GeoSciences 2014

Annual Conference of the Geoscience Society of 24th - 27th November 2014, Pukekura Raceway and Function Centre, New Plymouth ABSTRACTS

Geoscience Society

of New Zealand

Cover Photos:

Top Left: Mount /Egmont Volcano, with the conference venue, Pukekura Raceway and Function Centre, in the foreground. Photo by Ken George, Absolutely Organised. Top Right: Examining volcaniclastic deposits on the track to Holly Hut, Mount Taranaki. Photo by Alan Palmer, Massey University. Bottom: Tertiary strata exposed in the cliffs at Pukearuhe Beach. Photo by Kyle Bland, GNS Science.

Annual Conference of the Geoscience Society of New Zealand 24th – 27th November 2014, Pukekura Raceway and Function Centre, New Plymouth

ABSTRACT VOLUME

Conference Convenor Katherine Holt (Massey University)

Organising Committee Kate Arentsen, Alastair Clement, Maggi Damaschke, Sam McColl, Alan Palmer, Julie Palmer, Jon Procter, Bob Stewart, Manuela Tost, Georg Zellmer (Massey University)

Administration Janet George (Absolutely Organised Ltd.)

Symposium Convenors Paul Ashwell, Kyle Bland, Helen Bostock, Alastair Clement, Jaqueline Dohaney, Brad Field, Ewan Fordyce, Monica Handler, Chris Hollis, Anna Kaiser, Liz Kennedy, Emily Lane, Daphne Lee, Gert Lube, Sam McColl, Santanu Misra, Christof Mueller, Karoly Nemeth, Andy Nicol, Julie Palmer, Joe Prebble, Jon Procter, Mark Rattenbury, Hannu Seeback, Bob Stewart, Claudine Stirling, Daniel Thomas, Georg Zellmer

Field Trip Leaders Greg Browne, Maggi Damaschke, Mark Lawrence, Vince Neall, Andy Nicol, Alan Palmer, Rafael Torres-Orozco

Geoscience Society of New Zealand Miscellaneous Publication 139A ISBN 978-1-877480-40-9 ISSN (print) 2230-4487 ISSN (online) 2230-4495

Abstracts are organised in alphabetical order by family name of the first author

The bibliographic reference for individual abstracts is:

Author, A.N. (2014). Title of abstract. In: Holt, K. A. (ed.). Abstract Volume, GeoSciences 2014 Conference, 24th – 27th November 2014, Pukekura Raceway and Function Centre, New Plymouth, New Zealand. Geoscience Society of New Zealand Miscellaneous Publication 139A. p. x.

MID‐SHELF SUBMARINE CANYONS: IMAGING THE STRUCTURE AND ANCIENT SIESMICITY IN THE PROCESSES INVOLVED IN THE FORMATION AND MOOLIGHT FAULT ZONE IN THE MATUKITUKI EVOLUTION OF THE WAITAKI CANYON VALLEY, WANAKA

1 1 C. Abbey & A. Gorman S. Alder1, S. Smith1 & J. Scott1 1 Department of Geology, University of Otago, PO 1University of Otago, PO Box 56, Dunedin 9054 Box 56, Dunedin 9054 [email protected] [email protected] The Moonlight Fault Zone (MFZ) is a regionally The sea floor off the coast of New Zealand's Otago important fault zone that has a complex geological region is characterised by a narrow (15‐30 km history which despite its significance has been wide) and shallow (<150 m deep) continental shelf sparsely studied and as a consequence, is poorly incised by a submarine canyon system that feeds understood. During the it underwent into the Bounty Channel further offshore. reverse movement which is intriguing as the MFZ Although comprehensive bathymetric images of is steeply dipping to the west, thus an the area exist, there remain questions regarding “unfavourable” thrust fault, of which generally the processes involved in the formation and form at ̴30o, assuming an Andersonian stress evolution of these canyons. High‐resolution regime. seismic imaging of the subsurface will allow analysis of sedimentary structures in the vicinity of Fieldwork in the West Matukituki Valley found that the canyons, which will shed light on the processes reverse movements along the MFZ juxtaposed that led to their present configurations. intensely folded and massive greenschists to the west, against strongly foliated greyschists with This research will develop a high resolution model intense chevron folding to the east. A range of of the sedimentary architecture in the vicinity of fault rocks are present, including; networks of the Waitaki Canyon, one of the largest canyons in green cataclasite; solidified frictional melts the system, using existing and yet‐to‐be‐collected (pseudotachylytes) which occur as thin (200 µm ‐ seismic data. This will provide insight into the 1mm) fault veins sub‐parallel to foliation in the processes that have led to the development of the hanging wall greenschists, and rare injection veins canyon into its current form, as well as the branching into the host rocks and a thick (15 m) processes that it is currently experiencing. Data zone of fault breccia along the main fault trace from a number of sources are included: 2D and 3D which becomes increasingly foliated towards the seismic surveys from the oil and gas industry, fault trace. multichannel boomer seismic data collected by the University of Otago’s RV Polaris II, and high‐ A combination of optical microscopy, scanning resolution bathymetric images collected by NIWA. electron microscopy and X‐ray powder diffraction methods were used for analysis of these fault Preliminary interpretations suggest that there has rocks. In the pseudotachylytes features such as been migration of the Waitaki Canyon’s upper flow banding, glassy margins and newly grown channel through time, and that bulk movements mineral phases are strong evidence for a prior (slumps) are likely to be a major factor in this. melt phase. Breccias along the main fault trace Other sediment transport processes, such as become increasingly foliated (towards the fault hyperpycnal currents and coast‐parallel sediment trace) and contain an increasing amount of transport due to marine currents, will also be phyllosilicate phases (muscovite, chlorite and investigated for their potential influence. illite). The presence of these well aligned, phyllosilicate rich breccias along the fault trace has Furthermore, the role of glacio‐eustatic sea‐level likely influenced the strength of the fault, as they fluctuations in the initiation and evolution of have low friction coefficients (~0.4), which canyon systems will be assessed. This will be aided decreases stress along the fault plane. This by the records from nearby exploratory wells, decrease in stress increases the likelihood of particularly the Cutter‐1 well drilled near the head failure and may account for slip on this of the canyon in 2006. unfavourably oriented fault.

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A REMARKABLE MID‐PLIOCENE VOLANT MARINE hydrothermal systems in the upper crust than FOSSIL BIRD ASSEMBLAGE FROM THE SOUTHERN would otherwise be the case. TARANAKI COAST In Fiordland and Stewart Island the Grebe Shear D. Allen1 & R. Paul Scofield2 Zone (GSZ) and Freshwater Fault System (FFS) 11/b Endeavour St, New Plymouth 4310 mark the margin of continental 2Canterbury Museum, Rolleston Avenue, Gondwana. Transpressional deformation along Christchurch 8013 both structures between 125‐115Ma was likely [email protected] preceded by extension between 320‐130Ma when I and A‐type granitoids, and high‐K volcanic rocks The ocean has had a strong influence on the were emplaced/erupted periodically near both composition and evolution of the New Zealand structures. Three km‐scale intrusion‐related avifauna. Whilst penguins are well known in the metalliferous hydrothermal systems have been New Zealand Pliocene, the published record of delineated along the southern margin of the FFS in volant birds is minimal with only a couple of bony‐ Stewart Island. At North Red Head 140Ma toothed bird (Pelagornithidae) fossils and a single leucogranite hosts mineralogically complex veins shearwater (Procellariidae) cranium described. containing Mo, Ag, Te, Bi, Au, REE, Zr, Y, U, Th, F Here we detail new records of bony‐toothed birds, and Cl‐rich minerals. At “Hill 267m” intensely albatross (Diomedeidae) and petrels altered 300Ma leucogranite is riddled with (Procellariidae) from the Tangahoe Formation miariolitic cavities that contain pyrite and (Waipipian; Mid‐Pliocene) of New Zealand’s North molybdenite. Hydrothermal rutile in the granite Island that alter our ideas about the evolution and contains W and Nb. On the east side of South West biogeography of not only New Zealand’s marine Arm 300Ma ilmenite‐rich granite contains avifauna, but give us a new insight into the timing magmatic scheelite. Pyrite‐rich blebs and biotite of evolution of waterbirds worldwide. The potassic alteration overprinting the same granite Tangahoe Formation fauna lived during the most are associated with Mo, Te, Ag, Bi mineralization. recent time in Earth’s history when mean global More distal quartz veins cutting nearby 340Ma sea temperatures were substantially warmer for a tonalite contain Ag, Pb, Au, Te mineralization. In sustained period. Study of these fossils using CT Fiordland Cu, Pb, Zn, Ag mineralization scanning and modern medical imaging has enabled at Dana Peaks and molybdenite at Pomona Island us to establish better than ever before the occur along or adjacent to the GSZ. relationships of these fossils to modern taxa. We discuss the paleoenvironment of New Zealand The Carboniferous margin of Gondwana and during this biologically crucial epoch and how coincident younger faults mark a long lived radical changes in climate, currents and discontinuity in the crust and sub‐continental biogeography that occurred in the Pleistocene may lithospheric mantle of NZ. Metalliferous granites have affected the evolution of seabirds worldwide. and structurally controlled base metal mineralization formed sporadically along this discontinuity over a period of ~180Ma. The area which straddles this discontinuity is one of the METALLOGENESIS ALONG THE MARGIN OF more prospective sites for precious metal GONDWANA IN SOUTHERN NEW ZEALAND mineralization in NZ, consistent with the model 1 2 3 outlined above which is now being applied to A. Allibone , D. MacKenzie , R. Turnbull , A. 3 2 metal exploration globally. Tulloch & D. Craw 1 Rodinian (NZ) Ltd, PO Box 758, Wanaka 9343 2Department of Geology, University of Otago, PO Box 56, Dunedin, 9054 3GNS Science, Private Bag 1930, Dunedin 9054 [email protected]

Major precious metal deposits are commonly located near repeatedly reactivated trans‐ lithospheric faults at active continental margins. These faults provided pathways for asthenospheric melts and fluids which help drive larger

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SEDIMENT DEPOSITION, TECTONICS AND BLOCK AND ASH FLOW PRODUCTION AT HIGH PETROLEUM GENERATION IN THE SOUTHERN VISCOSITY LAVA DOMES P.A. Ashwell1, J.W. Cole1, E.L. Rhodes1, B.M. M.Arnot1, S.Bull1, M. Hill1 K.Kroeger1, C. Reilly1, D. Kennedy1 & M. Edwards1 Strogen1, H.Seebeck1, J. Baur1, T. Sahoo1, M. 1Department of Geological Sciences, University of Fohrmann1,2, A.Nicol1 & P. King1 Canterbury, Private Bag 4800, Christchurch 8140 1GNS Science, PO Box 30368, Lower Hutt, 5040 [email protected] 2Present address, OMVNZ Ltd., 10 Brandon St, Wellington. A major hazard of viscous lava dome eruptions is [email protected] the production of large block and ash flows, sourced from collapse of part, or all, of the dome. The geology and petroleum systems in the This collapse happens for a number of reasons Southern Taranaki Basin has been examined using such as the eruption rate, topography, vent 2D and 3D seismic reflection surveys tied to 35 morphology and the properties of the lava. Lava exploration wells. These seismic lines image a Late domes are a common volcanic landform in New Cretaceous to Recent sedimentary succession Zealand, and will likely comprise part of the next (<~80 Ma) that unconformably overlies Mesozoic large, rhyolitic eruption from within the Taupo basement with a total thickness of ~800 m to 8 Volcanic Zone. Identifying exactly how the km. Up to 15 seismic horizons have been variables affect the ability of a dome to collapse is interpreted throughout the southern basin and crucial in predicting the hazard potential of a were used to generate regional 3D horizon growing lava dome. models. The results presented here are based mainly on interpretations of individual seismic Here we present the findings of detailed field reflection lines and on structure contour, isopach, mapping of internal structures of lava domes from erosion and paleogeographic maps with temporal New Zealand and Guatemala, as well as resolution of ~1‐4 Myr since 23 Ma and ~5‐10 Myr experimental volcanology into changes in the prior to the Miocene. The improved lateral and porosity and permeability of an erupting lava vertical resolution of these maps has led to a dome, to compare and contrast the behaviour and greater understanding of the area’s geological and collapse potential of these domes. petroleum development. The sedimentary sequence comprises early transgressive strata (65‐ At Santiaguito volcano, Guatemala, dome or flow 23 Ma) followed by Early Miocene and younger collapses occur at all stages of growth, triggered by regressive units. Strata have been deformed by flow front over‐steepening or increases in multiple phases of deformation dominated by Late extrusion rate. The largest block and ash flows are Cretaceous‐Paleocene extension, Miocene and associated with the collapse of long, high volume younger shortening and, in the northern part of lava flows during periods of high extrusion rate, the basin, Plio‐Pleistocene extension. North‐ and is coupled to the degree of degassing of the trending anticlines and associated reverse faults magma prior to extrusion. appear to have generated minor topography which promoted northward flowing paleo‐drainage At Ruawahia dome, New Zealand, multiple and systems during the Late Miocene. These widespread block and ash flow deposits surround paleocurrents indicate that the northern South the flanks of the volcano; clasts within these Island, which was uplifted during the Neogene, deposits shows evidence of post‐collapse inflation, was an important source of basin sediments during similar to lava found on the leading edge of the the Cenozoic. dome. Conversely, Ngongotaha dome, New Zealand, shows little to no block and ash flow production. In these cases, the crystal content of the magma controls the production of large cracks which enabled more efficient degassing, and the palaeotopography influences the likelihood of collapse of the dome.

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CHALLENGES IN TEACHING UNDERGRADUATE RADIOGENIC ISOTOPE CONSTRAINTS ON THE GEOLOGY AND IMPROVING THE TRANSITION GLACIAL STATE OF ANTARCTICA AND FROM 100 TO 200 LEVEL PALEOCEANOGRAPHY OVER THE PAST 14 MILLION YEARS P.A. Ashwell Department of Geological Sciences, University of J.A. Baker Canterbury, Private Bag 4800, Christchurch 8140 School of Environment, University of Auckland, [email protected] Private Bag 92091, Auckland 1142 [email protected] As a recent hire in the position of Senior Tutor in geology, my focus is both on lab and field based The long‐lived neodymium, hafnium and lead (Nd‐ teaching. In particular this is guided by an Hf‐Pb) isotope systems are conservative water overarching goal of linking the introductory 100 mass tracers with decadal to millennial residence level courses (open to students of any background) times that are shorter than ocean mixing to 200 level courses (only geology majors). Here, I timescales. Their seawater isotopic composition will present my first impressions of teaching at reflects the age of continental crust being these levels, as well as the challenges that I have delivered to the ocean by glacial, fluvial and (to a encountered and changes to the courses that I lesser extent) aeolian processes, as well as have undertaken to improve learning and links continental weathering style. Thus, paleo‐ between the courses. seawater Nd‐Hf‐Pb isotope records provide unique constraints on past continental weathering driven Challenges that I have encountered include a low by global climatic conditions, reconfiguration of amount of retention of information from 100 to oceanographic circulation, and vigour of global 200 level, leading to the necessity of re‐teaching thermohaline circulation. We have determined a material covered in 100 level during 200 level labs continuous Nd‐Hf‐Pb isotopic record (ca. 3000 or lectures. This low knowledge retention rate analyses) of paleo‐deep waters (0‐14 Myr; may have a run on effect of reducing self resolution = 100‐400 kyr) from offshore eastern confidence in students own abilities, and may also New Zealand (Deep Western Boundary Current – be indicative of a culturally placed ‘tall poppy Antarctic Circumpolar Current). We have also syndrome’ within New Zealand students. determined their Pb isotopic composition at near‐ Universities are constantly trying to increase suborbital timescales (<20 kyr). The Nd isotopic student numbers while simultaneously reducing record over the past 14 Myr is extraordinarily time spent on marking or organisation and uniform and intermediate between North Atlantic increasing research loads on lecturers. This may (NADW) and Pacific deep waters – an observation be hampered by a lack of interest or information that has led to the hypothesis that the Nd isotope on geology at pre‐University levels, leading to few composition of Southern Ocean deep waters is ‘dedicated’ geology students at 100 level. dominated by mixing between the Atlantic and Pacific oceans with reduced export of NADW in The steep learning curve that students encounter glacial periods. However, our data do not support at 200 levels leads to challenges during field trips this interpretation and instead are consistent with which are part of the core degree structure. They Southern Ocean deep waters having a Nd isotopic require a high degree of self‐motivation and composition representative and overwhelmed by reliance, as students are on their own in the field continental crust weathered from Antarctica. with minimal supervision (as compared to a lab Moreover, Nd model and Pb‐Pb “ages” of the setting). Improvements to these courses, such as paleo‐seawater data are consistent with the mean streamlining of learning goals and improved pre‐ age of Antarctica’s continental crust. However, Pb‐ field trip training, may improve learning retention Hf isotopes show remarkable paleo‐deep water and reduce student stress during trips, potentially variability related to incongruent weathering of leading to benefits for other courses. Antarctica’s continental crust over the past 14 Myr. These variations reveal the glacial state of Antarctica on timescales that vary from the mid‐ Miocene to present‐day descent into the Icehouse World, through to Pliocene warmth immediately prior to onset of Northern Hemisphere glaciations,

4 and even over glacial‐interglacial Quaternary Electromagnetometers was deployed in May 2014 transitions. above the source of shallow SSEs at the northern (HOBITSS); roll‐over of those instruments and deployment of GPS‐Acoustic instruments is planned for 2015. Heat flow PRE‐STACK DEPTH MIGRATION OF 05CM‐04, IODP measurements will be acquired in 2015 in DRILLING, AND MARINE GEOPHYSICAL northern and southern Hikurangi, providing INVESTIGATIONS OF SUBDUCTION BEHAVIOUR understanding of the subduction zone thermal AT HIKURANGI MARGIN structure. We also plan to mature proposals for

1 1 2 regional 2D active source seismic on along‐ and D.H.N. Barker , S.A. Henrys , L.M. Wallace , P. across‐strike profiles, and targeted 3D seismic Barnes3, J. Mountjoy3, I. Pecher4, & international surveying of the shallow SSE source region collaborators offshore Gisborne. 1GNS Science, PO Box 30368, Lower Hutt, 5040 2 University of Texas Institute for Geophysics, 10100 Burnet Rd, R2200, Austin, TX 78758, USA 3National Institute of Water and Atmospheric COMMUNICATING SCIENCE ‐ THE “THIN ICE” Research, Private Bag 14901, Wellington 6241 EXPERIENCE 4School of Environment, University of Auckland, 1 2 Private Bag 92091, Auckland 1142 P.J. Barrett & the Thin Ice Team 1 [email protected] Antarctic Research Centre, Victoria University of Wellington, PO Box 600, Wellington 6140 Proposed International Ocean Discovery 2 Simon Lamb, Victoria University of Wellington, Programme (IODP) drilling and adoption of New David Sington, DOX Productions, London, Philip Zealand as a GeoPRISMS focus site have led to a England, University of Oxford, David Fairhead, c/‐ concentration of national and international Silverglade Studios, London, Philip Sheppard, Royal resources and experiments that will be conducted Academy of Music, London, Catherine Fitzgerald, in the next 5 years. The Hikurangi subduction Blueskin Films, Wellington, James Franklin, Heidi margin offers a globally unique laboratory to Roop and Suze Keith, Victoria University of investigate the physical controls on subduction Wellington, and Suzanne Harle, Green Planet earthquakes, including slow‐slip events (SSEs), and Films, California. tsunami. Indeed, the region offshore Gisborne may [email protected] be the only place world‐wide where well defined subduction interface SSEs occur at depths within “Thin Ice – the inside story of climate science” is a range of current scientific drilling. Several multi‐ 73 minute feature documentary released in 2013. scale seismic surveys now form a comprehensive our original aim was to make a popular film in dataset along the entire Hikurangi margin (e.g. which climate scientists told their story directly to 05CM; RAU07; PEG09; SAHKE; SO191; TAN1114). the public. In 2007, when filming began, climate These data are helping shape our knowledge about change had become a serious issue, and we the along‐strike changes in subduction slip thought that if climate scientists could tell their behaviour, guiding precise locations for drill sites own story directly to the public, their credibility and informing later generation passive and active would be obvious and action would surely follow. seismic experiments. The initial team comprised just Simon Lamb, an In particular, MCS reflection profile 05CM‐04 is Oxford geologist with film‐making experience, his central to the drilling transect in IODP proposals to friend David Sington, a London‐based film investigate slow‐slip behaviour on the plate producer, and Peter Barrett, a Victoria University boundary offshore Gisborne. We present a pre‐ academic with a concern for the future of the stack depth migration of 05CM‐04 and inversion of Antarctic ice sheet. Between late 2006 and the end magnetic data crossing the northern Hikurangi of 2009 Simon had filmed over 100 hours of margin. The derived velocity and depth image interviews in Antarctica, the Southern Ocean, New provide a high‐resolution geometry of the Zealand, England and Germany, including subducting plate and help constrain the location of interviews with key US scientists. The film and a earthquakes recorded on Ocean Bottom supporting website finally came together for Earth Seismographs (OBS). A larger array of OBS, Ocean Day, April 22, 2013, with screenings at 200 sites Bottom Pressure sensors, and Ocean Bottom

5 around the world. Responses made it plain we had have a sound understanding of the backscatter struck a chord. response to the various substrates that occur in volcanic arc environments, along with the Key features of the film are the human face it gives bathymetric controls on substrate distributions. climate science and scientists, and the conclusion These relationships can be established with the that our societal goal should be zero carbon use of ground‐truth data, which can also be used emissions. It also conveys a message of hope. to test the applicability of models developed for Since the film’s release it has been screened by one seamount to other seamounts within the invitation at over a dozen film festivals. In addition region. director/producer/photographer Simon Lamb has been awarded the 2104 Athelstan Spilhaus Award In this study we investigate the relationships for Science Communication from the American between substrate and MBES data for three Geophysical Union. It is now being distributed Kermadec arc volcanoes (Rumble II West, Rumble world‐wide with subtitles in 8 languages by Green II East and Brothers), and use logistic regression Planet Films marketing it to educational analysis and c‐means clustering to construct institutions world‐wide. We are also working predictive substrate maps for these regions. Video toward a 56 minute version for US public footage of the seafloor obtained using a deep broadcasting for screening in 2015. For more on towed image system is used as a ground‐truth. The the film and project see www.thiniceclimate.org incorporation of bathymetric derivatives was and www.greenplanetfilms.org. found to improve the predictive capacity of regression models substantially compared to the use of seafloor backscatter alone. A fine‐scale PREDICTIVE SUBMARINE SUBSTRATE MAPPING IN bathymetric position index, aspect eastness, and THE ACTIVE VOLCANIC ENVIRONMENT OF THE slope were found to be particularly significant KERMADEC ARC, NEW ZEALAND predictors for identifying hard vs soft substrates.

S. Barton1, 2, R. Wysoczanski1, G. Lamarche1, A. Pallentin1 & D. Sinclair2 PAPAROA COAL MEASURES: A FAULT BOUNDED 1National Institute of Water and Atmospheric BASIN BUT WHICH SIDE? Research, Private Bag 14901, Wellington 6241 1 1 1 1 2 K. Bassett , E. Cody , F. Monteith , M. Maitra Victoria University of Wellington, PO Box 600, 1Department of Geological Sciences, University of Wellington 6140 Canterbury, Private Bag 4800, Christchurch 8140 [email protected] [email protected]

The Kermadec arc is a region of high geological and The Late Cretaceous – Paleocene Paparoa Coal biological interest as it is home to a magmatically Measures of the Greymouth Coal Field have been and hydrothermally active volcanic front. variably modelled as deposited in a half‐graben rift Geological mapping of the substrate in this region basin (Nathan et al 1986, Newman & Newman can aid characterisation of the volcanic and 1992, Ward 1997, Kamp et al 1999), a tectonic histories of the seamounts, providing transtensional rift basin (Ettmuller et al 2006), and insight into subduction processes. Substrate a sag basin with no basin bounding fault (Suggate information is also essential for predicting the 2014). In all cases where a fault was postulated it distributions of biological assemblages, as an aid to was located on the eastern side of the basin understanding and protecting unique (Montgomerie ‐ Mt Davy faults) based on isopach communities. maps of the coal‐bearing strata from drillcore. However, field work by Gage (1952) revisited by However, direct mapping of the seafloor via Suggate (2014) has suggested that these faults imaging and sampling is time consuming, were not the primary basin bounding faults, expensive, and limited in terms of coverage. particularly during the latest Cretaceous – Predictive substrate mapping using backscatter Paleocene, and that strata thinned to the east. and bathymetry data obtained from multibeam echo sounder (MBES) systems enables large areas In the central and eastern portions of the basin, to be mapped comparatively inexpensively and coal‐bearing Rewanui and Dunollie Formations with greater and more complete coverage. In have been interpreted as deposited by small sandy order to achieve such maps, it is first necessary to meandering creeks flowing west and southwestward into the Goldlight lake with peat‐

6 forming mires in the floodplains. New research on study site, variability in the spatial distribution of the correlative conglomerate facies has the liquefiable layer appears to be small compared highlighted their importance in the northwestern to LDM variations. Geomorphic and topographic part of the basin. At 12 Mile Beach, the combined variability in areas underlain by sediments highly thickness of the Rewanui‐Dunollie conglomerates susceptible to liquefaction provide important clues is >800m with the intervening Goldlight lake relevant to land use planning and microzoning. absent. The basal contact is erosional and contains rip‐up clasts of the underlying Waiomo lake mudstones. The lower strata are poorly A CATALOGUE OF HIKURANGI, NEW ZEALAND, sorted boulder conglomerates fining up to SLOW SLIP EARTHQUAKES moderately sorted cobble conglomerates upsection. They are interpreted as steep alluvial B.P. Baxter fans that change to lower gradient braided rivers Victoria University of Wellington, PO Box 600, through time. Imbrication measurements show Wellington 6140 paleoflow was toward the southeast. [email protected]

Thick alluvial fan conglomerate deposition in the Slow Slip Earthquakes, also known as “silent west indicates high relief likely created by a basin earthquakes”, are episodic events similar to bounding fault. This is associated with thinning earthquakes that involve the release of and fining to the east with basin centre lacustrine accumulated strain, but over periods extending deposits grading eastward to coal‐bearing from days to months, rather than seconds. They meandering river deposits typical of half‐graben account for a significant portion of strain release in rift basin geometry. plate boundary zones.

One aim of the project is to develop methods for USING GEOMORPHOLOGY TO PREDICT THE the routine processing of GeoNet continuous GPS DISTRIBUTION OF LIQUEFACTION (cGPS) data for determining the location, moment, mechanism and duration of Slow Slip Earthquakes 1 1 1 S.H. Bastin , M.C. Quigley , & K. Bassett (SSEs) along the Hikurangi margin, and the 1 Department of Geological Sciences, University of uncertainties of these quantities. The primary Canterbury, Private Bag 4800, Christchurch 8140 result will be a catalogue of SSEs that is as [email protected] complete and homogenous as possible for this period. A secondary aim is to investigate apparent The 2010 Mw 7.1 Darfield earthquake and large differences in character between events in the NE aftershocks caused up to ten episodes of (short and frequent) as compared with those in liquefaction in the eastern Christchurch suburb of the SW (long and infrequent) of the North Island. Avonside. Field mapping, LiDAR, and aerial photography are used to identify 4872 surface The relevant cGPS data from 2000 to 2014 have liquefaction features including lateral spreading been processed and approximately 150 events fissures and aligned sand blow vents within have been identified and categorised, although not Avonside. Quantitative metrics of liquefaction all of these may comprise SSEs. A map of secular features including fissure length, orientation, and velocities split into components due to SSEs and density are combined with estimates of due to SSE‐free displacements raises questions liquefaction induced horizontal and vertical ground concerning current interpretations of the tectonics deformation to derive a land damage metric (LDM) of the Raukumara Peninsula and the Wairoa for a suite of 164 polygons throughout the study domain. area. LDMs are compared with the geologic, topographic, and geomorphic conditions of each Forward modelling of surface displacements polygon to seek relationships between intrinsic produced by movement on buried faults suggests properties and liquefaction‐induced ground that commonly‐used inversion techniques, based damage. Elevation (as a proxy for water table on the assumption of an homogenous half‐space depth) and proximity to modern river banks or below the ground surface, could, in some abandoned terrace risers play first‐order roles in circumstances, be significantly over‐estimating or controlling LDM variability. Near surface geology under‐estimating the apparent magnitude of the plays a secondary role in influencing the location source mechanisms. of lateral spreading fissures. On the scale of the

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This paper will present an overview of results This study uses a new approach; two obtained to date. samples that differ only in grain‐size are subjected to a single thermal history cancelling out uncertainties in the thermal history and allowing n to be calculated by GRAIN GROWTH KINETICS FROM EXPERIMENTS the relative grain growth of the two USING SUPERFINE ICE samples. To give well‐constrained n values the approach requires very fine‐grained L. Becroft1, M. Seidemann1, K. Lilly1, D.J. Prior1, starting materials. To date we have made R.E. Easingwood2, N. Golding3, W.B. Durham3, & progress in generating starting materials, M. Strauss2,4 testing the experimental approaches and 1Department of Geology, University of Otago, PO collecting pilot data. Preliminary experiments Box 56, Dunedin, 9054 give n values of 2 for clean bubble‐free ice. 2Otago Center for Electron Microscopy, University of Otago, PO Box 56, Dunedin, 9054 3Earth, Atmospheric and Planetary Sciences, MIT, Cambridge MA, USA. 3 P‐T‐t‐D EVOLUTION ACROSS A PALEOZOIC Biological Chemistry and Molecular GREENSCHIST TO AMPHIBOLITE FACIES Pharmacology, Harvard University, Boston, MA, TRANSITION IN GREENLAND GROUP ROCK IN U.S.A [email protected] SOUTH WESTLAND

Grain growth is the increase in mean grain size A. D. Belton1 & J.M. Scott1. in polycrystalline materials when exposed to low 1Department of Geology, University0 of Otago, PO stress and high temperature conditions, and is Box 56, Dunedin, 9054 described by the mean field equation: Dn‐ D n = 0 [email protected] kt. Where D is the mean grain diameter after time t, D0 is the initial mean grain diameter and k is the product of intrinsic diffusivity and A superb prograde metamorphic sequence in the the Arrhenius relationship of temperature. The Greenland Group is exposed in the Collie Range in growth exponent n reflects the microscale South Westland. Metamorphic grade progressively physics of the grain growth process, and is increases over a 6 km transect, from lower poorly understood in geologic materials greenschist facies slates and greywackes near the including ice. coast to microcline‐bearing amphibolite facies gneisses immediately northwest of the Alpine Knowing the growth exponent for ice is Fault. Four textural‐mineralogical zones are important to the interpretation of ice‐core grain defined. These span chlorite‐sericite‐albite to size data. High n values mean that the range of microcline‐oligoclase/labradorite assemblages and grain‐sizes converge more rapidly with time. For record progressive recrystallization throughout. example, zones of anomalously small grain size Whole rock analysis indicates a mobility of X (loss) that may be generated by localized creep could and Y (gain) with increasing grade. Textural Zone I be made less significant by grain growth and rocks are greenschist facies argillites and part of the history of the ice sheet will be greywackes that were folded into macroscopic missed. Growth exponents in ice are traditionally folds and contain an S1 schistosity. In Textural Zone set at 2, corresponding to one theoretical grain‐ II rocks, which are upper greenschist‐lower growth model; some new data confirm values of amphibolite facies but contain abundant detrital 2 for clean bubble‐free ice but suggest that they minerals, porphyroblastic biotite that overprints are closer to 4 for ice with a very small bubble S1. Textural zone III records near complete content. Estimation of n‐values from ice cores recrystallization and weak crenulation cleavage. or experiments have often been limited by very Textural zone IV rocks are completely recrystallized and contain metamorphic small differences between D and D0 so that there are potentially large errors in n that segregation. cannot be deconvolved from errors generated by uncertainty in the thermal history. In TZ III and IV amphibolites, two generations of muscovite occur. Syn‐kinematic muscovites define a penetrative foliation that is overprinted by

8 coarse poikiloblastic muscovites that represent two factors: the coherent rupture of a section of rehydration‐mediated retrogression of microcline. the fault of 25 km2 area, with average 3.5m slip, 116o rake and 3.1 km/s rupture velocity, and the

P‐T conditions for the S2 assemblages were presence of the shallow layer of sediments obtained by a combination of Ti‐in‐biotite immediately overlying the fault. The discretization geothermometry and phengite geobarometry. of the whole fault into several subfaults each with Peak metamorphism in the amphibolite facies TZ prescribed values of slip in the range 0.4‐3.5 m, IV occurred at ~ 620˚C and 4 kbar, whereas TZ III and variable rise time, allows parametric study of records temperatures of ~ 540˚C and 3.5 kbar. The the ground motion using several rupture scenarios. metamorphic textures observed are interpreted to The model with the coherent rupture described show that an early regional axial‐planar S1 cleavage above best reproduces the high (1.2 g ‐1.8 g) associated TZ I is overprinted by porphyroblastic accelerations observed at stations in the footwall biotite in TZII and by increasing intensity of S2 and hanging wall of the fault. The topography does fabrics in TZ III and IV. These results are tentatively not appear to contribute significantly to the high interpreted to show that the metamorphic accelerations observed in the near field, but it sequence in the Collie Range represents a tilted might produce Rayleigh waves propagating away section, with the highest grades exposed closest to into the basin. This is in agreement with particle the Alpine Fault. The change in the metamorphic motion surface wave analysis of the measured fabrics is interpreted to record initial shortening seismograms that reveals the contribution of and macroscopic folding (TZ I) at >371 Ma, Rayleigh wave energy to the observed long‐period followed by an elevated heat‐flow at ~340 Ma ground motions. Furthermore, arrival times of the perhaps due to crustal thinning. Thermal Rayleigh wave energy are consistent with relaxation caused coarse muscovite and biotite predicted travel times from our basin velocity porphyroblasts to overgrow the amphibolite facies model. assemblages.

THE CLAY CREEK LIMESTONE: STRATIGRAPHY, DEPOSITIONAL ENVIRONMENT, AND A KINEMATIC SOURCE MODEL OF THE M 6.3 CONSTRAINTS ON LATE MIOCENE‐EARLY FEBRUARY 22 2011 EARTHQUAKE IN PLIOCENE DEFORMATION ASSOCIATED WITH THE CHRISCHURCH, NEW ZEALAND SOUTHERN HIKURANGI MARGIN

1 1 1 R. Benites , Bill Fry , Anna Kaiser 1 1 T. L. B. Bertaud‐Gandar , C. B. Atkins & M. GNS Science, PO Box 30368, Lower Hutt, 5040 Hannah1 [email protected] 1SGEES, Victoria University of Wellington, PO Box 600, Wellington 6140 A simple, kinematic model of the rupture of the [email protected] M6.3 February 22 2011 earthquake in the city of Christchurch, New Zealand provides insights into Studies of the structure and tectonic history of the the factors influencing observed ground motions. southern Hikurangi Margin (e.g. Cape et al, 1990; The model is based on a squared 9 km x 9 km fault Nicol et al, 2002) provide evidence for an episode 0 0 dipping 75 , striking 64 and rupturing with a of intense tectonic shortening and deformation thrust mechanism. The fault is embedded in a during the Late Miocene or Early Pliocene. velocity model consisting of one layer over a However, the stratigraphy associated with this uniform half‐space representing the stiffest soil time interval is often complex and poorly‐ deposit and the bedrock underneath, respectively understood, and few details of Late Miocene (Brown, L.J.; Weeber, J.H. 1992). The free‐surface paleogeography are currently known in the of the soil layer is assumed to be flat, however, the Wairarapa (Beu, 1995). The Clay Creek Limestone bedrock interface (initially at 900 m depth) pinches is ideally positioned to provide a record of Late out as a 3‐D cosine shaped free‐surface Miocene‐Early Pliocene shortening and topography up to 225 m high, representing Banks deformation associated with the southern Peninsula. Hikurangi Margin. It is a coarse‐grained coquina limestone of Late Miocene age that outcrops Numerical modelling of the rupture shows that the irregularly over an estimated area of 50 km2 on the observed strong ground motion is mainly due to northern margin of the Aorangi Range. At some

9 locations, it directly overlies Mesozoic greywacke and the USAP. The core was drilled using the newly and argillite, while at others it overlies Miocene built New Zealand intermediate ice core drilling sandstone or mudstone. A more detailed system, which is based on the design of the Danish understanding of the stratigraphy of the Clay Hans Tausen drill. Creek Limestone and adjacent units is necessary in order to better constrain the timing and style of Roosevelt Island, an ice dome grounded 200m Late Miocene‐Early Pliocene deformation. Our below sea level, is situated at the northern tip of study aims to produce a detailed stratigraphic and the Ross Ice Shelf, which flows around it. The paleoenvironmental interpretation of the Clay dome has a maximum elevation of 550m above Creek Limestone and associated units, using sea level and exhibits a well developed Raymond techniques such as field mapping, measuring key Bump. Average annual snow accumulation is 20cm sections, and biostratigraphic analysis of macro‐ ice per year. The RICE core was drilled in the and microfossil samples. We will present vicinity of the topographic and Raymond Bump preliminary results and images from our study. divides. The core was processed at the New Zealand Ice Core Research Facility during May to

July 2013 (0‐500m) and May to August 2014 (500‐ RICE ‐ ROOSEVELT ISLAND CLIMATE EVOLUTION 760m). PROJECT ‐ A NEW, INTERMEDIATE DEPTH ICE CORE RECORD FROM COASTAL ANTARCTICA The record has been dated using annual layer count, volcanic markers, and correlated to WAIS N.Bertler1 & RICE Team2 via an exceptionally high resolution match 1Joint Antarctic Research Centre, Victoria between the WAIS and RICE continuous flow University and GNS Science, PO Box 600, methane measurements. Geophysical Wellington 6140 measurements (radar and strain rate measurements) provide information on the 2 RICE Team: B.Alloway, T.Baisden, T.Beers, thinning history of the island and further help to H.Berge, N.Bertler, T.Blunier, D.Bowden, E.Brook, constrain the age model. The RICE core provides a S.Canessa, C.Cary, G.Ciobanu, D.Clemens‐Sewall, high resolution record of the deglaciation history H.Conway, C. Cunde, R. Dadic, D.Dahl‐Jensen, N. in the Ross Sea region and a lower resolution Dunbar, B.Delmonte, R.Edwards, A.Ellis, record extending to >60ka. D.Emanuelsson, W. Feitang, J.Fitzpatrick, T.J. Fudge, A.Giese, V.Gkinis, I.Goodwin, M.Grant, Here we present the first data spanning the entire S.Haines, M.Hansson, B.Hawley, M.Hendley, record and offer initial conclusions. R.Hindmarsh, C.Hogan, Yang Jiao, J.Kaiser, D.Kalteyer, L.Keller, S.Kipfstuhl, H.Kjaer, E.Korotkikh, A.Kurbatov, L.Lanci, J.Lee, V.Maggi, D.Mandeno, S.Mawdesley, P.Mayewski, R.McKay, EVOLUTIONARY CHANGE WITHIN THE LATE A.Menking, U.Morgenstern, P.Neff, C. Noerling, NEOGENE PLANKTONIC FORAMINIFERAL LINEAGE S.Phipps, B.Proemse, A.Pyne, R.Pyne, J.Rawson, TRUNCOROTALIA E.Saltzmann, R.Scherer, S.Semper, J.Severinghaus, W. Shimeng, M.Simones, S.Sneed, E.Steig, R. Bicknell1, J. Crampton1, 2, M. Crundwell2, M. A.Tuohy, F.Valero‐Delgado, P.Vallalonga, S. Hannah1 Vatsyayani, J. Venkatesh, E.Waddington, J.West, 1SGEES, Victoria University of Wellington, PO Box A.Whiteford, H.Winton, D. Winski, D. Zhang, Z. Xin 600, Wellington 6140 [email protected] 2GNS Science, PO Box 30368, Lower Hutt 5040 [email protected] RICE is a collaboration between New Zealand, Australia, Denmark, Germany, Italy, People’s This study aims to document detailed evolutionary Republic of China, Sweden, U.K., and U.S.A. The change within a single planktonic foraminiferal overarching aim of the project is to help evaluate lineage over time. Planktonic foraminifera are the stability of the Ross Ice Shelf and West useful tools for studying evolution as their tests Antarctic Ice Sheet in a warming world. are easily preserved in deep sea environments. Cores collected by the Deep Sea Drilling Project The team recovered a 763m deep ice core from (DSDP) contain continuous records of deposition, Roosevelt Island during the 2011/12 and 2012/13 which offer excellent opportunities to study field seasons supported by Antarctica New Zealand evolutionary change within lineages. The lineage

10 of interest here is classed within the Truncorotalia were designed to awaken the enquiring scientist genus: the ancestor‐descendant pair Truncorotalia within children and adults through immersion in juanai and Truncorotalia crassaformis. This species the creative, curiosity‐driven, hands‐on, problem pair was chosen as they are relatively common solving process of real science. The Geocamp within the studied DSDP cores. Additionally, the initiative was developed and implemented due to evolutionary transition from Truncorotalia juanai a perceived lack of science awareness in the to Truncorotalia crassaformis occurred over the general public, and an apparent lack of recognition Miocene‐Pliocene boundary constrained the study of the value of science in NZ. Science isn’t just to between 5.9 and 4.5 Ma. Using closely sampled about white lab coats and test tubes! collections of Truncorotalia from approximately continuous sedimentary records from DSDP cores, Each Geocamp comprised a two‐week long field‐ we studied populations of these species. based course for intermediate school‐aged students and, very importantly, their teachers: our Abundant and extremely well‐preserved aim has been to “get the kids enthused, and teach specimens of the end member species and any the teachers.” Participants learned basic intermediate forms were collected from the DSDP (geo)science concepts using an observational and Sites 593 and 593‐A. Specimens were sampled inquiry‐driven approach, and then presented every 100 ka between 5.9 and 4.5 Ma. Where aspects of their learnings to their wider possible, at each interval 120 specimens were communities: the aim was to make the Geocamp identified and collected. These specimens were experience as close to doing “real science” as imaged using the AMOR foraminiferal imaging possible. The success of the Geocamps is system at Basel Natural History Museum in highlighted by teaching projects now implemented Switzerland. Digitised outlines of these images at some of the participating schools. were decomposed to a series of Fourier coefficients using a Fast Fourier transform. The The Geocamp model is readily and easily relationships between populations or shapes were transferable to any facet of science, to all age subsequently quantified using principal groups, and to any geographic area. We have now component analysis. The preliminary results successfully adapted and implemented the presented here suggest that the evolutionary concept for adults in on‐going marae‐based change between Truncorotalia juanai and wananga in collaboration with Ngati Kahungunu in Truncorotalia crassaformis was very gradual, with greater Hawke’s Bay, where the educational focus each intermediate form grading into the next. is on climate change, petroleum exploration, and There is no evidence of abrupt species changes, or natural hazards. The same hands‐on style of species sorting, within this data set. learning is being applied in these 3–4 day long wananga, with participants gaining a greater appreciation of how science “works”, and the fundamental role that science plays in New DINOSAURS, DISASTERS, AND THE POWER OF THE Zealand. PLANET! SCIENCE OUTREACH FOR COMMUNITIES FROM A CROWN RESEARCH INSTITUTE PERSPECTIVE FEEDING APPARATUS AND PHYLOGENETIC K. J. Bland1, R. H. Levy1, J. Thomson1, C. J. Hollis1, RELATIONSHIPS OF OLIGOCENE EOMYSTICETIDAE K. J. Clark1, F. J. Coyle1, & R. Faulkner1 FROM NEW ZEALAND REVEAL EARLY EVOLUTION 1GNS Science, PO Box 30368, Lower Hutt 5040 OF FILTER FEEDING IN BALEEN WHALES [email protected] (MYSTICETI)

GNS Science believes that effective R.W. Boessenecker1 & R.E. Fordyce1 communication of science, and community 1Department of Geology, University of Otago, PO engagement, are critical parts of doing business Box 56, Dunedin, 9054 for New Zealand’s Crown Research Institutes. [email protected] With financial support from the Todd Foundation, we developed and very successfully ran two The Eomysticetidae are a recently recognized community‐focussed educational events in family of archaic, purportedly toothless baleen Hawke’s Bay and Taranaki. Based around a whales. Named eomysticetids such as regionally‐focussed theme, these two “Geocamps” Eomysticetus whitmorei (Oligocene, USA) and

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Yamatocetus canaliculatus (Oligocene, Japan) are TIMING, SPATIAL DISTRIBUTION, AND ORIGIN OF characterized by an elongate and incipiently PALEO‐ROCKFALLS IN THE RAPAKI AREA OF THE narrow rostrum, a plesiomorphic braincase with a PORT HILLS, CHRISTCHURCH, NEW ZEALAND well‐developed sagittal crest and large temporal 1 1 1 1 fossae, and an elongate slightly bowed mandible J. Borella , M. Quigley , C. Gomez , D. Lague , D. 1 1 with unfused mandibular symphysis and “pan Gravley , & J. Pettinga 1 bone”. New fossils from New Zealand representing Department of Geological Sciences, University of a new genus and species of eomysticetid (OU Canterbury, Private Bag 4800, Christchurch 8140 22044, 22075, 22163 from the Waitaki region), [email protected] reveal new details of the feeding apparatus of the earliest toothless mysticetes. Palatal foramina More than 1,500 paleo‐boulders have been indicate the presence of baleen posteriorly, but mapped to determine the timing, spatial are absent from the rostral terminus – suggesting distribution, and origin of prehistoric rockfall that baleen was absent (or poorly developed) deposits in Rapaki. Paleo‐boulders consist of two anteriorly and forming a “subrostral gap” dominant lithologies: volcanic breccia and fine‐ analogous to right whales (Balaenidae). A well‐ grained basalt. We propose that boulder volume is developed glenoid fossa indicates primitive strongly influenced by layer/bed thickness and retention of a synovial temporomandibular joint degree of pre‐existing jointing within the source rock. The volcanic breccia comprises the majority (TMJ), which in concert with a delicately 3 constructed mandible, precludes dynamic lunge of larger boulders (50 boulders > than 10.0 m ), while boulders consisting of the finer‐grained feeding exhibited by modern balaenopterid 3 whales. The incipiently kinetic rostrum of basalt rarely exceed 2.0 m . Mapping shows that eomysticetids is more elongate and narrow than volcanic breccia boulders exhibit the longest run‐ any extant mysticete other than skim feeding right out distances but, unlike modern boulders whales (Balaenidae). The possible absence of generated during the 2010‐2011 Canterbury anterior baleen in concert with an anteriorly Earthquake Sequence, we find no paleo‐boulders elongated rostrum would permit water to flow present in the Rapaki village. This may provide unidirectionally through the oral cavity in a important evidence that forest present on the manner similar to right whales without inflicting mountainside prior to Maori and European extreme stresses upon the delicate TMJ; balaenids settlement reduced boulder run‐out distances. also possess a synovial TMJ. A cladistic analysis of Exploratory trenches have been excavated over 65 mysticete taxa coded for 362 adjacent to and behind several of the paleo‐ morphological characters recovers a monophyletic boulders to identify sediments deposited before Eomysticetidae (including Eomysticetus, and after boulder emplacement. Single grain OSL Yamatocetus, Micromysticetus, and several new dating of these bounding sediments will provide genera of Eomysticetidae from New Zealand) temporal constraint for boulder emplacement and positioned as the earliest diverging toothless associated shaking (i.e. paleo‐earthquake). mysticetes, agreeing with all previously published studies. Because eomysticetids are the earliest Field observations suggest a correlation exists obligately filter feeding mysticetes, our results between boulder surface roughness and age, indicate that skim feeding represents the primitive which could be used to determine timing of pre‐ mode of filter feeding amongst baleen whales. historic shaking events. Older surfaces show greater removal of finer‐grained host matrix

material and increased exposure of larger, more

resistant, volcanic clasts. High‐resolution point

clouds have been generated for twenty of the Rapaki paleo‐boulders using photogrammetry and SFM (structure‐from‐motion) software, with the aim of producing a roughness metric for each of the dated surfaces. Early efforts indicate that measuring the ‘rate of change of slope’ for each surface will prove most effective in quantifying the observed differences in surface roughness.

