høgskolen i Innlandet, 2Norges Geologisk Undersøkelse Monika Oftedal Voll1, Amund Rian Bråten1, - NGU, 3Sveiges Geologiske Undersøkelse - SGU Sigmund Slang1 and Morten Aanvik1

1University of Oslo The goal of the project is to record, manage and create values based on the region's common The small islands of Gressholmen and geological heritage. Achieved results will be a Rambergøya, situated in the Inner Oslo Fjord common framework for geological surveying, within the Oslo Rift, were mapped in 1:5000 scale registration and descriptions of geo resources in as part of the bachelor capstone course at Oslo selected areas in Indere Scandinavia. Other University. The islands comprise mid-Ordovician results are the testing of new methods for to earliest Silurian sediments, recording the local information on geological heritage through the expression of the global upper Ordovician use of new dissemination technology (VR / AR regression and early Silurian transgression. The technology), obtaining material about the rocks are dominated by shales, nodular shales geology of the region aimed at the public and and limestone, locally fossil rich. In the Silurian, residents and organizing an international the sequence formed part of the Caledonian fold seminar on geological heritage. and thrust belt. Repetition of layers and calcite Expected effects are increased local and regional filled thrusts (locally with slickensides) are awareness of the importance of geological common, indicating top-to-southeast heritage as a resource for tourism and business displacement. The islands themselves form a development. Increased cooperation between large scale overturned southeast verging tourism and nature management, increased anticline with numerous parasitic folds of awareness and pride of local landscapes, as well different orders. The compressional structures

292 are overprinted by north-south trending sub- The University Centre in Svalbard, UNIS, is vertical extensional faults, commonly with sub- Norway’s national high Arctic research and vertical slickenlines. Dikes of different education hub located in Longyearbyen, Svalbard compositions, mainly striking north, are present at 78°N. In Arctic Geology UNIS offers BSc, MSc on the islands. Both the faults and the dykes are and Phd- level courses and semester packages parallel to the nearby eastern Oslo rift margin, (30 ECTS) in geology and physical geography. All and are consistent with east-west Permian courses at UNIS include a significant field-based extension associated with its formation. The component, and the natural environment limited extent of the study area and the complex provides the “lab” facilities for the courses. Even tectonic evolution of the islands make them in this location Arctic field work can be highly suited for undergraduate mapping logistically demanding. Similar to any program in projects. In particular, successful mapping of the geology, it is beneficial to increase the students’ island requires integration of the various sub- exposure to hands-on and realistic exercises, in disciplines that make up the bachelor program, order to prepare them for field work. Increased including sedimentology, paleontology, exposure also allows students to continue mineralogy-petrology and structural geology, practicing field skills after returning to the within a tectonic framework. The mapping classroom. project provides a natural laboratory for revising, testing and developing field skills in an authentic We are active pioneers of emerging technologies context that prepares students for independent such as virtual outcrops and virtual reality as geological work in their later careers. relevant tools to be used in the classroom. Use of tablets in the field provides access to data, models and previous work (including classroom-based preparation exercises) during the field work, and POSTER allows for a more coherent learning experience between field- and classroom time. The aim of the Field-based education in the high digitally supported learning environment is to Arctic – how digital tools can support increase student learning and increase the use of active learning in Geology formative feedback. In addition it allows us to do hands-on, field relevant teaching year-round, Kim Senger1, Wesley R. Farnsworth1, Hanne H. including during the 4 month long dark season. Christiansen1, Graham Gilbert1, Holt Hancock1, Andy Hodson1, Lena Håkansson1, Maria Jensen1, In this contribution we share our experiences of Malte Jochmann1, Mark Mulrooney1, Riko using these emerging technologies in a harsh Noormets1, Snorre Olaussen1, Alexander Prokop1, Arctic environment in the framework of the Aleksandra Smyrak-Sikora1 and UNIS geology recently revised BSc package offering at UNIS adjunct staff1 using active learning. 1University Centre in Svalbard (UNIS), Dept. of Arctic Geology, N-9171 Longyearbyen, Norway

293 18. Other topics 18.1. Other Sessions energy, including geothermal, and injection projects for CO2 storage and other purposes.