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MODELING TOOLS FOR THE REAL‐TIME PALEOCLIMATIC AND PALEOCEANOGRAPHIC EVALUATION AND HISTORICAL RECONSTRUCTION RECORDS FOR NEW ZEALAND AND THE OF TSUNAMI EVENTS IN NEW ZEALAND SOUTHERN OCEAN FOR THE LAST 60 KA – CONTRIBUTIONS TO THE SOUTHERN HEMISPHERE 1 1 2 J.C. Borrero , D. Greer , D. G. Goring , & W.L. ASSESSMENT OF PALEO‐ENVIRONMENTS (SHAPE) 3 Power , PROJECT 1eCoast Ltd, PO Box 151, Raglan 3265 2Mulgor Consulting Ltd., PO Box 9320, Tower H. Bostock1, A. Lorrey2 & SHAPE community Junction, Christchurch 8149 1National Institute of Water and 3GNS Science, PO Box 30368, Lower Hutt, 5040 Atmospheric Research, Private Bag 14901, [email protected] Wellington 6241 2National Institute of Water and We assess tsunami hazards in New Zealand Atmospheric Research, Private Bag 99940, through a review of historical accounts, analysis of Auckland 1010 water level and current speed data and detailed [email protected] numerical modeling. The tsunamis of 2010 (Chile) The aim of SHAPE is to take an integrated and 2011 (Japan) were recorded on tide gauges approach towards reconstructing and throughout New Zealand, providing a rich water understanding the evolution of the Southern level data set for model comparison and Hemisphere climate. The project continues the calibration. Furthermore, a current meter at the momentum that was started with Australasian‐ entrance to Tauranga Harbor also captured these INTIMATE (Integration of Ice, Marine and tsunamis providing a unique current speed data Terrestrial records). The timescale has been set augmented by several concurrent water level expanded with the aim to provide good, high records. This information was used to calibrate resolution climate records from 0‐60 ka (the limit numerical models using the ComMIT modeling of radiocarbon dating) and thus incorporating the tool. A sensitivity study for tsunamis generated abrupt millennial scale climate change events from around the Pacific Rim indicates the relative evident in the Antarctic ice cores during Marine hazards from different source regions. Isotope Stage 3 (MIS3). Deterministic scenario modelling of significant historical tsunamis provides a quantitative Here we provide a collection of proxy records for estimate of the expected effects from possible this extended time period for New Zealand and the future great earthquakes. These models were Southern Ocean. These will be compared with tested in April 2014 after the Mw 8.2 earthquake other regions of the Southern Hemisphere and offshore of Iquique, Chile – an event of particular paleoclimate model simulations. concern given that the August 1868 Arica earthquake generated a tsunami of ~7 m in Lyttelton Harbor as well as runup of up to 10 m in the Chatham Islands. As the April 2014 event TARANAKI AND KING COUNTRY BASINS unfolded, it was initially unclear if an evacuation or JUXTAPOSED DURING THE EARLY MIOCENE: other emergency response would be necessary in SEISMIC EVIDENCE FROM THE MERCURY BASIN, New Zealand. Models run in real time, using NORTH TARANAKI sources based on inverted tsunameter data and R. Brand1 & H. Gordon1 finite fault solutions of the earthquake, suggested 1 that a damaging far‐field tsunami was not Kea Petroleum Holdings Limited, PO Box 19140, expected and emergency response teams and port Courtenay Place, Wellington 6149 authorities were advised that is was safe to stand [email protected] down. These results were ultimately confirmed The Mercury Basin is an Early Miocene (Waitakian‐ when the tsunami was recorded in Lyttelton Otaian) depocentre that has been mapped using Harbor with a maximum amplitude of ~15 cm. marine 3D seismic acquired by Kea Oil and Gas Ltd Nevertheless, this event reminded us of New in 2013. It is located in North Taranaki, east of the Zealand’s far‐field tsunami exposure as well as the Taranaki Fault yet west of the Tongaporutu hazard from sources in South America and the Basement High. Closest stratigraphic controls are Peru/Chile border region in particular. in the offshore Mokau‐1 and Pluto‐1 wells, but neither of these encountered the Early Miocene succession , up to 1500m thick in the Mercury

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Basin, which is better correlated with the Despite lack of seismic control along the coast Mahoenui basin‐floor flysch of the King Country between Pukearuhe Bay and Tongaporutu, it is Basin. Sedimentation ended during the Late Otaian tempting to propose that the entire Mt Messenger when the Basin was uplifted from bathyal water sequence (Tt) exposed in the stratotype at White depths and subsequently eroded through canyon Cliffs was deposited within this major canyon incision; (this uplift being coeval with inversion of (some 10km wide by 300m deep). the Mahoenui east of the Ohura Fault). Reverse movement occurred on west verging thrust faults, Displayed are some of the interpreted seismic the lowest and oldest being the Taranaki Fault. sections and 3D time slices which demonstrate the Further east thrusting continued throughout the canyon termination of widespread reflectors mid Miocene creating the Tongaporutu High over corresponding to the basin‐floor facies at the base which the Late Miocene Herangi Unconformity of the Mt Messenger. The canyon shoulders are rests upon Murihiku Basement. traced northwards into Pluto‐1 and west into Pohokura‐1 for youngest age control. This paper looks at the seismic and other evidence for the age, depositional style and paleogeography Canyons have been previously recognised within of the Mercury Basin. A question is posed as to the overlying Urenui Formation (e.g. Wai‐iti Beach) how the 1500m basin subsidence on the hanging but the scale of the present discovery is of quite a wall of the Taranaki Fault occurred here during the different magnitude. Questions arise as to the Early Miocene when elsewhere the eastern margin longevity of the canyon and the nature of the of the Taranaki Basin was undergoing controlling tectonic and/or eustatic processes. compression? Earlier work by GNS has highlighted the extremely high estimated rates of sedimentation and rapid It is concluded that the Mercury Basin is unique in sedimentological facies variation within the upper providing a snapshot of the juxtaposition of the Mt Messenger; now the abrupt transition from Taranaki and King Country Basins during the Early ‘basin‐floor’ to ‘slope‐fan’ may be understood Miocene, thus constraining the timing of west‐east within the confines of major slope progradation shortening along the Taranaki Fault Zone and the and canyon formation during the Tongaporutuan creation of the Tongaporutu Basement High. stage.

CANYON ON THE MOUNT: A NEW LOOK AT THE GEOCHEMICAL FINGERPRINTING OF TYPE SECTION OF THE MT MESSENGER TITANOMAGNETITE PROVENANCE IN IRONSANDS FORMATION ON THE WEST COAST OF THE NORTH ISLAND

1 1 R. Brand & C. Skinner1 R.L. Brathwaite & A.B. Christie 1 1Kea Petroleum Holdings Limited, P O Box 19140, GNS Science, PO Box 30368, Lower Hutt, 5040

Courtenay Place, Wellington 6149 [email protected] [email protected] Previous studies on the provenance of Interpretation of 3D seismic acquired offshore titanomagnetite in ironsands on the west coast of north Taranaki by Kea Oil and Gas Ltd in 2013, in the North Island have indicated that the ironsand conjunction with onshore seismic (KEA55‐13‐1 to ‐ was derived from erosion of Cenozoic volcanic 4) shot over the Mt Messenger Range in the same rocks, mainly the andesite volcanoes of the year, has identified a major canyon which down Taranaki area. Ilmenite is a minor component in cuts several hundred metres from within the the Waikato North Head ironsand deposit and in upper Mt Messenger Formation through the the coastal sands north of the Waikato River Herangi Unconformity onto Murihiku Basement. mouth, which suggests input from Taupo Volcanic The offshore data shows the comparatively steep Zone (TVZ) sources because TVZ ignimbrites northeastern flank of the canyon trending to cross contain minor ilmenite in addition to the coastline some 3km south of the Tongaporutu titanomagnetite. Geochemical analyses of River mouth (near Waikiekie stream). The titanomagnetites in Taranaki and TVZ volcanic southwestern canyon margin is mapped to cut the rocks show that those from Taranaki andesites Pukearuhe‐1 well at 682mAHKB, while further have higher MgO and generally slightly higher V2O3 inland the thalweg passes close to Uruti‐1. and Cr2O3 than TVZ ignimbrite titanomagnetites,

14 and that a MgO‐MnO plot clearly distinguishes characterization of the transformation of a between the two sources. Previous analyses of homogeneous volcanic column into a vertically and titanomagnetite in ironsand deposits at Taharoa, longitudinally stratified flow able to produce Raglan and Waipipi, and our electron probe similar deposit facies to those observed in nature. analyses (EPMA) of samples south of the mouth of the Waikato River, all lie in the Taranaki andesites In the scenario of a collapse of a dense column (5‐ field on the MgO‐MnO plot. Our EPMA analyses of 15% particle volumetric concentration), the PDC beach sand samples north of the Waikato River generated is a dense suspension that rapidly mouth show that some of the titanomagnetite sediments particles into a dense underflow (40‐ grains (about 10% of the grains analysed) plot in 50% particle volumetric concentration) able to the TVZ rhyolite‐ignimbrite field; as do analyses of progressively detach and behave separately from titanomagnetite in pumice clasts from the lower the more dilute and fully turbulent upper parts of Waikato River. This is consistent with the high the flow. Different regions of the flow will be MgO titanomagnetites and associated ilmenites detailed in terms of particle volumetric being derived from the TVZ via the Waikato River concentration, velocity profiles, particle transport after 22 ka ago when the Waikato River changed mechanism, and turbulent eddies across the flow course from flowing into the Hauraki Gulf to its runout. From the results of the large‐scale present position. experiments, we introduce our model of the formation and evolution of pyroclastic flows.

VIEWING INSIDE EXPERIMENTAL PYROCLASTIC FLOWS GEOTHERMAL‐INDUCED MICRO‐SEISMICITY : A CRACKING GOOD STORY 1 1 1 2 E.C.P. Breard , G.Lube , S.J. Cronin & J.Jones 1 1 1 C.J. Bromley & S. Sherburn Volcanic Risk Solutions, Massey University, Private 1 Bag 11222, Palmerston North 4442 GNS Science, Wairakei Research Centre, Private 2School of Engineering and Advanced Technology, Bag 2000, Taupo 3352 Massey University, Private Bag 11222, Palmerston [email protected] North Often we hear stories of the potential adverse [email protected] effects from hydraulic fracturing undertaken for energy purposes. Examples include groundwater Pyroclastic density currents (PDCs) are amongst contamination from coal‐seam gas wells or deep the deadliest flows on Earth and are commonly waste‐water disposal wells (from casing failures). produced by volcanoes worldwide. Direct Geothermal energy developments have resulted in observations of the flows are extremely rare and many cases of triggered micro‐seismicity, intrusive measurements inexistent. The Pyroclastic benefitting fluid transmissivity, but without Flow Generator built at Massey University allows significant adverse effects. Although there have the limitations encountered with natural flows to been no documented cases of severe damage or be overcome through its ability to simulate PDCs pollution from high‐pressure geothermal fracture with controlled initial conditions and to view and stimulation or continuous fluid measure internal flow properties. Hence, from safe injection/production, there remains an issue of laboratory investigations, calibration data can be hazard perception. This varies with location obtained that can be introduced into numerical because of differences in familiarity with natural models to enhance their validity and improve their seismicity. To help address the perception issue, efficiency in hazard predictions. the positive side of the story deserves an airing. The Pyroclastic Flow Generator produces experimental flows by fully controlled column In New Zealand, several producing geothermal collapse and is able to generate the full range of fields have triggered micro‐seismicity, others column dilutions with natural pyroclastic material. haven’t (eg. Ngawha, Ohaaki). The favoured We report results of a systematic series of mechanism is an indirect effect of increased fluid‐ experiments producing flows that reached flow on fracture networks. Seismic failure can be velocities of up to 30 m/s and runout distances of triggered on favourably‐oriented fractures, up to 30 m. We will present high speed movies and through micro‐stress perturbations from thermal, non‐invasive sensor data that allow the chemical, or pressure transients. Although the

15 fluid flow is driven by pressure gradients through the fractures, the perturbing stress transients are Siliciclastic stratigraphic units include quartz and largely induced by cooling contraction. The feldspar‐rich sandstones similar to other arkosic transients locally unlock asperities on pre‐stressed sandstones of , such as the Coverham fractures. and Wallow groups of Marlborough and the Hoiho Group of , and to the Rakopi and In some geothermal fields levels of natural North Cape formations of Taranaki Basin. In the seismicity are relatively low, and induced survey area, they comprise well to poorly sorted, seismicity has not been observed, despite very fine‐ to coarse‐grained, quartzose and prolonged periods of pressure and temperature feldspathic (plagioclase and K‐spar) rich, change from fluid production and injection. An micaceous sandstone. Some samples contain explanation is that the local reservoir stress volcanic (basaltic) lithics. Preliminary analyses conditions are probably not close enough to based on mineralogy alone suggest some of these critical. Therefore, reservoir fractures are not, in rocks could be excellent reservoir sandstones. Late these cases, poised for failure in the event of small Cretaceous to Eocene mudrocks are laminated to stress perturbations. non‐laminated, calcareous to non‐calcareous, very fine sandy mudstones. They are similar to Whangai The positive benefits and practical applications of and Waipawa formations of the northern and induced seismicity include information eastern North, and eastern South Islands. Affinities constraining the reservoir simulation models: a) can also be drawn with Late Cretaceous to Eocene locations of permeable upflows, b) depth of the mudrocks of New Caledonia. Carbonate rocks brittle‐ductile transition zone, and c) locations of recovered from TAN1312 are described in a fault‐bound compartments within geothermal separate talk by Mark Lawrence et al. reservoirs. Active fracturing enables the transmissivity to be maintained by countering mineral scaling. Long‐term energy extraction is A MULTI‐PROXY HOLOCENE PALEOCLIMATE thereby enhanced. RECONSTRUCTION FROM THE SUB‐ANTARCTIC AUCKLAND ISLANDS

.H. Neil³, C ,²׳I. Browne¹, C. Moy¹, G. Wilson¹ ⁴׳C. Beltran¹ & ,²׳SILICICLASTIC LITHOLOGIES RECOVERED IN Riesselman¹ DREDGE SAMPLES FROM REINGA BASIN ¹Department of Geology, University of Otago, PO Box 56, Dunedin, 9054 G.H. Browne1, N. Mortimer1, H.E.G. Morgans1, ²Department of Marine Science, University of C.D. Clowes1, C.J. Hollis1 & A.G. Beu1 Otago, PO Box 56, Dunedin, 9054 1GNS Science, PO Box 30368, Lower Hutt, 5040 ³National Institute of Water and Atmospheric [email protected] Research, Private Bag 14901, Wellington 6241 The Reinga Basin northwest of New Zealand is a 75 ⁴Department of Chemistry, University of Otago, PO 000 km2 frontier basin with typical water depths in Box 56, Dunedin, 9054 the range 500 ‐ 2500 m. The region is contiguous [email protected] with the Northland and the petroleum‐producing Taranaki basins to the east and south, respectively. Sediment cores recovered from fjords along the In November 2013, an 18‐day survey on board the eastern margin of the sub‐Antarctic Auckland RV Tangaroa (survey TAN1312) acquired dredge Islands (51°S, 166°E) are well‐located to record samples and multi‐beam data from 38 sites. Rock changes in oceanic circulation and precipitation‐ samples were collected using a 0.45 x 1.2 m induced catchment erosion, related to Holocene diameter steel rock dredge at locations selected on variability in the strength and position of the the basis of seismic and/or multi‐beam data. Southern Hemisphere westerly winds. We recovered a 5.75m core from Hanfield Inlet that is A range of rock types were dated using composed entirely of brown marine mud and silt, foraminifera, palynomorphs, radiolaria and and contains terrestrial organic matter that has macrofossils, and indicate a broad range of Late been washed in from the fjord catchment. Based Cretaceous to Recent ages. Some of the younger on the entrance sill depth of the fjord (10 mbsl), ages are likely to represent infillings of borings at our knowledge of regional sea level rise, and the the margins of samples, or modern ooze. lack of lacustrine sediments at the base, we infer that the base of the core is early Holocene in age.

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Benthic foraminiferal assemblages (125‐500μm mapping them for three hypothetical earthquakes fraction) in surface and downcore samples are on different types of subduction zones (Kermadec, dominated by three species, Nonionellina flemingi, Java and the Solomon Islands). These examples Cassidulina carinata and Quinqueloculina showed that the areas of shallow bathymetry in seminula. These species are either shallow infaunal either the local or far field can also make a or infaunal. We will combine a radiocarbon significant difference to both the CoV and chronology with stable carbon (δ¹³C) and oxygen skewness of the distribution of maximum tsunami (δ¹⁸O) isotope geochemistry of benthic wave heights at a point. foraminifera Nonionellina flemingi, Bolivina cf. earlandi, Trifarina angulosa, Bulimina marginata f. marginata and Cibicides species (all identified from Rose Bengal stained box‐core COMPOUND‐SPECIFIC D/H RATIOS OF LIPID samples) to reconstruct water column fluctuations BIOMARKERS AS A PROXY FOR HOLOCENE associated with frontal migration. These results CLIMATE AND HYDROLOGY, FIORDLAND, NEW will compliment bulk sediment C and N ZEALAND concentration and isotope measurements that P. Burrington1, C. Moy1, S. Fitzsimons2, K. monitor terrestrial organic matter delivery to fjord 3 1,4 2,5 sub‐basins over the past 12,000 years. We will Hageman , C. Beltran , J. Howarth , & J. Nichols6 attempt to track Holocene changes in sea‐surface 1 temperature using the δ¹⁸O of planktic Department of Geology, University of Otago, PO Box 56, Dunedin 9054 foraminifera Globigerina falconensis and 2 Globigerina bulloides, and by measuring the Department of Geography, University of Otago, PO Box 56, Dunedin 9054 distribution of alkenones produced by coccoliths 3 identified in sediment core smear slides. Department of Chemistry, University of Otago, PO Box 56, Dunedin 9054 4 Universite ́ Pierre et Marie Curie, Paris, France 5 THE EFEFCT OF UNCERTAINTY IN EARTHQUAKE GNS Science, PO Box 30368, Lower Hutt, 5040 6 FAULT PARAMETERS ON THE MAXIMUM WAVE Lamont‐Doherty Earth Observatory, Columbia HEIGHT OF A TSUNAMI University, Palisades, NY [email protected] D. Burbidge1, C. Mueller2 & W. Power2 1GNS Science & Geoscience Australia, P O Box The latitudinal position and strength of the 30368, Lower Hutt 5040 Southern Hemisphere westerly winds (SHWW) 2GNS Science, PO Box 30368, Lower Hutt 5040 plays a critical role in global CO2 air‐sea flux and [email protected] the distribution of rainfall in the southern mid‐ latitudes. Strengthening and southward shifting We have run several thousand tsunami westerlies are thought to be reducing the propagation models in order to determine the efficiency of the Southern Ocean carbon sink, effect of uncertainty in an earthquake's rupture which has direct implications for modern parameters (specifically strike, dip, rake, depth and atmospheric CO2 concentrations. Southern New magnitude) on the maximum wave height of the Zealand intersects the northern margin of the tsunami that it creates. We have shown that even SHWW belt, where a direct relationship exists for the simple case of a tsunami propagating over between annual precipitation and zonal wind flat bathymetry, the Coefficient of Variation (CoV) speeds. Reconstructing past hydrological variations of the maximum wave height was a complex from the southwest of the South Island (SWSI) can function of the choice of rupture parameter, provide a regional record of climatic response to distance and azimuth. For example, if the strike of changing SHWW. A 5.4 m sediment core spanning the fault was varied, the CoV was at maximum on the last 11.5 ka was recovered from South Mavora either side of the tsunami beam, but if the dip was Lake, Southland. Magnetic susceptibility, bulk varied the CoV was at a maximum along the strike organic C and N isotopes and concentrations, and of the rupture. We then created maps of the lipid biomarker (C21‐C33 n‐alkanes) concentrations, skewness of the distribution of the maximum wave distributions, and hydrogen isotope values (δD) height. They also showed a complex dependence serve as proxies for change in lacustrine on the choice of the rupture parameter, azimuth productivity, relative proportions of terrestrial and and distance. Finally, we have examined the effect aquatic input, and hydrology. Modern meteoric 18 of a realistic bathymetry on CoV and skewness by water isotope values (δ O, δD) collected over a

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12‐month period show 3‰ summer and winter Subtropical Front, dominated the Holocene seasonality in SWSI, providing a modern‐day Optimum. assessment of isotopic response to climate. Downcore interpretation of data suggests a period That trend of polar contraction and tropical of increased precipitation, rapid warming, and expansion continues today, but probably at an greater autochthonous input from 10.2‐9.0 ka. accelerated rate in response to temperature From 9.0‐4.6 ka, elevated n‐alkane concentrations gradients affected by greenhouse gases and the indicate increased terrestrial input, increased “ozone hole”. Since the 1940s, observations show aquatic productivity, and a warm/relatively humid a marked expansion of the subtropics as westerly climate. From 4.6 ka to present a predominance of storm tracks shift south and the South Pacific Gyre 13 long‐chain n‐alkanes, declining δCorg and spins up. Off eastern Australia, the extension of magnetic susceptibility, and increasing C/N values, the East Australian Current strengthened over signal decreased precipitation and lake 350km southward resulting in the subtropical productivity that may be associated with late colonisation of previously subantarctic habitats off Holocene cooling. We will present these findings Tasmania. Those Australian developments along with ongoing work measuring the δD of potentially reduced the Tasman Front inflow but intermediate (C21‐C27) and long‐chain (C29‐C33) n‐ that may be offset by an increase in the alkanes. These results will allow reconstruction of Subtropical Front linking Tasmania with lakewater evaporation and help provide a record southernmost New Zealand, as evinced by of westerly driven hydrological change in SWSI. reconstructions of the last interglacial period. Despite the ongoing subtropical expansion, Antarctica maintains a strong influence on modern NZ climate as far as the central North Island. IMPROVING ENVIRONMENTAL RECONSTRUCTIONS – A CASE STUDY FROM POST‐ GLACIAL SW PACIFIC OCEAN SHEAR‐WAVE AUTOMATIC PICKING AND L. Carter ANISOTROPY MEASUREMENT AT RUAPEHU Antarctic Research Centre, Victoria University, VOLCANO Private Bag 600, Wellington 6140 1 1 [email protected] C. Castellazzi & M.K. Savage 1SGEES, Victoria University of Wellington, PO Box Modern observations together with palaeo‐ 600, Wellington 6140 reconstructions provide insights into the [email protected] mechanisms and outcomes of polar/tropical influences in the SW Pacific since the Last Glacial An automatic shear‐wave picking program and an Maximum (LGM). During the LGM, Subantarctic automated shear‐wave splitting measurement tool and Polar fronts of the Antarctic Circumpolar (MFAST) are combined to build a possible near‐ Current (ACC) migrated north towards the Tasman real time application for monitoring local stress Sea concomitant with shifts of the Subtropical and fields around volcanoes. Over‐pressured magma Tasman fronts. This was a response to shifting chambers underneath volcanoes can change stress westerly zonal winds under evolving pole‐equator on the surrounding ground, leading to changes in temperature gradients. Off eastern NZ that the anisotropic structure of the rock and shear‐ migration was influenced by the regional wave splitting. Monitoring the stress evolution in bathymetry. ACC fronts compressed against the time could be a key element of eruption western boundary presented by forecasting. Here we present a fully automatic to strengthen the ACC and an offshoot that passed system using an adapted version of Diehl et al. through a gap in the western boundary to enhance [2009] shear‐wave picking program on the cyclonic Bounty Gyre and form a jet along the seismograms provided by the New Zealand eastern North Island. As a result, subantarctic GeoNet catalogue and having an origin time and surface waters dominated the upper ocean location based only on P picks. The best automatic facilitated by a weakened and possibly diverted picks are processed by MFAST which computes the subtropical inflow to northernmost NZ. As zonal corresponding shear‐wave fast direction fast, and westerlies returned south, polar influences splitting delay time δt, interpreted respectively as declined and the subtropical inflow via the the principal direction of stress underneath the eastward Tasman Front and to a lesser extent, the station and the amount of anisotropy integrated

18 along the wave ray‐path. We applied our system to that the frequency‐magnitude distribution of the nine years of local earthquakes recorded at seven LFE catalogue both as a whole and within stations around Ruapehu volcano, New Zealand. individual families is not consistent with a power Results are compared against MFAST law, but that individual families’ frequency‐ measurements coming from manual S picks when amplitude distributions approximate an available and show less than 10° difference for exponential relationship, suggestive of a 90% of fast measurements and less than 0.05 s characteristic length‐scale of failure. We interpret difference for 95% of δt measurements. Shear this LFE activity to represent quasi‐continuous slip wave splitting from automatic S arrival times are on the deep extent of the Alpine Fault, with LFEs slightly more consistent than those from manual highlighting asperities within an otherwise steadily arrival times. Nine years display of δt values shows creeping region of the fault. a possible cycle‐skipping behavior and a strong correlation with the shear‐wave initial polarization computed by MFAST. SEISMOLOGICAL CHARECTERIZATION OF THE DFDP‐2 DRILL‐SITE AND SURROUNDINGS, WHATAROA VALLEY, CENTRAL ALPINE FAULT, NEW ZEALAND LOW‐FREQEUNCY EARTHQUAKES REVEAL 1 1 2 PUNCTUATED SLOW‐SLIP ON THE DEEP EXTENT C.J. Chamberlain , A. Benson , C.M. Boese , C. 3 4 4 5 5 OF THE ALPINE FAULT Dyer , J. Eccles , A. Gulley , B. Guo , C.Rawles , S. Roecker6, M.K. Savage1, R. Sutherland1, C.J. Chamberlain1, D.R. Shelly2, J. Townend1, T.A. C.Thurber5, J. Townend1, & K. van Wijk4 Stern1 1SGEES, Victoria University of Wellington, PO Box 1SGEES, Victoria University of Wellington, PO Box 600, Wellington 6140 600, Wellington 6140 2Institute of Earth Science and Engineering, 2U.S. Geological Survey, Menlo Park, California, Auckland USA 3GNS Science, PO Box 30368, Lower Hutt, 5040 [email protected] 4School of Environment, University of Auckland, Private Bag 92091, Auckland 1142 We present our recently developed catalogue of 5Department of Geoscience, University of low‐frequency earthquakes (LFEs) associated with Wisconsin‐Madison, Madison, USA the deep extension of the transpressional Alpine 6School of Earth and Environment, Rensselaer Fault beneath the central Southern Alps of New Polytechnic Institute, New York, USA Zealand. Our database comprises a temporally [email protected] continuous 36 month‐long catalogue of 8760 LFEs within 14 families derived from data collected on Detailed analysis of the seismicity and seismic the SAMBA seismic deployment from 2009‐2012. velocity structure of the crust surrounding the To generate this catalogue, we first identify 14 central Alpine Fault is being undertaken in primary template LFEs within known periods of conjunction with a broad range of other seismic tremor and use these templates to detect scientific activities under the auspices of the similar events in an iterative stacking and cross‐ Deep Fault Drilling Project (DFDP). Real‐time correlation routine. The hypocentres of 12 of the analysis of seismicity within c. 20 km of the 14 LFE families lie within 10 km of the inferred DFDP‐2 drill‐site using RTQuake will be location of the Alpine Fault at depths of performed prior to and during the drilling approximately 20–30 km, in a zone of high P‐wave operations utilising data from a recently attenuation, low P‐‐‐wave speeds, and high seismic telemetered temporary network of reflectivity. The LFE catalogue consists of seismometers surrounding the drill‐site. persistent, discrete events punctuated by swarm‐‐‐ Additionally, records obtained since 2008 have like bursts of activity associated with previously been re‐analysed using standard earthquake and newly identified tremor periods. LFE rate detection techniques (sta/lta) and manual increases are also detected after large regional picking, and detection via cross‐ correlation earthquakes including the 2009 Dusky Sound waveform matching. The results of this (Fiordland), 2010 Darfield (Canterbury) and the analysis are being integrated with newly larger events in the Christchurch sequence. The developed P‐ and S‐wave tomographic velocity magnitudes of the LFEs range between ML – 0.8 models to refine hypocenters and and ML 1.8, with an average of ML 0.5. We find

19 earthquake magnitudes in the vicinity of the station estab‐ lished in 1997 and the ”Nga Awa DFDP‐2 and elucidate spatiotemporal patterns Purua” triple flash power plant established in 2010. of seismicity. Seismicity near DFDP‐2 is sparse Rotokawa Joint Venture, a partnership between and of low magnitude: analysis of seven Mighty River Power and Tauhara North No. 2 Trust months’ data recorded by an extensive network currently operates 174 MW of generation at in 2013 including four shallow borehole Rotokawa. An array of short period seismometers seismometers within 1.5 km of the drill‐site was installed in 2008 and occupies an area of revealed fewer than 40 earthquakes within 10 roughly 5 square kilometers around the site. Al‐ km of the DFDP‐2 drill‐site. Of these, all but two though both cultural and natural noise sources are earthquakes (M=2.6 and M=1.7 located c. 6 km recorded at the stations, the instrument separation northwest and c. 3.5 km north of DFDP‐2 distance provides a unique challenge for analyzing respectively) were deeper than 2 km and all but cross correlations produced by both signal types. five were deeper than 3 km. Preliminary cross‐ The inter‐station spacing is on the order of a few correlation detection work using 14 template kilometers, so waves from cultural sources events and one year’s continuous data reveals generally are not coherent from one station to on‐going clustered activity. In particular, many the other, while the wavelength produced by newly detected events are observed close to a c. natural noise is greater than the station 10 km‐deep cluster near Gaunt Creek known separation. Velocity models produced from these to produce fault zone guided waves. This two source types will be compared to known demonstrates that waveform matching works geological models of the site. Depending on the well even when waveform complexity is high amount of data needed to adequately construct and highlights the potential for using repeated cross‐correlations, a time‐dependent model of earthquakes occurring on or near the Alpine velocity will be established and compared with Fault to study temporal changes in fault zone geothermal production processes. properties late in the earthquake cycle.

OCEAN REDOX DYNAMICS DURING THE END‐ SHEAR VELO CITY OF THE EXTINCTION AND EARLY ROTOKAWA GEOTHERMAL FIELD USING AMBIENT NOISE RECOVERY

1,2 1 3 F. Civilini1, M. Savage1, & J. Townend 1 M.O. Clarkson , R.A. Wood , S.W. Poulton , S. 4 3 5 6 1SGEES, Victoria University of Wellington, PO Box Richoz , R.J. Newton , S.A. Kasemann , L. Krystyn 600, Wellington 6140 1 School of GeoSciences, University of Edinburgh, [email protected] West Mains Road, Edinburgh, EH9 3JW, UK 2Department of Chemistry, University of Otago, Ambient noise correlation is an increasingly popular Dunedin, 9054 seismological technique that uses the ambient 3 seismic noise recorded at two stations to School of Earth and Environment, University of construct an empirical Green’s function. Leeds, Leeds, LS2 9JT, UK Applications of this technique include 4Institute of Earth Sciences, University of Graz, determining shear velocity structure and Heinrichstraße 26, 8010 Graz, Austria attenuation. An advantage of ambient noise is 5Dept of Geosciences and MARUM‐Center for that it does not rely on external sources of Marine Env. Sciences, University of Bremen, seismic energy such as local or teleseismic earthquakes. This method has been used in the Germany 6 geothermal industry to determine the depths at Institute for Paleontology, Vienna University, which magmatic processes occur, to distinguish Althanstrasse 14, 1090 Vienna, Austria between production and non‐production areas, [email protected] and to observe seismic velocity perturbations associated with fluid extraction. We will present a The Permian Triassic mass extinction is widely velocity model for the Rotokawa geothermal field regarded as the most severe of the Phanerozoic near Taupo, New Zealand, produced from ambient extinctions. The event was associated with major noise cross correlations. Production at Rotokawa is carbon cycle disruption, not only at the Permian based on the ”Rotokawa A” combined cycle power Triassic Boundary (PTB) but also for the entire

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Early Triassic. These disturbances are recorded in UNRAVELLING THE INFLUENCE OF CONTINENTAL the δ13C record of both carbonate and organic LEVERING ON PALAEO SEA‐LEVEL CHANGES carbon, which show a series of positive and AROUND NEW ZEALAND negative carbon isotope excursions (CIEs) 1 2 3 throughout the Eary Triassic. These fluctuations A.J.H. Clement , P. L. Whitehouse & C. R. Sloss 1 are also linked to minor extinctions in the Early Physical geography group, Massey University, Triassic and a delay in total species recovery until Private Bag 11222, Palmerston North 4442 2 the Middle Triassic. One leading hypothesis Department of Geography, Durham University 3 invoked to explain these changes is oceanic anoxia, School of Earth, Environmental and Biological which provides a kill mechanism that is also Sciences, Queensland University of Technology potentially linked to observed changes in the [email protected] carbon isotope record. Multiple anoxic events have indeed been identified in various sections Recent research has identified previously around the world. However the link between the unobserved complex spatial variations in the globally recorded CIEs and the development of timing and magnitude of sea‐level changes around anoxia is not clear, with no consistent relationship the New Zealand coast since the end of the last emerging. glaciation. It has been hypothesised that this spatial and temporal variability in sea‐level change Here we present a new record of anoxia from the is driven by the isostatic response to the load Arabian platform using Fe‐S‐C systematics. This placed on New Zealand’s continental shelf by mixed sequence of continental margin carbonates meltwater derived from melting ice sheets. This and clastics records a shelf to basin transect for process is known as continental levering. the PTB and Early Triassic, which demonstrates the distinct CIEs mentioned above. The use of Fe‐ Following the end of the last glaciation the speciation in tandem with carbon isotopes places meltwater from melting ice sheets placed a load the local record of anoxia in a global context, thus on New Zealand’s continental shelf. This load helping elucidate the timing, development and caused the shelf to flex downwards, displacing the stability of anoxia. underlying viscous material of the Earth’s mantle. Coastal margins respond to this loading and Our data show sustained anoxic, non‐sulphidic consequent mantle displacement with complex (ferruginous) conditions across the PTB for both spatial variability, reflecting the local and regional slope and basin settings. Subsequently anoxia configuration of the coast and continental shelf. appears restricted to the positive CIEs. Here, non‐ Some locations experience uplift as a result, while sulphidic conditions were again dominant, which is other locations experience subsidence. For in contrast to a growing body of evidence example: our modelling predicts that in the indicating euxinic conditions for the PTB. S‐isotope Manawatu‐Wanganui region, as the meltwater‐ systematics provide further insight into controls on loaded continental shelf was flexed downward, the observed environmental conditions at this onshore areas above sea level were levered time. Together, our approach provides a detailed upward by up to 1 m over the past 10,000 years. In examination of ocean redox variability during this contrast, in Northland northerly locations subsided interval of extreme environmental disturbance, up to 10 m during the past 10,000 years as the tip thus enabling a greater understanding of C‐cycle of the Northland peninsula is surrounded by feedbacks and biological consequences. downward‐flexing continental shelf, with the amount of subsidence progressively reducing towards the south. We predict that these complex vertical land movements will contribute considerable spatial and temporal variability to reconstructions of sea‐level changes covering the

last 10,000 years. While the contemporary effects of vertical land motion on sea‐level change have been investigated, the effects on sea‐level changes over the past 10,000 years are very poorly understood, and are often not accounted for.

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SEDIMENTOLOGY OF THE PAPAROA COAL CONSTRUCTING AN ALPINE FAULT MEASURE LACUSTRINE MUDSTONES: PALEOSEISMICITY RECORD FROM SLUMPED IMPLICATIONS FOR SYN‐DEPOSITIONAL LACUSTRINE DEPOSITS IN THE CASCADE RIVER TECTONICS VALLEY, SOUTH WESTLAND, NEW ZEALAND E. Cody1 & K. Bassett1 G. Coffey1, C. Moy1, V. Toy1, C. Ohneiser1 & J. 1Department of Geological Sciences, University of Howarth2 Canterbury, Private Bag 4800, Christchurch 8140 1Department of Geology, University of Otago, PO [email protected] Box 56, Dunedin, 9054 2GNS Science, PO Box 30368, Lower Hutt, 5040 Sedimentary facies analysis was undertaken on the [email protected] lacustrine mudstones of the Greymouth Coalfield with a specific focus on the northwest section of Extending along the West Coast from offshore the coalfield. Caswell Sound to the Matyr River, the Southern Alpine Fault has the potential to produce major Sedimentology of the mudstones and surrounding earthquakes of magnitude 7 or greater during transitional facies outlined the discrepancy dominantly strike‐slip motion. Paleoseismic between current models of the basin and records of these earthquakes indicate recurrence interpreted field observations. On the intervals of 300 – 400 years over the last 1,300 northwestern margin of the coalfield, the Rewanui years. The tectonically complex Cascade River and Dunollie Coal Measures consist of over 1000m Valley follows the trace of the fault. In the valley of cobble to boulder conglomerate with large two outcrops of proglacial lacustrine silt are mudstone rip up clasts at the basal contact exposed along the river, within which, deformed between the Rewanui Coal Measures and the (folded) rhythmites bound by planar laminated Waiomo Mudstone. The Goldlight Mudstone, rhythmites have been identified. classified as a massive mudstone in the central part of the coalfield up to 150m thick, here grades Initial radiocarbon ages of 14,400 and 13,300 14C yr laterally into the Rewanui Coal Measures with the BP have been obtained from terrestrial plant occurrence of mouth bar and debris flow deposits, material isolated from samples near the base of coupled with thin turbidites. At this same location, one outcrop. Given the age range and laminae the Waiomo Mudstone displays abundant density, these dates suggest that the rhythmites turbidites and conglomerate lenses as well as are varves, but additional radiocarbon dates and occasional drop stones found near the top of the CT‐scans will be used to confirm this. Radiocarbon section. ages linked with varve counting will be used to Conversely, on the eastern margin there is a lack determine the timing and recurrence interval of of thick conglomerate and the Goldlight and earthquake events during this period. Waiomo mudstones instead grade to coal and carbonaceous claystone with the presence of Outcrop observations and x‐ray computed organic rich siltstone and occasional laminae tomography (CT) have shown a variety of fold inferred to be from low gradient turbidites. TOC geometries, all of which show some degree of and HI results have shown that the mudstones can asymmetry. Deformed horizons are interpreted to have high organic material within them, indicating be seismites formed by slumping. Earthquake that the lakes were stratified and leading to the shaking triggers an increase in pore fluid pressure, preservation of organic material. which destabilises the submarine slope causing failure and the release of silt into the sedimentary This evidence suggests that alluvial fan deltas with system. As silt is transported by downslope shear it occasional debris flows infilled the lake to the west is deformed in distinct layers. Displacement of while the eastern margin was dominated by volumes of silt into the basin also causes the marshy shorelines and small deltas from formation of seiche waves that apply shear stress meandering rivers. This leads to an interpretation to lake floor sediments causing further of a highly asymmetrical lake where the western deformation. Deviations in magnetic susceptibility margin is significantly steeper than the eastern and magnetic remanence declination observed margin. This suggests that the steeper side of the underneath and within deformed horizons may basin was also to the west rather than the east. also be a result of earthquake shaking. Data from these different proxies will be presented and

22 compiled to generate a record of earthquake Survey) sparked new interest in Pegasus Basin, an shaking from the Southern Alpine Fault. offshore frontier basin situated east of central New Zealand.

Covering an area of at least 75,000 km2, the basin EXPLORATION OF FORMER AVIAN BIODIVERSITY developed as a contiguous entity with the East THROUGH ANCIENT DNA PRESERVED IN Coast and Raukumara basins along the Gondwana EXCAVATED BULK‐BONE subduction margin during Permian to mid‐ Cretaceous time, only becoming a separate T. L. Cole1, A. Grealy1, K. Kinney2 & M. Bunce1 1 physiographic feature since inception of the Curtin University of Technology, Department of modern plate boundary at the start of the Environment and Agriculture, Perth, WA, 6102 2 Neogene. The basin fill comprises Early Cretaceous Brown University, Department of Ecology and syn‐tectonic strata overlain by up to 8000 m of Evolutionary Biology, Providence, Rhode Island, Late Cretaceous – Recent passive margin rocks. 02912 What differentiates the Pegasus from other basins [email protected] is a lack of Neogene convergent tectonic overprint and relatively little deformation. Understanding the role of human colonisation on island biodiversity can be useful for understanding Although no wells have been drilled in the Pegasus the tempo and mode of extinction processes. Basin, strata exposed onshore in southern Fossils from small‐bodied fauna including birds and Wairarapa and eastern Marborough provide useful fish are often fragmentary and difficult to identify, analogues for the sedimentary fill of the basin. however these taxa likely made up a large proportion of subsistence diet. Taxonomic Using field observations including measured identification may be aided using Ancient DNA sections, detailed description of sedimentary techniques. For example, when collectively pooled features and sample collection for reservoir for extraction as a bulk‐bone sample, the DNA of petrology, in combination with seismic morphologically unidentifiable bones may be interpretation of the PEG10 survey, this study sequenced to reveal valuable phylogenetic or provides a more complete understanding of the taxonomic information. This study presents bulk‐ geology of the Pegasus Basin. Reservoir petrology bone metabarcoding data from several New of appropriate geologic facies will shed light on Zealand and Hawaiian sites, with aims to reveal provenance and quality of strata that may be unrepresented and rare small‐bodied fauna, clarify found offshore, and identified in seismic. avifauna biodiversity loss and compare assemblages over time. Our results reveal extinct, Initial petrographic analyses of sandstones from extirpated and endangered taxa. Results can be Glenburn Formation (Late Cretaceous), Mungaroa useful in interpreting faunal responses to human Limestone (Paleocene), the Whakataki Formation colonisation, how humans historically used the (Early to earliest Middle Miocene) have revealed landscape, understand extinction and that intergranular porosity (estimated visually) is reintroduction events and infer how biodiversity highest in Neogene sandstones, and is lacking responded to anthropogenic influences. within Cretaceous and Paleogene sandstones, which do have minor fracture porosity.

THE GEOLOGY OF PEGASUS BASIN BASED ON Mapping indicates up to 1700ms TWT of Miocene SEISMIC DATA, WITH INSIGHTS FROM OUTCROP – Recent sediments overlying a bright amplitude CORRELATIVES IN SOUTHERN WAIRARAPA AND reflector interpreted to represent Oligocene NORTHEASTERN MARLBOROUGH carbonates.

T. Collier1, G. Browne2 & J. Crampton1,2 1SGEES, Victoria University of Wellington, PO Box 600, Wellington 6140 2GNS Science, PO Box 30368, Lower Hutt, 5040 [email protected]

Acquisition of high quality 2D seismic data by the New Zealand Government in 2009‐10 (the PEG10

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IN SITU COSMOGENC 10BE IN PYROXENES [1]Blard et al. (2008). Quaternary Geochronology 3, 196‐205. J. Collins1, K. Norton1 & A. Mackintosh2 1SGEES, Victoria University of Wellington, PO Box 600, Wellington 6140 2Antarctic Research Centre, Victoria University of DOES MY POSTERIOR LOOK BIG IN THIS? THE Wellington, PO Box 600, Wellington 6140 EFFECT OF PHOTOGRAPHIC DISTORTION ON [email protected] MORPHOMETRIC ANALYSES

1 1,2 Cosmogenic nuclides provide an efficient way to K.S. Collins & M.F. Gazley 1 quantify many Earth surface processes. Terrestrial SGEES, Victoria University of Wellington, PO Box cosmogenic nuclides are produced from the 600, Wellington 6140 2 interaction of secondary cosmic radiation with CSIRO, Mineral Resources Flagship, PO Box 1130, target atoms in Earth materials. These cosmogenic Bentley, WA 6102, Australia nuclides accumulate over time and allow us to [email protected] calculate how long a rock or land‐ surface has been exposed at the Earth’s surface, independent of the Geometric morphometric studies often use crystallisation age of the rock. One of the most photographs to capture raw shape information, commonly used systems is 10Be produced in‐situ in rather than directly measuring specimens. Digital minerals from the interaction of cosmic rays with photographs (theoretically) provide a consistent oxygen. Meteoric 10Be is produced in the data‐collection method, and can be readily atmosphere by the same production reactions, distributed to researchers worldwide. However, and can be strongly adsorbed onto mineral photographs of objects are not necessarily perfect surfaces. In order to calculate accurate in‐situ representations of them. A camera lens distorts cosmogenic 10Be exposure ages, it is essential to the image when a photograph is taken, and the remove the contribution from meteoric 10Be. extent of the distortion will depend on factors While this is relatively simple for quartz, reliable such as the make and model of the lens and methods have not been designed for most other camera, and user‐controlled variation such as the minerals. zoom of the lens, aperture, and shutter speed. Any morphometric study that utilises data digitised We adapt a cleaning method proposed previously from a photograph will therefore have shape [1] to remove the meteoric 10Be from pyroxene variation introduced to the dataset simply by the grains, allowing calculation of accurate in‐situ photography. The shape variation introduced is produced 10Be exposure ages for mafic rocks. We systematic and predictable and, if not accounted have tested this method using pyroxenes from an for, can lead to misleading results, suggest already dated glacial moraine on Mt. Ruapehu on clustering of specimens in ordinations without the North Island of New Zealand. biological basis, or induce artificial over‐splitting of taxa. Here, we illustrate the nature and magnitude Our results will open new avenues for in‐situ of the error that can be generated within a 30‐ cosmogenic 10Be dating, which have previously specimen dataset of Recent New Zealand relied predominantly on quartz, rather than Mactridae (Mollusca; Bivalvia) using only a single pyroxenes that are subject to weathering in the camera and camera lens (Nikon D800, Nikkor 24‐ surficial environment. Using this pyroxene cleaning 85 mm f2.8‐4.0). We provide recommendations for method, the minerals are crushed small enough to ways of better quantifying, reducing, and expose the pits that contain the meteoric 10Be, correcting this error. allowing us to leach it out. Because pyroxenes contain more major cations than quartz, standard separation techniques cannot be employed. We have optimised cation exchange chemistry for the larger cation masses of the mafic minerals. This method provides a useful terrestrial cosmogenic nuclide system to incorporate into cosmogenic exposure age studies in mafic settings.

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NEW TOOLS, OLD SHELLS: SYNCHROTRON MICRO‐ lived. These shape data can then be CT RECONSTRUCTION APPLIED TO THE analysed using the quantitative tools of PALAEOBIOLOGY OF CRETACEOUS‐PALEOGENE morphometrics. OSTRICH‐FOOT SNAILS (GASTROPODA, STRUTHIOLARIIDAE) In this paper we present preliminary results and images from work undertaken at the Australian K.S. Collins1, M.F. Gazley1,2, C.I. Schipper1 & J.S. Synchrotron to illustrate the potential of this Crampton1,3 method as a tool for palaeobiological research. 1SGEES, Victoria University of Wellington, PO Box 600, Wellington 6140 2CSIRO, Mineral Resources Flagship, PO Box 1130, Bentley, Western Australia, 6102, Australia NEW ZEALAND LATE EOCENE FLORAS – WAIAU 3GNS Science, PO Box 30368, Lower Hutt 5040 AND BALLENY BASINS, WESTERN SOUTHLAND [email protected] J.G. Conran1, J.K. Lindqvist2, D.E. Lee2, T. Biological shape reflects ancestry, ecology, and life Reichgelt2 & D.C. Mildenhall3 habits, making shape analysis (morphometrics) of 1ACEBB & SGC, School of Earth and Environmental fossils relevant to many fields of geoscience, Sciences, University of Adelaide, SA, Australia including biostratigraphy, phylogenetic analysis, 2Department of Geology, University of Otago, PO evolutionary studies, and palaeoenvironmental Box 56, Dunedin, 9054 analysis. In such as molluscs, which grow 3GNS Science, PO Box 30368, Lower Hutt, 5040 by adding new shell without destroying earlier‐ [email protected] formed shell, shape analysis can also reveal details of growth and development. However, the capture Sites such as Messel and Eckfeld provide of shape information can sometimes be remarkable windows through which to study both challenging, particularly when specimens of plant and animal life in the Northern Hemisphere interest are not conveniently flat and two‐ during the Eocene. Now, Middle to Late Eocene dimensional. Snails are extremely common fossils, sites in New Zealand and Australia are providing a with both biostratigraphic and view of Southern Hemisphere high‐latitude palaeoenvironmental utility; but their shape mesoforests from lake and river deposits and variation is hard to capture in a consistent, extensive coal deposits representing Eocene systematic way. swamps. Although there are few animal fossils from these deposits, Late Eocene sites in southern Struthiolariid snails are morphologically variable New Zealand at a paleolatitude of ~50oS indicate and have an interesting evolutionary history, as high floristic diversity. At Pikopiko, a petrified in they appear to have originated in New Zealand situ forest includes leaf beds containing diverse and spread around the Southern Hemisphere in a fern macrofossils, suggesting that they dominated number of discrete colonisation events. Untangling the understorey in the Eocene just as they do in the aspects of their shape that are heritable and modern New Zealand forests. The macrofossils are indicative of phylogeny from those that are dominated by Lauraceae and Myrtaceae, but there moulded by immediate environment is not a trivial is also a range of tree species and several palms, problem. Compared to external morphology, including a Calamus‐like rattan, but no Nothofagus internal shell features are likely to be relatively leaves. Fossil pollen at the site includes conservative and may provide important new data Casuarinaceae, Sapindaceae and Euphorbiaceae, for evolutionary analyses. External morphology is together with several Proteaceae and Nothofagus acted upon by the environment and may be useful (Fuscospora and Brassospora) pollen types. as a palaeoenvironmental indicator. Even when Abundant associated fossil epiphyllous fungi also the specimen is optimally preserved with a provide evidence for high, year‐round rainfall and complete shell, capturing the internal and external a relatively warm and humid climate. In contrast, shapes of an organism that grows in a spiral largely coeval floras near Puysegur Point (Balleny fashion, and is full of sediment, is difficult. High‐ Basin, southwest Fiordland) and Blackmount resolution micro‐computed X‐ray tomography is a (Waiau Basin), although similarly diverse, contain potential solution, allowing the digital abundant Nothofagus macrofossils (both reconstruction not only of the external shell, but deciduous and non‐deciduous leaf forms), also of the internal matrix‐filled space where the together with several species of Lauraceae and a range of other rainforest families. This indicates

25 that there was regional diversity and that indicate rapid warming from ca. 18 ka, valley‐ heterogeneity in the floras despite apparently filling lavas are interpreted as post‐glacial flows relatively uniform low paleo‐topography. When that were emplaced after glaciers had largely incorporated with paleoclimate evidence from the retreated. An 40Ar/39Ar eruption age of 9 ± 3 ka (2σ Northern Hemisphere, these southern New error) determined for a valley‐filling flow on the Zealand sites show that floras with mesothermal northern flank of Ruapehu indicates that glaciers characteristics persisted at high paleolatitudes had retreated to near‐historical extents by 12 ka. until the Late Eocene.

LAVA‐ICE INTERACTION ON A LARGE COMPOSITE THE MORPHOLOGY AND PHYLOGENY OF THE VOLCANO: A CASE STUDY FROM RUAPEHU, NEW MOST COMPLETE KEKENODONTID, OU 22294, ZEALAND WITH OBSERVATIONS ON THE FEEDING ECOLOGY OF LATE OLIGOCENE ARCHAECOETES 1 2 2 C.E. Conway , D.B. Townsend , G.S. Leonard , A.T. 1 1 3 1 1 J.E. Corrie & R.E. Fordyce Calvert , C.J.N. Wilson , J.A. Gamble 1 University of Otago, PO Box 56, Dunedin, 9054 1SGEES, Victoria University of Wellington, PO Box [email protected] 600, Wellington 6140 2GNS Science, PO Box 30368, Lower Hutt, 5040 3 Kekenodontids represent a group of Late US Geological Survey, 345 Middlefield Rd, MS‐ Oligocene enigmatic toothed whales from the 937, Menlo Park, CA 94025, USA. Waitaki region, New Zealand. Until recently, the [email protected] family Kekenodontidae included only one species, Kekenodon onamata, based on fragmentary Ice exerts a first‐order control over the distribution material. This, and a lack of more complete and preservation of eruptive products on glaciated specimens, led to taxonomic ambiguity: do volcanoes. Defining the temporal and spatial kekenodontids belong within the paraphyletic distributions of ice‐marginal lava flows provides Archaeoceti (primitive toothed whales) or in the valuable constraints on past glacial extents, and is Neoceti (Odontoceti, Mysticeti)? OU 22294 crucial for understanding the eruptive histories of represents an informative new species of such settings. We present a case study of effusive kekenodontid, and includes a nearly complete ice‐marginal volcanism from Ruapehu, a glaciated skull, both periotics, teeth, a fragmentary andesite‐dacite composite cone in the southern mandible, and associated postcrania from the Taupo Volcanic Zone, New Zealand. Kokoamu Greensand of Awamoko Valley. Flow morphology, fracture characteristics and Phylogenetic analysis identifies OU 22294 as a 40Ar/39Ar geochronological data indicate that lavas sister‐taxon to the Neoceti, making it the latest‐ erupted between ca. 51 and 15 ka interacted with diverging archaeocete. Past research showed that large valley glaciers on Ruapehu. Ice‐marginal lava the more‐basal basilosaurid archaeocetes went flows exhibit grossly overthickened margins extinct around the Eocene/Oligocene boundary, adjacent to glaciated valleys, are intercalated with possibly from competitive displacement by early glacial deposits, and are commonly ridge‐capping Neoceti. Kekenodontids now represent the first due to their exclusion from valleys by glaciers. recognized Oligocene archaeocetes, which lived Fracture networks produced via interaction with well past the first appearance of Neoceti. Further, ice and associated meltwater define the margins of fossil odontocetes and mysticetes occur with these lava flows. New and existing 40Ar/39Ar kekenodontids in the Kokoamu Greensand, raising eruption ages for ice‐marginal lava flows indicate questions about niche partitioning between the that glaciers extending to 1300 m above sea level three groups. Primitive features of the skull and were present on Ruapehu between 51–41 ka and dentition in OU 22294 suggest a macrophagous 27–15 ka. raptorial form of predation as in basilosaurids, whereas odontocetes and mysticetes had more‐ Younger lava flows located within valleys are derived feeding strategies (echolocation and filter‐ characterised by blocky flow morphologies and feeding, respectively). However, some features in fracture networks indicative of only localised and OU 22294 (such as a less‐attenuated rostrum and minor interaction with ice and/or snow, especially wider‐spaced cheek teeth, and published isotopic in their upper reaches at elevations of 2600–2400 data from tooth enamel) suggest feeding on m. Based on regional paleoclimate reconstructions multiple, smaller prey items at a low trophic level.

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Microwear analysis should elucidate the extent to Collins and Evans (2001) called ‘experience‐based which OU 22294 pierced and grasped its prey, or experts’, both in their respective vocational fields filter‐fed in a manner similar to the crabeater seal and the complex geography of the local region. (Lobodon carcinophaga). If demonstrated in OU With an emphasis on listening as well as talking, 22294, this would represent a third instance of the engagement process was an opportunity for filter‐feeding in marine , in addition to mutually‐based learning from all parties involved, mysticetes and lobodontine seals. from which emerged a set of ways to move forward in the event of the need for CO2 storage arising in this region.

WHO IS EDUCATING WHO? SMALL‐SCALE DELIBERATIVE ENGAGEMENT WTH THE TARANAKI COMMUNITY AROUND THE HYPOTHETICAL MANTLE GEOCHEMISTRY BENEATH SOUTH SITING OF A CARBON CAPTURE AND STORAGE WESTLAND, NEW ZEALAND: A STUDY ON FACILITY (CCS) PERIDOTITE XENOLITHS FROM HAAST PASS

F.J. Coyle J.A. Crase1 & J.M. Scott1 GNS Science and CO2CRC, PO Box 30368, Lower 1Geology Department, University of Otago, PO Box Hutt, 5040 56, Dunedin 9054 [email protected] [email protected]

Carbon Capture and Storage (CCS) is relatively new Peridotite xenoliths entrained in alkaline magmas to the portfolio of responses to climate change, can preserve a record of processes that affected and is still earning its ‘social licence to operate’. It them in the lithospheric mantle. In the Burke River is associated with a number of public perceptions in the Haast area, the Alpine Dike Swarm entrained of risk, such as the vulnerability of storage sites to a variety of spinel facies peridotites that are seismic events, catastrophic leakage and predominantly of harzburgite composition. A large groundwater contamination. As yet, there are no proportion of the spinels in these rocks form plans to deploy the technology in New Zealand, distinctive orthopyroxene‐clinopyroxene but the Taranaki region would be a likely region for symplectites and represent the decompression of CO2 storage, due to its oil and gas industry, garnet peridotite followed by equilibration in the potential storage reservoirs, and skilled local spinel facies at some point in the past. Spinel Cr# workforce. This provided an opportunity for very and olivine Mg# indicate that high degrees of early, small‐scale deliberative engagement with partial melting removed essentially all of the local stakeholders (urban community, farmers and primary clinopyroxene, and likely some of the landowners, local iwi, local/regional council, and orthopyroxene, in these peridotites. However, the the oil/gas industry) in May‐June 2013. mantle has been overprinted by metasomatism, with two types inferred from the geochemistry of This paper analyses the value of this engagement secondary clinopyroxene. The first type, affecting process for upstream conflict identification and most of the peridotites, is carbonatite problem‐solving. After a focus on the local metasomatism as indicated by low Ti/Eu, high context, climate change and energy, single‐ Th/U and high LREE of the clinopyroxene. The stakeholder group discussions pivoted around a second event, only affecting some peridotites, is future fictional scenario. An introduction to CCS silicate metasomatism as indicated by high Ti and was followed by the opportunity for participants to LREE concentrations in clinopyroxene. As the conduct their own research and participate in self‐ peridotites were devoid (or very close to devoid) guided question‐and‐answer sessions with a GNS of clinopyroxene prior to metasomatism, the scientist, before producing a ‘group viewpoint’. isotopic ratios of these grains should closely The project culminated in a final small‐scale, multi‐ represent the composition of the metasomatic stakeholder deliberative forum, where group agents. Clinopyroxene radiogenic isotopes are representatives were involved in solution‐focused comparable to that of the HIMU mantle reservoir. decision‐making around risk, HIMU‐like ratios have also been recorded in the information/communication needs and risk host Alpine Dike Swarm, which suggests that the management. Whilst the scientists were dike swarm could share a similar source to the acknowledged ‘experts’ in their field, all metasomatic agent, or could be derived from participants in the research could be termed what melting of the HIMU‐enriched mantle lithosphere.

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MICROSTRUCTURAL EVOLUTION OF CALCITE reflecting grain annealing immediately following FAULT GOUGE DEFORMED IN EARTHQUAKE‐LIKE the experimental slip pulses. LABORATORY EXPERIMENTS

K. Crookbain1 & S. Smith1 1Geology Department, University of Otago, PO Box MICROSTRUCTURAL AND THERMOBAROMETRIC 56, Dunedin 9054 CONSTRAINTS ON ALPINE FAULT ZONE [email protected] KINEMATICS AT MID‐CRUSTAL DEPTHS

1 2 1 Earthquakes often rupture through carbonate A.J. Cross , S. Kidder & D.J. Prior rocks in the upper crust, It is important to 1Department of Geology, University of Otago, PO understand microstructures produced during Box 56, Dunedin, 9054 faulting in carbonate rocks to help to identify the 2Earth and Atmosphere Science, The City College mode in which particular carbonate‐bearing faults of New York, New York, NY 10031, USA. may have slipped in the past (i.e. seismically during [email protected] an earthquake or aseismically during creep). This is relevant for earthquake hazard analysis and it is Despite an inference of nominally steady‐state also an important first step in using fault rock deformation in many ductile shear zones, microstructures to quantify fault mechanical mylonitic rocks commonly contain heterogeneity behaviour (e.g. dynamic stresses, frictional heal in the form of compositional layering, grain size anomalies). variation and the presence of rigid porphyroclasts. In this contribution, we analyse the link between This study involves a microstructural analysis of rheology, kinematics and microstructure in calcite fault gouges experimentally‐deformed mylonitic samples containing quartz layers under “earthquake‐like” conditions (slip velocity deflected around garnet porphyroclasts during <1 ms‐1; displacements <5 m; normal stresses < 30 ductile deformation at mid‐crustal depths in the MPa). The specimens were deformed in the Slow Alpine Fault Zone. We present data from optical to High Velocity Rotary‐Shear frictional Apparatus analysis of quartz microstructures, grain size and (SHIVA) at the INGV, Rome. Three samples made CPO quantification by electron backscatter of pure calcite gouge were analysed in this work. diffraction (EBSD) and titanium‐in‐quartz (TitanIQ) The samples were deformed in a ring‐shaped thermobarometry. During shearing around rigidly (external/internal diameters of 55 mm and 35 mm) rotating garnet porphyroclasts, quartz undergoes gouge sample holder. Scanning Electron progressive grain size reduction in response to a Microscope images were collected of the three local increase in stress and strain rate. C‐axis deformed samples using polished thin sections cut maxima rotate around the kinematic vorticity axis approximately parallel to the slip direction and and record a local increase in the ratio of simple to perpendicular to gouge layer boundaries. Using pure shear, leading to an increase in the representative SEM images, grain boundaries were asymmetry of quartz c‐axis pole figures. manually traced and grain boundary maps were analysed using Image SXM. Ti concentrations reveal quartz deformation temperatures in the range of 500°C, which we Three distinct microstructural domains were propose record the cessation of grain boundary identified in the deformed calcite gouges; 1) migration during exhumation. Owing to the rapid plastically deformed layers of gouge rates of microstructural change in quartz observed recrystallization, 2) transitional layers with partial in this study, we propose a modified geotherm for recrystallization and 3) brittly deformed layers. The the central Alpine Fault Zone, in which a transition plastically deformed layer becomes thicker with in the geothermal gradient occurs at 11 km depth increasing mechanical work (and heating) and to place the 500°C isotherm at the brittle‐ductile grains also evolve in this layer to become more transition. We conclude that microstructures in elongate and aligned parallel to gouge layer layers deflected around rigid porphyroclasts can boundaries, resembling calcite mylonites in higher‐ provide valuable information on deformation temperature creep experiments. Grain sizes in the kinematics in ductile shear zones. plastically deformed layer generally decreases as slip rate increases, but the data indicate some late stage grain growth and polygonizaltion, probably

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BUILDING GEOLOGICAL MODELS OF NEW GEOCHEMISTRY OF AUCKLAND ISLAND LAKE ZEALAND’S PEGASUS BASIN AND ITS GAS SEDIMENTS: RECORDING LATE HOLOCENE HYDRATE SYSTEM: TOWARDS A BETTER CHANGES IN THE SOUTHERN HEMISPHERE UNDERSTANDING OF GAS HYDRATE FORMATION WESTERLY WINDS PROCESSES L. Curtin1, C. Moy1, G. Wilson2 1 G.J. Crutchley1, P. Barnes2, K. Kroeger1, M. Hill1, J. University of Otago Department of Geology, PO Mountjoy2, I. Pecher1,3 Box 56, Dunedin 9054 2 1GNS Science, PO Box 30368, Lower Hutt, 5040 University of Otago Department of Marine 2National Institute of Water and Atmospheric Science, PO Box 56, Dunedin 9054 Research, Private Bag 14901, Wellington 6241 [email protected] 3University of Auckland, Private Bag 92091, Auckland 1142 The Southern Hemisphere Westerly Winds [email protected] (SHWW), a zonal wind field in the Southern Hemisphere mid‐latitudes, are one of the primary The Pegasus Basin, on the southern end of New controllers of air‐ocean CO2 flux in the Southern Zealand’s Hikurangi margin, developed as a passive Ocean. As the winds shift poleward and intensify, margin from the end of subduction along the upwelling of CO2‐rich deep ocean water is around 105 Ma to the initiation of enhanced, and the ocean’s role in reducing the the modern plate boundary around 25 Ma. Seismic rate at which anthropogenic CO2 accumulates in reflection data acquired in 2009 and 2010 show the atmosphere is diminished. Furthermore, the well‐developed bottom‐simulating reflections strength and latitudinal position of the SHWW (BSRs) throughout the basin and also indications control storm tracks in the Southern Hemisphere for deeply‐sourced fluid migration. and directly influence precipitation patterns in the South Island of New Zealand. However, past We have used the seismic data, together with variability of the SHWW is poorly understood. previously published age constraints, to identify Tracking past changes in the winds across a range and map key stratigraphic horizons from the of Southern Hemisphere latitudes could help to ancient subduction margin on the East, through infer potential future changes in the wind field due the sedimentary basin, and up onto the modern to rising global temperatures. There are few subduction margin on the West. Although the lines terrestrial records of past SHWW variability, are sparsely spaced across the basin, key particularly at Sub‐Antarctic latitudes where stratigraphic horizons can be traced with landmasses are scarce and the modern westerly confidence throughout the basin. We have used maximum is located. Lake sediment cores from the BSRs to map the extent of the gas hydrate system Auckland Islands (50°S) provide an opportunity to throughout the basin. Together, these study Holocene SHWW variability in this crucial chronostratigraphic interpretations and gas gap. A high‐resolution record of recent hydrate indicators are enabling us to construct a environmental change on the Auckland Islands has 3D geological model of the basin that will be been compiled from short sediment cores from converted to depth using seismic velocities from three lakes using multiple physical and the available data. The geological model will geochemical methods. The sediments collected provide the basis for modelling fluid flow are diatom‐ and plant macrofossil‐rich and contain processes through the basin and ultimately to no carbonate. Biogenic silica wt.% varies between simulate gas hydrate formation using Petromod. 5‐20%. Physical properties measured using a We will present the latest results of this project Geotek core logger include p‐wave velocity, and outline the implications for gas hydrate gamma density, magnetic susceptibility, and formation in the Pegasus Basin. colour spectrophotometry. We will discuss downcore variations in bulk stable carbon and nitrogen isotopes, wt.% biogenic silica, n‐alkane distributions, and compound‐specific hydrogen isotopes, and how these changes relate to SH climate during the latest Holocene. Ultimately, these sediment records will provide a useful comparison to lake and fjord records from the South Island, allowing us to build a regional perspective of Holocene shifts in the SHWW.

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THE ANITA ULTRAMAFICS: AN ULTRA‐DEPLETED absent. We suggest that this ultramafic massif SLICE OF NEW ZEALAND’S SUBCONTINENTAL records a tectonic history involving decompression LITHOSPHERIC MANTLE from garnet facies to spinel‐plagioclase facies, with a loss of plagioclase via melting, and then final T.A. Czertowicz1, J.M. Scott1, J.M. Palin1, T.E. exhumation. Waight2, Q.H.A. van der Meer2, C. Münker3 S. Piazolo4 1Department of Geology, University of Otago, PO Box 56, Dunedin, 9054 WHAT LIES BENEATH? THE GEOCHEMICAL 2Copenhagen University, Øster Voldgade 10, 1350 EVOLUTION OF THE EAST OTAGO MANTLE Copenhagen, Denmark 1 1 3Department of Geology and Mineralogy, H.B. Dalton & J.M. Scott 1 University of Köln, Zülpicher Str. 49a, 50674 Köln, Department of Geology, University of Otago, PO Germany Box 56, Dunedin, 9054 4Department of Earth and Planetary Sciences, [email protected] Macquarie University, Sydney, NSW, Australia [email protected] Harzburgitic and lherzolitic mantle xenoliths entrained in the Miocene by the alkali basalts of New Zealand’s lithospheric mantle is relatively old the Dunedin Volcanic Group and emplaced in East and compositionally heterogeneous, with fertile Otago, New Zealand, have ‘locked‐in’ the intricate and depleted domains that have early histories history of the sub‐continental lithospheric mantle decoupled from the overlying Palaeozoic‐Tertiary (SCLM). Geochemical analysis of 36 peridotite continental crust. Our contribution has been to samples from three neighbouring localities in East study the Anita Ultramafics – a c. 1 km wide x 20 Otago reveals a remarkable degree of km long and remarkably fresh orogenic peridotite heterogeneity within the SCLM. Different realms of massif located close to Milford Sound in the the SCLM have experienced diverse degrees of mountains of Fiordland. The unit is composed of depletion by partial melt extraction and this has porphyroclastic dunite and harzburgite. Spinel‐ been followed by, in some cases significant, light pyroxene symplectites indicate the former rare‐earth element (LREE) enrichment. presence of garnet peridotite, although the massif Interrogation of clinopyroxene trace element now contains spinel facies assemblages. Several geochemistry suggests mantle metasomatic geochemical traits indicate extensive melt processes are responsible for this enrichment, with extraction (olivine Mg# ≈ 92.5, spinel Cr# ≈ 70, carbonatite melts the most likely metasomatic orthopyroxene maximum Al2O3 ≈ 1 wt%), and a agent, while the influence of silicate melts cannot composition very similar to cratonic lithosphere. be ruled out. Radiogenic isotope systematics (Sr, Such extreme melting likely requires the fluxing of Pb) indicate the East Otago SCLM has an enriched peridotite by hydrous fluid to lower the local HIMU‐like composition similar to the alkali basalts solidus. The Anita Ultramafics are therefore erupted during Cenozoic intraplate volcanism. interpreted to be depleted residues from extensive Samples which have experienced the greatest melting in the mantle wedge above a subducting degree of metasomatism have a narrow isotopic slab. range compatible with HIMU‐like compositions. It is suggested here that the HIMU‐like signature Despite its depleted composition, the peridotite observed in the East Otago SCLM is of massif has been subtly metasomatised. Abundant metasomatic origin. Based on orthopyroxene‐ hydrous minerals (hornblende, tremolite, chlorite, clinopyroxene trace element equilibrium diffusion talc, bowenite) indicate interaction with water‐ modelling it is thought that this metasomatic bearing fluids. Some of these minerals represent event occurred at least 100 Ma ago, while hydration during exhumation (tremolite, chlorite, Zealandia was contiguous with Gondwana. The talc and bowenite), but hornblende appears to presence of HIMU‐like isotopic signatures in the represent an earlier metasomatic event. We mantle beneath West Antarctica and Eastern constrained the nature of this initial Australia may indicate a pervasive metasomatic metasomatism using mineral trace element and Sr, event with a common HIMU‐like metasomatic Nd, Pb and Hf isotopic analysis. Coupled Eu and Sr agent. positive and negative anomalies indicate the influence of plagioclase, despite this mineral being

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BUILDING A HIGH‐RESOLUTION DISTAL TEPHRA THE GEONET CGPS NETWORK AND ITS POSSIBLE RECORD FROM MULTIPLE SITES AROUND MT. CONTRIBUTION TO A LOCAL TSUNAMI EARLY TARANAKI, NORTH ISLAND, NEW ZEALAND WARNING SYSTEM

M. Damaschke1, S.J. Cronin1, K.A. Holt2 & A. Hogg3 E. D’Anastasio1, C. Mueller1, N. Fournier1, & Y. 1Volcanic Risk Solutions, Massey University, Private Kaneko1 Bag 11222, Palmerston North 4442 1GNS Science, PO Box 30368, Lower Hutt 5040 2Institute of Agriculture and Environemnt, Massey [email protected] University, Private Bag 11222, Palmerston North 4442 Tsunamis induced by nearby large offshore 3Waikato Radiocarbon Dating Unit, University of earthquakes are one of many natural hazards New Waikato, Private Bag 3105, Hamilton 3240 Zealand is facing. International studies [email protected] demonstrated the effectiveness of using real‐time GPS data in Tsunami Early Warning Systems. The Based on new coring at four new sites in northern displacement recorded by real‐time cGPS stations and eastern Taranaki, and an integration of past can be used to gain insights into the earthquake coring, analysis and dating studies, this project source and its tsunamigenic potential within few aims to produce the most detailed eruption record minutes from the event. yet for Mt. Taranaki. With sites containing sedimentation records spanning from 36,000 years GNS‐Science and GeoNet are currently evaluating to the present, we have already built one of the their early warning capabilities in case of a tsunami longest high‐resolution volcanic eruption records being generated by an event on the Hikurangi from any volcano in the world. Here we present subduction zone with a focus on weakly‐felt slow‐ the latest results from new coring sites collected rupture earthquakes (Mueller et al., this session). over the last 12 months. Swamps and present and The 1947 earthquake and tsunami offshore paleo lakes at Tariki, North Inglewood, Midhurst Gisborne served as template. As part of this and Eltham are located under the known main project we analysed to what extent the cGPS dispersal axes of major tephra falls. Extending network is capable of detecting the ground from soil‐stratigraphy studies, the swamp/lake displacement simulated in a set of time‐dependent sites provide a deposition/preservation models. 1HZ GPS data from a selection of 54 environment well suited for trapping fine‐grained stations were post‐processed and epoch‐by‐epoch and thin deposits, characteristic of small to 1Hz “earthquake free” time series have been medium scaled eruptions (Volcanic Explosivity obtained. In the same area, 4 PositioNZ‐RT sites Index 2‐3). By applying a multiple‐parameter were processed in real time. The noise of post‐ approach to andesitic tephra correlation we are processed and real‐time solutions has been able to determine long‐term changes in frequency, assessed and compared to the set of time‐ magnitude and geochemical composition of dependent displacement simulations (Ristau & Taranaki eruptions. Titanomagnetite phenocrysts Kaneko, this session). Results show that: a) the have proven to be the most useful candidates for noise frequency and amplitude contents are geochemical purposes, since andesitic glass shards similar over the 54 stations; b) the real‐time have highly heterogeneous compositions caused outputs are generally twice as noisy as the post‐ by microlite growth and are more strongly affected processed solutions; c) the simulated by weathering. The scope and location of the displacements on near‐field stations should be coring sites will also allow us to develop a new detectable by using the real‐time processing record of paleo‐wind directions and provide the strategy. basis for correlation of tephras from Taranaki to deposits recorded in Auckland and the Central If all the cGPS stations on the East Coast were North Island. By linking magma chemistry to streaming 1Hz data, and the data were processed eruption size and style records, we aim to improve in real time, we would be able to rapidly detect hazard forecasts at Taranaki and increase and measure with reasonably good accuracy the awareness and preparedness for future hazards in displacement caused by a large earthquake within this region. few minutes from the origin time. This study provides practical guidelines for upgrading the GeoNet network to a real‐time network.

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POCKMARKS OF THE CHATHAM RISE AND EARLY MIOCENE FOSSILS INFORM ON THE FURTHER SOUTH EVOLUTION OF NEW ZEALAND’S AVIFAUNA – A WORLD VIEW B. Davy1, I. Pecher2, J. Bialis3, R. Coffin4 S. Sarkar3, J. Hillman3, K. Waghorn2 K. Kroeger1 and SO226 V.L. De Pietri1, R.P. Scofield2, A.J. Tennyson3, S.J. Scientific party5 Hand4, S.W. Salisbury5, & T.H. Worthy1 1GNS Science, PO Box 30368, Lower Hutt, 5040 1School of Biological Sciences, Flinders University, 2School of Environment, University of Auckland, GPO 2100, Adelaide 5001, SA, Australia Private Bag 92019, Auckland 1142 2Canterbury Museum, Rolleston Ave, Christchurch 3GEOMAR Helmholtz Centre for Ocean Research 8013 Kiel, 24148 Kiel, Germany 3Museum of New Zealand Te Papa Tongarewa, PO 4Naval Research Laboratory, Washington DC, Box 467, Wellington 6140 20375USA 4School of Biological, Earth and Environmental 5University of Otago, PO Box 56, Dunedin 9054 Sciences, University of New South Wales, Australia [email protected] 5School of Biological Sciences, University of Queensland, Brisbane, Queensland 4072, Australia The availability of modern multibeam swath‐ [email protected] bathymetry data in the New Zealand region has led to the widespread recognition of fluid‐escape Worldwide, Early Miocene (23–16 Ma) avifaunas structures or “pockmarks”. provide an important evolutionary framework for understanding avian dynamics and faunal changes 2 Very large ( > 20,000 km ) pockmark fields linked to climatic and geological factors occurring discovered along the south‐western Chatham Rise over the last 23 million years. This is because this slope (Davy et al. 2010) were grouped aerially into interval immediately predates the major pockmarks ranging from approximately 200 m transitions traditionally associated with the wide x 5 m deep to some giant pockmarks, 12 km Miocene (i.e., geologic, climatic, faunal and floral wide x 200 m deep – the largest known pockmarks changes) that influenced the evolutionary history world‐wide. It was proposed by Davy et al. that the of terrestrial vertebrates. The only Miocene pockmarks all have a gas‐hydrate source with terrestrial fauna known from Zealandia is that of St dissociation at peak stadial glacial low stands Bathans, in Central Otago (Altonian, 19–16 Ma). (giant pockmarks) and during post‐glacial warming New Zealand’s Recent terrestrial vertebrate fauna (200 m wide pockmarks). The 500 m isobath is famously dominated by birds, a pattern that was occurrence for the upper limit of small 500 m also reflected in its composition during the Early diameter pockmarks was one of the principal Miocene. Recent and ongoing paleontological factors in the Davy et al [2010] gas hydrate research has provided important insights into the interpretation. composition and taxonomic diversity of the St Bathans avifauna, as well as into the antiquity of The distribution and associated features of New Zealand’s endemic avian lineages, and pockmarks on the Chatham Rise margins, possible colonisation patterns resulting in New Canterbury slope and Inner are Zealand’s iconic Quaternary bird fauna. In this described, contrasted and related to regional overview we outline these recent advances and crustal structure. The presentation will also draw provide a phylogenetic and biogeographical on some of the highlights from a 2013 seismic framework linking NZ’s past and present avifaunas. survey by R/V Sonne to the Chatham Rise (Bialas Furthermore, we compare this Early Miocene et al. 2013) investigating the nature of pockmarks assemblage with that of coeval avian fossil already reported and discovering fresh giant localities worldwide, many of which are pockmarks and their associated unusual sub‐ characterised by unusual biogeographical seafloor plumbing. As a companion survey (Bialas occurrences linked to the different environmental et al. 2013) designed to detect methane presence conditions in the past, suggesting that the in the water column or sub‐seafloor found no distribution of certain lineages of birds today does evidence of methane presence, the possible not necessarily reflect ancient patterns. Although nature of fluids causing seafloor pockmarks are much data for Gondwanan Early Miocene avian discussed. localities is still lacking, we note that, similar to Australia and contrary to patterns observed in the

Northern Hemisphere, the long interval of geographical isolation has contributed to the high

32 level of taxonomic endemism associated with New SWFZ from Mw 8 earthquakes along the Alpine Zealand’s terrestrial faunas. Fault will help us to better understand plate boundary behaviour and better understand frequency of strong ground motions irrespective of source. PRELIMINARY RESULTS FROM RECENT SURFACE RUPTURES ALONG THE SOUTH WESTLAND FAULT ZONE, A MAJOR SOURCE OF SEISMIC HAZARD JUMPING TRACK: WHY DOES LAHAR AVULSION PROXIMAL TO THE PLATE BOUNDARY, SOUTH OCCUR? ISLAND, NEW ZEALAND A.Death1, J. Procter1, & G. Kereszturi1 1 2 2 G. De Pascale , N. Chandler‐Yates , F. Dela Pena 1Volcanic Risk Solutions, Massey University, Private 2 & P. Wilson Bag 11222, Palmerston North 4442 1 Fugro Geotechnical (NZ), 32A Unit B, Birmingham [email protected] Drive, Middleton, Christchurch 8024 2Department of Geological Sciences, University of Lahars have commonly been described as rapidly Canterbury, Private Bag 4800, Christchurch 8140 flowing mixture of debris and water. From a [email protected] rheological perspective the behaviour of these sediment‐laden flows are not consistent with Understanding the earthquake potential from other water dominated floods. Lahars are a active faults is critical for understanding seismic common occurrence on Mt. Ruapehu, with more hazard. On the South Island of New Zealand, much than 50 events since 1861 AD recorded in the attention has been focused on the plate boundary Whangaehu Valley alone. Within this historic Alpine Fault thought to generate major record three lahars have been recorded as either earthquakes, although limited attention has been bifurcating from the normal stream path or focused on the onshore faults adjacent to the avulsing into a neighbouring catchment e.g. the Alpine Fault that are important sources of seismic hazardous 1995 lahar that avulsed into the hazard and sources of geomorphic change. The Waikato Stream/Tongariro River from the South Westland Fault Zone (SWFZ) may be Whangaehu. responsible for some of the paleoseismic records previously attributed to the Alpine Fault and The March 2007 Lahar was a result of a Crater Lake through study of the SWFZ, we may better out‐break from the breach of a tephra dam understand plate boundary behaviour. We created during the 1995‐96 eruptions. Just over discovered the first Quaternary exposure of the eight km from source part of the lahar overtopped SWFZ that shows evidence for repeated, reverse‐ the main channel and continued down a style surface ruptures with ~ 2 m of vertical motion distributary called “Chute”. This avulsion process is per event from Late Pleistocene to present based well documented at Mt. Ruapehu and a number of on offsets we documented in alluvium. Ongoing volcanoes, however the rheological, geomorphic dating will provide insight into event timing. Based and sedimentological processes behind this on the regional Quaternary geology and behaviour is currently poorly understood. In this deformation we document proximal to the SWFZ, research we assess different sedimentological and the SWFZ is indeed active and presents both geomorphic signatures that could possibly cause earthquake as well as surface rupture hazards in lahars to avulse. Sediment deposits along a section South Westland. Prospecting with cone of the Whangaehu River were analysed to penetration testing (CPT) helped us map the strike determine if there is a sedimentological signature of the fault in the subsurface based on offset units, that causes avulsion. LiDAR data pre and post the which appears to be sub‐parallel with the Alpine March 2007 lahar has been examined to Fault. Important ly, the vertical offsets we determine geomorphological properties of the document demonstrates repeated activity, while channel and infer rheological influences on the mapping and logging results show that the zone of lahar. In conjunction with this an ArcGIS model has surface deformation is up to 200 m around the been developed to combine these SWFZ, which will clearly impact existing and sedimentological and geomorphic factors that planned infrastructure proximal to this fault during influence flow avulsions. The model is primarily the next event. Our preliminary results suggests based on the sensitivity of flows to various channel that decoupling paleoseismic records from morphologies, however scenarios have been perhaps up to Mw 7.5 earthquakes from along the developed to simulate the effects of sediment

33 deposition on the channel morphology. The STUDENT PERCEPTIONS OF GEOLOGIC NOTE‐ variations in these factors have revealed the TAKING WITH IPADS primary causes of lahar avulsion in the Whangaehu Valley, Mt. Ruapehu. J. Dohaney1,2, B. Kennedy1,2 & D. Gravley2 1Geoscience Education Group, University of Canterbury, Private Bag 4800, Christchurch 8140 2Department of Geological Sciences, University of LIQUEFACTION HAZARD IN THE TARANAKI Canterbury, Private Bag 4800, Christchurch 8140 REGION [email protected]

G.D.Dellow1 & W.F.Ries1 During fieldwork, students and professionals 1GNS Science, PO Box 30368, Lower Hutt, 5040 record information and hypotheses into their [email protected] geologic notebook. In a pilot study, students (n=11) on an upper‐level volcanology field trip We present a regional‐scale assessment of the were given iPads, with an open‐source geology liquefaction hazard in the Taranaki Region. note‐taking application (GeoFieldBook) and Liquefaction hazard combines the susceptibility of volunteered to record notes (i.e., digital notes) the soils of the region to liquefaction and the during a day at the Tongariro Volcanic Complex likelihood of strong enough ground shaking and the Orakei Korako geothermal site. occurring to trigger liquefaction. This allows assessment of liquefaction hazard — the The digital notes were compared to hardcopy probability of a given severity of liquefaction notes from earlier parts of the fieldtrip and occurring in a given timeframe. students were interviewed several weeks after to reflect on using this technology. The notes and Significant liquefaction hazard in Taranaki is interviews were reviewed and evaluated with the limited to only a few areas. The primary reason for aim of describing their experiences with an this is the fortuitous lack of young, non‐cohesive emphasis on perceived benefits and challenges of fine‐grained sediments in areas where the hardcopy and digital note‐taking. groundwater table is close (within 1‐5 metres) of the ground surface. Students indicated that digital note‐taking resulted in “quicker” transcription of notes, which they The liquefaction hazard was compiled and mapped translated to improved “efficiency” and the ability principally based on published 1:250,000 scale to collect more data. Students also had differing geological mapping (QMap which is compiled from views of the utility and purpose of notes (data geological mapping at a scale of 1:50,000) and the collection, hypothesis‐making, for research or for GNS National Seismic Hazard Model. The industry, etc.). Some major perceived liquefaction classifications assigned to the disadvantages with digital note‐taking included different map units were tested through the that the iPads are expensive and fragile (not field‐ analysis of a geological database of 900 boreholes hardy) and they felt that the software was limiting in the region. The liquefaction hazard derived from to structural measurements (not aimed explicitly the borehole and the geological mapping were at volcanology information). Additionally, the generally in agreement. However, in some cases software does not allow for sketching capabilities, there were discrepancies between borehole which several students mentioned as a interpretations and the hazard determined from disadvantage to digital note‐taking. map units. The liquefaction hazard maps produced in this study identify areas where detailed site More student experiences will be collected in evaluation of the liquefaction hazard is warranted. order to further support and improve note‐taking strategies and geologic reasoning in the field.