The presentation will open for a discussion on ORAL how best to develop guidance for the use of the UNFC in the Nordic region for the commodities it Beyond Classification – Managing has been developed for. Resources Sustainably

Sigurd Heiberg1, Per Blystad2, Kerstin Brinnen3, Charlotte Griffiths4, Tom Heldal5, Janne Hokka6, POSTER Erika Ingvald7, Kaj Lax7, Hannu Makkonen6 and Harikrishnan Tulsidas4 DETERMINATION OF 1Petronavit a.s and Petrad, 2Petronavit a.s., 3Svemin, PALAEOPRODUCTIVITY USING 4 5 6 UNECE, Geological Survey of Norway, Geological CARBON QUALITY IN AN END Survey of Finland, 7Geological Survey of Sweden MEMBER MIXING MODEL

Successful resource management requires Justin Fadipe1 and Maarten Felix1 relevant information on the resource base, 1Department of Geoscience and Petroleum, Norwegian University of Science and Technology adequate framework conditions set by

Governments and society and enterprising capacity, also termed integrative dynamic To improve our understanding of the global capabilities in the public, private and financial carbon cycle as well as the impact of sectors. We begin by addressing how the United anthropogenic contributions to this cycle, it is Nations Framework Classification for Resources important to understand the link between (UNFC) is built to house resource inventories and palaeoproductivity and the amount of carbon the guidance provided for applying this to that is ultimately buried. There has been much minerals in Finland, Norway and Sweden. The debate regarding the fate of organic matter (OM) information is carried by the project, not the during its transition to the sea floor, and about deposit. Focus is on the quantities that the project the quantification of OM remineralisation and will yield in the form of sales and non-sales preservation within subaqueous sediments. production and how much will be left in the subsoil. Inventories are constructed by This study applies a kinetic model with the aim of categorising separately the economic and social quantifying the decay of organic matter in both conditions for development, their industrial the water column and during the early stages of status and the uncertainty with which the sedimentation. Laboratory derived decay rate quantities are defined. The projects themselves constants for different constituents of organic carry other important management information matter together with the duration required to such as time series of production, costs, labour settle through the water column, were used to etc. The classification is mapped (bridged) to produce a quantitative estimate of carbon flux to other key classifications such as the CRIRSCO the sediment. The approach demonstrates its template, the SPE PRMS and the new Russian validity when compared to measured trap data classification for oil and gas (RF2013). This from literature. In addition, a comparison facilitates the reporting of a UNFC inventory in between the modelled flux and empirical these classifications. equations showed similar outputs for both. The model results also compared well with (more Being a project based resource classification, the limited) measured sediment column data. UNFC has been adapted not just to fossil energy and mineral resources, but also to renewable

294 Estimating palaeoproductivity utilising the POSTER proposed kinetic model, necessitates the distinction of the relative contributions of marine Frequency-magnitude analysis for and terrigenous sources to total organic carbon landslides in Sogn og Fjordane (TOC). Bulk geochemical measurements of TOC and hydrogen index (HI) are used in an end Håvard Mongstad1, Graziella Devoli2 and member mixing model, whereby the degraded Karianne S. Lilleøren1 marine end member values are obtained by 1Department of Geosciences, University of Oslo/Norway, 2 applying the kinetic model. Application of the Hydrology Department, Norwegian Water Resources and Energy Directorate, Oslo/Norway kinetic model to carbon quality provides reasonable estimations of degraded HI end- members. The county of Sogn og Fjordane in Norway has a climate and topography which makes it

vulnerable for debris avalanches, debris flows POSTER and slush flows. The recently established landslide forecasting service at NVE Surface kinematics of sorted circles (www.varsom.no) is able to predict their spatial using Structure from Motion and temporal occurrence. However, a better understanding of these processes, their spatial photogrammetry in Juvfonne and distribution, dimensions, mechanisms and Juvasshøe dynamics is needed to improve the performance of the service, especially at local scale. Andrea Gaustad1 1Geografisk institutt, NTNU The main objective of the study is to investigate if the landslide warning for the county can be improved by considering the landslide Sorted circles are a form of periglacial patterned magnitude. The analysis implies mapping of ground that are recognized by characteristic landslides and an analysis of meteorological and geometric shape. Sorted circles are believed to sedimentological conditions of which the events have an important function as a carbon reservoir were triggered from. The analysis focus on in high latitudes. landslides in soil (debris avalanches, debris flows, This research project is looking at sorted circles slush flows) from 2011 and throughout 2017. A close to Juvfonne and on Juvasshøe, Norway, sample from the landslide events will be visited using Structure from Motion photogrammetry in field to perform analysis on landslide volume, (SfM). The aim of this study is to understand the thickness of deposit and some other landslide changes of sorted circles during one melting parameters. season at two different locations. Changes in the The study will also implement an analysis of the circles will be traced by tracking features in the events that had a corresponding landslide orthoimages. warning level associated with it. A validation will then be performed to compare the predicted outcome with the resulting outcome of the meteorological event. This part of the master thesis might clarify challenges the landslide warning service has today. It may also enlighten improvements or adjustments that is needed to

increase the landslide warning service accuracy.

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