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LAKE OHAU: A 17,000 YEAR SEASONALLY‐ LATE OLIGOCENE TO PLIOCENE ANTARCTIC RESOLVED RECORD OF CLIMATE CHANGE CLIMATE AND OCEANOGRAPHIC RECONSTRUCTIONS USING MOLECULAR AND G.B. Dunbar1, R. Levy2, M.J Vandergoes2, H. A. ISOTOPIC BIOMARKER PROXIES Roop1, S.J. Phipps3, S.J. Fitzsimons4, J.D. Howarth2 1 1 1 2 & Lake Ohau Science Team. B. Duncan , R. McKay , T. Naish , J. Bendle , R. 3 2 3 1Antarctic Research Centre, Victoria University of Levy , H. Moossen , & T. Ventura 1 Wellington, P O Box 600, Wellington 6140 Antarctic Research Centre, Victoria University of 2GNS Science, PO Box 30368, Lower Hutt, 5040 Wellington, P.O. Box 600, Wellington 6140 2 3Univeristy of New South Wales, Sydney, Australia School of Geographical, Earth and Environmental 4University of Otago, PO Box 56, Dunedin 9054 Sciences, University of Birmingham, United [email protected] Kingdom 3GNS Science, PO Box 30368, Lower Hutt 5040 Seismic profiles show a ~70 m thick sedimentary [email protected] sequence exists beneath the southeast arm of Lake Ohau (44°10'S, 169°49'E; 500 masl) that we Atmospheric CO2 reconstructions ranged between believe contains a 17,000 year record of regional 500 and 300ppm across intervals of significant environmental change. Coring the full 70 m record climate and environmental change from the late by our research team is anticipated for February Oligocene to the Pliocene, indicating that major 2015. To date a series of ~6 m long cores collected climate thresholds were passed during periods of from the same location contain mm‐scale relatively modest CO2 variation. This implies the sediment couplets. The couplets are defined Earth’s climate system is highly sensitive to primarily by differences in grain size based on feedbacks associated with changes in global ice colour, x‐ray, ITRAX μ‐XRF and laser grain size sheet and sea‐ice extent, as well as terrestrial and analyses. A chronology for these cores has been marine ecosystems. This study focuses on several developed from 210Pb and 137Cs profiles, as well as key intervals during the evolution of the Antarctic 14C ages and pollen biostratigraphy, which show Ice Sheet, in particular the Oligocene/Miocene our cores span the last 1200 years at an average boundary, at which the East Antarctic Ice Sheet accumulation rate of 5mm/yr. The high expanded to close to or greater than present day sedimentation rate confirms the couplets are volume, and the Mid‐Miocene Climate Optimum deposited on annual timescales. Intriguingly, over (MMCO ~17‐15 Ma), a period of global warmth this time period there is a strong positive and moderately elevated CO2 (350‐>500 ppm) correlation between century‐scale changes in Lake which was subsequently followed by rapid cooling Ohau core colour and reconstructed indices of the at 14‐13.5 Ma. Modelling of global climate, Southern Annular Mode (SAM) from numerical vegetation, and ice sheet extent has tried to models, Antarctic ice cores and southern reconcile the various feedbacks that occurred hemisphere mid‐latitude (SHML) tree rings. At during these intervals. However, modelling studies these latitudes SAM exerts a major control over are limited by a lack of geological data of the flow of westerly winds and precipitation hydrological processes and high latitude patterns. Thus our initial results point to the SAM temperatures. being a key determinant of decadal to century scale changes in South Island precipitation. This study will produce new proxy climate However, in order to closely examine the reconstructions using terrestrial and marine relationship between precipitation, lake organic biomarkers from Antarctic drill cores and sedimentation and hemispheric climatology we are outcrop samples that span from the undertaking a detailed monitoring study of the Oligocene/Miocene boundary up to the Pliocene, lake and comparing hindcast climatology with our including the MMCO, and the subsequent cooling existing core stratigraphy. Our ability to examine event that followed. Variations in n‐alkane climate change at seasonal resolution over abundances and concentrations will be used to millennia holds a key to understanding the likely identify changes in the distribution of terrestrial future importance of highly variable climate vegetation. These and other biomarkers will be modes (SAM, ENSO, IPO) to SHML climate. We analysed to determine biomarker syngeneity and discuss how this research can be used to inform abundances across a range of lithologies. Bacterial near‐term projections of New Zealand’s future ether‐lipids will be analysed to determine climate. terrestrial mean annual temperatures and soil pH (via the methylation and cyclisation indexes of

35 branched tetraethers – MBT and CBT, available on DVD, and the digital map can be respectively). Tetraether‐lipids of Crenarchaeota accessed through the GNS website and web found in marine sediments sampled from servers. continental shelves around Antarctica will be used to derive sea surface temperatures using the TEX86 index. SATELLITE RADAR ANALYSIS OF POSTSEISMIC GROUND DEFORMATION ASSOCIATED WITH THE 2010‐2011 CANTERBURY EARTHQUAKE SEQUENCE THE NEW 1:1 000 000 GEOLOGICAL MAP OF NEW ZEALAND P. Faegh Lashgary1, J. Townend1, M. Motagh2, C. Williams3, & I. Hamling3 1 1 1 S.W. Edbrooke , D.W. Heron , P.J. Forsyth & R. 1Victoria University of Wellington, PO Box 600, 1 Jongens Wellington 6140 1 GNS Science, PO Box 30368, Lower Hutt 5040 2 GFZ German Research Centre for Geosciences, [email protected] Potsdam, Germany 3 GNS Science, PO Box 30368, Lower Hutt 5040 In 1865, the year the New Zealand Geological Pegah.Faegh‐[email protected] Survey was established, James Hector produced the first geological map of New Zealand at a scale We measure and interpret ground deformation th of about 1:2 000 000. In 2015, the 150 that occurred during and after the 2010–2011 anniversary, a new 1:1 000 000 Geological Map of Canterbury earthquake sequence using satellite New Zealand will be printed, and a provisional radar interferometry observations. The dataset copy is presented here. The new map is based on includes 11 COSMO‐SkyMed (CSK) acquisitions in the recently completed QMAP 1:250 000 scale an ascending orbit from October 2010 to February Geological Map of New Zealand and incorporates 2011, 19 CSK acquisitions in a descending orbit the advances in understanding of New Zealand between February and November 2011, and 66 geology that came from it. It also includes geology TerraSAR‐X (TSX) acquisitions in a descending orbit of the Kermadec and Subantarctic islands, which between February 2011 and May 2014. The data were not included in QMAP coverage. are analysed to assess postseismic deformation following the 4 September 2010 Darfield The small scale of the map dictates a (Canterbury) earthquake, coseismic deformation chronostratigraphic emphasis where geological related to the December 2010 aftershock swarm, units are distinguished primarily by age of and approximately three years of postseismic deposition or emplacement. Sedimentary units deformation following the 22 February 2011 are differentiated and coloured according to their Christchurch earthquake. The surface deformation depositional age, with overprints used to data are interpreted using a variety of geophysical distinguish those deposited in non‐marine and models including afterslip and poroelastic rebound coastal environments. Late Cretaceous and to understand the role of competing processes in younger igneous rocks are coloured shades of red governing deformation at different points in the to pink, rather than the colours assigned to earthquake sequence. sedimentary units of comparable age. Metamorphic rock units are portrayed according to their known or inferred protolith age; Haast Schist rocks have overprints differentiating textural metamorphic grade. Major allochthonous units are distinguished by having a diagonal white stripe overprint on the underlying protolith colour. Basement sedimentary rocks are portrayed according to age and tectonostratigraphic terrane affinity. Most known active faults are shown, but of necessity only selected “inactive” faults are shown. The map will be published as two sheets, North and South islands, with detailed geological legends; an illustrated explanatory text will come later. Digital vector data for the map are already

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DISTINGUISHING STORM AND SEISMOGENIC SEEKING THE LOST MAMMALS OF ZEALANDIA TURBIDITES IN LACUSTRINE RECORDS FROM THE SOUTHERN ALPS, NEW ZEALAND R.E. Fordyce1, M.D. Gottfried2, C. Loch3, K.D. Rose4, & H.‐D. Sues5 1 2 S. Fitzsimons & J.Howarth 1Department of Geology, University of Otago, PO 1 Department of Geography, University of Otago, Box 56, Dunedin 9054 PO Box 56, Dunedin, 9054 2Department of Geological Sciences, Michigan 2 GNS Science, PO Box 30368, Lower Hutt, 5040 State Univ., East Lansing, MI 48824, USA [email protected] 3 SJWRI, Faculty of Dentistry, University of Otago, P O Box 56, Dunedin 9054 Precisely dated lacustrine sediments from lakes 4Center for Functional Anatomy & Evolution, Johns adjacent to active plate boundaries have the Hopkins University, Baltimore, MD 21205, USA potential to yield records of the frequency and 5Dept. of Paleobiology, National Museum of magnitude of landscape perturbations. However, Natural History, Smithsonian Inst., Washington DC distinguishing earthquakes from other 20013, USA perturbations such as floods and non‐seismically [email protected] generated mass wasting remain challenging impediments to the development of lacustrine Land mammals are known in Gondwana from the paleoseismology. In this study we have used lakes Middle onwards. Given the other likely located along the strike of the Alpine fault in the passengers on Zealandia, as it broke away from South Island of New Zealand to develop a precisely Gondwana, land mammals were probably there dated chronology that records seismic shaking too. Yet, modern New Zealand lacks indigenous from episodic rupture of the fault and high ground‐dwelling mammals, and no conclusive magnitude storm events. Storm deposits can be fossils have been reported. (An early Miocene distinguished from seismic shaking deposits on the find from Manuherikia Group includes basis of the layer sequence, thickness, frequency bones similar to those of a megachiropteran bat.) and the regional extent of perturbations. We report the search for land mammals from Earthquake deposits consists of 150 to 200mm loosely‐cemented shallow marine sedimentary thick turbidites that are interpreted as coseismic rocks that could be sieved at <1 mm: the Chatton mass wasting deposits formed by the collapse of Formation (late Oligocene), and the Otaio Gorge lake margin and delta sediments during seismic Sandstone (early Eocene), both from eastern South shaking. These deposits lack soft sediment Island. deformation and liquefaction structures because the lakes are adjacent to the Alpine fault and Shelly sands of the near‐shore Chatton Formation experience catastrophic collapse of subaqueous produced a few chondrichthyan (shark, ray) teeth slopes during earthquakes. The seismic deposits and many teleost (bony fish) otoliths from 300 kg, are overlain by stacks of 2 to 100mm thick but no land vertebrates. The Otaio Gorge hyperpycnites that represent landscape responses Sandstone yielded tens of thousands of teeth and to seismic shaking. These deposits are generated bone fragments >0.8 mm size from 1320 kg of by sediment liberated by seismic shaking and loosely cemented molluscan coquina and cm to transported to the lakes during floods within ~50 dm cross‐bedded, glauconitic, very fine quartz years of the earthquakes. These deposits are sandstone and siltstone, with Ophiomorpha overlain by alternating organic‐rich and inorganic burrows. The reported age is Waipawan or silt beds that record relatively long periods Mangaorapan (~56‐49.2 Ma). Material was picked between major earthquakes (c 200yrs) when the under the microscope or under a magnifying lens. landscape is in a quiescent state interrupted by Almost all the vertebrates are chondrichthyan or episodic delivery of sediment from precipitation‐ teleost teeth and bone fragments; no land driven landsliding and flooding. We conclude that mammal remains have been identified. However, distinguishing flood and seismic deposits depends one isolated tooth, with a high, lingually recurved on building a robust and independently testable conical crown (height ~18 mm, basal diameter ~8.5 depositional model that couples landscape mm), may be crocodylian. There are no keels, but responses to perturbations with lacustrine indistinct mesiodistal ridges. The surface is processes. unornamented, and shows subvertical microwear. Growth lines are visible in the broken basal section adjacent to a bluntly subconical pulp cavity and in SEM of a polished section; enamel microstructure

37 is unrevealing. If crocodylian, this is the first record by means of further geochemical proxies and from Zealandia older than about 18 Ma. It measurement of lamina thickness. confirms that tetrapod remains other than penguins can be recovered from older Cenozoic strata. BRITTLE DEFORMATION AND FAULTING IN FOLIATED BASEMENT ROCKS OF COASTAL OTAGO, NZ TROPICAL INFLUENCE ON MIOCENE NEW ZEALAND M. Frank1 & S. Smith1 1Geology Department, University of Otago, P O B.R S. Fox1, W.J.D’Andrea2, G.S. Wilson3,4 & D.E. Box 56, Dunedin 9054 Lee4 [email protected] 1School of Science, University of Waikato, Private Bag 3105, Hamilton 3240 Fault and fracture networks in foliated basement 2Lamont‐Doherty Earth Observatory, 61 Rte 9w, rocks control the strength, fluid flow properties Palisades, NY 10964, United States and seismogenic behaviour of the crust. 3Department of Marine Science, University of Understanding faulting patterns in foliated Otago, PO Box 56, Dunedin 9054 basement rocks is important because much 4Department of Geology, University of Otago, PO seismicity (e.g. in the south island of New Zealand) Box 56, Dunedin 9054 occurs within basement rocks and basement faults [email protected] are commonly linked to the formation of major ore bodies (e.g. in central Otago). Strongly foliated Foulden Maar is an Oligocene/Miocene maar schists (and greywackes) are extremely well volcano located near Middlemarch, Otago. The exposed across extensive, clean outcrops along crater is filled with ~100 m of annually laminated coastal sections in Otago, providing an important diatomite which represents a continuous, very opportunity to study the nature of brittle high resolution record of ~100 kyr duration. The deformation and faulting and how they are diatomite is dated to the period 23.03‐22.93 Ma, influenced by rock anisotropy. and is coeval with the peak and rapid deglaciation phases of the Mi‐1 Antarctic glaciation event. Using high‐resolution aerial photography, Spectral analysis of physical properties (density, lineaments (n=6625) with lengths of a few metres reflectance, colour) and organic geochemical (δD, to c. 200 m were mapped along the 16.5 km‐long δ13C) records from the deposit reveals orbital‐scale coastal platform between Taieri Mouth and frequencies, chiefly obliquity, as well as an 11‐kyr Chrystalls Beach, Otago, to provide regional‐scale cycle. The 11‐kyr cycle corresponds to the half‐ context for future fieldwork. Significant patterns precession cycle which has a strong influence on noted in the lineament data include strong insolation only at and near the Equator. The preferred orientations trending 50‐70° and 120‐ appearance of this tropical cycle in mid‐latitude 140°. Comparison to regional‐scale faults in the Miocene New Zealand is unexpected, and suggests Otago region (as recognised on GNS QMAP) shows a teleconnection between the tropics and New a strong correlation between the coastal Zealand at this time. One possible mechanism for lineaments trending 120‐140° and a set of NW‐SE this teleconnection is ENSO variation, which striking regional faults. However, many faults in originates in the tropics and is known to affect the Otago region, including the nearby Akatore New Zealand climate at the present day. Fault, trend NE‐SW (30‐40±10°), an orientation Significant ENSO‐scale (2‐8 year) variation is that is conspicuously absent in our coastal present in the high‐resolution colour records from lineament analysis. Preliminary fieldwork indicates Foulden Maar, and is expressed chiefly by changes that identified lineaments correspond to first‐ in lamina thickness (interpreted as a proxy for order (continuous faults up to a few metres wide, diatom productivity). If ENSO variation is indeed filled in some cases by breccias), second‐order the mechanism for the transmission of the half‐ (faults up to tens of centimetres wide, vein‐filled) precession cycle to the mid‐latitudes, it should be and third‐order (small‐displacement faults and modulated on an 11‐kyr scale. A new project, veins associated with breccias) features. Extensive funded by the National Science Foundation, is structural and geochemical analysis will be currently underway to investigate this hypothesis undertaken to establish cross‐cutting relationships amongst the various lineaments sets as well as the

38 nature of brittle faulting and veining (e.g. P‐T extract from our model are strongly suggestive of conditions of faulting, fluid sources, influence of a thin (<10km) low velocity zone within or above schistosity on fault patterns). the subducting slab which is also present in our 3D shear‐wave model.

THE HIKURANGI SUBDUCTION SYSTEM AS SEEN BY SURFACE WAVES INTRAPLATE BASALTIC VOLCANISM ACROSS ZEALANDIA AND THE HIMU CONUNDRUM 1 2 2 1 B. Fry , Y. Yin , F. Deschamps & M. Reyners 1 1 2 1 J.A. Gamble , M.R. Handler , R.J. Wysoczanski & GNS Science, PO Box 30368, Lower Hutt 5040 3 2 C. Timm Institute of Earth Sciences, Academia Sinica, 1 Taipei, Taiwan SGEES, Victoria University of Wellington, PO Box [email protected] 600, Wellington 6140 2National Institute for Water and Atmospheric Seismic velocities in the earth can be used to infer Research, Private Bag 14901, Wellington 6241 3 the 3D geometry of structures arising from plate GNS Science, PO Box 30368, Lower Hutt, 5040 tectonics. Moreover, the additional information [email protected] contained in the azimuthal dependence of wavespeed (azimuthal anisotropy) can in certain Intraplate volcanism across Zealandia, SE Australia, circumstances be seen as a marker of current and the Ross Sea Embayment and Marie Byrd Land, historic strain. Because the depth sensitivity of a Antarctica defines a magmatic province characterised by basalts where many show high surface wave is dependent on its period, 206 204 87 86 broadband wavespeed information can also be Pb/ Pb (19.5 – 22.5, HIMU), Sr/ Sr ~ used to solve for 3D velocity structure. Based on 0.7035±0.01, Light Rare Earth enrichment these principles, we invert surface wave dispersion ((Ce/Yb)n > 10), and convex‐upward mantle data to calculate isotropic and anisotropic normalised incompatible element multi‐element velocities between 6 and 50 second periods in patterns, peaking at Nb‐Ta. Moreover, trace North Island, New Zealand. This is a region with a element abundances and ratios (e.g. Zr/Nb, Ba/Zr, subduction system including back‐arc spreading as Y/Zr) resemble those Ocean Island Basalts (OIB) well as upper plate block rotation. We generate and are distinct from MORB, suggesting derivation interstation empirical Green's Functions from from an enriched (OIB‐like) source. stacked ambient noise cross‐correlations recorded from station pairs of the GeoNet network and Using geochemical data from Auckland Islands, temporary experiments. Measurements of Carnley Volcano as an exemplar, this talk will fundamental‐mode Rayleigh‐wave dispersion are explore the petrogenesis of primitive basalts from made using multiple filtering and frequency‐time the Auckland Islands. Our preferred model analysis and manual selection of the dispersion envisages partial melting across the asthenosphere curves. This collection of dispersion curves is then – lithosphere boundary, leading to an aggregated inverted for lateral variations in both isotropic and melt column where the asthenospheric source is azimuthally anisotropic wavespeeds at discrete modelled by Primitive Mantle [1] and periods. Each discrete period provides a different subcontinental lithospheric mantle (SCLM) by depth sensitivity range, yielding information on Depleted MORB Mantle [2] enriched by addition of depth dependence of the velocity variations. We 1% Carbonatite (from Hoernle et al, 2002, CMP, then use the suite of isotropic solutions to develop 142). Partial melting progresses from the garnet a 3D shear wave velocity model. We define an stability field into the spinel field and evolution of anomalous region of slow velocities accompanying primitive, near primary, basalts is controlled by trench‐perpendicular fast propagation under the olivine (ol) + clinopyroxene (cpx) fractionation and east coast, near the shallow Hikurangi subduction subsequently, ol + cpx + plagioclase. This model is zone. The structure appears at periods of about 21 driven by “edge – driven” convective flow [3] seconds and is most prominent at periods of about induced along the trailing edges of the Zealandia, 28 seconds. Toward the western North Island, Antarctic, and SE Australian lithospheric plates and farther from the trench, the isotropic group ultimately linked to the break‐up of Gondwana velocity and shear wave velocity is relatively fast and formation of the Southern Ocean and Tasman with the fast‐propagating axis parallel to the Sea. In the convective flow model, the trailing edge trench direction. The isotropic dispersion curves of a lithospheric plate experiences thermal and

39 mechanical (detachment?) erosion along the cheloniid‐like (turtle) xiphiplastron, shark teeth of interface with convecting mantle, leading to the family Odontaspididae (sand tigers), and bony heating and decompression partial melting. In this fish remains. Plant fossils include numerous seeds, scenario, SCLM is the source of the HIMU amber, leaves and in situ tree stumps up to 53 cm signature, an argument supported by peridotite in diameter. Foraminifera include Elphidium xenoliths that reveal both cryptic and patent (rare excavatum, and species of Trochammina and amphibole) metasomatism. Haplophragmoides, unlike any modern New Zealand species: they suggest that most of the [1] Sun & McDonough, (1989). Geological Society molluscs lived in a sheltered, brackish, mid‐high of London 42, 313 – 345. tidal estuarine paleoenvironment. The neretid [2] Workman & Hart, (2005). Earth and Planetary Clithon(?) pomahakaensis and the turtle plastron Science Letters 231, 53 ‐ 72. plate suggest that sea temperatures were at least [3] (see King and Anderson, 1998, EPSL, 160) marginally subtropical.

THE PALEOECOLOGY OF THE ESTUARINE UPPER OLIGOCENE POMAHAKA FORMATION, OTAGO, A METHOD FOR SOURCE ROCK EVALUATION BY NEW ZEALAND WELL LOGGING DATA IN TIGHT RESERVOIR‐CASE STUDY FROM SANTANGHU BASIN OF WESTERN H.J.L. Gard1, D.E. Lee1, R.E. Fordyce1 & A.G. Beu2 CHINA 1Geology Department, University of Otago, PO Box X. Ge1,2, Y. Fan1,2, Z. Fan1,2, H. Liu3 & D. Gu3 56, Dunedin 9054 1 2GNS Science, PO Box 30368, Lower Hutt 5040 College of Geosciences in China University of [email protected] Petroleum, Qingdao, China 2CNPC Key Well Logging Laboratory in UPC, The upper Oligocene (Duntroonian) Pomahaka Qingdao, China 3 Formation, one of the few paleo‐estuarine Tuha Department Divisions of Logging Co., CNPC, deposits known from New Zealand, crops out Hami, Xinjiang, China along the Pomahaka River and Waikoikoi Stream [email protected] near Tapanui, West Otago. Sediments include lignite seams interbedded with fossiliferous muds, The abundance, quality and distribution of source silts and occasionally sands. A drill core indicates rock are vital for predictions of oil and gas that the entire sequence may be up to 90m thick. accumulation zones of tight reservoir. Methods of The Pomahaka Formation rests unconformably on quantitation of TOC and source rock typing are Caples Terrane basement of low metamorphic proposed combined with geochemical and grade and is overlain by the glaucony‐rich Chatton geophysical logging data. Relationship among Formation. Unusual well‐preserved fossils not logging response, physical properties and TOC found elsewhere are present in the muddy and were well studied, then three methods (empirical silty sediments. Shellbeds are up to 1 m thick and formula, multiple regression and support vector different molluscan‐dominated assemblages occur regression algorithm) were applied for TOC at different horizons. Bivalves include Hormomya, prediction. After analysing logging responses of ?Barbatia, two oysters (?Crenostrea and source rocks, types of source rock were classified Crassostrea), Hinemoana acuminata, cf. into four types using Fuzzy Spectral Clustering‐ Potamocorbula and two new species of venerids, Fisher Discriminant analyses. The result showed Tellinota n.sp. and ?Eumarcia n.sp. Gastropods TOC is positive correlated with AC, CNL and RD include the small neretid Clithon(?) pomahakaensis and negative correlated with DEN. What’s more, with extraordinary colour markings, Batillaria there are certain positive correlations pomahakaensis, Melanopsis pomahaka, Batillona between TOC and U, TH and GR. Calculation amara, Maoricrypta, Pomahakia aberrans, results by multiple regression can basically reflect together with new species of Potamopyrgus and the overall tendency of TOC but with a low the freshwater genus Melonoides. Small drillholes, accuracy (mean square error is 30%); results by possibly made by the predatory gastropod empirical formula is preciser than multiple ?Xymene, are present in many molluscs. A species regression (mean square error is 18%) and results of a lobster‐like decapod and trace fossils were by support vector regression achieves the highest found in concretions. Vertebrate fossils include a accuracy (mean square error is 5.4%). The abundance of source rock is high in the area but

40 the evolutionary stage of hydrocarbon generation Bombacacidites and Cupanieidites suggests a is mainly in immature and low mature stage, type I warm temperate to subtropical setting. of source rock develops well, then follows the type II1, type II2 and type III of source rock are rare distributed. BIOGEOCHEMICAL CYCLING OF CADMIUM IN THE SOUTH WEST PACIFIC OCEAN

E. George1, C. H. Stirling1 & M. Gault‐Ringold1 THE MIOCENE FLORA OF BEACHLANDS: FRUITS, 1Department of Chemistry & Centre for Trace SEEDS, LEAVES, WOOD AND FUNGI Element Analysis, University of Otago, PO Box 56,

1 2 3 Dunedin, 9054 I.J. Geary , B.W. Hayward , J.G. Conran , D.C. [email protected] Mildenhall4, J.M. Bannister5 & D.E. Lee5 1 Department of Ecology, Lincoln University, PO Box The biogeochemical cycling of cadmium (Cd) is 85084, Lincoln 7647 likely to be an important component of the 2 Geomarine Research, 49 Swainston Rd, St Johns, ocean’s biological pump and thereby global Auckland 1072 climate. Moreover, the nutrient‐like distribution of 3 ACEBB & SGC, School of Earth and Environmental Cd and its linear relationship with phosphate Sciences, University of Adelaide, SA, Australia makes Cd a useful proxy of past nutrient utilisation 4 GNS Science, PO Box 30368, Lower Hutt 5040 in the oceans. However, the processes controlling 5 Department of Geology, University of Otago, PO the distribution and uptake of Cd remain poorly Box 56, Dunedin 9054 understood. [email protected] As a diagnostic tracer, stable isotopes of Cd have A newly discovered fossil flora from outcrops on a the potential to offer more insight about the wave cut platform near Beachlands, southeast biogeochemical cycling of Cd in the oceans. Auckland includes wood, leaves, fruits and seeds, Additionally, Cd stable isotopes may in itself act as pollen and spores, bracket fungi and amber. a potential proxy for the past and present nutrient Fossiliferous horizons up to 5 m thick occur in utilisation. The limited data acquired so far shows fluvial to ?estuarine sediments deposited in a considerable variability in the Cd isotopic paleovalley cut into Early Miocene Waitemata composition between different regions, suggesting Group sediments. The age of the deposit is the influence of different processes including uncertain, but it is probably Late Miocene to biological uptake, particle scavenging, atmospheric possibly early Pliocene. There is one in situ rooted input and the mixing of different water masses. tree stump and numerous 30 ‐ 50 cm diameter Further studies are therefore required to logs up to 5 m long, many with an east‐west understand more about the marine cycling of Cd. orientation. Leaf beds up to 10 cm thick extend 2 over several 100 m . Some leaves have cuticle The simultaneous collection of Cd isotopes using preserved, and preliminary investigation suggests Multiple Collector Inductively Coupled Plasma the presence of Nothofagus and several species of Mass Spectrometry (MC‐ICPMS) with double Lauraceae. Hundreds of three‐dimensionally‐ spiking protocols has increased the ability to preserved fruits/seeds represent more than 10 measure Cd isotopic fractionation with taxa in at least 5 families, including uncertainties at the 0.01% level. Using these Menispermaceae, Combretaceae and methods, we present measurements of Cd isotopic Elaeocarpaceae. Several specimens of rarely‐ composition and concentration for water samples preserved bracket fungi are present. Miospores collected from a comprehensive suite of depth include at least 15 types of ferns, with well‐ profiles during the GEOTRACES GP13 zonal section. preserved Cyathidites spores dominating. The This cruise transect extends for 5,500 km from diverse pollen flora includes several podocarps, offshore Australia to the remote interior of the and pollen from extinct Asteraceae, but is subtropical Pacific Ocean. There is a strong dominated by Brassospora‐type beech. The longitudinal gradient, with respect to the supply of depositional environment was clearly mesic from trace metal‐bearing dust and phytoplankton the abundance of microthyriaceous fungi biomass, along this transect, allowing the commonly found growing on leaves under moist biogeochemical cycling of Cd, in relation to other humid conditions. The presence of micro‐ and macro‐nutrients, to be systematically

41 investigated across a gradation of changing working toward incorporating numerical modelling oceanographic settings. results from physics based synthetic seismicity and ground‐motion models.

RETHINKING PROBABILISTIC SEISMIC HAZARD ANALYSIS MODELLING THE SUBSURFACE VELOCITY STRUCTURE OF THE TONGARIRO VOLCANIC M.C. Gerstenberger1, M.W. Stirling1, G. McVerry1, CENTRE, NEW ZEALAND, USING AMBIENT NOISE D. Rhoades1, D. Harte1, R. Van Dissen1, B. CROSS‐CORRELATION Bradley2, A. Nicol1, J. Zhao3, A. Christophersen1, & B. Fry1 H. Godfrey1, M. Savage1 & B. Fry2 1GNS Science, P O Box 30368, Lower Hutt 5040 1Institute of Geophysics, SGEES, Victoria University 2Dept. of Civil and Natural Resources Engineering, of Wellington, PO Box 600, Wellington 6140 University of Private Bag 4800, Christchurch 8140 2GNS Science, PO Box 30368, Lower Hutt, 5040 3Geotechnical Department of Civil Engineering in [email protected] Southwest Jiaotong University, Chengdu, China [email protected] Volcanic hazard monitoring and successful eruption prediction requires robust measurements Since the early 1980s seismic hazard assessment in of temporally varying data. In the case of Ruapehu New Zealand has been based on Probabilistic and Tongariro Volcanoes, in the central North Seismic Hazard Analysis (PSHA). The most recent Island of New Zealand, changes in the subsurface version of the New Zealand National Seismic volcanic system may not manifest as surface Hazard Model, a PSHA model, was published by activity or be accompanied by detectable Stirling et al, in 2012. This model follows standard seismicity in the TgVC; thus eruptions occur with PSHA principals and combines a nation‐wide very little or no warning. Recent observation of model of active faults with a gridded point‐source variation of shear‐wave velocities, measured using model based on the earthquake catalogue since ambient noise cross‐correlation, prior to activity at 1840. These models are coupled with the ground‐ other volcanoes around the world has the motion prediction equation of McVerry et al potential to be used as a hazard monitoring tool. (2006). Additionally, we have developed a time‐ Furthermore, ambient noise cross‐correlation can dependent clustering‐based PSHA model for the be used to produce high resolution, 3D velocity Canterbury region (Gerstenberger et al, 2014) in models of subsurface structure. We have used this response to the Canterbury earthquake sequence. technique to develop a database of high quality, reference cross‐correlation functions, ready to be We are now in the process of revising that national used for monitoring, using data from the dense model. In this process we are investigating several temporary seismograph deployments operating in of the fundamental assumptions in traditional 2001 and 2008 along with data from the PSHA and in how we modelled hazard in the past. permanent GeoNet array at those times. For this project, we have three main focuses: 1) Preliminary results suggest an average 5 s period how do we design an optimal combination of Rayleigh wave velocity for the study area of 2.4 multiple sources of information to produce the kms‐1. This database will be used to create a high best forecast of earthquake rates in the next 50 quality 3D shear‐wave velocity model of the years: can we improve upon a simple hybrid of Tongariro Volcanic Centre. fault sources and background sources, and can we better handle the uncertainties in the data and models (e.g., fault segmentation, frequency‐ magnitude distributions, time‐dependence & clustering, low strain‐rate areas, and subduction zone modelling)? 2) developing revised and new ground‐motion predictions models including better capturing of epistemic uncertainty – a key focus in this work is developing a new strong ground motion catalogue for model development; and 3) how can we best quantify if changes we have made in our modelling are truly improvements? Throughout this process we are

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ANTARCTIC MELTWATER PULSES FROM A AUTOMATED STATISTICAL MATCHING OF POSITIVE ICE‐OCEAN FEEDBACK MECHANISM MULTIPLE TEPHRA RECORDS

N. Golledge1,2, L. Menviel3,4, G. Denton5, L. R. Green1, M.Bebbington2, S.Cronin2 & G.Jones1 Carter1, C. Fogwill3, M. England3,4 & G. Cortese2 1Institute of Fundamental Sciences, Massey 1Antarctic Research Centre, Victoria University of University, Private Bag 11222, Palmerston North Wellington, PO Box 600, Wellington 6140 4442 2GNS Science, PO Box 30368, Lower Hutt, 5040 2Volcanic Risk Solutions, Massey University, Private 3Climate Change Research Centre, University of Bag 11222, Palmerston North 4442 New South Wales, Australia [email protected] 4ARC Centre of Excellence for Climate System Science, Australia Establishing a detailed record of past volcanic 5Dept. of Earth Sciences & Climate Change events is important for probabilistic volcanic Institute, University of Maine, USA hazard forecasting, as well as for understanding [email protected] the dynamics and history of a wide range of other geomorphic, climatic, soil‐forming and Global mean sea level at the last glacial maximum environmental processes. Compiling detailed (c. 21 ka) was 130 m lower than at present, with tephra records is complicated by: highly variable the equivalent ice volume locked up in ice sheets tephra distribution over time; difficultly in in both hemispheres. Melting of these ice sheets correlating tephras based on physical and chemical took place episodically [1], with at least two properties from site to site; along with uncertainty periods of abrupt sea‐level rise ‐ `meltwater in age determinations. Multiple sites are needed pulses' ‐ taking place [2,3]. Although the timing to build the most accurate composite tephra and magnitude of these events is increasingly well‐ record, but correctly merging them by recognising constrained [4], the sea‐level contribution from events in common and site‐specific gaps remains Antarctica remains vigorously debated [5]. Here complex. we use a data‐constrained ice‐sheet model, driven with timeseries‐forcings from empirical proxies We present an automated statistical procedure for and from an intermediate complexity Earth system matching tephra sequences model [6], to reconstruct the pattern and timing of between multiple deposition sites, using stochastic Antarctic ice‐sheet recession from 25 ka to local optimization techniques. This approach present. Our suite of transient simulations eliminates implausible matches through careful indicates that ice‐sheet mass loss peaked during reasoning, while heuristically searching over the two periods broadly coincident with meltwater remaining alternatives. If individual tephra age pulses 1A and 1B [3], contributing to sea‐level at determinations are not significantly different rates of up to 1 m per century at ~14 ka. Together between sites, they can be pooled to derive a with global oceanic proxies, our results offer more precise date of each eruption. The known compelling evidence that Antarctica may have stratigraphic constraints and compositions of the contributed to MWP1A as a consequence of tephras can be used to verify possible matches reduced Southern Ocean overturning following returned by the procedure. Heinrich Event 1, when warmer subsurface water Our method of identifying plausible matches is thermally eroded grounded marine‐based ice and demonstrated through the application to five instigated a positive feedback that further long sediment cores from the Auckland region. accelerated ice‐sheet retreat. These sites include tephras from local Auckland

Volcanic Field eruptions as well distal units [1] Carlson et al., (2012). Nature Geoscience 5, erupted from Taupo, Okatania, Mayor Island, 607‐613. Taranaki (Egmont), and Tongariro volcanic centres. [2] Clarket al., (2009). Science 325, 710. The new correlated record compiled is statistically [3] Stanford, J. et al., (2011). Global and Planetary more likely than previously published Change, 79, 193‐203. arrangements from this area. [4] Deschamp et al., (2012). Nature 483, 559‐564. [5] Carlson & Clark, (2012). Reviews of Geophysics, 50(RG4007). [6] Menviel et al., (2011). Quaternary Science Reviews 30, 1155‐1172.

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KINEMATICS OF THE GREBE MYLONITE ZONE, possibility of multiple deformation events that EASTERN FIORDLAND have resulted in prism slip at 600̴ ˚C.

J.W. Grieve1, D.J. Prior1 & J.M. Scott1 1Department of Geology, University of Otago, PO Box 56, Dunedin, 9054 USING EARTHQUAKE‐LIKE LABORATORY [email protected] EXPERIMENTS TO REVEAL ANCIENT SEISMICITY IN CARBONATE‐BEARING FAULT ZONES The Jaquiery Gorge, eastern Fiordland provides an 1 1 excellent 1000 m wide cross section through the J. R. Griffiths & S.A.F. Smith 1 Grebe Mylonite Zone (GMZ). The GMZ comprises Department of Geology, University of Otago, PO three principal lithologies with amphibolite facies Box 56, Dunedin, 9054 metamorphic assemblages: meta‐diorite, meta‐ [email protected] granodiorite and meta‐granite. All lithologies have a steeply west dipping foliation containing a Currently, pseudotachylites are the only shallow south plunging mineral lineation. GMZ unequivocal indicator of seismic slip in the rock mineralogy is dominated by quartz, oligoclase, record, but pseudotachylites do not form in certain orthoclase and two amphiboles, lithologies (e.g. carbonates) and are mainly magnesiohornblende and pargasite. Quartz with restricted to depths of >5 km. Seismically active irregular grain boundaries and undulose extinction carbonate‐bearing areas such as central Italy, indicate recrystallisation by grain boundary Greece and the Himalayan belt would benefit from migration (GBM). Paleopiezometry of a better understating of how ancient seismicity is recrystallised quartz estimates differential stresses preserved in the rock record, to better evaluate of ̴20 Mpa. Plagioclase core and mantle structures the future hazard. are common and suggest sub grain rotation recrystallisation. Tabular amphibole grains show Using a unique dataset of synthetic fault rocks no evidence of recrystallization. Sigma type produced in earthquake‐like laboratory porphyroclasts occur throughout the GMZ, experiments, this project aims to quantify the however no definitive sense of motion can be microstructures produced in mixed calcite‐ inferred as both dextral and sinistral senses are dolomite gouges. Specifically, the project focuses present. on the microstructural evolution of samples deformed under identical “seismic” conditions Crystallographic preferred orientation (CPO) data (Slip vel. = 1 m/s, σn = 18 MPa) but taken to of quartz, plagioclase and amphibole were increasing displacements of 0.03 – 0.4 m obtained using electron backscatter diffraction (representative of slip during approx. Mw 4‐6 (EBSD). In amphiboles [100] a‐axes align earthquakes). preferentially perpendicular to foliation with [001] c‐axes aligned parallel to lineation; an Quantitative analysis of SEM images, combined orthorhombic symmetry that provides no with chemical and optical analysis, shows that information on shear sense. Plagioclase (001) and grain size and gouge fabric evolve systematically (010) planes orient perpendicular to the foliation, with increasing displacement. The bulk of the [100] and [001] directions align parallel to microstructural changes occur within the first c. lineation. These planes and directions are not 0.1 m of slip, during a transient strengthening and components of recognised slip systems for dynamic weakening phase during which grain oligoclase, although they are recognised in more comminution occurs by cataclasis. The weaker calcic compositions suggesting a change in calcite phase wraps around relatively rigid composition or previously unrecognised slip dolomite clasts to define coarse foliations formed systems. Further complexities in plagioclase fabrics entirely by brittle processes. After c. 0.1 m of slip, may indicate more complex deformation. Quartz strain has localised within the gouge layers and CPOs show predominantly Y maxima fabrics, temperature sensitive processes (e.g. thermal [0001] c‐axis directions plot within the plane of decomposition, grain‐scale plasticity and foliation, however variations in orientation to the recrystallization) become increasingly important lineation indicate the possibility of different near the localized slip surface. During this phase, kinematics relative to those observed in the field. cataclastic processes in the bulk gouge layer slow Interpretation of quartz fabrics indicate a down or cease but the coarse foliations continue sinistral/west side down sense of motion with the

44 to rotate slowly towards parallelism with the roughness and surge temperature; and (c) how localized slip surface. dunes and antidunes (the characteristic type bedforms of dilute pyroclastic density currents) are Our results indicate that relatively small‐ emplaced. We also demonstrate examples of LUSI displacement, seismic slip events in upper‐crustal surges interacting with model buildings and fault rocks could generate foliated fault rocks. This infrastructure to highlight future research paths on may leave a lasting microstructural signature of the experimental volcano to investigate PDC seismic slip in the rock record. destruction dynamics.

PYROCLASTIC SURGES FROM PELE – RECENT ERUPTIONS AT MASSEY VOLCANO INVESTIGATIONS OF PLANT SUBFOSSIL CUTICLES AT A HOLOCENE RAISED BOG COMPLEX, 1 1 1 G. Lube , E.C.P. Breard , G. Kereszturi , S.J. NORTHERN NEW ZEALAND Cronin1& J. Jones2 1 Volcanic Risk Solutions, Massey University, Private C. Haenfling1 & R. Newnham1 Bag 11222, Palmerston North 4442 1SGEES, Victoria University of Wellington, PO Box 2 Schl. of Eng. and Advanced Technology, Massey 600, Wellington 6140 University, Private Box 11222, Palmerston North [email protected] 4442 [email protected] Plant macrofossil remains from Moanatuatua Bog (37°55’S 175°22’E) in the northern North Island of Dilute pyroclastic density current (PDCs), or New Zealand are being used to test the hypothesis pyroclastic surges, are one of the most frequently that subfossil plant cuticles of the two principal occurring and highly dangerous phenomena of bog species Empodisma robustum and explosive volcanic eruptions. They are able to Sporadanthus ferrugineus can give robust readily spread over complex terrain, to surmount reconstructions of local bog surface vegetation significant topographic barriers, and to develop changes during the Holocene. This hypothesis will lethal dynamic pressures near the ground surface. be tested by comparing the cuticle records with a Due to the high complexity of natural turbulent pollen record obtained from the same sedimentary gas‐particle mixture flows, there remain large sequence, developed independently by Ignacio uncertainties and controversies around their Jara (VUW). detailed transport, flow transformation and sedimentation processes. PELE – the Pyroclastic Subfossil plant cuticles from peat deposits are a flow Large‐scale Experiment at Massey University ‐ neglected source of information in plant is a new large‐scale facility for experimental macrofossil analysis. E. robustum and S. studies of pyroclastic density currents. It is used to ferrugineus cuticles have the advantage of being repeatedly generate life‐scalable currents easier to recognize than their respective pollen involving 500‐6,500 m3 natural volcanic material remains. Due to their excellent preservation and and air that achieve velocities of 7‐30 ms‐1, flow high identification potential, subfossil plant thicknesses of 2‐4.5 m and runouts of >35 m. The cuticles should be a significant tool in peat studies experimental PDCs are synthesized by a controlled and plant macrofossil analysis. ‘eruption column collapse’ of variably diluted ash‐ Sampling at two scales of resolution will test the lapilli suspensions dropped from a modified research hypothesis as well as providing hopper onto a variably inclinable, instrumented information about the vegetation pattern on the channel. bog in the Holocene and about the successive response of the plant assemblage to fire events on We here present results from a series of hot and the bog surface. Developing a methodology to cold surge experiments to reveal the first views retrieve, identify and quantify E. robustum and S. inside these dangerous phenomena. Along with ferrugineus cuticles from the Moanatuatua peat high‐speed video footage, thermal infrared core is the first goal in this study. Sampling at a imaging, and data from a variety of geophysical coarse resolution (~ every 50cm) will offer an flow sensors we show (a) how the eruption column insight into the bog development and the collapses transform into violent and strongly successional pathway of the local vegetation. As a density stratified currents; (b) how the internal next step, the application of this method will flow structure is altered by both substrate sample subfossil cuticles at a finer resolution

45 around prominent charcoal layers as an radially and are unaligned with faults, indicating abundance of macroscopic charcoal particles gravitational control. indicates a local fire event on the bog surface. This will investigate the response of the local In light of this apparent segregation, the Akaroa vegetation to fire events and the time of recovery Volcanic Complex magmatic system is modelled for S. ferrugineus and E. robustum. with a vertically segregated magma reservoirs stemming from magma at depth. Key processes include: Primitive basalts rising (V‐type) via open MAGMA PROPAGATION, STRESS AND ERUPTIVES: fractures (highly buoyant magmas, with limited SPATIAL AND GEOCHEMICAL ANALYSIS OF THE degassing and/or fractional crystallization), magma AKAROA VOLCANIC COMPLEX pooling in dike plexuses (fractional crystallization and degassing), solidification and sealing of vertical S.J. Hampton1, E. Gaddis2, D. Hobbs3, J. Johnson4 conduits driven by increases in gravitational stress & D.M. Gravley1 (cone growth), lateral L‐type intrusions of evolved 1Department of Geological Sciences, University of (trachytic) magma from upper plexuses, and Canterbury, Private Bag 4800, Christchurch 8140 continued magma propagation via new pathways. 2Department of Geoscience and Department of Over time and with rejuvenation and migration of Biology, Williams College, Massachusetts, USA magma, this process repeated building an 3Department of Geology and Geophysics, aggregate volcanic complex. University of Utah, Salt Lake City, USA 4Department of Geological Sciences, University of Colorado, Boulder, USA [email protected] TRACE ELEMENTS IN NEW ZEALAND PHOSPHORITE NODULES

Magmatic intrusions and eruptions are dictated by 1 2 attributes including volume, composition, tectonic M.R. Handler , R.J. Wysoczanski & G. Frontin‐ Rolle’t1 environment, and gravitational stress. The balance 1 of tectonic and gravitational stresses is critical in SGEES, Victoria University of Wellington, PO Box 600, Wellington 6140 understanding new growth, yet is incompletely 2 characterized. This study investigates the influence National Institute of Water and Atmospheric of gravity and tectonics on magma propagation (V Research, Private Bag 14901, Wellington 6241 and L‐type) and their related eruptives in the [email protected] Miocene Akaroa Volcanic Complex, Banks Peninsula. The occurrence of phosphorite nodules on the Analysis of orientations (valleys, ridges, dikes), Chatham Rise has been known since the early compositions, and locations of features (lava flow 1950’s. Shortly after, their economic potential as a sequences, dikes, domes, and eruptive vents), and source of rock phosphate fertiliser and possibly of relationships between physical and geochemical metals such as uranium was recognised. It has only attributes, reveal a segregation of features both by been in the last decade, however, with the demise proximity to eruptive centres and elevation. Lava of traditional sources of phosphate for New flow sequences, sourced from main vents, indicate Zealand (such as Nauru) that the economic cyclic magmatic processes. Basaltic vents demand for phosphate has increased and (parasitic) occur at low elevations, while exploration of this resource has resumed. undifferentiated dikes exist from the shore Spanning much of the length of the Chatham Rise, platform to upper ridges. Trachytic features are apatite‐ and glauconite‐rimmed phosphorite restricted and evenly distributed in an elevation nodules have formed via phosphatisation of zone of 400‐700m. Segregation of features by Miocene chalk. Early studies have shown these to elevation indicates a close links between have on average ~ 20 wt% P O but have also gravitational stress and magma propagation. 2 5, flagged high U concentrations (100’s of ppm) as Zonation of trachytic domes is likely due to a well as ppm levels of several other metals [e.g. combined critical load stress and buoyancy Cullen, 1978, Marine Geology 28: M67‐M76]. The preventing magma ascension. Low elevation vents viability of these marine phosphate lag deposits display tectonic control in their alignment with co‐ for economic exploitation hinges on the eruptive faults. Dikes however, when grouped composition of the nodules and their host

46 sediments: requiring sufficient mineralization subsidence – such as seamount subduction, back combined with acceptably low levels of trace tilting on an upper plate fault, coseismic metals that may be eco‐toxic (e.g. As, Cd, Cr, V and subsidence related to subduction earthquakes or U). forearc basin development.

High precision, inductively coupled plasma mass Only two rapid, possibly co‐seismic, vertical spectrometry trace element analyses of displacement events are recognised in the core phosphorite nodules and associated sediments will sediments: 1). ~1.2 m of subsidence at 5.6±0.5 ka be presented here together with major element (cal yrs BP). This correlates in age with a ~5.5 ka data acquired by x‐ray fluorescence spectrometry. subsidence and paleotsunami in sediment cores in These data extend the range of trace metals northern Hawkes Bay, ~35 km to the south, previously investigated, including potentially eco‐ inferred to be a subduction interface earthquake; toxic elements. The nodule and sediment samples 2). ~1 m of uplift (relative sea‐level fall) at ~3.8 ka. analysed comprise varying grain sizes from This correlates in age with uplifted marine terraces multiple sites along the Chatham Rise, as well as at Pakarae and Mahia, 40 km to the north and from a recently discovered locality on Bollons south, suggesting uplift of the south‐western Seamount. The compositions of the nodules and Poverty Bay could be related to rupture on an associated sediments will have implications for offshore upper plate fault. Alternatively, it could mining of the resource, eco‐toxicity to the habitat, be related to rupture on the subduction interface and their potential as a suitable source of rock beneath Poverty Bay. phosphate fertiliser. The two coseismic events identified do not account for majority of the Holocene vertical deformation in south western Poverty Bay FORAMINIFERAL RECORD OF HOLOCENE PALEO‐ suggesting both coseismic and aseismic processes EARTHQUAKES ON THE SUBSIDING SOUTH‐ are at play. This is consistent with contemporary WESTERN POVERTY BAY COASTLINE, NEW GPS measurements that indicate the subduction ZEALAND interface in this area is currently dominated by steady aseismic creep and slow slip events – i.e., 1 1 1 B.W. Hayward , A.T. Sabaa , H.R. Grenfell , plate motion is accommodated largely 2 2 2 3 U.Cochran , K.Clark , N.J. Litchfield , L.Wallace , aseismically. M. Marden4 & A. Palmer5 1 Geomarine Research, 19 Debron Ave, Remuera, Auckland 1050 2GNS Science, PO Box 30368, Lower Hutt, 5040 SURFACE WAVE STRUCTURE OF CANTERBURY 3Institute of Geophysics, University of Texas, AND SEISMIC VELOCITY CHANGES FOLLOWING Austin, USA THE 2010 DARFIELD EARTHQUAKE. 4 Landcare Research, PO Box 445, Gisborne 4040 1 1 1 5 R. Heckels , M. Savage & J. Townend Institute of Agriculture and Environment, Massey 1 University, Private Bag 11222, Palmerston North Institute of Geophysics, SGEES, Victoria University 4442 of Wellington, PO Box 600, Wellington 6140 [email protected] [email protected]

The 2010‐2011 Canterbury earthquake sequence Foraminiferal faunas in 29 short cores (max depth occurred largely on previously unmapped and 7 m) of estuarine and coastal wetland sediment buried faults, including the Greendale Fault. were used to reconstruct the mid‐late Holocene Accurate models of the near‐surface velocity (last 7000 yrs) elevational history on the southern structure are vital to understand fault shores of Poverty Bay. This coast is on the characteristics and earthquake resilience. southwest side of a rapidly subsiding area beneath western Poverty Bay. Modern analogue technique Cross‐correlations between seismic station pairs paleo‐elevation estimates based on fossil can approximate their corresponding Green's foraminiferal faunas indicate that our four study functions, i.e., the impulse response of the Earth areas have gradual mid‐late Holocene subsidence between two stations. These functions can be used rates that increase from the southwest (mean ~0.6 for a wide variety of studies, including surface m/kyr) to northeast (mean ~1.0 m/kyr). Several wave dispersion, seismic velocity mapping, noise processes could be generating this area of gradual

47 source analysis and monitoring temporal seismic shallow, locked megathrust fault. Here the coupled velocity changes. plate interface is 20‐30 km deep beneath land and can be sampled with onshore/offshore data from 3 We have determined surface wave dispersion and sides. We have published a 2D Vp model (Henrys present preliminary results of temporal velocity et al., 2013) incorporating coast‐to‐coast onshore‐ changes following the Darfield 2010 earthquake. offshore transect of 50 stations and utilising first Knowledge of these will give insights into arrivals from 2000 offshore MCS shots on either characteristics of the Greendale Fault and the side. The transect velocity model also combined regional structure. Temporal velocity changes first arrivals from 800 stations with 100 m spacing could show changes in noise sources or post‐ recorded from 12 in‐line, 500 kg onshore dynamite seismic relaxation through crack‐healing. explosions. Using the 2D Vp model we obtain the scatterer distribution of explosion waveform coda Using data from a temporary deployment to and applied reverse‐time migration to image the monitor the Darfield 2010 earthquake aftershock plate boundary, a broad zone of reflectivity under sequence, nine‐component cross‐correlation the Tararua Ranges, and upper‐plate faults. In functions have been obtained. Surface wave addition, the 1st arrival tomography is extended to dispersion was analysed using the FTAN method. include (i) first arrivals from the dense temporary Preliminary results reveal fundamental mode array of 50 seismometers with c. 7 km spacing Rayleigh and Love waves and first higher‐mode augmented with 25 regional network instruments Rayleigh waves. Fundamental mode Rayleigh to record 49 local and 45 teleseismic earthquakes waves dominate correlations for frequencies of 0.5 over a four month period and (ii), 69,000 offshore Hz to 1 Hz for stations separated by less than 50 ‐1 airgun shots from 17 MCS lines crisscrossing two km. Higher mode velocities up to 3 km.s have sides of the array. We combine all shot and been observed and dominate at frequencies less earthquake recordings to simultaneously invert c. than 0.5 Hz. For inter‐station paths along the 750,000 first arrivals for velocity structure and Greendale Fault we observe a small increase in hypocenters in the densely sampled volume. seismic velocities c. 0.04 % in the four months Results from 3D, Vp tomography provide improved following the Darfield earthquake. resolution over previous studies. Our improved velocity model provides a high‐resolution

geometry of the subducting plate to support SEISMIC IMAGING BENEATH THE WELLINGTON interpretation of other phases identified in SAHKE REGION, NORTH ISLAND, NEW ZEALAND shot gathers and local earthquakes.

1 2 2 2 S. Henrys , E. Kurashimo , H. Sato , T. Iwasaki , D. 3 1 4 2 USING SEDIMENT SAMPLES AND SUBSURFACE Okaya , R. Sutherland , T. Stern , T. Iidaka , T. 2 4 2 PROFILES TO GROUND TRUTH SUPERVISED Ishiyama , M. Savage , K. Mochizuki , & D. 1 AUTOMATED SEGMENTATION OF MULTIBEAM Eberhart‐Phillips 1 BACKSCATTER FROM THE CHATHAM RISE GNS Science, PO Box 30 368, Lower Hutt 2Earthquake Research Institute, the University of J.I.T. Hillman1, G. Lamarche2, A.R. Gorman1, A. Tokyo, Japan 2 3,4 2,3,4,5,6 3 Pallentin , I.A. Pecher & SO226 Scientists Department of Earth Sciences, University of 1Department of Geology, University of Otago, P O Southern California, USA 4 Box 56, Dunedin 9054 SGEES, Victoria University of Wellington 2National Institute of Water and Atmospheric [email protected] Research, Private Bag 14901, Wellington 6241 3 We present 2 and 3D seismic imagines from the School of Environment, University of Auckland, Seismic Array HiKurangi Experiment (SAHKE). This Private Bag 92019, Auckland 1142 4GNS Science, PO Box 30368, Lower Hutt, 5040 joint project involving New Zealand, Japan, and US 5 institutions aims to investigate the subduction GEOMAR Helmholtz‐Zentrum für Ozeanforschung Kiel, Wischofstr. 1‐3, 24148 Kiel, Germany zone fault characteristics beneath Wellington. 6 Situated above where the Pacific Plate is Texas A&M University, College of Science and subducting beneath the Australian plate at a rate Engineering, 6300 Ocean Drive, Corpus Christi, USA of c. 42 mm/yr, the Wellington region provides a [email protected] unique opportunity to investigate the frictional The use of supervised automated segmentation of properties, geometry, and seismic potential of a multibeam backscatter data to characterise

48 seafloor substrate type is a relatively novel [email protected] technique that is not yet fully developed. In particular the use of data acquired using low The Late Cretaceous to Paleocene Whangai frequency multibeam systems, such as the 12 kHz Formation (and its correlatives) is a widespread, EM120, presents difficulties due the ability of the thick (>400 m), fine‐grained, relatively signal to penetrate up to 5 m below the seafloor. homogenous siliciclastic sedimentary succession This study tests the accuracy of supervised that can be traced from New Caledonia to the automated segmentation carried out using the Great South Basin, southern New Zealand. SonarScope© software, through comparison of Whereas it is lithologically homogeneous, it almost expected versus observed sediment types from certainly records various sediment sources. Within substrate classes and physical property data. We the East Coast Basin, preliminary results of heavy use sediment samples, underwater video tows and mineral assemblage studies record varied seismic profiles acquired during Cruise SO226, over provenance characteristics. On this basis, we have the large pockmarks of the Chatham Rise. integrated studies of detrital grain provenance and detrital zircon fission track analysis with major and Interpretations of seafloor substrate are derived trace element data from key Whangai Formation from classes delineated in the supervised outcrops in the East Coast Basin. automated segmentation according to the Generic Seafloor Acoustic Backscatter (GSAB) model. Key Typically, bulk‐rock geochemistry requires the stratigraphic units, such as high‐amplitude lithified application of costly laboratory based methods carbonates, can be identified in subsurface seismic that require extensive sample preparation. The profiles and correlated to layers in sediment cores, development of portable X‐ray fluorescence (pXRF) facilitating the development of a rudimentary 3D technology allows the rapid collection of large model of sediments. This is then compared to the datasets with minimal sample preparation. The substrate classes derived from the segmentation. pXRF data collected from the various lithostratigraphic divisions of the East Coast Basin Correlating physical property data to substrate allows us to develop high‐spatial resolution classes revealed that the amplitude of returned datasets to assess whether it is possible to backscatter frequently corresponds to lithologies distinguish provenance characteristics, and at depths of up to 4 m below the seafloor. The provide a chemostratigraphic classification. This results of this study also highlight several issues in method has the potential to be combined with the process of substrate classification, primarily sequence‐ and bio‐stratigraphy data, as well as due to the fact that the GSAB model is based on with heavy mineral provenance information to the grain size and roughness of the seafloor. This refine spatial, temporal and depositional does not account for several other parameters relationships for the Late Cretaceous to Paleogene which may influence backscatter levels such as the successions of the East Coast Basin. porosity and pore fluid content. Better understanding the limitations of this model, Key sections throughout the East Coast Basin have however, allows first order interpretations of been sampled and analysed for detrital zircon substrate type and sediment properties to be fission track ages and heavy mineral assemblages derived from the supervised automated to provide provenance information, whilst the segmentation. pXRF analysis adds to this data by enabling correlation between sections, and vertical and lateral variation in composition to be resolved. Using this integrated approach, we can gain DEVELOPING A CHEMOSTRATIGRAPHIC insights into hinterland tectonics during the Late FRAMEWORK FOR THE WHANGAI FORMATION Cretaceous to Paleocene.

1, 2 1,3 1, 2 B. R. Hines , M. Gazley , J. S. Crampton , K. Bland2 & D. Seward1 1SGEES, Victoria University of Wellington, PO Box 600, Wellington 6140 2GNS Science, PO Box 30‐368 Lower Hutt 5040 3CSIRO, Mineral Resources Flagship, PO Box 1130, Bentley, WA 6102, Australia

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THE THREE R’S OF CARBON BURIAL IN NEW IMAGING THE SUBDUCTING PACIFIC PLATE USING ZEALAND FJORDS: RUNOFF, REDOX, AND AFTERSHOCKS OF THE SOUTHERN COOK STRAIT RECYCLING EARTHQUAKES

1,2,3 1 2 3 J. Hinojosa , C. Moy , G. Wilson , C. Stirling , & H. Hirschberg1, K.M. Jacobs1, J.N. Louie2, M.K. 4 T. Eglinton Savage1 & S.C. Bannister3 1 Department of Geology, University of Otago, PO 1Victoria University of Wellington, PO Box 600, Box 56, Dunedin, 9054 Wellington 6140 2 Department of Marine Science, University of 2University of Nevada, Reno, NV, United States Otago, PO Box 56, Dunedin 9054 3GNS Science, PO Box 30368, Lower Hutt 5040 3 Department of Chemistry, University of Otago, PO [email protected] Box 56, Dunedin, 9054 4Department of Earth Sciences, Eth Zürich, Zürich, We present seismic migrations using aftershocks Switzerland of the Cook Strait (M 6.5) and Lake Grassmere [email protected] earthquakes (M 6.6). Following these two large earthquakes we began the Seddon Earthquake Continental margins are significant sites for carbon Aftershock Structural Investigation (SEASI) and burial, and fjord margins in particular have been deployed a line of 21 seismometers stretching shown to accumulate and sequester large amounts approximately 400 km along the strike of the of organic matter. The fjords of southwest New Hikurangi subduction zone in order to use the Zealand, located in Fiordland National Park, rapidly ongoing aftershocks to illuminate the structure of ‐ accumulate carbon‐rich sediments (up to 3 mm yr the subducted Pacific slab. The SEASI line ties into 1 ) and may bury those sediments long‐term as sites the SAHKE line, which was an array of up to 900 of net carbon export. However, the ultimate fate seismometers that recorded air gun and explosion of carbon in these systems depends on the efficacy shots in deployments from 2009‐2011. The SAHKE of processes such as carbon delivery and project characterized the structures perpendicular remineralization. to the strike of the subduction zone. Our results use the SAHKE line as a starting point and look for Using a suite of geochemical proxies (C and N strike‐parallel variations in the depth of the Moho concentrations and isotopes, GDGT distributions, and other structures. Previous studies have trace element concentrations), we investigated suggested potential changes along strike in this carbon cycling and burial in New Zealand’s fjord region, and the deep slow slip events (> 35 km) systems. Bulk organic geochemistry of surface beneath Kapiti island also indicate the potential for sediments shows a strong terrestrial organic variation in properties along strike. carbon component, driven by high regional ‐1 precipitation (up to 6 m yr ). This precipitation is a We have used 246 M > 3 earthquakes that direct result of the Southern Hemisphere westerly occurred from September 2013 through January winds: As moisture‐laden winds hit the Southern 2014 to create common receiver gathers. Our Alps, rain falls on the windward side of the analysis suggests that earthquake relocation (using mountains and drains into the fjord basins. This the temporary GeoNet array deployed during the runoff is rich in terrestrial organic matter. Once sequence) is an important step to produce clean the carbon settles in the fjords, we show that migrations. Multicomponent prestack depth oxygen content plays a major role in organic migration of these receiver gathers, with operator matter preservation. In well‐oxygenated systems antialiasing control and prestack coherency that experience vigorous circulation, organic filtering, produces reflectivity sections using a 1‐D matter respiration is more likely to occur velocity model derived from the SAHKE project. An efficiently. initial P‐P migration shows a north‐dipping reflector at 15‐25 km depth under the earthquake In addition to surface sediment geochemical data, sequence, and suggests the Moho at 20‐25 km we will present high‐resolution downcore analyses depth. From Wellington, a reflector dips very over the last 3,000 years to show how climatic gently south from 25‐35 km depth, which is shifts (e.g., shifts in the westerlies) may have probably the slab interface. These results are influenced carbon delivery and burial in New helping to build 3‐D image of the plate interface in Zealand’s fjords during the late Holocene. the Marlborough and Wellington regions.

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CORRELATIONS BETWEEN SHAKING THE CARBON THE IPCC FORGOT: IMPLICATIONS CHARACTERISTICS, HYDROLOGICAL RESPONSES FOR LOCAL CLIMATE CHANGE IN COMING AND SHALLOW AQUIFER GEOLOGY DURING THE CENTURIES CANTERBURY 2010‐2011 EARTHQUAKES C.J. Hollis1 & G.R. Dickens2 1 C. Holden1 & S.C. Cox2 Department of Paleontology, GNS Science, P O 1GNS Science, PO Box 30368, Lower Hutt 5040 Box 30368, Lower Hutt 5040 2 2GNS Science, Private Bag 1930, Dunedin 9054 Department of Earth Sciences, Rice University, [email protected] Houston, TX 77005, USA [email protected] Shaking and hydrological responses of groundwater during the Canterbury earthquake Projections for future climate change released by sequence have been examined across the the Intergovernmental Panel on Climate Change in hydrogeological transition from unconfined to Assessment Report 5 (IPCC, AR5) in 2013 and 2014 confined aquifers. Data along a 35 km‐wide west‐ are based on four Representative Concentration east profile through Christchurch have been Pathways (RCPs) for greenhouse gas emissions. analysed to compare observations from the inland These RCPs range from a very optimistic low zone of unconfined aquifers, where groundwater emissions scenario, peaking about now (!), to the levels are deepest and have a component of most pessimistic (and arguably most realistic) downwards flow, with effects in the coastal zone scenario with emissions continuing to increase where aquifers are confined, levels are shallow or throughout the coming century; the projected pressures above ground (artesian) due to a increase in average global temperatures by 2100 component of upwards flow. Nearly all sites were ranges from 1° to 3.7°C. However, the projections in spring recovery prior to the 4 Sept 2010 Mw7.1, based on these RCPs omit several potential carbon and in summer recession prior to the 22 Feb 2011 cycle feedbacks that can amplify and accelerate Mw6.3, but pre‐earthquake trends were not global warming. accelerated by the earthquakes. Prominent groundwater level increases were recorded during The geological record provides several examples of both earthquakes, with response style strongly past times when additional earth surface carbon related to the hydrogeology: unconfined aquifers components amplify global warming via positive responded and recovered quickly (closed‐system feedbacks. The best known example, the spike responses < 1 day); whereas pressure Paleocene‐Eocene thermal maximum (PETM), was changes in confined aquifers had longer‐lasting an episode of pronounced and rapid global effects (>days) and those with artesian pressures warming 56 million years ago that lasted ~200,000 appear to have lost water. Shaking recorded by years. Super‐imposed upon a long‐term gradual GeoNet seismometers was quantified in terms of warming trend, the PETM was associated with a PGA, PGV, arias intensity, peak frequency, peak rapid release of at least 2000 billion tonnes of dynamic stress and other spectral characteristics. carbon. Possible sources of this carbon include Provisional analysis suggests the magnitude of methane stored within submarine gas hydrate hydrological response appears more‐strongly systems or polar permafrost. Excellent local related to hydrogeology than variations in shaking. geological records of the PETM reveal its dramatic By comparing hydrological response characteristics impact on the southwest Pacific: mean annual with nearby thorough range of ground shaking temperatures increased by 3‐5°C, significant metrics we hope to be able to isolate controlling species turnover occurred within the marine biota, parameters of the seismic and hydrological and an accelerated hydrological cycle has been responses. inferred from increased continental erosion.

The widely held view that the carbon cycle feedbacks associated with the PETM and other Eocene “hyperthermals” operated on timescales that are too slow to concern New Zealand’s “farmer at the gate” may need reconsideration given recent accounts of catastrophic releases of permafrost carbon (“compost bombs”) and the accelerated expulsion of methane from submarine reservoirs.

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DEVELOPING A NEW ZEALAND recently being determined as 45 to 50 cal. ka using TEPHROCHRONOLOGICAL FRAMEWORK FOR THE a combination of 238U/230Th disequilibrium and (U– SHAPE TIMEFRAME Th)/He ages on zircon, and radiocarbon. Maximising the potential of these markers to help K.A. Holt1, D.J. Lowe2, S.J. Cronin3, P.A.R. Shane4, achieve the goals of SHAPE clearly requires better M. Danisik2 & A.G. Hogg5 age control. High‐precision radiocarbon dating of 1Institute of Agriculture and Environment, Massey charcoal, and 238U/230Th disequilibrium and (U– University, Private Bag 11222, Palmerston North Th)/He zircon ages, are viewed as the best 4442 methods to obtain new dates. 2School of Science, University of Waikato, Private Bag 3105, Hamilton 3240 3Volcanic Risk Solutions, Massey University, Private Bag 11222, Palmerston North 4442 DIFFERENTIATION OF POLLEN OF NEW ZEALAND 4School of Environment, University of Auckland, SPECIES OF FUSCOSPORA USING AUTOMATED Private Bag 92091, Auckland 1142 IMAGE CAPTURE AND ANALYSIS 5Radiocarbon Dating Laboratory, University of

Waikato, Private Bag 3105, Hamilton 3240 K.A. Holt [email protected] Institute of Agriculture and Environment, Massey University, Private Bag 11222, Palmerston North Tephrochronology has played an integral role in 4442 the NZ‐INTIMATE project. A framework of 22 [email protected] marker tephra erupted from Taupo Volcanic Zone (TVZ), Tuhua (Mayor Island) Volcanic Centre (VC), Accuracy of pollen‐based palaeovegetation and Egmont volcano from 30 cal. ka to the present reconstructions is often hampered by poor underpins the NZ‐INTIMATE climate event taxonomic resolution, whereby different taxa have stratigraphy. It is now timely to review the morphologically indistinguishable pollen. This is potential for extending the New Zealand particularly problematic in groups where members tephrochronological framework to 60 cal. ka as have very different ecological requirements. There part of the SHAPE project. are several such groups in New Zealand. Studies of pollen morphology are the basis for determining An examination of the tephrostratigraphy of long taxonomic resolution. Traditionally, these studies sediment records from terrestrial sites (Auckland are done manually. Analysts observe and measure maars, Lake Omapere, Lake Poukawa) and a typically limited number of pollen grains from a offshore (Bay of Plenty, Hawkes Bay, and wider similarly limited number of samples, and this Southwest Pacific Ocean) yields six well‐defined provides the ‘reference’ for the taxa/taxon. tephra deemed as suitably widespread markers, However, technological developments in the fields including one from Taupo VC, namely Tahuna of automated microscopy and image analysis are tephra, and five from Okataina VC, namely realising the capacity for high throughput analysis, Omataroa (unit K), Mangaone (unit I), Hauparu which can vastly increase the number of (unit F), Maketu (unit D), and Rotoehu. observations and samples which can be analysed Furthermore, several units from Tuhua Volcanic in a pollen morphology study. Through increasing Centre preserved in offshore cores in the Bay of sample size, a more accurate picture of the range Plenty offer potential if they can be correlated to of morphological variation within and between other sites. The framework may be further taxa can be obtained, which in turn can facilitate expanded through recognition of well‐known further differentiation, beyond that achieved by eruptions in cryptotephra form thus expanding manual methods. their known distribution, and through further fingerprinting and correlation of widespread Recent work on Leptospermum scoparium and andesitic tephra from Egmont and Tongariro Kunzea ericoides pollen has demonstrated how Volcanic Centres. through applying automated image capture and analysis, two pollen types long regarded as Of the tephra named above, most have relatively indistinguishable are actually quite distinct. This poor age control, limited to a relatively few presentation will examine application of the same radiocarbon dates or ages interpolated from techniques to another key New Zealand pollen sedimentation rates. The Rotoehu tephra has taxon – Fuscospora, which is common in received considerable attention, its age most Quaternary pollen records. The pollen of the four

52 members of this genus are also generally accepted state of unstable sliding. The velocity of Tasman as indistinguishable. Glacier is shown to be proportional to the 24‐hour rainfall magnitude in the surrounding catchment Hundreds of pollen grains of each of the four and peak velocities correspond with the peak rate species have been imaged and analysed using the of glacier surface uplift. The sensitivity of glacier automated palynology system ‘Classifynder’ speed to water input is increased by glacier down (www.classifynder.com). In addition, a sample of wasting, which lowers the effective pressure at the Fuscospora‐type pollen from a late Quaternary bed, indicating that rain induced speed‐up events lake sediment sequence was analysed and will become increasingly common on Tasman compared with the data from the four species, to Glacier. demonstrate application in New Zealand palaeovegetation reconstructions.

AGGRADATION AND AGE OF LATE QUATERNARY GRAVELS BENEATH THE CANTERBURY PLAINS RAIN INDUCED UNSTABLE SLIDING – TASMAN AND IMPLICATIONS FOR GLACIAL ADVANCE AND GLACIER RETREAT

1 1 2 H.J. Horgan , B. Anderson , R. Dykes , C. S. Hornblow1, A. Nicol2, M. Quigley1, R. 3 3 Chamberlain & J. Townend VanDissen2, D. Barrell3 1 Antarctic Research Centre, Victoria University of 1Department of Geological Sciences, University of Wellington, PO Box 600, Wellington 6140 Canterbury, Christchurch 8140 2 Institute of Agriculture and Environment, Massey 2GNS Science, P O Box 30368, Lower Hutt 5040 University, Private Bag 11222, Palmerston North 3GNS Science, Private Bag 1930, Dunedin 9054 4442 [email protected] Institute of Geophysics, SGEES, Victoria University of Wellington, PO Box 600, Wellington 6140 The age and depositional history of the near‐ [email protected] surface gravels of the Canterbury Plains is important for estimating the activity of faults that Alpine glaciers and ice caps are anticipated to underlie the plains. Research into the contribute significantly to sea level rise over the sedimentation history on the plains has long been coming century. This contribution will take place hindered by the difficulty of dating the gravel‐ due to changes in surface mass balance and dominated deposits. Interpretations of the dynamic discharge. The potential for discharge depositional history have relied on limited acceleration has been highlighted as a major radiocarbon (14C) and optically stimulated source of uncertainty in sea level rise predictions. luminescence (OSL) dates at widely scattered Estimating the upper bound of potential locations. accelerations is of particular interest as it allows the limits of realistic scenarios of sea level rise to OSL dating from trench and quarry sites near the be determined. Implicit in this approach, however, Greendale Fault provide seven new ages from sand is the assumption that we have observed, or can lenses in Burnham Formation gravel deposits at predict, the full spectrum of glacier behaviour. depths of 0.9 to 4.0 m, and one from loess in a surficial channel incised into the gravel (depth of Changes affecting basal slip can cause the flow of 0.55 m). The intra‐gravel sand lenses returned glaciers and ice sheets to accelerate rapidly. median ages ranging from 20.2±1.9 to 33.0±2.0 ka During times of heavy rainfall, Tasman Glacier in while the loess yielded an age of 10.0±0.7 ka. This the Southern Alps of New Zealand accelerates to loess age indicates that in this location about 10 speeds of up to 40 times its normal speed (from 40 kyr may have elapsed between fluvial ‐1 to 1600 m a ). Peak speeds are maintained for abandonment of the surface by the Waimakariri periods of less than 12 hours before the glacier River and deposition of Holocene loess, and velocity returns to close to background levels. highlights the importance of sampling from within gravel deposits themselves to constrain the age of These observations, which were obtained using the sediment package. Intra‐gravel ages are multi‐year continuously recording GPS, greatly compatible with previously published OSL and 14C expand the observed range of glacier speed ups in dates from elsewhere on the Canterbury Plains response to water inputs, and likely represent a (e.g. [1]). The gravel depositional ages are

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generally in correct stratigraphic order and cluster DISASTER VIEW: CROWD SOURCED DISASTER in time intervals of ~20 to 24 and ~28 to 33 ka. IMAGERY

We propose a model for multiple periods of fluvial J.F.Irons sediment deposition and quiescence on the Institute of Agriculture and Environment, Massey Waimakariri and other Canterbury Plains glacial University, Private Bag 11222, Palmerston North outwash fans since at least 33 ka. The data 4442 highlight that the penultimate surface rupture on [email protected] the Greendale Fault occurred at about 20‐30 ka, and that a subsequent episode of gravel Correct decisions can only be made when there is deposition removed or obscured the surface trace accurate information available. In a disaster, poor of the fault, until its re‐emergence in the 2010 communications and poor physical access limit Darfield Earthquake. information acquisition by central authority. However, large numbers of those in the affected [1] Rowan et al., (2012). Quaternary area will have cellular telephones with the ability Geochronology 8, 10‐22. to capture images. The proposal is to provide a digital mapping platform, similar to Google Street View™, where photos taken by members of the public can be uploaded to provide dense visual THE GEOLOGY OF A SECTION OF THE PAHIATUA imagery of damage in near real time of emergency BASIN, MANGATAINOKA RIVER VALLEY, NORTH situations. ISLAND, NEW ZEALAND

1 1 1 1 The majority of cellular telephones can capture K. Horton , A. Palmer , J. Palmer & R. Singh 1 images, and these images carry with them Institute of Agriculture and Environment, metadata. Where the phone is GPS capable, these Massey University, Palmerston North co‐ordinates are part of the metadata. To protect [email protected] privacy, various social media sites normally strip this information from the image. If, however, Pahiatua Basin, a Late Miocene to Recent basin, is images with metadata were sent to a site capable located in the East Coast fold and thrust belt of interpreting this GPS data and assigning the immediately east the major strike-slip fault zone image to a GIS location, a central image source that bounds the axial ranges. The sedimentary would become available as and where data can be succession represents a shallowing marine transmitted over data networks. environment overlain by terrestrial sediments.

The Totaranui Formation, an important unit in this sedimentary succession, is the oldest member of THE ANCHORITE FAULT SYSTEM ‐ MIOCENE the Mangamaire Group. It is widely distributed, FAULTING IN THE HAURAKI GULF occurring on both ridges of the Mangatainoka 1 1 Valley, but is not present south of Mangamaire. This J.F.Irons , J.A.Palmer study revises the stratigraphy of the Totaranui 1Institute of Agriculture and Environment, Massey Formation and subdivides it into five members – University, Private Bag 11222, Palmerston North Lower Mangamaire Sandstone, Lower Totaranui 4442 Coquina Limestone, Upper Totaranui Flaggy [email protected] Coquina Limestone, Totaranui Limestone Conglomerate and the Upper Mangamaire A long series of faults crossing the Hauraki Gulf Sandstone. The formation overlies the Marima links the Whangarei Harbour Fault with the Sandstone in the west and the Makuri Group in the Waiwhango Fault in the northern Coromandel east and underlies the Mangahao Formation in the Peninsula. Hereby named the Anchorite Fault west. The Totaranui Formation varies in thickness, System [AFS], initial activation at ~21.5 Ma is but has a maximum thickness of 110m. Lithofacies contemporaneous with the end of the show change from a low energy to a high energy emplacement of the Northland Allochthon; we environment consistent with the shoaling of the suggest the AFS is structural failure of the anticline Pahiatua Basin in the past 10 million years. It is / nappe which provided the driving slope for considered a potential aquifer in the region. emplacement.

54 The height of the resultant scarp (~1500m) and the substitute, import, or produce locally. We import presence of a debris field 40km x 70km – Kawau 69% of our oil and pay in US dollars, difficult when Subgroup ‐ indicate a large and rapid release of the exchange rate is high and even more difficult energy, and provide the geological scenario for the should it revert to the historic average. Continued sudden plunging to bathyal depths of basal use will have environmental consequences but Waitemata Group as described by previous there are no magic alternatives for transport fuels. workers. The AFS scarp now forms the eastern boundary of Waitemata Group. Despite the height Our vast offshore territory includes many of the scarp, formations on both sides of the fault sedimentary basins. There have been few offshore were created at bathyal depth. On the upthrown wells, except in the area of the Taranaki side, Colville Formation demonstrates sudden continental shelf. Are New Zealand's only immersion, bathyal sedimentation and progressive commercial accumulations of oil and gas in the restoration to coastal shallows, indicating rebound eastern Taranaki Basin? I don't know the answer from submergence by ~17.5Ma. and neither do you.

The lineation appears to be associated with Self‐sufficiency in oil and gas would help this volcanics at Whangarei (Taurikura Volcanic country build resilience, to better meet the Complex), Coromandel (Beesons Island Volcanics) challenges which this century will bring. A and Anchorite Rock, in mid Hauraki Gulf. systematic study is warranted. We make some effort, but insufficient effort, and must reconsider Volcanic activity took place at Taurikura from how government research money is spent. Will approximately 23Ma to 16Ma. As activity your work improve the social and economic well‐ decreased near Whangarei, the Beesons Island being of those who fund it through their taxes? If Volcanics commenced on the AFS and en echelon not, why are you doing it? faults near Coromandel. Beesons Island Volcanics were active from 16Ma to 13Ma, at which point Anchorite Rock erupted, ending the main sequence of fault related volcanic activity. PLANT DIVERSITY AND PALEOCLIMATE OF THE MIOCENE LANDSLIP HILL SILCRETE, GORE LIGNITE MEASURES, SOUTHLAND

THE DEAL WITH THE DEVIL J.A. Jackson1, T. Reichgelt1, J.G. Conran2, K.J.M. Dickinson3 & D.E. Lee1 M.J. Isaac 1Department of Geology, University of Otago, PO Emeritus Scientist, GNS Science, PO Box 30368, Box 56, Dunedin 9054 Lower Hutt 5040 2ACEBB & SGC, School of Earth & Environmental [email protected] Sciences, University of Adelaide, Australia 3Department of Botany, University of Otago, PO Strict measures to limit fossil fuel use are possible Box 56, Dunedin 9054 but unlikely, for democratic governments will do [email protected] what is popular with the majority. People in poor countries aspire to the lifestyle which oil, gas and The Miocene Landslip Hill silcrete from southern coal allow us. Abrupt cessation of fossil fuel use is New Zealand is a fluvial deposit consisting of implausible and our species will have to live with quartz sand cemented by amorphous silica, in the climate change consequences. which numerous randomly oriented three‐ dimensional plant fossils are preserved as moulds. How resilient is New Zealand? We try to pay for a Leaf fossils include eight conifer morphotypes, two first world lifestyle through the export of little‐ monocots and about 30 distinct angiosperm leaf processed agricultural commodities such as milk morphotypes with dicotyledonous or magnoliid powder but our balance of payments is negative. affinities. Additionally, eight different fruit or seed Expansion of dairy farming to balance the books types are recognised. Some morphotypes have comes at a significant environmental cost. affinities with Araucariaceae, Podocarpaceae, Nothofagaceae, Casuarinaceae, Elaeocarpaceae Gas generates 20% of our electricity and sustains and Lauraceae. Quantitative paleoclimate industry; our reserves peaked in 2002. We still rely estimates for temperature and precipitation on oil and, if we cannot yet give it up, must variables were obtained by cross‐correlating

55 physiognomic variation of dicotyledonous and A quantitative temperature reconstruction from magnoliid leaf morphotypes with two pre‐existing Adelaide Tarn and a preliminary integration of modern leaf assemblage calibration datasets using both records suggest significant early‐Holocene the Climate Leaf Analysis Multivariate Program warming in the South Island. While a more modest (CLAMP). Preliminary results indicates a diverse temperature increase is observed in the northern floral assemblage growing in a much warmer and North Island. At the same time, multiple proxies more humid climate than present day Southland, from tropical and extra‐tropical latitudes imply with moderate to high average precipitation with that precipitation sourced from the extra‐tropics relatively little seasonal variation and a more or (westerly) may have reduced over most of the less year‐round growing season. country. This reduction could have been compensated in northern and eastern areas by an enhanced subtropical (easterly) precipitation, a circulation pattern in some ways analogous to the NEW PALYNOLOGICAL INVESTIGATIONS FROM present‐day positive phase of SAM. Evidence for NEW ZEALAND PROVIDE INSIGHTS INTO this scenario will be examined using the pollen REGIONAL AND HEMISPHERIC CLIMATE records from Adelaide Tarn & Moanantuatua. VARIATIONS DURING THE HOLOCENE PERIOD.

I. A. Jara1, R.M. Newnham1, M.J. Vandergoes2 & J.M. Wilmshurst3 TURBIDITES OF THE SOUTHERN HIKURANGI 1SGEES, Victoria University of Wellington, PO Box CHANNEL, NEW ZEALAND

600, Wellington 6140 1 1 2 2 M.R. Jeromson , L.J. Strachan , P. Barnes , J. GNS Science, PO Box 30368, Lower Hutt 5040 2 2 2 3 Mountjoy , L. Northcote & A. Orpin Landcare Research, PO Box 40, Lincoln, 1 Canterbury 7640 School of Environment, University of Auckland, [email protected] Private Bag 92091, Auckland 1142 2National Institute of Water and Atmospheric Environmental reconstructions based on Research, Private Bag 14901, Wellington 6241 vegetation are particularly well suited to New [email protected] Zealand (34‐47°S; NZ) due to its location across sub‐tropical and extra‐tropical latitudes, an Relatively little is known about depositional flow extensive pre‐human forest cover and a late processes along and across the Hikurangi Channel. settlement history. Previous palynological studies This poster presents the results of a have been focused on the transition out of the last sedimentological investigation of three, archived Ice Age. These have revealed important vegetation short (<3.5 m) sediment cores, collected by NIWA, changes; while the use of numerical techniques from the southern Hikurangi Trough off Wairarapa. have allowed quantitative reconstructions of The aim of the study is to understand depositional temperature variations associated with those flow processes, from a high resolution analysis of changes. However, pollen‐based climate selected beds. The three cores form a lateral reconstructions for the Holocene period are transect from the channel thalweg, to the north comparatively fewer and less well resolved, which western levee and distal overbank basin floor prevent more detailed investigations about the environments, allowing comparison of lateral climate controls over this period. facies changes. Laser particle sizing, magnetic susceptibility and vacuum gasometric techniques Here we present two new postglacial pollen are used to investigate, analyse and characterise profiles from different vegetation‐climate settings each core, with focus on key event beds. The beds in NZ: (1) a 13,000 year‐long sequence from selected are normally graded sandy‐silts that have Adelaide Tarn (40°56’S; 172°32’W), a small lake been interpreted as deposits of low‐density near the tree line in the beech (Nothofagus) forest turbidity currents. Turbidite caps are muddy and of the northwestern South Island; and (2) an exhibit a spike in the percentage of calcium estimated 15,000‐17,000 year‐long sequence from carbonate (CaCO3), which may indicate the Moanatuatua (37°58’ S; 175°21’E; 60 m.a.s.l), a presence of an overlying hemipelagic layer. lowland peat bog in the Broadleaf‐conifer forest Comparison of the sedimentary facies in each area of the northern North Island. environment provides an insight into the flow processes and depositional characteristics of the Hikurangi Channel, and more generally, insights

56 into levee over‐spilling and flow stripping interdisciplinary studies encourages has the processes. A conceptual model of flow evolution potential to develop more comprehensive, from channel to overbank will be presented. transferable skills applicable to the “real world”, by helping students identify and leverage disciplinary connections often taken for granted by expert scientists. Despite this, the traditional AIRBORNE GRAVITY ACROSS NEW ZEALAND tertiary education system provides limited 1 1 2 2 opportunities to work outside of disciplinary J. McCubbine , E. Smith , M. Amos , R. Winefield 3 boundaries and little support to do so. & F. Caratori Tontini 1Victoria University of Wellington, PO Box 600, Interdisciplinary curricula are most effective when Wellington 6140 2 knowledge is constructed from the ground up, Land Information New Zealand, National Geodetic with links between individual disciplines made Office, Wellington 3 during the later stages, at which time foundational GNS Science, PO Box 30368, Lower Hutt, 5040 knowledge has been solidified. They are also most [email protected] effective when implemented using active learning Land Information New Zealand has recently (i.e., hands on) techniques. Using these completed the first national airborne gravity recommendations, interdisciplinary curricula has survey of New Zealand. The aim of the the potential to be highly impactful in outreach programme was to determine gravity anomalies at and recruitment, both at the secondary and a 10 kilometre wavelength and thereby compute a tertiary level. This is particularly relevant to national geoid with at least 3 centimetre accuracy. geoscience, where anecdotal evidence suggests that many majors begin tertiary studies in other The airborne gravity data consist of a uniform set subjects and the potential for cross‐disciplinary of measurements that cover the whole of New recruitment is high. Zealand, including the shallow coastal areas and rough topography that have previously been This work will situate concepts relating to extremely difficult to survey. Over 50,000 line‐ approaches and implications of interdisciplinary kilometres of surveying were completed in two studies in a real curriculum development example. campaigns during August ‐ October 2013 and The “Living with Volcanoes” activity is a ninety February – June 2014. minute, one‐off introductory geoarchaeology activity, developed with the above benefits and The key steps taken in the data collection and framework in mind. Geoarchaeology, the reduction will be outlined along with an analysis of integration of earth science techniques into the internal consistency of the data and archaeological investigations, bridges the arts and comparison to the existing global gravity model sciences with applications to past, present, and EGM2008. future human‐environment interactions. Learning goals and more holistic aims were used to align the curriculum content with concepts and skills deemed central to geoarchaeological and DEVELOPMENT OF INTERDISCIPLINARY interdisciplinary thought. The curriculum was GEOSCIENCE CURRICULA: APPROACHES AND piloted with upper year secondary school students IMPLICATIONS in Northern England, followed by an assessment of its effectiveness, proving successful at improving A. Jolley1 & G. Ayala2 geoarchaeological knowledge and perceptions of 1Department of Geological Sciences, University of interdisciplinarity. Canterbury, Private Bag 4800, Christchurch 8140 2Archaeology, University of Sheffield, Western

Bank, Sheffield S10 2TN, United Kingdom

[email protected]

As society increasingly encounters challenges within an interconnected earth system, interdisciplinary research and teaching are becoming more frequent in the geosciences. The broader learning environment that

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THE ROLE OF SITE AMPLIFICATION, POLARITY frequency range at sites generally classed as rock AND TOPOGRAPHIC EFFECTS IN THE PORT HILLS according to the New Zealand design standards. DURING THE CANTERBURY EARTHQUAKE SEQUENCE CHARACTER AND ORIGIN OF LATE NEOGENE SUBSIDENCE AND SEDIMENTATION OF TARANAKI A. Kaiser1, C. Holden1, C. Massey1 & R. Benites1 BASIN 1 GNS Science, PO Box 30368, Lower Hutt 5040 [email protected] P.J.J. Kamp1, K.R. Lucas1 & K.A. Vincent1 1School of Science, University of Waikato, Private Significant building damage and permanent Bag 3105, Hamilton 3240 ground displacement occurred in the southern [email protected] Port Hills suburbs of Christchurch during the Canterbury earthquake sequence. Damage It is possible with a high degree of certainty to map patterns indicate that local amplification of ground the unfolded position beneath Taranaki and motions likely contributed to the most severe Wanganui basins (on Australia plate) of the leading effects. The Canterbury earthquake sequence edge of the subducted Pacific Ocean lithosphere. provides an internationally significant case study Our hypothesis is that interactions at the leading to understand the influence of topography and edge of this slab and behind it caused a marked local stratigraphy on ground‐motion amplification change in the stress regime of overriding Australia in hillside areas. plate, expressed in basin subsidence, coastal onlap and a change from reverse to normal faulting. We We present site‐response analyses based on have tested this hypothesis by the mapping of GeoNet national strong motion stations, as well as stratigraphic horizons using open‐file seismic four small‐scale temporary seismic arrays installed reflection data sets tied to well logs for age in the Port Hills following the 2011 February control. This establishes the lag timing of coastal Christchurch earthquake. These stations are onlap, the end of reverse faulting and start of spread across narrow north‐south trending normal faulting in relation to the transit of the volcanic spurs with a variety of topographic leading edge of the slab beneath the region. In shapes. The spurs are also overlain, in part, by general, coastal onlap lags slab emplacement by 0 thick (up to 10m) loess deposits. Site amplification, – 0.5 m.y. Some reverse faults continue to show polarization and dependence on source back‐ displacement for up to 0.5 m.y. amounting to azimuth are assessed using H/V and site‐to‐ about 20 km after the slab was emplaced beneath reference spectral ratio methods applied to them, giving rise to folding of the surface of aftershocks of the Canterbury earthquake marine onlap (e.g. Kahurangi Fault). The start of sequence. Results are also compared with detailed normal fault offset shows variable lag time, with 2D modelling at key locations. faults farther from the Cape Egmont Fault Zone having longer lag times. A key factor in explaining Consistent amplification peaks at hill‐top locations the lag patterns is due to the scale and location of at 1 – 3 Hz appear to be related to slope shape, inherited topography, which relates to prior with the estimated wavelength of amplification crustal thickening. The widespread late Neogene comparable to the ridge width at a given location. subsidence of Taranaki and Wanganui basins is The strongest amplification at these frequencies considered to be caused by emplacement of the generally occurs on top of narrow, steep‐sided subducted slab and associated mantle processes ridges. Our results imply that relatively low‐ rather than being due to interaction across the velocity material comprising the eastern Port Hills plate interface. has enhanced amplification in this area. At higher frequencies > 3 Hz, significant amplification is associated with local material contrasts or sharp local convex breaks in slope.

Our results show that both local topography and material contrasts strongly influence ground motion in the Port Hills. These observations have implications for slope stability studies and engineering design in hillside areas, given that significant amplification can occur over a broad

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LEAD IN THE LIVING ENVIRONMENT ‐ THE A RE‐APPRAISAL OF THE FRACTURED TIKORANGI ANNUAL COST TO THE NEW ZEALAND ECONOMY LIMESTONE IN THE WAIHAPA‐NGAERE‐TOKO‐ TARIKI WELLS B. Keet 1Geo & Hydro – K8 Ltd, 32 Keirunga Road, R. Kellett1 & S. Ward1 Havelock North 4130 1New Zealand Energy Corp., PO Box 8440, New [email protected] Plymouth [email protected] Lead and other heavy metals in house dust are detrimental to human health, especially to the The producing interval in the Waihapa Oilfield is health of young children. Until 2009 the the Oligocene Tikorangi Fm comprising a mixed international literature and research focussed on siliciclastic‐limestone sequence up to 300 m thick. serious lead poisoning leading to dramatic The matrix porosity is very low so oil production decrease in IQ. More recently the focus has comes from steeply dipping fractures. There have shifted to average nationwide low level lead been several episodes of fracturing, an early poisoning, leading to small but far from Miocene phase that has largely healed, and a late insignificant lowering of the nation’s population IQ Pliocene phase that is open. The bulk of the work level. on the depositional history and complex fluid flow in the Tikorangi Fm stems from the research of The main source of the lead in the living Hood [1]. environment is from anthropogenic sources accumulating in the geologic substrate of our living Since 2013 NZEC, and its partner L&M Energy, environment: the garden soil. From there it is have reviewed the vast amount of data compiled transported into our homes and from there into by the previous operators to identify key elements our bodies through various mechanisms and of the fracture and petroleum system. These data pathways. include core (368 m in 5 wells), standard logging suites, image logs, full‐wave‐form sonic logs, and The costs of this lead exposure are staggering. vertical seismic profiles. These data sets provide Several studies in the US found the annual cost to information on the rock properties and the exceed $US 50 billion, while a study in France fractures at a range of vertical scales from the estimates the annual cost for that country at Euro microscopic to the 30 – 50 m seismic scale. Drilling 20 billion. This means the cost to society due to complications in many wells produced incomplete low level lead poisoning 6 – 10 times that of logging suites, so some novel methods have been Asthma. used to identify fracture density, including fluid Phasing out of lead‐based paint and leaded fuel in losses and other drilling parameters. New Zealand occurred much later than it did in the US or EU. Therefore mitigation efforts in our The fracture density is not evenly distributed country have to be more intense and are more vertically or laterally. The northeast trending faults urgent. However the contrary is current reality. that create the fractures step in an en echelon Mitigation only incurs a one‐off cost, while it pattern across the Waihapa‐Ngaere‐Toko Field. benefits many generations of house dwellers. The more brittle sparry calcite facies supports a stronger fracture density. The mud‐rich zones are In the cost benefit analysis presented the more ductile and the fractures have healed. similarities and differences with overseas studies Getting the most information out of the existing will be highlighted and a case made for shifting our well data is key to maximising the efficiency of focus from home insulation to dealing with this producing the field, and planning new wells to tap emerging environmental geohazard. undrained portions of the fracture system.

[1] Hood (2000). PhD Thesis, University of Waikato.

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THE EARLY EOCENE FLORA FROM OTAIO RIVER the conifer family Araucariaceae have been recovered. E.M. Kennedy1, J.I. Raine1, E.M. Crouch1, J.M. Bannister2, H.E.G. Morgans1 & J.G. Conran3 The palynoflora in the leaf‐bearing unit is diverse 1GNS Science, PO Box 30 368, Lower Hutt 5040 and contains a number of thermophilic taxa 2Department of Geology, University of Otago, PO including Spinizonocolpites prominatus (Nypa: Box 56, Dunedin 9054 Arecaceae), Malvacipollis subtilis (cf. Austrobuxus: 3School of Earth & Environmental Sciences, DX 650 Picrodendraceae) and Cupaneidites species (cf. 312, The University of Adelaide, SA 5005, Australia Cupaniopsis: Sapindaceae). Conifer pollen is [email protected] dominant over angiosperm.

Earliest Eocene estuarine to non‐marine mudstones and coals within the Broken River Formation in Otaio River, South Canterbury, RECENT ERUPTIONS AT WHITE ISLAND: provide a glimpse of the surrounding vegetation in QUANTIFYING THE AMOUNT OF MATERIAL LOST the form of sparse leaves and abundant TO THE GEOLOGICAL RECORD palynomorphs. Pollen and spores have been 1 2 G. Kilgour & E. Bowyer examined from throughout the coal measures and 1 GNS Science, Private Bag 2000, Wairakei provide a record of vegetation change. Leaves 2 University of Bristol, Queens Rd, Bristol, UK have been recovered from a limited stratigraphic [email protected] horizon in the lower part of the section and although variable in their preservation quality they White Island erupted in two very short bursts on provide sufficient information for employment of 4th August, 2012 and 11th October, 2013 both after leaf morphology‐based paleoclimate analysis intense periods of unrest. The largest of the two (CLAMP and Leaf Margin Analysis). Temperature eruptions occurred at ~ 8 pm on October 11. Both estimates derived from leaf morphology suggest a events were captured by the camera near the old warm temperate to sub‐tropical climate. sulphur factory under low light conditions, which allowed us to determine the rates of plume ascent

and surge flow rates crudely. Palynology, leaf fossils, bulk carbon isotopes, sedimentology, foraminifera and nannofossil We focus on the October eruption where we have analysis have been employed to characterise the assessed photographs of the crater floor to exposures and the paleoenvironments they determine the number and size of ballistic impacts, represent. Miospores and dinoflagellate cysts coupled with ground‐based measurements. We indicate that the coal measures are earliest Eocene then used the area of altered ground from (New Zealand PM3b/lower MH1 miospore zones, photographs to determine the deposit extent, Waipawan to early Mangaorapan); the leaf flora is again along with ground‐based thickness Waipawan (PM3b zone). The presence of the measurements. These data are used to describe dinoflagellate cyst genus Apectodinium in the dynamics of the eruption. combination with an apparent negative shift in the bulk carbon isotope record suggest that the leaves A serendipitous sample was collected near the were deposited during the Apectodinium acme camera site that would otherwise have been lost that occurred during the globally significant high from the depositional record. We use this sample to determine the amount of material transported CO2 and high temperature Paleocene‐Eocene Thermal Maximum (PETM). out of the crater once effective mixing between the surge and atmosphere took place. This is a rare Macromorphology of the leaves indicates the example where we can calculate the amount of presence of a moderate diversity of broadleaved material lost from the geological record. We then angiosperms, at least one fern and rare podocarps discuss the results of a visit one year after the and araucarians. Leaf cuticle preservation allows eruption to again assess the effect of erosion of confirmation of taxonomic inferences from the deposit. These results can then be used to macromorphology in some instances. Leaf cuticles better understand the geological vs. eruption of the dicot families Proteaceae, Lauraceae, record at an active volcano. Araliaceae, as well as the monocot Ripogonum and

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STRATIGRAPHY AND SEDIMENTOLOGY OF A CHARACTERISING CHANGE IN POSTGLACIAL SATELLITE VENT OPERATED BY CLIMATE BY SEISMIC IMAGING IN LAKE OHAU PHREATOMAGMATIC TO LAVA FOUNTAINING ERUPTIONS: THE OHAKUNE BASALTIC COMPLEX M. Krause1 & A.R. Gorman1 1University of Otago, Department of Geology, P O 1 1 1 1 S. Kosik , K. Nemeth , J. Procter , G. Kereszturi & Box 56, Dunedin 9054 1 S.J. Cronin [email protected] Volcanic Risk Solutions, Institute of Agriculture and Environment, Massey University, Palmerston The sediments of Lake Ohau, a glacial lake in the North 4442 Southern Alps of New Zealand, provide a critical [email protected] record for evaluating Quaternary paleoclimate models, glacial history and past tectonic activity. The Ohakune basaltic complex is a tuff ring – New Zealand, extending between latitudes of 34˚‐ scoria/spatter cone complex located in the 47˚, lies across the prevailing westerly wind belt, southern ring plain of Ruapehu volcano. This which makes it a key Southern Hemisphere monogenetic volcano was investigated previously location for climate studies and especially by Houghton and Hackett (1983) based on the Quaternary climatic fluctuations. The Mackenzie limited extent of quarry walls. Since the 1980s, Basin contains three large fluvio‐glacial lakes: intensive quarrying has exposed a 30 m thick, 200 Ohau, Pukaki and Tekapo that occupy glacial m long lateral sequence of phreatomagmatic valleys within 30‐40 km of the Alpine Fault, the deposits from the proximal to distal positions of a major plate boundary in the region. They are tuff ring. The volcanism began along a NW‐SE thought to contain high‐resolution sedimentary fissure with a phreatomagmatic phase, as records of the last 16‐20 ka.10Be dates from demonstrated by the presence of a fine ash‐ recessional moraines indicate that glacial recession dominated, weakly‐bedded ≥3 m thick basal occurred at Ohau at 17,380 ± 510 yr. Moraine belts succession abundant in accidental lithic clasts from from the last local glacial maximum (LLGM) from fluvial/laharic gravel and boulder beds, indicating Ohau and the Chilean Lake District (CLD) show a shallow subsurface magma–water interactions similar dates with respect to glacial advances and that initiated pyroclastic density currents (PDC). retreats, furthermore EPICA Dome C δD signals This unit is topped by medium‐ to thick‐bedded show that warming occurred ~17,900 ka, both of spatter and accidental lithic rich units separated by which are consistent with deglaciation at Lake thin PDC‐dominated units. These sequences Ohau and Pukaki. indicate that the rising magma erupted through vents along a 500 m long fissure and formed This project will build on a 2011 dataset of single‐ separate vents and craters. At the NW end of the channel boomer data that covered the entire lake fissure a scoria/spatter cone formed through and extend over 50 km. In a New Zealand first, relatively steady Strombolian to lava fountaining new multi‐channel streamer will be collected in eruptions, depositing homogeneous, massive‐ conjunction with a boomer source to characterise bedded pyroclastic deposits. In contrast, at the SE these post‐glacial sediments and especially to end of the fissure the eruptions were dominated constrain their seismic velocities. Preliminary by phreatomagmatic explosions interspersed with interpretations of seismic lines show no active short‐lived lava fountaining from multiple vents. tectonics in the lake. Interpretations of the data in This sequence could be interpreted as a reflection the north are hampered by gas accumulations of the quick changes in magma discharge rate, sourced from shallow organic‐rich sediments; degasing and the degrees of interaction with however, the southern portion of Lake Ohau is external water. The crater rim of the tuff ring is remarkably free of such contamination. In this inferred to have frequently collapsed due to vent location, in 2015, a Marsden Funded project will shifting, based on the presence of local landslides drill to extract a core record (approximately 100 m and chaotic deposit arrays. The volcanic edifice has TD) of the sediments that will be tied to the been eroded by a fluvial network that was re‐ seismic data. established in the same drainage system through which the Ohakune volcano originally erupted. Two well‐preserved radial gullies in the southern flank of the tuff ring record intense post‐volcanic erosion.

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MULTI‐DISCIPLINARY TSUNAMI HAZARD STUDY with landslide‐generated tsunami needs to be IN THE SOUTHWEST PACIFIC: EXAMPLES FROM studied for a full understanding of the hazard. WALLIS & FUTUNA AND SAMOA

G. Lamarche1, C. Bonnifait2, J. Goff3, E. Lane4, J. Mountjoy1, B. Pelletier5 & S. Popinet6 UNCERTAINTY IN TSUNAMI RUN‐UP DUE TO 1NIWA, Private Bag 14901, Wellington 6241 VARIATIONS IN NEAR‐SHORE BATHYMETRY 2Atelierworkshop Architects, Wellington 3UNSW, Sydney E.M. Lane1 & E.K. Walters2 4NIWA, P O Box 8602, Christchurch 8440 1National Institute of Water and Atmospheric 5IRD, Nouméa, New Caledonia Research, PO Box 8602, Christchurch 8440 6CNRS Paris 6, France 2Ocean Engineering, Texas A&M University, [email protected] College Station, Texas, USA [email protected] Following the September 2009 Southwest Pacific Tsunami, we undertook an assessment of the Accurate modelling of tsunami run‐up and tsunami hazard in Wallis and Futuna (W&F), and inundation is important in determining the Samoa, respectively ~500, ~650 and ~160km from tsunami hazard. Knowledge of the undersea the earthquake epicentre, using four independent bathymetry is an important component of that approaches together providing strengthened modelling. Bathymetry guides the waves, causing hazard characterisation: (1) post‐tsunami survey. them to shoal, refract, reflect and focus. Small In W&F we investigated the damage generated by scale changes bathymetry can also affect the wave the 2009 tsunami during a 10‐day survey run‐up by increasing surface roughness. This (undertaken by UNESCO‐IOC in Samoa). Maximum presentation focusses on the effects of inundation of 95m and run‐up height of 4.4m were intermediate scale bathymetry variations, inferred from observations of damage to between these two end members. These vegetation and infrastructure; (2) Paleotsunami intermediate scale variations may not be well investigation. Nineteen trenches were logged and captured by the available bathymetric information sampled in W&F for multi‐proxy sediments studies – especially in the near shore zone where to characterise catastrophic seawater inundation techniques like multi‐beam side‐scan sonar are not events. This enabled us to infer two paleotsunamis able to be used. Uncertainty in this nearshore in ~470BP and 1940BP; (3) Numerical modelling. bathymetry can lead to uncertainty in the overall Fourteen scenarios of tsunami were generated amount of run‐up observed. We wish to be able to using the Gerris flow solver. The sources are local, quantify these uncertainties. Features such as regional and distant earthquake faults. Results stop banks are critical thresholds where small show that Wallis is protected from tsunami by the changes in tsunami height can lead to large barrier reef, but inundation depths of 2‐3m occur changes in inundated area making knowledge of in populated areas. In Futuna, flow depths uncertainties important. exceeding 2m are modelled in several populated areas; In South Upolu, one extreme scenario from Our baseline case is a planar beach with the the shows inundation of the old incoming wave specified at the off‐shore edge. village and mangrove of Sa'anapu; and (4) We model a series of random perturbations of this Archaeological, interviews and close engagement case, all with mean zero and with varying standard with the local population. This approach was deviations. Intermediate scale bathymetric further developed in Samoa with the village of changes are unlikely to be random noise, thus we Sa'anapu. Excellent support from the council of simulate these variations by specifying a radial Matais (chief) was critical in obtaining essential bathymetric wavelength and randomising the collective memories on past natural disasters. Of phase. We consider three general cases: even particular importance were the potential impacts sized bathymetric variation and ‘bars’ (with of tsunamis on reef and mangrove which have wavenumber four times higher is one direction significant ecological, economic, and cultural than the other) in both the long shore and the values. Here we were able to develop a plan for cross shore direction. These perturbations break the relocation of the old village on the coastal sand the long shore symmetry of the tsunami and dune in a safer area using culturally appropriate produce a distribution of run‐up heights. We and accepted protocols. The hazard associated compare these with the baseline case and produce

62 relationships between bathymetry and run‐up for uptake by a range of users from scientists to height variations. We also consider the ability of local councils, to the general public. The database contours to capture these bathymetric variations comes with a Disclaimer that describes its and to provide accurate grid for nearshore tsunami limitations with respect to scale and accuracy and modelling. will be partnered by a citable companion paper (Langridge et al., in review). The 1:250k Active Faults Database and the AFDB2003 will be ACTIVE FAULTS DATABASE OF NEW ZEALAND maintained and updated as new data come to VERSION 2.0 AT 1:250,000 SCALE hand. We also hope in future to be able to include more active folds and offshore active faults as data R. Langridge1, W.F. Ries1, N.J. Litchfield1, R.J. Van comes to hand. Dissen1, P. Villamor1, D. Heron2, D. Townsend2, J. Lee2 & B. Lukovic2

1Active Landscapes, GNS Science, PO Box 30368, CARBONATE LITHOLOGIES RECOVERED IN Lower Hutt 5040 DREDGE SAMPLES FROM THE REINGA BASIN 2Regional Geology, GNS Science, PO Box 30368, 1 1 1 Lower Hutt 5040 M.J.F. Lawrence , H.E.G. Morgans , A.G. Beu 1 [email protected] GNS Science, PO Box 30368, Lower Hutt 5040 [email protected] The Earthquake Geology team at GNS Science has completed a decadal update of the GNS Active The Reinga Basin northwest of New Zealand and is 2 Faults Database in conjunction with the Regional a 75 000 km frontier basin with typical water Geology Department. The main output is a new depths in the range 500‐2500 m. The region is realisation of the database, at 1:250,000 scale. contiguous with the Northland and the petroleum‐ Active faults are defined as faults that have producing Taranaki basins to the east and south, ruptured/caused ground deformation during the respectively. In November 2013, an 18‐day survey last 125,000 years, except in the Taupo Rift where on board the RV Tangaroa (survey TAN1312) the timeframe of activity is the last c. 25,000 years. acquired multibeam and dredge samples from 38 The database is presented spatially in a selected sites. Rock samples were collected using Geographic Information System (GIS), as lines a 0.45 x 1.2 m diameter steel rock dredge at which represent ground surface traces, with locations selected on the basis of seismic and/or corresponding attributes. This talk will describe multibeam data. the philosophy, steps and rules that were used in developing the new database. A large proportion of the dredged samples are limestones. Biostratigraphic analysis indicates the An important goal of this project has been to samples range predominantly from early Eocene construct a database at a uniform scale that is to middle Miocene in age, although a few consistent with other GNS Science databases, Paleocene ages were also obtained. Thin section particularly the QMAP Geological Map of New analysis shows limestone rock types range from Zealand. Linework has been derived primarily from carbonate mudstones to wackestones (dominantly QMAP and the existing, multi‐scale GNS Active foraminifera and generally bathyal in origin) to Faults database (AFDB2003). Within the new shallow water packstones and grainstones 1:250k Active Faults Database fault trace data are containing common to abundant bivalve, merged to form faults (and sometimes fault echinoderm and bryozoan debris. Algae, sponge sections and fault zones). Attribute fields, in spicules and gastropods have also been found. numeric or character form, provide information Non‐carbonate detrital grains (quartz, subordinate about the fault trace data (e.g., ACCURACY) and feldspar), usually comprising <10% of the rock fault activity parameters (e.g., SLIP_RATE). The 17 volume, are restricted to shallow water attribute fields are the result of integrating and carbonates. Authigenic components comprise simplifying existing GIS active fault attribute fields various calcite cements filling intra‐ and/or (e.g., from the AFDB2003 Database and QMAP). interparticle porosity, local silicification, and glauconite occurs in many samples. One sample The 1:250k Active Faults Database will be viewed comprised cloudy‐centre clear‐rim, euhedral online (http://data.gns.cri.nz/af/) and also be dolomite rhombs. Dissolution of bioclasts easily downloadable in several different formats resulting in mouldic porosity and recrystallization

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(neomorphism) of bioclastic material is also ants), Trichoptera (caddisflies), and Coleoptera observed. (beetles), with weevils particularly diverse. The Foulden fish fauna includes Galaxias and eels, The Reinga Basin bathyal carbonates have while the arthropod fauna comprises ~ 20 families characteristics similar to the onshore Amuri in orders Araneae (spiders), Plecoptera Limestone, including local silicification. The (stoneflies), Odonata (dragonflies), Isoptera shallower water packstones and grainstones (termites), Hemiptera, Coleoptera, Hymenoptera, resemble facies that occur in Te Kuiti Group Trichoptera, and Diptera, which represent faunas limestones. Preliminary analyses suggest that typical of soil, leaf litter, forest floor or lacustrine none of the Reinga limestone samples represent habitats. Many fossil taxa have close relatives in potential reservoir lithologies but could be the extant New Zealand biota: others are now possible seals. Siliciclastic samples recovered from locally extinct. Coprolites containing quartz sands TAN 1312 are described in a separate talk by Greg sourced from outside the lakes are present at Browne et al. Foulden, but ubiquitous at Hindon. Together with a feather, they indicate the presence of volant birds, presumably waterfowl. Both Foulden and FOULDEN AND HINDON MAARS: CONTRASTING Hindon Maars are crucial in reconstructing MIOCENE KONSERVAT‐LAGERSTÄTTEN DEPOSITS Miocene lake and forest ecosystems in New IN SOUTHERN NEW ZEALAND Zealand, in particular the terrestrial arthropod component. This highlights the importance of D.E. Lee1 , U Kaulfuss1 , J.M. Bannister2, J.G. maar lake sediments as fossil and climate archives Conran3, D.C. Mildenhall4 , T. Reichgelt1 & J.K. in New Zealand and elsewhere. Lindqvist1 1Geology Department, University of Otago, PO Box 56, Dunedin 9054 2Botany Department, University of Otago, PO Box SEISMIC CHARACTERISATION OF THE UPPER 56, Dunedin 9054 SEDIMENTARY SEQUENCE ASSOCIATED WITH 3ACEBB & SGC, School of Earth & Environmental DFDP‐2, WHATAROA VALLEY Sciences, University of Adelaide, Australia 1 1 1 4GNS Science, PO Box 30368, Lower Hutt 5040 P. Lepine , A.R. Gorman , & A. Kovács 1 [email protected] Department of Geology, University of Otago, P O Box 56, Dunedin 9054 The Konservat‐Lagerstätten diatomite deposits of [email protected] Foulden and Hindon Maars in Otago are key sites for reconstructing early Miocene Southern The glacio‐fluvial sediments of the Whataroa Hemisphere terrestrial ecosystems. Although the Valley contain a geological record of the changes maars are similar in size, age, sedimentology and in climate that occurred as the valley was filled by geological setting and both possess exceptionally sediments following the retreat of Pleistocene well‐preserved fossils, there are marked contrasts glaciers, but this record is greatly affected by the between their respective biotas. Both include significant motion that has occurred on the Alpine numerous leaves, flowers with in situ pollen, Fault over the same period. fruits/seeds, fish and arthropods and the climate at both sites was warm temperate to subtropical. A series of hammer seismic reflection lines The forest surrounding Foulden Maar was an collected in December 2013 will be combined with evergreen, Lauraceae–dominated notophyll vine sediment samples collected during DFDP‐2 drilling forest with a diverse understorey, lianes, epiphytes to characterise sediments of the Whataroa Valley and several canopy layers. None of the ~3000 overlying presumably glacially carved basement. leaves collected to date are of Nothofagus. In The high‐resolution data will be used for three contrast, the Hindon Maar forest has abundant purposes: characterisation of sedimentary strata and diverse Nothofagus, as well as lianes, conifers deposited in the valley, further constraint of the and cycads. Fish are more abundant at Hindon: Alpine Fault trace on the coastal plain and they include larval to adult stages of taxa within contribute to the characterisation of the DFDP‐2 Galaxiidae, some with preserved soft tissue. drilling site. The Whataroa2013 survey consists of Insects are common, and include representatives four profiles totalling 3 km in length. Geophone of Hemiptera (‘bugs’), Hymenoptera (wasps and spacing was 5 m with shot points located between every second geophone (spacing of 10 m). Profiles

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4 and 5 were collected on the coastal plain running blocks, along the Fiordland coast from Chalky Island approximately perpendicular to the Alpine Fault. to Long Reef, 7 km southeast of Puysegur Point. These lines were collected in an attempt to image Alluvial granitic boulder fan deposits at the base of the Alpine Fault in the near surface sediments. the formation are overlain by a >200 m thick Profiles 1 and 2 lie on a river terrace and are meandering channel and floodplain association of orientated parallel to the Alpine Fault. These upward‐fining cycles of inclined‐stratified arkosic profiles characterise the sediments in the lower coarse‐medium sand, carbonaceous mudstone, and section of the Whataroa Valley. Additionally, they resinite‐rich coal seams ≤2 m thick. Leaves are have been collected as part of a larger data set for abundantly preserved in calcite‐cemented muddy site characterisation of the DFDP‐2 drill site. siltstone exposed along the southern entrance to Preservation Inlet opposite Coal Island. A coastal Initial results from lines 1, 2 and 4 show reflections association of thinly bedded tidal sand and with two‐way travel times of approximetly 0.45 s. mudstone, delta mouth sand bodies, and thick dark Using a near surface velocity of 2000–2500 m/s brown bay‐fill mudstone conformably overlies the this corresponds to reflective sedimentary units as alluvial plain succession at Long Reef and Gates deep as 250 m in the valley. These units can be Harbour. It includes biohermal concretionary clusters interpreted as glacial sediments overlying of heavy‐shelled oysters (Crenostrea sp.), a few lacustrine/marine sediments deposited in a deep gastropods and smaller bivalves, and sparse benthic glacially carved lake or fiord. foraminifera.

DEPOSITIONAL SETTINGS OF EOCENE DELTAIC 3D RECONSTRUCTION OF GEOTHERMAL CALCITE SUCCESSIONS, WAIAU AND BALLENY BASINS, VEINS USING EBSD, CHEMICAL DATA AND OTHER WESTERN SOUTHLAND MACHINES THAT GO PING

J.K. Lindqvist1, D.E. Lee1 & J.G. Conran2 A. Lister1, D. Prior1, D. McNamara2 & M. Brenna1 1Department of Geology, University of Otago, PO 1Department of Geology, University of Otago, PO Box 56, Dunedin 9054 Box 56, Dunedin 9054 2ACEBB & SGC, School of Earth and Environmental 2GNS Science, PO Box 30368, Lower Hutt 5040 Sciences, University of Adelaide, SA, Australia [email protected] [email protected] The crystallographic structures of geothermal Diverse macrofloras have recently been collected minerals precipitated in fractures located within from Middle‐Late Eocene alluvial sediments of the active geothermal reservoirs have the potential to Beaumont and Macnamara Formations in Waiau and record significant information concerning the Balleny basins. Beaumont Formation extends kinematics of fracture formation and sealing over westward of the NW‐trending Ohai Rift around the time. It is important to understand these processes eastern faulted edges of NNE‐aligned Waiau Basin. when developing reservoir models, especially Drilling data indicates that Beaumont Formation when defining the influences of secondary exceeds 250 m in thickness along the eastern margin. permeability for high temperature geothermal Stacked fining‐upward arkosic sand–mudstone±coal systems. Therefore by reconstructing geothermal cycles predominate. Coal beds are generally thin (<3 calcite filled fracture veins in 3D space, an m) and appear to be concentrated towards the top advanced insight into the complex nature of vein and base of the formation. Leaf fossils have been crystal growth evolution and related chemical collected from sandy siltstone close to the northeast patterns can be extracted. These can then be used head of Waiau Basin east of Blackmount, and from to constrain how precipitated mineral veins coaly mudstone underlying a sandstone bed that control fracture permeability. hosts cemented tree stumps of Pikopiko Fossil Forest on the bank of Waiau River. Beaumont Formation is This paper presents a detailed pilot study which at‐ regionally overlain by lacustrine mudstone and thin tempted to recreate and evaluate the complex turbidite sands of the Orauea Formation. The internal structure of geothermal precipitated Macnamara Formation in Balleny Basin was calcite veins located in a greywacke basement deposited some 200 km southwest of Pikopiko and hosted geothermal reservoir. By integrating to the west of the later‐active Hauroko‐Moonlight sequential slices (spaced ≈100 m apart) 2D Fault Zone. It is exposed, often in small fault‐bound Electron Backscatter Diffraction (EBSD) and Energy

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Dispersive X‐Ray (EDX) data into modelling uplift event does not correlate. Therefore the software, a 3D view of the vein can be generated. uplift is not considered to have occurred at the This allows for a better insight into the evolution same time as a Hikurangi Margin subduction of crystal growth and subsequent permeability paleoearthquake. Instead, the likely mechanism is relating to fracture sealing. Initial results highlight rupture of an inferred offshore, landward‐dipping, the complexities of reconstructing 3D EBSD over upper plate reverse fault, as has been previously the variation of scales, step sizing and slice spacing interpreted. The close proximity of this fault to the used in this study. The calcite veins imaged coast means it poses a significant regional seismic indicate that a fracture fill mechanisms from and tsunami hazard. flowing geothermal fluids may be the main controlling process with crystal orientation controlled by space in 3D as well as the preferential growth axis of calcite. EVIDENCE OF LATE AMAZONIAN VOLCANISM IN THE HYDRAOTES CHAOS BASIN, MARS: A GIS STUDY

AGE AND ALTITUDE OF A YOUNG MARINE R. C. Loame1, A. Pittari1 & M.A. Bishop2 TERRACE ON THE WAIRARAPA COAST: 1University of Waikato, Private Bag 3105, Hamilton IMPLICATIONS FOR HIKURANGI MARGIN 3240 TECTONICS 2Planetary Science Institute, 1700 East Fort Lowell,

1 1 1 Suite 106, Tucson, AZ, USA N. Litchfield , U. Cochran , K. Berryman & K. [email protected] Clark1 1 GNS Science, P O Box 30368, Lower Hutt 5040 Mars has a substantial history of volcanism, most [email protected] of which occurred before the Amazonian Period began around 3 ± 0.5 Ga. Late Amazonian (<300 Holocene marine terraces along the Wairarapa Myr) volcanism is associated with localised areas coast have been studied at reconnaissance scale, of thinned, weakened lithosphere. The Hydraotes but there have been insufficient radiocarbon ages Chaos region, a fractured, subsided and eroded of in situ fossil material to provide the necessary terrain of mesas and valleys around a smooth resolution to compare the timing of uplift with basin floor of up to ‐5000 m elevation, was events elsewhere along the Hikurangi Margin. In photographed by the High Resolution Imaging this study we obtained 10 new radiocarbon ages Science Experiment (HiRISE). The images revealed for the youngest Holocene marine terrace along multiple cone and flow features with little erosion. the Honeycomb Rock – Riversdale Beach coast, Not all cone and flow features on Mars are true east of Martinborough. These new ages were volcanoes, and mud volcanoes have been combined with existing ages in the Oxcal modelling observed in neighbouring regions including Chryse tool to calculate the timing of uplift and terrace Planitia and Valles Marineris. abandonment. Terrace altitudes were also surveyed using Real Time Kinematic Global Broad geological units (cone deposits, rough‐ and Navigation Satellite System (RTK GNSS). smooth‐surfaced lavas, basin floor sediments) and

th geomorphic features (primary impact craters, The resulting (95 percentile) ages for the time of fluvial troughs, lava ridges and levees) in uplift in each of three areas along the 35 km Hydraotes Chaos were mapped from HiRISE stretch of coast are: 665‐621 cal. yr BP (Glenburn, images in ArcMap 10.1. Mineralogical data from south), 719‐657 cal. yr BP (Flat Point, centre), and the Thermal Emission Spectrometer (TES) on board 655‐557 cal. yr BP (Riversdale Beach, north). If the the Mars Global Surveyor, which detected high Flat Point ages are considered to slightly pre‐date abundances of plagioclase, clinopyroxene, and (i.e., because the shells we sampled were already high‐Si glass and/or sheet silicates in the area. dead at the time of the earthquake) a single uplift Impact craters traced during the mapping process event, then the best estimate for the timing of were used to obtain age estimates using Hartmann uplift is 635 ± 20 cal. yr BP. The amount of uplift is type Martian crater diameter distribution approximately 2 ± 0.5 m. Preliminary comparison isochrons. Stratigraphic relationships and age with the timing of inferred subduction estimates were used to construct a possible paleoearthquakes, manifest as subsidence events sequence of events. in Hawkes Bay and Marlborough, suggests this

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The cone and lava flow geomorphology support To extract DNA from allophane has been difficult volcanic origins for the features in Hydraotes because of the strong chemical bonding between Chaos, and may be analogous to that of cinder allophane and DNA/RNA (through the phosphate cones and/or rootless cones on Earth. TES group), and abundant humic substances which mineralogical data indicates cones without flows bind to DNA and prevent the amplification of DNA are of tholeiitic basaltic composition, while cones via PCR. Current extraction methods for allophane with rough‐surfaced flows are closer to basalt‐ fail, or are very inefficient. We have thus andesite, further supporting volcanic origins. developed a new method using a two‐step Crater counts dated the basin floor surface as extraction and gel‐purification procedure. We Middle Amazonian, indicating a period of fluvial or applied our method to three buried soils on glacial resurfacing. Cone and flow features are Holocene tephras and obtained enhanced DNA estimated to be Late Amazonian, some possibly as yields from 1.5 to 8.3 µg g−1 and fragments mainly recent as 40 Ma. 16 kb in length, along with a small portion of fragments in the range 100s to 1000s of base pairs. Plant DNA [trnL] of Araliaceae (ivy‐family) and Myrtaceae (myrtle‐family) extracted from a buried DO BURIED ALLOPHANIC SOILS ON HOLOCENE soil may have originated from early‐mid Holocene TEPHRAS IN NEW ZEALAND CONTAIN ANCIENT plants growing on the soil prior to its burial ~5500 DNA AND CAN WE EXTRACT IT TO RECONSTRUCT years ago, or from downward leaching of DNA PAST ENVIRONMENTS? from ‘modern’ plants that grew decades before the current (pasture) vegetation. We are working 1 1 1 1 D.J. Lowe , Y.‐T. Huang , H. Zhang , R. Cursons , to separate these hypotheses. N.J. Rawlence1,2, G.J. Churchman3, L.A. Schipper1 & A. Cooper4 1School of Science, University of Waikato, Private Bag 3105, Hamilton 3240 USING PALAEOENVIRONMENTAL DNA 2 Allan Wilson Centre, Department of Zoology, (PALENDNA) TO RECONSTRUCT PAST University of Otago, PO Box 56, Dunedin 9054 ENVIRONMENTS: 3School of Agriculture, Food and Wine, University PROGRESS AND PROSPECTS

of Adelaide, South Australia 5005 1 1,2 3 4Australian Centre for Ancient DNA, University of D.J. Lowe , N.J. Rawlence , J.R. Wood , J. Young4, G.J. Churchman5, Y‐T. Huang1 & A. Adelaide, South Australia 5005 4 [email protected] Cooper 1School of Science, University of Waikato, Private Allophane is a nanocrystalline aluminosilicate clay Bag 3105, Hamilton 3240 2 mineral comprising tiny hollow spherules 3.55.0 Allan Wilson Centre, Department of Zoology, nm in diameter. It forms rapidly from the University of Otago, PO Box 56, Dunedin 9054 3 precipitation of solutes derived from dissolution of Landcare Research, PO Box 40, Lincoln, volcanic glass and crystals in well‐drained tephras. Canterbury 7640 4 With its small size, large surface area (up to 1500 Australian Centre for Ancient DNA, University of m2 g−1), and variable surface‐charge characteristics Adelaide, South Australia 5005 5 that arise via (OH)Al(OH2) groups at wall School of Agriculture, Food and Wine, University perforations, allophane has strong affinity for of Adelaide, South Australia 5005 water, metal cations, anions, organic molecules [email protected] and DNA. Allophane spherules form nanoaggregates up to ~100 nm in diameter, and Palaeoenvironmental DNA (PalEnDNA) is defined associated nanopores, poorly accessible to as ancient DNA (aDNA) originating from microbes and enzymes, could provide refuges for disseminated genetic material within disseminated DNA. Such a ‘protection mechanism’ palaeoenvironmental samples. Sources of might enable DNA to become stored and hence PalEnDNA include marine and lake sediments, preserve, potentially, ancient DNA (aDNA) in peat, loess, till, ice, permafrost, coprolites, allophanic paleosols. Any aDNA preserved in such preserved gut contents, dental calculus, tephras, paleosols, once recovered and identified, could paleosols, and soils as well as deposits in caves or provide a genetic signal to help reconstruct past rockshelters and archaeological sites. PalEnDNA terrestrial environments. analysis provides a relatively new tool for Quaternary and archaeological sciences and its

67 applications have included palaeoenvironmental Marwick 1953 and Holcothyris (?) kaiwaraensis and palaeodietary reconstructions, testing Campbell 1965 In this study, about ten species are hypotheses regarding megafaunal extinctions, recognised, with nearly all the material coming human‐environment interactions, taxonomic from the Murihiku Terrane on the west coast of studies, and studies of DNA damage. Because the North Island. PalEnDNA samples comprise markedly different materials, and represent wide‐ranging depositional Two key localities for Temaikan brachiopods are and taphonomic contexts, various issues must be Opuatia Cliff at Port Waikato, and a quarry in the addressed to achieve robust, reproducible Marokopa Valley. Two species of fairly large findings. Such issues include climatic and temporal terebratulide are tentatively assigned to the limitations, the biological origin and state (free cosmopolitan genus Loboidothyris. Two species of versus bound) of PalEnDNA, stratigraphic Zeilleria are also present. A new species of reliability, sterile sampling, ability to distinguish Kutchithyris, less strongly folded than hendersoni, modern from aDNA signals, DNA damage and PCR is present at Marokopa. amplification, DNA extraction methods, and taxonomic resolution. Captain Kings Shellbed is a metre‐thick middle Heterian shellbed that can be traced from Kawhia The combination of PalEnDNA with analysis of to the Awakino Valley. It has a rich and diverse plant macrofossils and pollen is providing an fauna in which terebratulides are prominent. enhanced means to reconstruct past Kutchithyris hendersoni is probably the most environments, and PalEnDNA researchers are also abundant. A species with distinctive wavy beginning to obtain a greater understanding of the concentrics probably represents a new genus. power and limitations of the technique. To utilise The same two species of Zeilleria continue from the PalEnDNA technique, scientists need to plan the Temaikan, and are joined by a species of the field procedures and sample collection techniques related genus Aulacothyris. The ribbed carefully. The discipline needs better terebratulide Terebratulina is also present. understanding of DNA damage and degradation rates in PalEnDNA, and procedures to distinguish Brachiopods are much less common in the later between true taxonomic diversity and mis‐coding part of the Jurassic (latest Heterian, Ohauan and lesions. Methods to determine the degree of Puaroan stages). A second species of mixing of ancient and modern DNA in samples are Terebratulina is present. A rare form is the small also required. Multiple proxies, replicable genus Disculina. Holcothyris (?) kaiwaraensis is stratigraphies, and reliable dating methods can be known only from the Late Jurassic Pahau Terrane used to help determine the stratigraphic reliability of North Canterbury. of PalEnDNA assays and to increase taxonomic resolution in conjunction with the construction of Affinities of the fauna are poorly known, due to DNA sequence reference databases. Publication of the lack of nearby faunas for correlation. failures in DNA extraction methods is also critical Loboidothyris, Aulacothyris and Zeilleria are for specific deposits or soils, environments, and cosmopolitan. Kutchithyris is Tethyan. Disculina is time periods. described from Southern England and France, but may have a much wider distribution.

TEREBRATULIDE BRACHIOPODS FROM THE MIDDLE AND LATE JURASSIC OF NEW ZEALAND

D.A.B. MacFarlan MacFarlan Geological Services Ltd, 13 Fairfax Terrace, New Plymouth 4310 [email protected]

Terebratulide brachiopods are present throughout the New Zealand Mesozoic, and by the Jurassic are second only to rhynchonellides in abundance and diversity. Only two species have been described from the Late Jurassic, Kutchithyris hendersoni

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TIME LAPSE INVESTIGATIONS ON THE ACOUSTIC PROPOSED MOVEMENT MECHANISMS AND AND GEOCHEMICAL EFFECTS OF CO2 INJECTION IN CAUSES FOR THE ‘EARTHQUAKES’ LANDSLIDE, SANDSTONE CORES OTAGO, NZ

1 1 1 J. MacFarlane , L. Adam , K. van Wijk , J. S.T. McColl1, M.J. Crozier2 & C.J. Beaven1 2 3 Shragge , K. Higgs 1Institute of Agriculture and Environment, Massey 1 School of Environment, University of Auckland, University, Private Bag 11222, Palmerston North Private Bag 92091, Auckland 1142 4442 2 University of Western Australia, 35 Stirling 2SGEES, Victoria University of Wellington, PO Box Highway, Crawley, Perth, Australia 600, Wellington 6240 3 GNS Science, PO Box 30368, Lower Hutt 5040 [email protected] [email protected] The ‘Earthquakes’ Landslide is a peculiar pre‐ Carbon geosequestration, or the geological storage historic landslide located near Duntroon, Otago. of CO2, is an emerging field of research and The landslide owes its name to its defining feature, technology. One of the biggest challenges of this a large (500 × 100 x 40 m) graben reminiscent of technology is to ensure that this gas is safely normal‐fault (tectonic) grabens. The bedrock is stored in the subsurface. Surface seismic methods Oligocene gently‐dipping weak marl overlain by are used to monitor the movement of CO2 in the calcareous greensand grading into cemented reservior. However, it is assumed that only fluid bioclastic limestone cap rock. The landslide has replacement and pressure changes are the main developed on the northern edge of a sub‐ control on changes to seismic signitures over time horizontal mesa‐like hill bounded by steep slopes (time‐lapse changes). Currently a good produced by fluvial‐incision on four sides. A rare understanding is lacking of how rock‐fluid lateral spread style of mass movement has geochemical alteration affects these time‐lapse previously been described on the southern side of changes. In particular, we are investigating how the mesa. To elucidate the mechanical failure the injection of CO2 affects the physical and mechanism and the preconditioning factors seismic properties of carbonate‐cemented responsible for the geometry and development of sandstone cores. The samples used correspond to the landslide, we undertook geological mapping, the Mangahewa Formation at the Pohokura Field, RTK GPS surveying, augering, and Ground New Zealand. Petrophysical properties are Penetrating Radar (GPR) surveys of the landslide measured through XRD, NMR and CT scan analysis, and surrounding slope. Geological mapping while seismic properties are measured using a indicated that the graben ‘extension’ direction is non‐contact ultrasonic source‐receiver. The oriented along‐strike of the gently dipping bedrock samples range in P‐wave velocity from 2100‐3500 (i.e. not in the dip‐direction). Further, there is no m/s, carbonate content from 1‐22% and porosity evidence of substantial valley bulging or sliding of from 4.5‐12.5%. Previous investigations have the downslope graben wall, and the surface found that CO2 injection causes a decrease in P‐ expression of the graben ‘fault’ scarps are wave velocity, with an accompanying increase in everywhere steep (sub‐vertical), casting doubt on porosity and permeability as a result of the a purely‐extensional mechanism of graben dissolution of carbonate minerals. We aim to development. The GPR data indicate that the quantify these changes, and examine how the graben owes part of its relief to a paleo‐channel, petrophysical properties of the rock affect the which can be traced along part of the graben. quantitative changes in properties. This study will However, the paleo‐channel accounts for only a contribute towards the monitoring of time‐lapse small part of the graben relief; but, it may have changes in CO2 injected reservoirs, which will have influenced the location of graben development by implications world‐wide. New Zealand has set eroding, and thus locally reducing the thickness targets to significantly reduce its CO2 emissions and strength of the limestone cap rock. We and carbon geosequestration is being explored as hypothesise that the Earthquakes Landslide is a viable option to meet these goals. Before carbon unique example of a large, incipient lateral spread, geosequestration is implemented in New Zealand facilitated by relief development (fluvial incision) we believe that further steps must be made to be and the presence of a deformable marl underlying able to monitor to movement of CO2 in the a structurally‐weakened cap rock than has allowed subsurface and understand the effects that the a combination of brittle and ductile deformation. injection of CO2 will have in the subsurface.

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TECTONIC EVENTS AND THEIR INFLUENCE ON interpretation shows that the two are very HUMAN POPULATIONS: THE EVIDENCE OF different depositional environments within a single ARCHAEOLOGY AND HISTORY megasequence. Although genetically related they were separated by perhaps 1000m of water depth

B. McFadgen at the time of deposition. School of Maori Studies, Victoria University of Wellington, 6240 The Matemateaonga, Urenui and Mount [email protected] Messenger Formations, onshore Taranaki, form a single depositional system in the Taranaki Series; Humans and their hominin forebears have lived similarly the Motueka Sands belong with the with tectonic events for hundreds of thousands of Manganui and Moki in an earlier pulse of slope‐ years. Earthquakes have devastated landscapes, advance during the Southland Series. Lack of towns, and cities, yet communities have been outcrop and sparse drilling in the south Taranaki extraordinarily resilient and resistant to moving to Basin have contributed to their lack of recognition safer locations. Paradoxically, this has had positive in stratigraphic syntheses. cultural and economic benefit for human societies. The topsets of this megasequence have been Recent archaeological research suggests that traced laterally on the seismic up to 80 km along human physical development is closely related to the eastern margin of the basin. Near the Kupe tectonic plate boundaries, and that civilisation Field these topsets are cut by several major itself is a result of seismic activity. In modern canyon systems, some of which are feeder times, earthquakes, along with other calamitous canyons to the Moki submarine fans. The late events, have played a Schumpeter‐like role of stage of canyon fill on the shelf is likely to be creative destruction, and have stimulated dominated by fine‐grained deposits which could economic development. This talk briefly reviews form lateral seal to the Motueka sand reservoirs. the effects of tectonic activity on human communities, and outlines some of the Recognition of the Motueka Sands as distinct from implications for how modern communities might the Moki provides a good illustration of the respond to future events. importance of using sequence stratigraphic rather than lithostratigraphic interpretation in Taranaki exploration. The sands represent a substantial, THE MOTUEKA SANDS – RECOGNISING THE SHELF high‐quality reservoir target in a sparsely drilled area of the south‐eastern Taranaki Basin. H.F. Mingard1 & M. Beggs2 1Mingard Geoscience Ltd, Ahuriri Road, RD2, Christchurch 7672 2New Zealand Oil and Gas Ltd, P O Box 10725, FAULT PROPAGATION AND DAMAGE IN LAYERED Wellington 6143 ROCKS: THE EFFECT OF TRANSVERSE ANISOTROPY [email protected] S. Misra1, S. Ellis1 & N. Mandal2 1 When Motueka‐1 was drilled in 1990 it GNS Science, PO Box 30 368, Lower Hutt 5040 2 encountered stacked high porosity Lillburnian Department of Geological Sciences, Jadavpur sands which the Operator dubbed the “Motueka University, Kolkata 700032, India Sands Member [of the Manganui Formation]”. [email protected] Nearly twenty years later this section was re‐ interpreted as Moki basin‐floor sands, which form This study aims to probe the role of inherent the reservoir in the Maari field to the north. mechanical anisotropy in controlling damage zone Tuatara‐1 targeted the interval 40 km further localization in both the tip and wall regions of a south but found instead a continental section of fault or fracture. Rocks are often mechanically interbedded conglomerate, siltstone, shales, anisotropic due to the presence of bedding planes, sandstone and coals. penetrative crystallographic or shape fabrics and compositional foliations. Inherent cracks, fractures Although both Moki and Motueka sands have and faults often act as mechanical flaws to similar laterally extensive, high seismic amplitudes, intensify local stresses, leading to mechanical the context provided by regional seismic facies failure at their tips. Earth scientists have used flaw‐ controlled mechanics to understand a wide variety

70 of geological and geophysical phenomena indicate‐ an evolving sediment source. including flanking structures, wing fractures, Microtextures in aluminous schists elucidate secondary fracture‐controlled hydraulic structural and mineralogical changes, which are conductivity and growth of crustal‐scale tectonic divided into four fabrics: S1) primary foliation faults. In this study, analogue and numerical observed as relict quartz inclusion trails in garnet; models were deformed under compressive S2) development of pervasive lepidoblastic biotite stresses either parallel, perpendicular or at an foliation with quartz, muscovite, andesine and angle to the plane of anisotropy under a constant late‐stage garnet growth; S3) crenulation of the strain rate. We show from our experiments that earlier foliation; and S4) a chlorite, epidote and the damage localization can dramatically change muscovite lineation. depending on the orientation of the planar anisotropy (). Under layer‐normal ( = 0°) and Cation‐exchange thermometry broadly indicates layer‐parallel compression ( = 90°), pre‐existing increasing conditions of peak equilibration faults are reactivated. Fault slip leads to southeast across the unit, ranging from mechanical instabilities within the anisotropic approximately 580°C and 5.5 kbar to 640°C and 7.6 layering, causing damage zones in the tip regions. kbar. Rare metamorphic overgrowths on detrital For  = 0° the planar anisotropy arrests the zircon potentially record a event propagation of tensile fractures across the plane of consistent with timing of Terrane Amalgamation in anisotropy and promotes localised plastic shear northwest Nelson and localised amphibolite facies instabilities at the crack tips, whereas a metamorphism in juxtaposed fault slices. Several combination of layer opening and distributed generations of mineralized veins cross‐cut the shear banding occurs when the plane of anisotropy foliation. K‐feldspar veins contain Cu‐sulphides is parallel to the compressive direction. For associated with myrmekite replacement reactions ° the faults experience little or no and grain boundary fracturing. Kyanite veins reactivation and instead, bulk (distributed) inter‐ containing an assemblage kyanite + staurolite + layer slip occurs. Our results have implications for garnet + andesine + biotite record 600°C and 5.6 the deformation style of strongly anisotropic rocks kbar conditions. Chlorite‐carbonate veins record a such as schist. They show how the deformation later greenschist‐facies event where sulphur mechanism and degree of localization will be enriched fluid has reacted with ankerite nodules, strongly influenced by the orientation of principal forming pyrrhotite moat structures. stresses and inherited cracks to the plane of the foliation. THE BASAL UNCONFORMITY OF THE EOCENE BRUNNER COAL MEASURES: A LOW RELIEF LANDSCAPE WITH MINOR FAULTING METAMORPHISM CONTROLLED DEVELOPMENT OF CU‐FE‐S VEINS IN THE ONEKAKA SCHIST, NW F. D. Monteith1 & K. N. Bassett1 NELSON 1 University of Canterbury, Private Bag 4800, Christchurch 8140 N. Moerhuis1, J.M. Scott1, J.M. Palin1 [email protected] 1Geology Department, University of Otago, PO Box 56, Dunedin 9054 The unconformity at the base of the West Coast’s [email protected] Eocene (Bortonian) aged Brunner Coal Measures The Onekaka Schist, a constituent of the east‐ (BCM) has long been recognized as having board Takaka Terrane in northwest Nelson, is a topographic relief and in places, a substantial north‐trending fault slice of stratigraphically intact weathering profile. However investigations into ‐ meta‐conglomerates, the contribution of faulting versus relict relief in sandstones, mudstones and quartzites deposited development of paleotopography along the from a Continental Island Arc environment. Zircon unconformity have been limited (Flores & Sykes age populations indicate Ross‐Delamerian, Pan‐ 1996; Titheridge 1993). New research on the African and Grenville Orogenic provenance unconformity and immediately overlying deposits consistent with Paleozoic metasediments of the has provided evidence for a low relief landscape Western Province. Changes in zircon population affected by minor faulting. Investigations into the density from Ordovician to Silurian lithologies weathering profile show marked lateral variations in degree of weathering and thickness (1m ‐

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>10m), indicating broad areas of low relief with millions of years. Geological mapping, lithofacies intense soil development. To the south in the analysis and petrology, here represented by the Greymouth area, the basal Paleocene Brunner Oamaru volcano, reveal discordant to locally Conglomerate rests conformably on Late concordant boundaries separating deposits from Cretaceous ‐ Paleocene Paparoa Coal Measures, different construction episodes. Individual representing a final surge of tectonic activity in the volcanoes that overlap in this edifice exhibit Paparoa Basin. This is followed by gradual infilling complex erosion features formed during a single by low gradient meandering rivers and eruption, such as slumping and other sedimentary development of peat mires, overlain by marine structures, which are distinct from the inter‐ Eocene Island Sandstone. To the north and into volcano contacts marked by biogenic the Buller Coal Field valley infilling did not accumulations or other slow‐formed features. commence until the mid‐Eocene and often shows no signs of syndepositional faulting. In the The edifice overall was constructed over millions southern Buller coal field, BCM lie with angular of years as volcanoes formed and were unconformity on an as yet undated but probable subsequently partially degraded prior to an Paleocene conglomerate indicating active faulting adjacent vent opening and adding another volcano and tilting in this location. Finally, direct evidence to the edifice. Though no central vent or long‐ of minor syndepositional faulting can be found in active volcano ever formed, this repeated growth outcrop in the northern Buller Coal Field on the of 'monogenetic' volcanoes at a single site could Stockton Plateau and near Seddonville with offsets be seen as a novel style of polygenetic volcanism. of strata ranging from 2‐15m. We conclude that Absence of a magma chamber based on a the BCM were deposited in a relatively quiescent significant lack of magma fractionation indicates a tectonic setting with minor faulting until the onset mantle‐sourced magma. Consequently a of the subsequent Challenger Rift System. mechanism for building a stack of volcanoes at one site is unclear.

IS A SET OF OVERLAPPING SURTSEYAN VOLCANOES A POLYGENETIC VOLCANO? LITHO2014: A NEW ZEALAND STRATIGRAPHIC B.L. Moorhouse1, J.D.L. White1 & J.M. Scott1 SCHEME FOR EVERYONE 1Department of Geology, University of Otago, PO N. Mortimer1, M.S. Rattenbury2 & P.R. King2 Box 56, Dunedin 9054 1 [email protected] GNS Science, Private Bag 1930, Dunedin 9054 2GNS Science, PO Box 30368, Lower Hutt 5040 Since the eruption of Surtsey (1963‐1965) multiple [email protected] studies have been made of the resulting island. The pre‐emergent base of the volcano, however, We formally introduce 14 new high‐level remains submarine and unincised resulting in stratigraphic names to augment existing names limited studies of this section being conducted. and to hierarchically organise all of New Zealand’s onland and offshore to Holocene rocks An alternative to studying the submarine portion and unconsolidated deposits. The two highest‐ of Surtsey is to study volcanic deposits with a level units are Austral Superprovince (new) and similar magma type that were erupted in a Zealandia Megasequence (new). These encompass submarine environment but are now exposed all stratigraphic units of the country's Cambrian to subaerially. A number of such deposits are Early Cretaceous basement rocks and Late exposed along the north eastern coastline of the Cretaceous‐Holocene cover rocks and sediments Otago region, South Island, New Zealand, which respectively. hosts numerous intraplate basaltic volcanoes that erupted in Surtseyan style onto a submerged Most high‐level constituents of the Austral continental shelf at between 35 and 30 Ma. Superprovince are in current and common usage: Eastern and Western Provinces consist of 12 Currently thought to be part of a monogenetic tectonostratigraphic terranes, ten igneous suites, volcanic field, the stratigraphy of exposed volcanic five batholiths and Haast Schist. Ferrar, Tarpaulin edifices of north east Otago suggest that they and Jaquiery Suites (new) have been added to comprise multiple volcanoes built by eruptions at existing plutonic suites to describe all known effectively the same sites, but separated by compositional variation in the Tuhua Intrusives.

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Zealandia Megasequence consists of five There are only very subtle thermochronological predominantly sedimentary, partly unconformity‐ signals in the basement that may be attributed to bounded units and one igneous unit. Momotu and the collision of the with the Haerenga Supergroups (new) comprise lowermost Chatham Rise, or to Late Cretaceous and Eocene rift to passive margin (terrestrial to marine continent‐ocean rift margin development along transgressive) rock units. Waka Supergroup (new) the Subantarctic and Auckland slopes. In contrast, includes rocks related to maximum marine apatite thermochronometers in basement rocks flooding linked to passive margin culmination in have been reset to near zero ages in response to the east and onset of new tectonic subsidence in (1) extensional sedimentary basin development in the west. Māui and Pākihi Supergroups (new) the Great South and Canterbury Basins, (2) local comprise marine to terrestrial regressive rock and Miocene intraplate volcanism and (3) oblique sediment units deposited during early and late collision in Fiordland and the Southern Alps. Neogene plate convergence. Zircon U‐Th‐He ages from a dredge sample of Rūaumoko Volcanic Region (new) is introduced to Precambrian granite at the southern tip of the describe all igneous rocks of the Zealandia Campbell Plateau indicates it probably is not in Megasequence and contains the new petro‐ place but was ice‐rafted from East Antarctica. tectonically different Whakaari (subduction‐ related), Horomaka (intraplate) and Te Raupua (allochthonous ocean basin) Supersuites. The Litho2014 scheme provides a complete, high‐level PROBABILISTIC LANDSLIDE‐GENERATED TSUNAMI stratigraphic classification for the continental crust HAZARD IN COOK STRAIT of the New Zealand region. J.J. Mountjoy1, W.L. Power2, E.M. Lane3, C. Mueller2, X. Wang2 1National Institute of Water and Atmospheric THERMOTECTONIC STABILISATION OF THE Research, Private Bag 14901, Wellington 6241 BASEMENT AND BASINS OF SOUTH ZEALANDIA 2GNS Science, PO Box 30368, Lower Hutt 5040 3National Institute of Water and Atmospheric 1 2 3 1 N. Mortimer , B. Kohn , D. Seward , A.J. Tulloch Research, PO Box 8602, Christchurch 8440 4 & T. Spell [email protected] 1GNS Science, Private Bag 1930, Dunedin 9054 2University of Melbourne, Melbourne VIC 3010 Modelling the hazard associated with landslide‐ Australia generated tsunami over large regions has received 3Victoria University of Wellington, PO Box 600, very little attention worldwide, with most studies Wellington 6140 focused on individual landslide scenarios. Deeply 4University of Las Vegas, Las Vegas, NV 89154, USA entrenched submarine canyons are one of the [email protected] principal means by which steep and unstable seafloor slopes can occur near to the coastline, We present new apatite and zircon fission track and populated regions. We have developed a and helium ages, and mineral Ar‐Ar ages for drill probabilistic model workflow to quantify the core, dredges and surface samples from the landslide‐generated tsunami hazard to central southern South Island, Great South Basin, New Zealand from slope failures occurring within Canterbury Basin, Campbell Plateau, and Chatham the Cook Strait Canyons. Rise regions of the Zealandia continent. Looking at the thermochronology of half a continent is Landslides are a primary process enlarging the instructive and adds to the known tectonic upper Cook Strait canyon system between the framework. Combined with existing data, our North and South Islands of New Zealand. Evidence results indicate that much of the exhumed for previous slope failure within the canyon in the geological basement of the Campbell Plateau and form of landslide scars defines the type of failures Chatham Rise region had become occurring, their geometry, and indicates the thermotectonically consolidated (exhumed to volume distribution. We have concurrently near‐present day levels) by the end of the Early developed a Monte Carlo modeling approach for Cretaceous (100‐120 Ma). earthquake triggered landslide frequency, and a magnitude‐frequency relationship for landslide occurrence based on previous landslide

73 occurrence. We use these to drive a tsunami event similar to the March 1947 tsunami generation and propagation model to derive earthquake to create data sets that are used to probabilistic hazard curves for specific coastal assess GeoNet’s detection capabilities and sites. potential required updates to the network. A suite of detection, classification and inversion The project has provided insight into the influence algorithms has been tested with the simulated of steep canyon topography on wave generation data. from landslides. It has demonstrated that Wellington is susceptible to hazards from landslide Our findings indicate that an event similar to the tsunami and will provide probabilistic hazard 1947 Gisborne Tsunami Earthquake could be curves that can be used to assess tsunami risk to classified as potentially tsunamigenic from seismic coastal populations in central New Zealand. In the data alone (Ristau & Kaneko, this session). It also longer term we envisage that the results of this should be detectable and classifiable by the project will be combined with tectonic‐source geodetic network in real time (D’Anastasio et al. tsunami to assess the overall tsunami hazard. The this session). However, a combination of kinematic developed model workflow is intended as a and static deformation (seismic and geodetic) data template to be applied to other local and global is required to drive a full rapid detection, situations where submarine canyons come within classification and inversion algorithm chain. For an close proximity of populated regions. operational Early Warning system to be implemented a large portion of the geodetic sensor network needs to be upgraded to stream data in real time to GeoNet. A LOCAL AND REGIONAL TSUNAMI EARLY WARNING SYSTEM FOR NEW ZEALAND: A

FEASIBILITY STUDY EFFECTS OF RUPTURE COMPLEXITY ON LOCAL C. Mueller1, Y. Kaneko1, E. D’Anastasio1, X. Wang1, TSUNAMI INUNDATION: IMPLICATIONS FOR R. Wang2, Y. Zhong3, J. Ristau1, R. Benites1, J. PROBABILISTIC TSUNAMI HAZARD ASSESSMENT Salichon1, N. Fournier1, B. Fry1, C. Holden1, W. 1 1 Power & K. Gledhill 1 1 2 1 1 C. Mueller , W. Power , S. Fraser & X. Wang GNS Science, P O Box 30368, Lower Hutt 5040 1 2 GNS Science, P O Box 30368, Lower Hutt 5040 Section 2.1: Physics of Earthquakes and 2Massey University Joint Centre for Disaster Volcanoes, GFZ‐Potsdam, Germany 3 Research, PO Box 756, Wellington 6140 School of Earth and Space Sciences, Peking [email protected] University, China [email protected] We investigate the influence of earthquake source complexity on the extent of inundation caused by Local tsunami mitigation in New Zealand is based a resulting tsunami. We simulated 100 scenarios on self evacuation following long‐duration or with sources on the Hikurangi subduction‐ intense ground motions. Slow‐rupturing ‘tsunami interface in the vicinity of Hawke’s Bay/Napier and earthquakes’, as have occurred historically on the Poverty Bay/Gisborne. For both target areas Hikurangi margin (1880 and twice in 1947), might rupture complexity was found to have a first order not be felt strongly enough to trigger self effect on flow depth and inundation extent for the evacuation. Tsunami propagation and inundation local tsunami sources considered. patterns depend strongly on slip kinematics and distribution. To establish an effective early The position of individual asperities in the slip warning system for such events, rapid inversion is distribution on the rupture interface control to needed to resolve these properties. some extent how severe inundation will be. However, predicting inundation extent in detail We will give an update on recent results from on‐ from investigating the distribution of slip on the going efforts at GNS in collaboration with rupture interface proves difficult. international partners to assess the feasibility of implementing a local tsunami early warning The distribution of inundation extent for one system targeting on ‘Tsunami Earthquakes’ in New earthquake of given magnitude but different Zealand. We performed simulations of kinematic realisations of non‐uniform slip is skewed. The and static surface displacements for a scenario extent of inundation predicted by a uniform

74 distribution of slip on the rupture interface is fault will mainly affect the Wellington south coast. roughly represented by the median of this A simultaneous rupture of Wharekauhau Thrust distribution. Assuming uniform slip on the rupture would further enhance the generation of tsunami interface therefore will underestimate the waves. Geodetic studies suggest that slip released potential impact and extent of inundation. For in a large Hikurangi earthquake is potentially example, simulation of an MW 8.7 to MW 8.8 concentrated at the southern part of the interface earthquake with uniform slip reproduced the area and was found to lead to increased inundation in potentially affected by inundation of an equivalent the Hikurangi scenarios. Non‐uniform slip non‐uniform slip event of MW 8.4 for Napier. distributions that happen to concentrate slip in the Cook Straight region have much the same effect. The extent of inundation does not follow a simple relationship to the magnitude of the earthquake. This study is the first we know of that attempts to Therefore de‐aggregation, to establish the understand the effects of rupture complexity on contribution of different sources with different slip tsunami generation by earthquakes on upper plate distributions to the probabilistic hazard, cannot be faults, in this case the Wairarapa and Wellington performed based on magnitude considerations Faults. The results of this study help to understand alone. the role of earthquake complexity on tsunami generation by these faults. We propose to use parameters of the tsunami wave field measured offshore as predictors for inundation severity to perform de‐aggregation based on simulations with the linear wave A GEOPHYSICAL STUDY OF THE KELLYVILLE AND equations. ONEWHERO MAAR CRATERS IN THE SOUTH AUCKLAND VOLCANIC FIELD

K. Mullane1, A. Pittari1, A. Gorman2 & B. Fox1 INVESTIGATION OF THE EFFECTS OF EARTHQUAKE 1School of Science, University of Waikato, Private RUPTURE COMPLEXITY ON TSUNAMI Bag 3105, Hamilton 3240 INUNDATION HAZARD IN WELLINGTON 2Department of Geology, University of Otago, PO HARBOUR Box 56, Dunedin 9054 [email protected] C. Mueller1, X. Wang1 & W. Power1 1GNS Science, P O Box 30368, Lower Hutt 5040 The South Auckland Volcanic Field (SAVF) is a [email protected] Pleistocene basaltic monogenetic field with a close association to the nearby Auckland Volcanic Field Recent investigations of the effects of earthquake (AVF). Phreatomagmatic eruption craters (maars) rupture complexity have shown that not only the generally offer detectable contrasts in the distribution of near shore tsunami amplitudes but subsurface rock density and magnetic signals. also the extent of inundation is strongly Geophysical surveys offer insight into delicate dependent on the specific instance of earthquake subsurface diatreme features that cannot be slip distribution. identified by surface investigation alone. Interpretation of gravitational and magnetic We have investigated the effects of different anomalies can contribute to the development of a examples of potential slip distributions on the syn‐eruptive and post‐eruptive sedimentary tsunami inundation hazard posed by three history. Gravity and magnetic surveys will be earthquake sources for the shore areas of the conducted across multiple transects through two Wellington Harbour and Wellington’s south coast: SAVF maar craters: the Kellyville and Onewhero the Hikurangi subduction interface (Mw = 9.0), the maars. Kellyville maar is of interest because Wairarapa Fault (Mw = 8.1) with a potential multiple scoria cones occur within the maar crater contribution of the Wharekauhau Thrust, and the suggesting a relatively complex subsurface Wellington Fault (Mw = 7.4). plumbing system. A post‐eruptive lacustrine unit, diatomite, is also present, providing a substantial We find that the crustal fault sources (Wellington density contrast to underlying scoria/basalt Fault and Wairarapa Fault) pose less of an deposits. Onewhero maar is the largest explosion inundation hazard than the studied events on the crater in the SAVF. It is not currently known if the Hikurangi subduction interface. The Wairarapa symmetrical crater has formed from a larger than Fault scenarios suggest that an earthquake on this

75 normal eruption with one root zone or if the excavated at Trotter 2, west of Dannevirke structure has been created by multiple root zones, (Hanson 1998). The widespread occurrence of with a complex evolutionary history. Shallow these lake‐forming landslides suggests a major country rock geology is exposed at both volcanic paleoearthquake in the region (here referred to as centres, the Te Kuiti Group at Onewhero and the the Namunamu paleoearthquake) was responsible Waitemata Group at Kellyville. Both occur as lithics for their formation, and the trees preserved on the in the surrounding tuff deposits. Preliminary floor of Lake Namunamu provide the best geophysical data and models will enable us to accessible date for this event. ascertain the depth of the eruption crater before infill as well as outline the subsurface plumbing systems of these “monogenetic” events. SIMULATING LAHARS IN A ROTATING DRUM

A. C. Neather1, S. J. Cronin1, J. R. Jones2 & G. MAJOR EARTHQUAKE ON WELLINGTON Lube1 (MOHAKA) FAULT CAUSES REGIONAL 1Volcanic Risk Solutions, Massey University, Private LANDSLIDING, CIRCA 2,200 YR BP Bag 11222, Palmerston North 4442 2SEAT, Massey University, Private Bag 11 222, V.E. Neall1 & I.A.N. Stringer2 1 Palmerston North 4442 Institute of Agriculture and Environment, Massey [email protected] University, Palmerston North 4442 2 7 Collingwood Street, Palmerston North 4410 Lahars are a particularly hazardous type of [email protected] granular flow [1]. They are a two‐phase flow, consisting of a mixture of volcanic rock and other One of the difficulties of ascertaining debris (the solid phase) and water (the liquid paleoearthquakes, particularly from fault trench phase) from one or more sources [2,3]. excavations, is deciphering whether landsliding or colluvial deposition is from cyclonic rainstorms or We attempt to simulate lahars in the laboratory by from earthquakes (plus rains immediately after making use of a rotating drum, a piece of earthquakes). Information from Lake Namunamu equipment commonly found in industrial research in the Hunterville district, provides evidence of a [4,5]. Granular material, when rotated in a drum, major earthquake around 2,220 ± 80 cal. yr B.P. creates a flowing body on top of an erodible bed; which, with careful dimensional analysis can be Of special note is that the landsliding did not result analogous to a lahar. in flowage, which would have been expected with a heavy rain triggering mechanism. Rather the Results to date include detailed maps of the landslide was of a block slide type which dammed various regions in a flowing granular material a former stream valley, without destroying the correlated to the speed of rotation and hence forest in the floor of the valley opposite. The momentum of the flows. Also, we have identified former forest trees are now preserved below lake two new phenomena; high speed rotations appear level and the outermost tree rings provided the to include features similar to Kelvin‐Helmholtz radiocarbon date (Wk 964). instabilities, and enclosed regions of sub‐rotation, This date matches the age (NZ100) of drowned which we tentatively name Neather cells. standing trees in Lake Waikaremoana (Wellman in Grant‐Taylor and Rafter 1963), presumably also [1] Neall (1976). Bulletin of Engineering Geology created by an earthquake‐triggered landslide. It and the Environment 13, 233 ‐ 240 may be that an initial landslide upstream of Lake [2] Smith & Fritz (1989).Geology 17, 375‐376. Colenso was also triggered by this event, prior to a [3] Smith & Lowe (1991) SEPM Special Publication subsequent landslide that formed the Lake, a little 45, 59 – 70. time later. [4] Ding et al., (2001). Chemical Engineering Science 56, 1769‐1780. It has previously been hypothesised that there was [5] Mellmann (2001).Powder Technology 118, 251‐ a major earthquake on the Wellington (Mohaka) 270. Fault between deposition of the Waimahia Tephra at c. 3,230 yr B.P. and the Taupo Tephra at c. 1,800 yr BP. The best evidence comes from a trench

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BUILDING UP A BASELINE ENVIRONMENTAL environmental management, hazard mitigation, DATABASE and energy and mineral opportunities, tourism and recreational use, as well as providing key baseline H. Neil1, G. Lamarche1, M. Clark1, A. Rowden1 & A. knowledge on which to build well targeted future MacDiarmid1 research. NIWA, Private Bag 14901, Kilbirnie, Wellington 6241 [email protected] ARE THE PLEISTOCENE JABAL AKWA New Zealand has a vast complex seascape, and MONOGENETIC VOLCANOES IN THE JIZAN dynamic and biologically diverse marine REGION (SW SAUDI ARABIA) PARTIALLY BURIED environment, which poses unique problems for MAAR – SCORIA CONE COMPLEXES? both data acquisition and data discovery. There is rapidly growing interest in New Zealand for K. Nemeth,1 N. El‐Masry2 & M.R. Moufti2 offshore hydrocarbon and mineral resources. 1 Institute of Agriculture and Environment, Massey Under the NZ’s Exclusive Economic Zone University, Private Bag 11 222, Palmerston North (Environmental Effects) Act 2012, consent 4442 applications must include an Impact Assessment, 2 Geohazards Research Centre, King Abdulaziz which requires knowledge of baseline information. University, Jeddah, Kingdom of Saudi Arabia Recent surveys in offshore frontier regions provide [email protected] such information. The intracontinental Al Birk volcanic field along the Offshore New Zealand has been the focus of Red Sea (Tihamat Asir) in SW Saudi Arabia consists numbers of research, industry and publically‐ of at least 200 scoria and spatter cones, lava fields funded geophysical surveys and environmental and domes/dome coulees, each formed in the past studies. Valuable insight into the deep‐sea is 1 My. In spite of the proximity to the Red Sea gained from bathymetric datasets which contain coastline, the low‐lying setting and abundant dry ~1.5 million km2 of multibeam coverage. Although valley networks indicative of former streams, there this represents only 15% of the marine estate has been no report of phreatomagmatic‐ mapped in detail, a variety of geomorphological influenced volcanism. Near the city of Sabya, two and geological structures relevant to the large scoria cones stand out from an aeolian sand hydrocarbon sector can be interpreted. Seafloor field: Jabal Akwa Al Shamiah in the north and Jabal reflectivity (backscatter) is used as a proxy for Akwa Al Yamaniah in the south. Both volcanic benthic habitat. Some ground‐truthing of nominal complexes are associated with a suspiciously benthic habitats and bottom features have been circular lava field suggestive of some ponding conducted using underwater imaging and direct effect caused by obstacles. While Jabal Akwa Al seafloor sampling. Distribution of megafauna from Shamiah is clearly a central cone complex with predictive habitat suitability modelling and breached craters, the exposed part of Jabal Akwa knowledge of other activities in the region, Al Yamaniah suggests a different story. Its upper particularly fishing, are also available. These lava field surrounds the westward breached scoria surveys have generated a comprehensive cone and the lava field seems to be ponded and collection of geological, oceanographic, biological banked against an earlier tuff ring that is partially and environmental data that together provide the buried. Tuff deposits are intercalated with a fluvial means to develop environmental baselines. terrace along the Wadi Sabya and aeolian deposits in the south. The nearly 40 m thick pyroclastic Acquiring encompassing, unambiguous seafloor succession shows a general trend of fining upward, data at scales relevant to offshore infrastructures from a lithic‐dominated lapilli tuff and tuff breccia or biohabitat is not achievable in the medium in the base that gradually transforms to better term. However, using a combination of datasets sorted, finer grained and more juvenile‐rich allows us to provide a unique view of the pyroclastic units nearer the top. The estimated topography and composition of the seafloor, its volume of accidental lithics in the tuff ring units ecological characteristics and biodiversity and the nearly 1 km wide circular lava field hotspots. These databases provide significant indicate substantial excavation of a crater, benefits for all stakeholders of the marine suggesting that Jabal Akwa Al Yamaniah is a buried environment, revealing potential for fisheries, maar complex. While no basal tuff ring units are

77 exposed at Jabal Akwa Al Shamiah, the circular MARINE‐TERRESTRIAL COMPARISONS AND distribution of the ponded lava may be the result OCEAN VENTILATION IN THE EAST TASMAN SEA of the presence of a maar beneath. DURING THE LAST GLACIAL‐INTERGLACIAL CYCLE

1 1 2 R. Newnham , M. Ryan , G. Dunbar , M. Vandergoes3, H. Neil4, B. Alloway1, H. Bostock4 & 5 NATIVE METALS IN THE CANTERBURY BASIN Q. Hua 1SGEES, Victoria University of Wellington, PO Box R.J. Newman1 600, Wellington 6140 1University of Canterbury, Private Bag 4800, 2Antarctic Research Centre, Victoria University of Christchurch 8140 Wellington, PO Box 600, Wellington 6140 [email protected] 3GNS Science, PO Box 30 368, Lower Hutt 5040 4National Institute of Water and Atmospheric Examination of cuttings from the Clipper‐1 well in Research, Private Bag 14901, Wellington 6241 the offshore Canterbury Basin has revealed a 5Australian Nuclear Science and Technology variety of unusual mineral assemblages. Of Organisation, Sydney, Australia particular interest are native metals rarely found in [email protected] nature, including iron, copper, lead and aluminium. These have been identified through We present preliminary results from two projects examination of polished sections and use of SEM that are part of our wider investigations into Late EDS to determine elemental composition. Two Quaternary climate evolution in the East Tasman distinct areas of intense mineralisation have been Sea (ETS) and adjacent Westland. The first uses the identified: a lower band at 3550m depth that is occurrence of terrestrial pollen in marine extremely rich in native iron and associated iron sedimentary sequences from the ETS to enable minerals, and an upper band at 2050m depth that direct land‐sea correlation and to provide a means contains both aluminium and iron. The upper, Al‐ for transferring Marine Isotope Stage chronologies rich band is located immediately above limestone to terrestrial records that extend beyond the range deposits indicating that carbonates are an of radiocarbon. Both applications require an important factor in the formation of native Al. implicit assumption that the time lag between Copper and lead are found together along with pollen release and final deposition at sea – here graphite in a rare assemblage that occurs in both referred to as the residence time – is negligible in bands. The metals are closely associated with comparison with the chronological resolution of volcanic glass and mineral‐cemented sediments, the marine sedimentary sequence. To assess the indicating that they cannot be man‐made extent of the residence time of pollen delivered contaminants. into the ETS, we have (1) radiocarbon dated pollen‐bearing sediments transported in Producing native metals in a natural setting contemporary fluvial settings in Westland, and (2) requires a highly reducing environment and very compared independently dated pollen events low oxygen fugacity. The proposed mechanism for common to marine and lake sediment records producing these conditions in Clipper‐1 is a mafic spanning the last glacial‐interglacial cycle. intrusion interacting with carbonaceous sediments, coals and limestone. Assimilation of The second project seeks to radiocarbon date organic matter lowers oxygen fugacity in the melt terrestrial pollen, planktic and benthic and produces gases such as CO that both displace foraminifera from a transect of cores that span oxygen and act as a reductant. The result may be across intermediate and circumpolar depths from described as a naturally‐occuring blast furnace. the ETS to address changes in the surface, intermediate and deep water marine reservoir age during the last glacial‐interglacial cycle. The benthic‐planktic age difference varies with time and location, being relatively large (2‐3 ka) for upper Circumpolar Deep Water but reducing for

Antarctic Intermediate Water. These results are consistent with greater storage of older carbon in deeper water and provide the first numerical values for intermediate and deep water marine reservoir age in the ETS. A progressive reduction in

78 benthic‐planktic age difference commences early ≥ 6.5 earthquakes with recurrence intervals of ≥10 in the last deglaciation, consistent with an increase kyr are necessary to reconcile the historical in ventilation of ocean deepwater and exchange of earthquake catalogue and NSHM earthquake carbon between the deep and surface ocean and sources. These inferred unmapped active faults between the surface ocean and the atmosphere. are capable of generating earthquakes up to magnitude Mw ~7.8 and, in many cases, will be located in low strain rate areas where they are expected to make an important contribution to the IMPLICATIONS OF HISTORICAL LARGE seismic hazard. MAGNITUDE EARTHQUAKES FOR THE INCOMPLETENESS OF NEW ZEALAND’S PREHISTORICAL EARTHQUAKE RECORD DISCOVERY OF A NEW ACTIVE FAULT IN A. Nicol1, R. Van Dissen1, M. Stirling1, M. WELLINGTON HARBOUR AND IMPLICATIONS FOR Gerstenberger1 & W. Ries1 REGIONAL SEISMIC HAZARD EVALUATIONS 1GNS Science, P O Box 30368, Lower Hutt 5040 1 1 1 1 [email protected] S.D. Nodder , P.M. Barnes , S. Woelz , A.R. Orpin 1National Institute of Water & Atmospheric Moderate to large magnitude earthquakes in the Research Ltd, Private Bag 14901, Kilbirnie, Canterbury (2010‐2011) and Cook Strait (2013) Wellington 6421 sequences caused significant damage, yet [email protected] ruptured active faults that were not previously known to exist. These earthquakes fuel questions A newly discovered, active reverse fault (informally about how many unmapped active faults have the named the “Mount Victoria Fault”), with near‐ potential to generate future damaging surface expression, has been mapped within inner earthquakes and how best to accommodate these Wellington Harbour, between Lambton Harbour in the New Zealand National Seismic Hazard Model and Kaiwharawhara. The fault is downthrown to (NSHM). Historical moderate to large magnitude the northwest, has a sea‐floor scarp up to 1 m‐high earthquakes since 1840 have been analysed to and extends offshore for approximately 2 km. Mid‐ estimate the likelihood of rupture occurring on Holocene reflectors are dislocated on the southern hidden active faults that are not explicitly and middle sections of the fault trace, becoming accounted for in the NSHM. We consider 105 more gently folded at its northern end, with shallow earthquakes (≤25 km focal depth) with maximum vertical sub‐surface fault offsets ranging magnitudes Mw 5‐8.2 that were located onshore from 3–7 m. Deformation at the southernmost or ruptured faults that extend onshore (e.g., extent becomes more distributed, and perhaps Napier 1931 Mw 7.8 earthquake). Given the transferred to two other associated structures in relatively short duration of the historical record Lambton Harbour and Oriental Bay. From the and the rates of seismicity over this time interval, available shallow seismic data, the fault does not the number of earthquakes considered is small appear to be connected structurally to the active, and only permit first‐order conclusions. About half strike‐slip Wellington Fault off Kaiwharawhara. of all historical earthquakes Mw ≥ 7.0 ruptured active faults that based on today’s state of Estimated slip rates on the Mount Victoria Fault knowledge would have been mapped. For the are ca. 0.6 ± 0.3 mm/y over the last 10,000 years, most part, the remaining 50% of historical events with at least two surface‐rupturing earthquakes on ‘unmapped’ active faults either did not displace (EQ) recognised, dated at ~6,200 ± 900 years the ground surface or were located in areas where (EQ1), with up to ~2 m of co‐seismic vertical the rates of erosion/burial exceed fault‐slip rates. displacement, and ~8,400 ± 1,300 years (EQ2). The Incompleteness of active faults in the NSHM is occurrence of other unresolved earthquakes, greatest for earthquake sources with long however, cannot be discounted. Based on the New recurrence intervals of ≥10 kyr. Historical Zealand National Seismic Hazard Model empirical earthquakes of Mw ≥ 6.5 on faults with recurrence relationships, the most compelling earthquake‐ intervals of ≥10 kyr are about 10 times more source scenario involves fault rupture lengths frequent than predictions based on NSHM fault along the fault of ca. 30 km, generated by sources with the same magnitude and recurrence earthquakes of magnitude Mw 6.8–7.1. This interval ranges. Several hundred additional suggests that the fault could extend beneath unmapped active faults capable of generating Mw Wellington City and southwards to the south

79 coast, possibly via Island Bay (or Lyall Bay). Such the magnitude of the cosmogenic nuclide‐derived earthquakes would produce average co‐seismic rates. High annual precipitation in the Southern displacements (~1.9–2.3 m) and recurrence Alps supports rapid soil generation through intervals (average ~3500 years, range ~2,100– increased chemical weathering rates and extensive 7,700 years) that are compatible with the new vegetation cover. When applied more broadly, the offshore data from Wellington Harbour. Further climate‐dependent soil production model suggests work is required to delineate the possible onland that actively eroding mountain belts may display a continuation of the Mount Victoria Fault and to linear relationship between weathering and better resolve its Holocene earthquake history and erosion in strongly orographic settings, such as in potential hazard to Wellington City. New Zealand’s Southern Alps.

WEATHERING, SOIL PRODUCTION, AND EROSION ACROSS CLIMATIC AND TECTONIC GRADIENTS THE UNSTABLE KAIKOURA CANYON, NORTHEASTERN SOUTH ISLAND: AN ACTIVE K.P. Norton1 & I.J. Larsen2 CONDUIT FOR TECTONIC AND CLIMATIC EVENT‐ 1SGEES, Victoria University of Wellington, PO Box TRIGGERED SEDIMENT TRANSPORT ON A VERY 600, Wellington 6140 NARROW SHELF 2California Institute of Technology, Geological and 1 1 2 Planetary Sciences, Pasadena, CA, USA A.R. Orpin , J.J. Mountjoy & C.R. Alexander [email protected] National Institute of Water and Atmospheric Research, Private Bag 14901, Wellington 6241 Weathering is one of the fundamental processes 2Skidaway Institute of Oceanography, Savannah, that sustain life on our planet. Physical weathering GA 31411, USA breaks down rock for soil production and chemical [email protected] weathering is thought to operate as the ultimate long‐term negative feedback on atmospheric CO2 Kaikoura Canyon lies at the southern apex of the concentrations. There remains, however, Hikurangi Trough off the northeastern South uncertainty as to the relationship between Island. Because of its proximity to plate‐boundary chemical and physical weathering at very fast deformation the region is subject to periodic rates. If chemical weathering becomes kinetically earthquakes, affecting the episodic riverine limited at rapid erosion rates, as has been shown delivery of sediment to the coast, along with in a number of locations around the globe, then down‐canyon remobilisation and transport into the fastest erosion rates will be associated with the Hikurangi Channel system. The upper reaches reduced chemical weathering. This has led to a of the canyon are incised into bedrock and debate as to whether tectonically active mountain truncate overlying Quaternary strata. The partly ranges or rolling plains are the main source of CO2 infilled Kaikoura canyon head incises into the very drawdown through silicate weathering. narrow (<1 km) and shallow (~30 m) shelf, intersecting the northward littoral transport At the heart of this debate is the dearth of pathway. A potential landslide‐tsunami hazard was chemical weathering data at fast erosion rates. previously identified here. New cosmogenic nuclide‐derived denudation rates from the West Coast of the New Zealand Southern Recent seismic data and cores show a shore‐ Alps are among the fastest in the world and are attached post‐glacial sediment prism over 40 m linearly correlated with chemical weathering rates. thick at the shelf break. Radioactive nuclide The associated soil production rates reach an profiles of excess Pb‐210 and Be‐7 determined order of magnitude faster than previous estimates from precision‐short cores indicate on‐going outer and far exceed the suggested maximum soil shelf sediment accumulation at rates up to 1.5 production rate. This suggests that very fast cm/y. Excess Pb‐210 profiles in the upper canyon weathering and soil production is possible in such axis show little decay over 40 cm, indicating rapid active landscapes and extreme climates. We accumulation from mass flows or intense investigate the controls on these rapid rates with a biological mixing. These new data require a re‐ climate‐driven soil production model. evaluation of realistic tsunami sources, while indicating that Kaikoura Canyon is very active as a When applied to the Southern Alps, the model sediment conduit, with delivery events likely at predicts very rapid soil production that matches decadal timescales.

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FORGOTTEN WORLD THE NZGD2000 DEFORMATION MODEL, A TOOL FOR MAINTAINING ACCURATE SPATIAL J. Palmer1 & C. Field2 COORDINATES IN NEW ZEALAND DUE TO 1Institute of Agriculture and Environment, Massey DEFORMATION ON THE PACIFIC‐AUSTRALIA University, Private Bag 11 222, Palmerston North PLATE BOUNDARY 4442 2New Plymouth ‐ Geoscience Society of New C. Pearson1, C. Crook2, N. Donnelly2 & P. Denys1 Zealand Taranaki Branch member 1School of Surveying, University of Otago, PO Box [email protected] 56 Dunedin 9054 2Land Information New Zealand, PO Box 5501 Today the community of Tangarakau, King Wellington 6145 Country, is home to fewer than 10, a mere shadow [email protected] of the former settlement that at its peak in 1926 had a population of around 1200. In 1929 the While John Beavan is best known for his enormous Egmont Coal Company commenced a small coal contributions to our knowledge of the tectonics of mining operation in the Tangarakau Gorge to New Zealand, he also made a significant supply sub‐bituminous coal to fire a power station contribution to the development and maintenance and locomotives during the construction of the of the NZGD2000 datum and the associated railway from Stratford to Taumaranui. A narrow NZGD2000 deformation model (NDM). Over the 610mm gauge tramway ran between the years John provided versions of the deformation underground coal mine in the gorge to the railway model and transformations between NZGD2000 settlement at Tangarakau, a distance of about and various versions of the ITRF. In this paper we 6km. The mine was closed in 1936 and has been discuss key aspects of the NZGD2000 datum left to crumble away. including the development of a datum transformation between ITRF2008 and NZGD2000, There are several small coal measure outcrops in and a major update to the NZGD2000 deformation Tangarakau Gorge. These mostly belong to the model. The NDM contains a submodel Mangapapa Coal Measures, upper Mokau Group, representing velocities across the country caused and are part of a regressive sequence deposited in by continuous tectonic deformation, in addition to the late Early Miocene in response to uplift and submodels of representing deformation associated shallowing of the Whangamomona Block, southern with major earthquakes (including the Dusky King Country. The top of the coal measures crops Sound earthquake of 15 Jul 2009 and the four out at road level opposite the mine entrance. Here earthquakes between September 2010 and horizontal burrows in the upper part of the coal December 2011 that make up the Canterbury are evidence of deposition in a shoreline to earthquake sequence). These earthquake shallow marine setting. The coal beds dip in a submodels may contain separate component to generally south‐easterly direction beneath the represent coseismic and postseismic deformation. road and crop out again on the true left bank of The submodels deal with earthquake the Tangarakau River. Farther east and south the displacements in two different ways [1]. In the coal is subsurface. It’s presence in the subsurface first, known as a forward patch, the reference has been confirmed by 6 exploration wells drilled coordinates are unchanged, and the deformation in the Tangarakau – Whangamomona area by Solid model accounts for the deformation associated Energy between 2009 and 2011. Confirmation of with the co‐seismic and secular parts of the model. extensive coal deposits at depth in southern King In the second, known as a reverse patch, the Country begs the question how does this reference coordinates are changed to reflect the regressive transitional sequence fit with the co‐seismic portion of the deformation and the Oligocene – early Miocene marine maxima deformation model only needs to account for the reported elsewhere? secular part of the deformation. A consequence of the use of reverse patches is that the epoch 2000 coordinates change to reflect the changes caused by the earthquakes, even though they occurred well after the reference epoch of the datum.

[1] Winefield et al., (2010). FIG Congress 2010 Sydney, Australia, 11‐16 April 2010

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MAJOR ELEMENT AND STRONTIUM ISOTOPE U‐PB DATING OF SAMS CREEK (NORTHWEST GEOCHEMISTRY OF GLACIERS, LAKES AND RIVERS NELSON, NEW ZEALAND) WITHIN THE MACKENZIE AND WAITAKI BASINS M.P.R. Phillips1, J.M. Palin1, M.W. Sagar1 & P.V.M. 1 1 2 V. Pettinger , C.E. Martin , S. Sander Angus2 1 Department of Geology, University of Otago, PO 1Department of Geology, University of Otago, Box 56, Dunedin 9054 Dunedin 9054 2 Department of Chemistry, University of Otago, PO 2MOD Resources Ltd, 18 Princes St, Dunedin 9016 Box 56, Dunedin 9054 [email protected] [email protected] Gold mineralisation at Sams Creek occurs within Water and ice samples were taken from an array an under‐explored region of Northwest Nelson of locations extending from the Tasman and with a rich alluvial gold history dating back to the Hooker Glaciers, Lakes Tekapo, Pukaki and Ohau 1850s. Gold at Sams Creek is hosted by an A‐type through to State Highway 1 North of Oamaru. peralkaline microgranite dike extending 7km along Samples were collected at the beginning of each strike up to 60 metres in thickness. season from November 2013 (summer) to September 2014 (spring). There is a general lack of Multiple stages of hydrothermal activity have time series data for radiogenic isotopes that altered the dike including the precipitation of late prevents proper assessment of uncertainties in arsenopyrite veins, base metal sulphides, and gold. estimated annual averages. The few rivers for Gold‐silver alloy (~80‐85% Au) occurs as small which time series data is available for indicate that growths (up to 40 μm) cementing and in‐filling Sr concentrations can vary by more than a factor brecciated and fractured arsenopyrite (the most 87 86 of two, and Sr/ Sr can vary by several per mil. abundant ore‐related mineral). Here, the current research attempts to add to the field by providing a time series data set across Hydrothermal zircons occur as clusters and each season for a single year for New Zealand’s stringers of <1‐15μm anhedral crystals along Waitaki and Mackenzie basins. arsenopyrite grain boundaries and within the same micro fractures occupied by gold grains. It is The average relative molar abundance of major suggested that these zircon originated from cations in all waters sampled follows the order 2+ + 2+ + hydrothermally remobilised Zr derived from Ca (66%) > Na (20%) > Mg (8%) > K (5%). original igneous phases of the SCD. Zircons also Sample Ca/Sr values range from 0.19 – 0.85 occur in un‐mineralized samples as relatively large µmol/nmol in the Tasman Glacier terminal lake ellipsoidal to faceted individual grains associated and Tasman Glacial ice, respectively. Seasonal with primary mafic minerals and are interpreted as variation in cation concentrations were observed, late magmatic in origin. These zircons are up to with a general decrease throughout the ~25μm in size and many grains exhibit a spongy catchments from summer to winter. An exception (?dissolution) texture. was the heavily impacted water of the lower Waitaki, which had higher dissolved U‐Pb analysis by LA‐ICP‐MS indicates a mid‐ concentrations in the winter. This could result Cretaceous age for dike emplacement (109 ± 9 Ma) from the influence of Ca‐rich sediments of the and the main gold bearing hydrothermal event lower Waitaki Basin or anthropogenic fertilizers. (114 ± 6 Ma). Analysis of a second group of hydrothermal zircons, associated with more 87Sr/86Sr ratios in the dissolved load, will be advanced replacement of sulphide grains, yields a measured in order to further assess the sources of Late Cretaceous age of 80 ± 4 Ma. This date solutes in these catchments from chemical possibly represents a later remobilizing weathering. hydrothermal event, but limited data requires that further investigation be conducted to assess this possibility.

The proposed Cretaceous emplacement age differs significantly from the published Carboniferous age (319 ± 8 Ma) from 40Ar/39Ar analysis of amphibole by Tulloch and Dunlap (2006). The Cretaceous mineralisation age is in agreement

82 with an estimate constrained by structural DEVELOPING ROBUST TSUNAMI FORECASTS FOR mapping which suggests syn‐deformational PORTS AND HARBOURS formation. W.L. Power1, J.C. Borrero2, D. Greer2 & D.G. 3 Goring 1GNS Science, PO Box 30368, Lower Hutt 5040 2 BASALT ‘CRICKET’ BALLS AND SHATTERED eCoast Ltd, PO Box 151, Raglan 3265 3 RHYOLITE; ERUPTION DYNAMICS OF A BASALTIC Mulgor Consulting Ltd, PO Box 9320, Tower TUFF SUCCESSION AT KINLOCH, TAUPO VOLCANIC Junction Christchurch 8149 CENTRE [email protected]

A. Pittari1, M.A. Matheson1, R.M. Briggs1 & M.D. Tsunami large enough to cause disruption to ports Rosenberg2 and harbours have occurred several times in the 1School of Science, University of Waikato, Private past decade. As New Zealand’s economy is heavily Bag 3105, Hamilton 3240 dependent on imports and exports it is important 2GNS Science, Wairakei Research Centre, Private that forecasts are accurate, both because tsunami Bag 2000, Taupo 3352 damage to ships and facilities is expensive to [email protected] repair and can be mitigated given warning, but also because preventable false alarms are costly. Basalt is a volumetrically small, but genetically Two main approaches to tsunami forecasting are important magma composition of the central available. The first is to build a database of pre‐ Taupo Volcanic Zone. A small field of at least five calculated scenario models which can be referred basaltic monogenetic centres occur at the to during an event; and the second is to use a northern end of the Taupo Volcanic Centre prepared configuration to model an event in real between Kinloch and Acacia Bay, north of Lake time. Both of these have pros and cons. This talk Taupo (Punatekahi scoria cone complex, 140 ka, will describe the development of a pre‐calculated Stipp 1968, Aust. Nat. Univ. PhD thesis; K‐trig set of tsunami forecasts for key New Zealand scoria cone and tuff; Kaiapo tuff; Mine Bay tuff; ports: Marsden Point, Port of Tauranga, Port Acacia Bay tuff, ~100‐200 ka, Wilson and Smith Taranaki, and Lyttelton Harbour. A key component 1985, J. R. Soc. NZ, 15, 329‐337). We report a of this work is to understand the limitations of the previously unpublished phreatomagmatic centre pre‐calculated scenario approach, as a prepared (Kinloch tuff) exposed in a lakeshore cliff near scenario is only ever going to be an approximation Kinloch and discuss its volcanic process origins. to a real event; this leads to an analysis of The exposed ~ 7 m‐thick Kinloch tuff deposit appropriate factors of safety. overlies a succession of interbedded tephras and palaeosols, and is overlain by a ~ 4 m‐thick poorly sorted lithic cobble‐rich mass flow deposit. CENOZOIC BIOGEOGRAPHY USING POLLEN FROM Several north‐trending normal faults offset the THE FRED DATABASE Kinloch tuff and underlying succession by 1‐2 m, but have not offset the overlying mass flow J.G. Prebble1, E.M. Kennedy1, D.C. Mildenhall1, J.I. deposit. Three facies have been identified within Raine1, T. Reichgelt2 & H. Seebeck1 the tuff deposit: (1) alternating weakly‐laminated 1GNS Science, PO Box 30368, Lower Hutt 5040 fine ash and thin‐ to medium‐bedded, coarse ash 2University of Otago, PO Box 56, Dunedin 9054 to lapilli pyroclastic surge‐dominant facies, with [email protected] low angle cross bedding and erosional scours; (2) massive, lithic block and spheroidal basalt lapilli‐ FRED (online at http://www.fred.org.nz/) is a bomb pyroclastic fall facies; and (3) thick‐bedded, database recording fossil localities in New Zealand internally massive, poorly sorted lapilli ash facies. and nearby regions including SE Pacific islands and Facies 1 comprises the lower 5.5 m of the section the Ross Sea region of Antarctica. FRED contains and facies 2 and 3 are intercalated within the about 98000 locality records registered at regional upper 1.5 m, suggesting a predominantly recording centres since 1946. phreatomagmatic‐driven eruption. Beds of spheroidal basalt lapilli and bombs, often with In this project, we seek to synthesise the pollen pumiceous inclusions, and rhyolite lithic blocks observations from New Zealand Cenozoic (facies 3) indicate brief periods of coarse‐scale sediments that are stored in FRED, and to magmatic and country rock fragmentation.

83 document biogeographic variation through time. records of past regional variability in a warmer To do this, we have compiled presence/absence world. observations of 340 published taxa from >2500 individual sporomorph assemblages of Paleocene‐ We report on the first stages of a model‐data Pliocene age. comparison project for the early Holocene, which has three aims. The first is to generate sub‐ Samples were restricted to those collected from millennial scale multi‐proxy sea surface outcrop or cores; drill cuttings were excluded. A temperature records for 12‐6ka from a suite of two‐tier hierarchy of age determination was used. marine sediment cores that form a latitudinal Samples with ‘non‐pollen’ age estimates were transect from New Zealand into the Southern separated from samples with ‘pollen‐only’ age Ocean (36⁰S‐60⁰S). Methods used to estimate sea estimates. Where multiple age estimates were surface temperature at each site include Mg/Ca available, a ‘best overlap’ age was estimated. The from planktonic foraminifera, alkenones and paleogeographic coordinates of each sample was assemblage‐based techniques using foraminifera, inferred using the GPlates model radiolaria, dinoflagellates and diatoms. The (http://www.gplates.org/). Ecological and second aim is to compare the results of these sea environmental observations from modern surface temperature data with outputs of a analogues to the fossil palynospecies were used to climatic model for this interval, the CCSM3 TraCE interpret pollen associations observed in principal simulations. Additional proxies (faunal and floral component analyses of time slices defined by New assemblage data, bulk sediment properties, Zealand stages. nitrogen isotopes, and measurements of sedimentary iron concentration) will be used to infer semi‐quantitative estimates of primary productivity during this interval. Finally, the proxy IMPACT OF A WARMER WORLD ON SOUTHERN data will be utilised to infer water mass conditions OCEAN CIRCULATION AND BIOPRODUCTIVITY: and the position of frontal systems during the THE EARLY HOLOCENE early Holocene.

1 1 2 J.G. Prebble , G. Cortese , H. Bostock , L. Armand3, E. Calvo4, G. Dunbar5, B. Hayward6, M. 7 8 9 2 Kienast , K. Kim , D. Kulhanek , H. Neil , J. VOLCANIC DEBRIS AVALANCHES; 10 1 8 Pedro , G. Scott & H. Yoon UNDERSTANDING EMPLACEMENT AND 1 GNS Science, P O Box 30368, Lower Hutt 5040 APPROACHES TO MODELLING AND SIMULATION: 2 National Institute of Water and A CASE STUDY FROM TARANAKI, NZ. Atmospheric Research, Private Bag 14901, Wellington 6241 J.N. Procter1, M. Roverato2, M‐A. Brideau3, A.V. 3Macquarie University, Sydney Zernack4, S.J. Cronin1 4Institute of Marine Sciences, Barcelona 1Institute of Agriculture and Environment, Private 5Victoria University Wellington, PO Box 600, Bag 11222, Massey University, Palmerston North Wellington 6140 4442 6 Geomarine Research, 49 Swainston Rd, St Johns, 2Universidade de São Paulo, IGC Instituto de Auckland 1072 Geociências, Rua do Lago, 562, Cidade 7Dalhousie University, Nova Scotia Universitária, São Paulo, Brazil 8Korea Polar Research Institute BGC Engineering Inc. Suite 800 ‐ 1045 Howe Street, 9IODP, Texas A&M University Vancouver, BC, Canada 10University of Copenhagen, Denmark 4TMI, PO Box 1341, Palmerston North 4440 [email protected] [email protected]

In the New Zealand region, the sparse data Fourteen unconfined debris avalanche deposits available suggest sea surface temperatures during (DADs) <200ka in age are preserved on the Mt. the early Holocene ranged up to 3⁰C above Taranaki ring plain, providing a record of a high‐ present, but timing and magnitude of warming impact, low‐frequency hazard. The youngest of varied across the region. These temperatures are these events, the ~7ka Opua and 26.5ka within the range of those expected in the coming Pungarehu formations, exhibit the typical chaotic, century. The early Holocene sedimentary archive polymodal, polylithologic and extremely poorly has great potential to provide well resolved sorted characteristics of DADs. Despite the

84 apparent invariance of these large‐scale shaping discourse around, contemporary research properties, the sedimentological characteristics from across all areas of science. Despite growing gradually change from proximal to distal areas, academic interest in science journalism, media with the finer fractions increasing with distance. research in this field is typically generalised or, SEM analyses of clay and silt grains show typical when discipline‐specific, focuses on a limited range hackly textures and micro‐cracks. The lack of of largely anthropocentric topics, such as human variation in the crack distribution or frequency biology, medical science and climate science. within the deposit suggests cracking occurred at While there are undoubtedly issues that pervade source. Similarly the analysis of macro‐scale all media/science relations, we contest that the fracture patterns within domains and/or less‐studied disciplines ‐ which also generate megaclasts show no alignment or preferred research of global reach and relevance ‐ exhibit orientation of stress fields. media interactions with unique aspects that merit Deposit surface morphology varies with distance study. from source. A chaotic surface occurs in proximal regions, which then gives way to ridges of mounds The purpose of our on‐going research is to oriented in flow‐parallel direction. These examine the media/science relationship in one eventually transform into clusters of mounds and such neglected area of reporting: palaeontology. more widely spaced fields of individual mounds in While limited and often anecdotal, existing distal areas. literature has proposed a general air of Both debris avalanches were generated dissatisfaction with these interactions amongst gravitational sector collapses which flowed down palaeontologists and journalists alike, rooted in a individual catchments. Abrupt changes in fundamental culture clash between the two topography and slope resulted in the professions. In addition to raising recurring themes transformation of the flows into a more cohesive of Science Journalism Studies (e.g. accessibility, mobile body, which formed lobes marked by accuracy and sensationalism), many mound/hummocky ridges. commentators propose the media’s alleged The granular flow model Titan2D has been applied ‘dinomania’ ‐ a singularly overwhelming obsession to evaluate possible emplacement conditions and with dinosaurs ‐ as a problematic and unparalleled collapse parameters. While useful for defining quirk of palaeontological reportage. The extent of initial collapse parameters and major flow paths, this trend, however, has not been quantified. Titan2D could not adequately simulate the complex rheological transformations of a In this presentation we report preliminary results collapsing/sliding pile through granular flow, into a from a content analysis of around 600 long‐runout, clay‐rich, cohesive flow with high palaeontological news stories. Our study is limited fluidity. It is also difficult to adequately define to those articles specifically covering simulation parameters for this rapidly changing palaeontological research that were published in flow from the deposits. Hence computer 60 prominent, international, English‐language simulations of major flow paths must be used newspapers during the previous calendar year. We alongside insights from geological mapping to identify a number of recurring topics and news provide future‐focused hazard zones for debris frames, discuss these in light of existing literature, avalanches. and investigate the feasibility of extending our analysis to identify longer‐term trends.

PALAEONTOLOGY IN THE PRESS: DINOMANIA, DISCOVERIES AND THE ‘GEE WHIZ!’ FRAME THE EXTENT OF WEST COAST IGNEOUS ROCKS REVEALED BY AEROMAGNETIC I. Randall1,2 & K.A. Campbell2 DATA, NEW ZEALAND 1School of Social Sciences, University of Auckland,

Private Bag 92091, Auckland 1142 M.S. Rattenbury 2School of Environment, University of Auckland, GNS Science, P.O. Box 30368, Lower Hutt, 5040 Private Bag 92091, Auckland 1142 [email protected] [email protected] Aeromagnetic data acquired over the West Coast For the general public, the news media play a for the New Zealand Government and industry significant role in providing information on, and have revealed a wide range of total magnetic

85 intensities that generally correlate well with records predominantly coarse terrigenous clastic known geological mapping units of differing deposition in a wave dominated fan delta and magnetic susceptibility. Strongly positive nearshore to offshore shallow marine anomalies are associated with igneous rocks; environments. The fan delta environment is notably Mesozoic mafic metavolcanic and characterised by sub‐aerial to subaqueous, plastic ultramafic rocks, Late Cretaceous basalt and some or pseudoplastic, clast‐rich debris deposits of the Early Cretaceous intrusions. The Pounamu consistent with flows associated with partial Ultramafic rocks in the Southern Alps have some collapse of steeply dipping, unstable, prograding of the highest intensity anomalies recorded by the delta foresets resulting in avalanching of sediment surveys and the Dun Mountain Ultramafic Group from the top of the delta system. The fan delta serpentinised peridotite rocks and dikes also have facies are interpreted to represent a Gilbert‐type very strong magnetic expressions. Isolated fan delta with a fluvial signature in the top delta anomalies along the Alpine Fault are attributed in zone, steeply dipping foresets, and more of a part to ultramafic rocks incorporated into the marine signature in beds at the front delta zone. mylonite zone. Greenschist bands within the Wave sorted conglomerates preserved in this Alpine Schist are well expressed magnetically. sequence are accumulated on a tectonically active Many of the Separation Point and Rahu Suite Early coastline characterised by high‐energy wave Cretaceous intrusions are strongly magnetic, activity and sporadic intense storms. including the Berlins Porphyry and the Pensini Granodiorite that contribute to the Inangahua The Nukumaruan Konewa Formation was Magnetic Anomaly. The strong anomalies deposited in a shallow marine setting located associated with the Hohonu Range and many along the western flanks of the Ruahine Range in other foothills are caused by magnetic granitoids the eastern part of the . Analysis of and dikes. The Hohonu Batholith may persist to conglomerate clasts and paleocurrent data the west under Quaternary and older Cenozoic indicate the source of the gravel was an elevated cover and be the cause of the Kumara Magnetic basement located in the vicinity of the present day Anomaly. Other Cretaceous and most of the northern Ruahine Range, some 40 ‐70 km north of Devonian intrusions have a very weak magnetic Pohangina. The gravels were transported by a intensity and it is difficult to distinguish them paleo‐river system which flowed into the magnetically from Greenland Group southeastern Wanganui Basin, delivering vast metasedimentary and gneissic rocks. Many long quantities of terrigenous sediment into a shallow linear anomalies are attributed to mafic igneous marine environment. Correlation in the region dikes intruding the basement rocks. Late supports a fan delta about 1.5 km across. The Cretaceous Arnott Basalt in South Westland is climate at the time of deposition is interpreted as highly magnetic and its associated aeromagnetic a glacial period characterised by river aggradation anomaly indicates a wide distribution including in and coastal progradation. a newly discovered anticline near Fox Glacier that has been almost completely obscured by glacial outwash and till. A PRELIMINARY ACCOUNT OF THE FLORAL DIVERSITY AND CLIMATE OF THE MUDDY CREEK LEAFBED, GREY LAKE, CENTRAL OTAGO PALEOENVIRONMENT AND SEDIMENTOLOGY OF 1 1 1 A WAVE DOMINATED PROGRADING FAN DELTA T. Reichgelt , W.A. Jones , D.T. Jones , J.M. 2 1 3 SEQUENCE, PLIO‐PLEISTOCENE KONEWA Bannister , J.I.T. Hillman , D.C. Mildenhall , J.G. 4 1 FORMATION, POHANGINA, NEW ZEALAND Conran & D.E. Lee 1Department of Geology, University of Otago, PO C. Rees1, J. Palmer1, & A. Palmer1 Box 56, Dunedin 9054 2 1Institute of Agriculture and Environment, Massey Department of Botany, University of Otago, PO University, Private Bag 11 222, Palmerston North Box 56, Dunedin 9054 3 4442 GNS Science, PO Box 30368, Lower Hutt 5040 4 [email protected] ACEBB & SGC, School of Earth and Environmental Sciences, University of Adelaide, SA, Australia A 66‐m‐ thick sequence of Plio‐Pleistocene Konewa [email protected] Formation exposed in southern Pohangina Valley,

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A newly discovered leaf bed in the Early Miocene 4Earth Sciences, School of Science, University of St. Bathans Member of the Manuherikia Group, Waikato, Hamilton 3240 Central Otago is described. Previous studies on the 5Lamont‐Doherty Earth Observatory, Columbia St. Bathans Member have focused on dispersed University, Palisades, NY 10964, USA cuticle, but near Muddy Creek a ~20 x 20 m, ~3 m [email protected] high mud lens is exposed, showing excellent preservation of both leaves and cuticle. The Southern New Zealand has a rich sedimentary deposit is lensoidal, wedged between cross‐ record of early Miocene terrestrial bedded sandstones and capped by Quaternary paleoenvironment. The broad picture emerging deposits. The mud lens has fine mm‐scale from these records indicates a major transition in laminations. There is no clear evidence of leaf the terrestrial climate of southern New Zealand transport, nor is there any alternation of grain‐ during the period of Drake Passage opening and size. The depositional environment was probably corresponding amplification of the Antarctic an oxbow‐lake, or abandoned channel from a Circumpolar Current. The general trend was from braided river system feeding into Lake subtropical, warm‐temperate humid climate Manuherikia. during the early Miocene toward increased Antarctic influence, resulting in cool‐temperate Plant fossils are preserved in oxidized and conditions in the late Miocene. Additionally, unoxidized mudstone; the unoxidized mudstone is sedimentological and paleobotanical evidence grey‐black and leaf outlines are difficult to suggests that during certain time intervals in the distinguish, but have excellent cuticular Miocene, New Zealand’s climate was characterized preservation (~80%). The oxidized mudstone is by an increased seasonal gradient. brown‐red and has good preservation of macromorphological characteristics, but no cuticle Today southern New Zealand seasonality is most is preserved. Fruits and possibly seeds are present, pronounced in the light regime, with twice as but as yet, no floral remains. The leaf assemblage many daylight hours and three times higher solar is diverse, with relatively even representation of altitude angle in summer than in winter; in leaf morphotypes. Podocarps are relatively contrast the summer/winter precipitation ratio is common and moderately diverse. Some palm‐like much less seasonal at ~0.8–1.0. In modern day fronds and other monocots have been recovered, monsoon‐dominated oceanic climates in the but most of the leaf fossils belong to Magnoliids Pacific region, summer precipitation can be 6–8 and/or Eudicots. Nothofagus‐type leaves are times higher than winter precipitation, but the absent from the main mud lens, but present at the light regime is much less seasonal. The restricted bottom of the section in highly oxidized mudstone. seasonal precipitation gradient in New Zealand is The excellent cuticular preservation at Muddy mostly the effect of the influence of the westerly Creek preserves evidence of microscopic fungal wind belt, which brings moisture‐laden air year‐ colonies together with ~50–100 µm insect round, particularly in southern New Zealand. puncture marks. In situ preservation of fungal However, with reduced Antarctic influence in the hyphae, high abundance of Podocarpaceae, early Miocene, seasonal reduction of the westerly together with results from CLAMP analysis winds could have arrested the main moisture suggests relatively high humidity in a somewhat supply. cool environment. Using a theoretical model of evapotranspiration, based on quantitative estimates of climatic parameters and paleolatitudinal position, we SEASONAL CLIMATIC GRADIENTS IN THE EARLY present paleoenvironmental reconstructions that MIOCENE OF NEW ZEALAND delineate the seasonal parameters of early Miocene climate in southern New Zealand. These T. Reichgelt1, E.M. Kennedy2, J.M. Bannister3, reconstructions suggest that the seasonal shifting B.R.S. Fox4, W.J. D’Andrea5 & D.E. Lee1 of main moisture supply, together with a mid‐ 1Department of Geology, University of Otago, PO latitudinal light regime in New Zealand, could Box 56, Dunedin 9054 account for amplified seasonal precipitation 2GNS Science, PO Box 30368, Lower Hutt 5040 gradients. 3Department of Botany, University of Otago, PO Box 56, Dunedin 9054

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CENOZOIC MARINE SEQUENCE OF SWINBURN 15 YEARS OF ZOOMING IN AND ZOOMING OUT: REGION, MANIOTOTO, CENTRAL OTAGO DEVELOPING A NEW SINGLE SCALE NATIONAL ACTIVE FAULT DATABASE OF NEW ZEALAND M. Richards1 R.E. Fordyce1 & D.E. Lee1 1Department of Geology, University of Otago, PO W. Ries1, R. Langridge1, P. Villamor1, N. Litchfield1, Box 56, Dunedin 9054 R. Van Dissen1, D. Townsend1, J. Lee1, D. Heron1 & [email protected] B. Lukovic1 1GNS Science, PO Box 30368, Lower Hutt 5040 The Maniototo Basin preserves localised Cenozoic [email protected] marine strata that can be correlated into Waitaki Valley, with formational names as used in the We are currently reconciling multiple digital southern Canterbury Basin. The clastic‐dominated coverages of mapped active faults into a national strata were derived from a schist source on coverage at a single scale (1:250,000). This seems Zealandia during maximum submergence. at first glance to be a relatively simple task. However, methods used to capture data, the scale Long‐recognised marine strata from the Maniototo of capture, and the initial purpose of the fault are the Naseby Greensand and Green Valley mapping, has produced datasets that have very Limestone. The basin‐wide greensand is now different characteristics. identified as a composite of units including Whaingaroan? and Duntroonian fossils, and The New Zealand digital active fault database Kokonga‐Green Valley Limestone is Otekaike (AFDB) was initially developed as a way of equivalent. We now detail a ~200 m section at managing active fault locations and fault‐related Swinburn Creek, comprising massive fossiliferous features within a computer‐based spatial marine rocks with a pervasive micaceous, very fine framework. The data contained within the AFDB quartz sand to silt component. The sequence is comes from a wide range of studies, from plate variably (in places richly) glauconitic, grading up to tectonic (1:500,000) to cadastral (1:2,000) scale. muddy limestone capped unconformably by The database was designed to allow capture of basaltic volcanics. Formations include: Wharekuri field observations and remotely sourced data (truncated by the Marshall unconformity), without a loss in data resolution. This approach Kokoamu, and Otekaike. Foraminifera and has worked well as a method for compiling a ostracods date these units as Whaingaroan to centralised database for fault information but not Waitakian; low planktic foraminiferal percentages for providing a complete national coverage at a are consistent with limited oceanic influence. single scale. Uncommon fossil scallops (Pectinidae) in the Janupecten‐Lentipecten lineage are consistent with During the last 15 years other complementary foraminiferal ages. This sequence is thicker, more projects have used and also contributed data to clastic‐dominated, and nearer to sediment source the AFDB, most notably the QMAP project (a (probably Otago Schist) than in the Waitaki. A national series of geological maps completed over nearby stratigraphically lower sequence includes 19 years that include coverage of active and quartzose coal measures, inferred estuarine inactive faults at 1:250,000). AFDB linework and mudstones with rare molluscs, and shales, attributes was incorporated into this series but consistent with a paralic to estuarine setting. No simplification of linework and attributes has dates are available. In summary, the Swinburn occurred to maintain map clarity at 1:250,000 sequence formed in a shallow, possibly early‐ to scale. mid‐Cenozoic epicontinental sea with a productive The main goal of the current project has been to source of terrigenous clastics. There is no firm provide the best digital spatial representation of a evidence of outer shelf settings. fault trace at 1:250,000 scale and combine this with the most up to date attributes. Where

datasets have conflicting line work and/or attributes, data was reviewed through consultation with authors or review of published research to ensure the most to date representation was maintained. The current project aims to provide a coverage that will be consistent between the AFDB and QMAP digital

88 and provide a free download of these data on the underlying low angle detachment faults and lower AFDB website (http://data.gns.cri.nz/af/). and upper crustal basement lithologies. This result strengthens the growing body of evidence for prolonged and widespread reactivation of Cretaceous structures during younger and THE INFLUENCE OF THE MOKIHINUI orthogonal phases of extension associated with METAMORPHIC CORE COMPLEX ON PALEOGENE the Challenger Rift System, while raising questions BASIN EVOLUTION: REACTIVATION OF as to what extent these inherited structures were CRETACEOUS STRUCTURES IN AN EVOLVING reactivated during Miocene and younger STRESS REGIME? transpressional regimes.

1 2 1 N.K. Riordan , R.E. Turnbull , C.M. Reid & K.N. Bassett1 1Department of Geological Sciences, University of TSUNAMI EARLY WARNING FROM EARTHQUAKE Canterbury, PB 4800, Christchurch 8140 RUPTURE DURATION AND DOMINANT PERIOD 2GNS Science, Dunedin Research Centre, Private Bag 1930, Dunedin 9054 J. Ristau1 & Y. Kaneko1 [email protected] 1GNS Science, P O Box 30368, Lower Hutt 5040 [email protected] The influence of mid Cretaceous extensional tectonics and corresponding crustal thinning on An effective early warning system for tsunami at New Zealand’s modern structural setting is local or regional distances requires notification increasingly well understood. However, the within 5 – 15 minutes. New Zealand is surrounded influence of inherited Cretaceous structures on the by a number of potential local and regional intervening Paleogene and Neogene history tsunami sources making a tsunami early warning remains uncertain. Variation within the Oligocene system critical for coastal regions. The method for stratigraphic record overlying the Paparoa identification of potential tsunamigenic Metamorphic Core Complex has been shown to earthquakes presented here uses the first 60 s of coincide with underlying Cretaceous structures, data after the P‐arrival which allows for a rapid however, it remains unclear whether this assessment (~5 – 10 minutes) of the tsunami relationship extends temporally or geographically potential of an earthquake. This method estimates into other parts of the Challenger Rift System. We the apparent rupture duration and dominant present sedimentological and stratigraphic data period of an earthquake. An earthquake with a from Eocene (Rapahoe Group) and Oligocene (Nile long rupture duration and low dominant period is Group) strata that overlie a newly discovered core more likely to be tsunamigenic. A number of large complex, herein named the Mokihinui Core magnitude (M > 7) tsunamigenic and non‐ Complex, along the South Island’s northern West tsunamigenic earthquakes from around the world Coast. In particular, the distribution of the Eocene were tested using local or regional distance data. Courtney Limestone (coralline algae limestone), Included in the dataset are several slow‐rupture Island Sandstone (calcareous quartz sandstone), tsunami earthquakes which generate large and Kaiata Formation (mudstone and muddy tsunamis but have very little high‐frequency sandstone), are shown to coincide with the upper energy, are often not felt strongly, and have low (to the south), lower, and upper (to the north) initial magnitudes (M < 7). We also tested crustal rocks of the core complex respectively. synthetic data for a slow‐rupture tsunami Oligocene lithologies with relatively deep‐water earthquake on the Hikurangi subduction zone, outer platform and slope limestone facies similar to the 1947 Gisborne earthquakes. The (Whitecliffs and Little Wanganui formations) are method reliably triggers on earthquakes which are absent atop lower crustal basement, occurring on known to have generated tsunamis, including upper crustal basement to the north and south. A slow‐rupture tsunami earthquakes, and pronounced increase in thickness is also distinguishes large magnitude earthquakes that recognised from 0‐10’s of metres to 100’s of did not generate a tsunami. The method is based metres for both the Kaiata Formation and Nile on the frequency content of the waveforms and is Group across the newly proposed Grenadier independent of the mechanism, and can be detachment fault. These examples highlight the thought of as analogous to a “smoke detector”. It strong correlation between the composition and provides information on whether the earthquake distribution of overlying Paleogene facies with has frequency content characteristic of a

89 tsunamigenic earthquake, but not whether it three test events suggest that landslide numbers generated a tsunami or how large a tsunami might from an Alpine fault event are likely to exceed be. This method provides a rapid warning for more 40,000 and could be as high as 170,000. Coseismic detailed modelling and, for a local source with a landsliding from Alpine fault events therefore tsunami travel time < 30 minutes, may be the only clearly presents a substantial hazard and further warning available. efforts to understand the effects of this landsliding are required in order to better understand the hazard posed.

MODELLING COSEISMIC LANDSLIDE SUSCEPTIBILITY FROM AN ALPINE FAULT EARTHQUAKE VULNERABILITY OF CRITICAL INFRASTRUCTURE NETWORKS TO COSEISMIC LANDSLIDING FROM T.R. Robinson1, T.R.H. Davies1, T. Kritikos1, T. AN ALPINE FAULT EARTHQUAKE Wilson1, & C. Orchiston2 1 1 1 1Department of Geological Sciences, University of T.R. Robinson , T.R.H. Davies , T. Wilson , and C. 2 Canterbury, Private Bag 4800, Christchurch 8140 Orchiston 1 2University of Otago, Dunedin 9054 Department of Geological Sciences, University of [email protected] Canterbury, Private Bag 4800, Christchurch 8140 2University of Otago, PO Box 56, Dunedin 9054 Recent mountainous earthquakes such as the 1999 [email protected] Chi‐Chi and 2008 Wenchuan events have vividly demonstrated that earthquake hazard in Earthquakes account for 30% of all disaster mountainous environments is not simply the damage costs globally, causing >US$760 billion in strong ground shaking which results. damage since 1900. The majority of building Consequential landsliding can be as, or more damage arises from strong ground shaking, devastating than the initial earthquake. Studies of however damage to critical infrastructure, the effects of previous Alpine fault earthquakes particularly road and utilities networks, is appear to suggest that large earthquakes on this predominantly a function of landslides and fault result in widespread landsliding within the liquefaction. The Alpine fault has been shown to Southern Alps. Estimating this hazard pre‐event is present a substantial landslide hazard during therefore vital for disaster risk reduction and ruptures, with >40,000 landslides expected across 2 preparedness planning. Yet currently modelling a >50,000 km area. Assessing the vulnerability of coseismic landslide susceptibility requires either a road and utilities networks to such landsliding is substantially complete coseismic landslide therefore vital to understand the earthquake inventory from an historic event in the region or hazard as a whole. Using a landslide susceptibility densely spaced, detailed geotechnical data. As map developed from observations of similar neither of these are available for the Southern earthquakes in mountainous terrains we assess Alps, susceptibility modelling has not been the vulnerability of the State Highway and high possible. voltage electrical transmission networks to Alpine fault generated landsliding. The most vulnerable This work therefore utilises complete landslide sections of highway are SH6 between Hokitika and inventories from the 1994 Northridge, 1999 Chi‐ Haast, SH7 (Lewis Pass) between Hanmer Springs Chi, and 2008 Wenchuan earthquakes to and Reefton, and SH73 (Arthurs Pass) east of the statistically model landslide susceptibility from Waimakariri River. In total >230 km of highway has mountainous earthquakes. These events show that a high vulnerability to landslides, resulting in on a regional scale, susceptibility is controlled >20,000 people in West Coast region being predominantly by ground shaking, slope angle and vulnerable to isolation. SH69 and SH7 between position, and distance to faults and streams. Reefton and Greymouth is identified as the most Applying the observations to an M8 Alpine fault critical section of the network, with only limited earthquake yields the first coseismic susceptibility vulnerability to landslides. If this route remains map for such an event. This shows that high functional post‐earthquake, access to ~20,000 susceptibility affects an area >50,000 km2, people in Greymouth, Hokitika, and the Grey predominately focussed on the western rangefront Valley will be possible. The electrical transmission and within the southern Marlborough faults network is shown to be more robust with only 32 system. Observations of landslide densities in the steel pylons in Arthurs Pass demonstrating high

90 vulnerability; the Inter‐Island link has only low First, significant 238U/235U fractionation was vulnerability. Nevertheless, loss of wooden‐pole observed in the water column of the Black Sea, supported sections south of Hokitika could render suggesting the reduction of U induces 238U/235U >20,000 people without power until repairs can be fractionation. Second, the 238U/235U of underlying completed. Mitigation methods to reduce the sediments is related to the water column through vulnerability to both networks are therefore likely the isotope fractionation factor of the reduction to substantially reduce the impacts of a future reaction but is influenced by mass transport Alpine fault earthquake. processes. These results provide important constraints on the use of 238U/235U as a proxy of the redox state of ancient oceans.

TRACING ANOXIC CONDITIONS IN THE OCEANS USING FRACTIONATION OF 238U/235U

1 1 1 MAFIC‐FELSIC INTERACTIONS IN THE ORUANUI J.M. Rolison , C.H. Stirling , R. Middag , M.J.A. SUPERERUPTION: INSIGHTS INTO PRE‐ AND SYN‐ Rijkenberg2, & H.J.W. de Baar2 1 ERUPTIVE PROCESSES AND MAGMA CHAMBER Department of Chemistry, University of Otago, P DYNAMICS O Box 56, Dunedin 9054 2 Royal Netherlands Institute for Sea Research S.M. Rooyakkers1, C.J.N. Wilson1 & C.I. Schipper1 (Royal NIOZ), P O Box 59, Texel, The Netherlands. 1SGEES, Victoria University of Wellington, PO Box [email protected] 600, Wellington 6140 [email protected] Tracking the history of free oxygen in Earth’s atmosphere is of vital importance to In silicic volcanic systems, mafic magmas are understanding the evolution of life on Earth. parental to rhyolites, and provide heat and Transitions from reducing to oxygenated volatiles that can drive magma chamber processes conditions in the ancient ocean‐atmosphere and trigger eruptions. Owing to their higher system can be inferred from elemental density, these magmas rarely reach the surface in abundances of redox‐sensitive metals (e.g. Fe, Mo, rhyolite‐dominated volcanic centres, although Cr, U, V) in reducing organic‐rich marine occasionally may be erupted as a minor sediments. However, local depositional processes, component. The chemistry, mineral assemblages such as variable mass accumulation rates, can and textures of any mafic material evacuated significantly impact the observed relative during large silicic eruptions hold valuable enrichments of redox‐sensitive metals, thereby information on processes and interactions hindering an accurate interpretation of the occurring within the magma body during and sedimentary record of the redox state of ancient immediately prior to such an eruption. These oceans. The isotopic compositions of redox‐ processes are investigated in this MSc thesis work sensitive metals, including uranium (U), in marine by examining and documenting textural sediments have recently emerged as powerful relationships and mineral and glass chemistry in diagnostic tracers of the redox state of the ancient juvenile mafic clasts (52‐63% SiO2) from the 25.4 ocean‐atmosphere system. Interpretation of ka Oruanui supereruption (c. 530 km3 magma) of sedimentary isotopic information requires a Taupo volcano. thorough understating of the environmental controls on isotopic fractionation in modern anoxic The groundmass of the Oruanui juvenile mafic environments before being applied to the paleo‐ clasts consists of framework of acicular plagioclase record. In this study, the relationship between and amphibole microlites, with interstitial rhyolitic ocean anoxia and the isotopic fractionation of U glass. The disequilibrium groundmass textures, was investigated in the water column and including hopper and swallowtail plagioclase, and sediments of the Black Sea. The Black Sea is the stellate clusters of amphibole, are characteristic of world’s largest anoxic basin and significant rapid diffusion‐controlled crystallization at high removal of U from the water column and high U undercooling. This indicates the mafic magma was accumulation rates in modern underlying chilled upon injection into the host rhyolite. sediments has been documented. Removal of U Thermal modelling of cooling rates will be used in from the water column occurs during the redox conjunction with BSE imagery, x‐ray tomography 6+ 4+ transition of soluble U to relatively insoluble U . and electron microprobe analyses of microlites in The primary results of this study are two‐fold. order to quantify how the quench crystallization

91 process is manifest in the textures and mineral lavas and ignimbrites has revealed that rhyolitic chemistry of the mafic clasts. Textures will be volcanism occurred at WK‐TH just prior to ~ 0.9 compared and contrasted with pre‐existing Ma, and was dominant in the same area after experimental work, in order to aid quantitative ~0.35 Ma. However, stratigraphy and dating reveal interpretation of the conditions under which they an apparent >500 ka lapse in volcanic activity or formed. local deposition between those episodes.

Preliminary results highlight a spectrum of textural The ages of pyroclastic strata from the Tauhara types, ranging from fine‐grained and glassy to (south‐eastern) area make it clear that a relatively coarse with abundant stellate clusters of substantial volume of Whakamaru group acicular amphibole. This diversity indicates ignimbrite was emplaced into and then eroded crystallization occurred over a range of conditions from the southern TRB between ~0.35 and 0.31 and timescales. Further work will focus on Ma, and then after ~0.31 Ma, replaced with as constraining the conditions under which these much as 2.5 km thickness of tuffs and sediments. different textural groups crystallised, and the processes responsible for this diversity. These ages help constrain the timing of broader scale developments of the TRB, including fault formation/reactivation, which were also likely to have been major influences on hydrological VOLCANO‐TECTONIC EVOLUTION OF THE evolution of the system. These ages provide an WAIRAKEI‐TAUHARA GEOTHERMAL SYSTEM: important contribution to understanding the INSIGHTS FROM U‐PB DATING OF ZIRCONS structure and subsidence of the Whakamaru caldera, and evolution of the Taupo‐Reporoa Basin 1,2 1 2 M.D. Rosenberg , C.J.N. Wilson , G. Bignall , S.A. and the eastern side of central TVZ. Alcaraz2, F. Sepulveda3 & T.R. Ireland4 1SGEES, Victoria University, PO Box 600, Wellington 6140 2GNS Science, Wairakei Research Centre, PB 2000, INSIGHTS INTO GLACIATIONS AT THE AUCKLAND Taupo 3352 ISLANDS 3Contact Energy Ltd, Wairakei Power Station, PB B. Ross1, A.R. Gorman1 & G.S. Wilson1 2001, Taupo 3352 1 4RSES, The Australian National University, University of Otago, Department of Geology, PO Canberra, ACT 0200, Australia Box 56, Dunedin 9054 [email protected] [email protected]

The combined fields of Wairakei and Tauhara (WK‐ The Southern Ocean south of New Zealand hosts TH) make up one of the largest geothermal small and isolated groups of volcanic islands that systems in the Taupo Volcanic Zone (TVZ). In a protrude above New Zealand's continental shelf. The largest of these are the Auckland Islands, volcanic‐structural context, the WK‐TH system is 2 located in the Taupo‐Reporoa Basin (TRB) across a which have an area of approximately 500 km region of narrow horst‐graben structures defined (above sea level). The larger size of the Auckland by predominantly NE‐striking faults of the active Islands has implications for the environmental Taupo Rift. The system also lies within the conditions on the land and in the neighbouring Whakamaru caldera near its south‐eastern margin. seas. In particular, the prevailing westerly winds are much less harsh on the eastern side of the New U‐Pb ages and volcanic and sedimentary island, making this relatively sheltered position stratigraphy refined from >200 geothermal wells ideal for harbouring glaciers during Quaternary up to 3 km deep, are combined to reveal focussed glaciations. Evidence of this glaciation is observed episodes of volcanism from ~ 310 ka to ~120 ka. in the U‐shaped valleys and fjords that dominate The ages conform to stratigraphic order and the the topography of the islands. The regular volcanic extrusions (each ~0.1 km3 to ~7 km3) occur in a geology and limited sediment sources of the spatial cluster in the uppermost ~1.5 km of strata Auckland Islands facilitates the preservation of a beneath the Wairakei (north‐western) area. sub‐Antarctic climatic history in the sediments of present‐day fjords and their ancient offshore U‐Pb dating (by SHRIMP‐RG ion microprobe) of equivalents. What makes the Auckland Islands magmatic zircons from hydrothermally altered special is their larger landmass, which serves to

92 maintain not only a climatic history in the Along with the locations of landslides, the sedimentary record but also preserve the powerful Landslide Database contains information on the and dramatic effects of erosion; be that erosion timing of landslide events, the type of landslide sub‐aerial, sub‐marine or glacial. movement, the triggering event, volume and area data, and damage consequences for each landslide 402 km of 2D seismic data collected on the where this information is available. Landslide data leeward (eastern) shelf of Auckland Island in early has been collected and summarised from a variety 2014 reveal numerous deep in‐filled valleys of sources including aerial photograph beneath a relatively flat seabed. The deepest of interpretation, field reconnaissance and media these valleys has a maximum depth of 130 m accounts. There are currently over 28,000 below modern sea level. 3D interpretations of landslide records in the database. Future work will these valleys have been undertaken and sediment involve the development of automated data thicknesses have been mapped. upload routines and mobile applications to allow the public to report a landslide. Preliminary data shows that the southern portion of the island has deeper, steeper and longer fjords, whereas the northern portion has flatter and less dramatic paleo‐valley topography. The data USING X‐RAY DIFFRACTION TO DETERMINE provide new information on the extent of the VOLCANIC ERUPTION STYLES ON EARTH AND glaciations that occurred at the Auckland Islands MARS and enable the assessment of interactions between glaciers, the climate and ocean M. C. Rowe1, K. T. Wall2, B. S. Ellis3, M. Schmidt4, conditions. J. D. Eccles1, S. Cammell1, Y. Heled1, & E. Hutchinson1 1School of Environment, University of Auckland, Private Bag 92091, Auckland 1142 DEVELOPMENT OF A NATIONAL LANDSLIDE 2Washington State University, School of the DATABASE FOR NEW ZEALAND Environment, Pullman, WA 99164, USA 3Institute fur Geochemistry and Petrology, ETH B.Rosser1, G.D. Dellow1, P.J. Glassey2 & S. 1 Zurich, 8092 Zurich, Switzerland Haubrook 4Department of Earth Sciences, Brock University, 1GNS Science, PO Box 30368, Lower Hutt 5040 2 Saint Catharines, Ontario, Canada LS2 3A1 GNS Science, Private Bag 1930, Dunedin 9054 [email protected] [email protected] Explosive basaltic volcanism is common to both A national landslide database is being developed Earth and Mars. Phreatomagmatic eruptions and as a repository for all New Zealand landslide data. “magmatic” explosive eruptions, such as The spatial database is being developed using strombolian or plinian eruptions, have distinctive open‐source software (PostGIS). The database is eruptive processes resulting in varied groundmass being used for landslide hazard and risk textures. Here we demonstrate that groundmass assessment and as a tool to develop a probabilistic crystallinity determined by X‐ray diffraction can landslide hazard model for New Zealand. distinguish broadly defined eruption styles. Crystallinity, determined from X‐ray diffraction is A unified landslide data model has been developed advantageous because it 1) is a true measure of to enable the New Zealand landslide database to crystalline and amorphous components, 2) can be be a repository for potentially all New Zealand determined remotely, and 3) is measured rapidly landslide data. The new database incorporates on small volumes of material. Terrestrial results data from existing databases that were developed on end‐member eruption styles suggest rapid and populated for different purposes. Therefore, quenching of phreatomagmatic volcanic products the national database presented here contains by ground/surface water results in lower landslide data with a variety of scales, accuracy groundmass crystallinity compared to air‐cooled and attributes. The national database is also volcanic ejecta characteristic of strombolian or designed for future data collection on an on‐going plinian eruptions. Based on numerical modelling basis. of Martial plinian eruptions, the distinction between eruptive styles on Mars are reduced compared to Earth with only 20‐30% syn‐eruptive

93 crystallization. Applying the technique developed and then extrapolated through time to the present on terrestrial volcanics, the crystallinity of Martian or near future. sediments analysed from Gale Crater by the CheMin tool on the Mars Science Laboratory rover For model selection, a predictive density can be are consistent with a strombolian or plinian used to assess how well a model forecasts eruptive origin and may imply widespread subsequent eruptions as it evolves through time, dispersal of volcanic ejecta across the surface of allowing some of the parameters of each model Mars. under consideration to vary as an eruption occurs, whilst keeping the baseline model constant. Here, Preliminary results from the Auckland Volcanic we develop this idea and extrapolate three well‐ Field, which demonstrate a “drying out” of established spatio‐temporal models far into the volcanism, or a transition from phreatomagmatism future via numerous simulations to assess whether to strombolian style eruptions, have minimal the cumulative future behaviour of a volcanic distinction in crystallinity between eruption styles. system based on each model is geologically Juvenile magmatic clasts from early plausible or consistent with observations phreatomagmatic events have anomalously high elsewhere. groundmass crystallinities and may imply distinctive eruption dynamics prior to cooling or quenching of volcanic groundmass. Deep degassing may promote early groundmass GROSS DEPOSITIONAL ENVIRONMENT MAPS AND nucleation and crystallization prior to rapid RISK ANALYSIS FROM THE MID CRETACEOUS TO quenching, or ground/surface water may be PALEOCENE SECTION IN THE GREAT SOUTH BASIN insufficient to fully quench volcanic clasts, allowing further crystallization during slower air‐cooling in T. R. Sahoo volcanic systems experiencing “drying out”. GNS Science, PO Box 30368, Lower Hutt 5040 [email protected]

The distribution of petroleum system elements, EXTRAPOLATING SPATIO‐TEMPORAL MODELS such as source, reservoir and seal rocks, provides THROUGH TIME key inputs to understand basin prospectivity. Gross Depositional Environment (GDE) maps M.G. Runge1, M.S. Bebbington2, S.J. Cronin2 & typically include these elements. The main aim of J.M. Lindsay1 this study is to develop a series of updated GDE 1School of Environment, University of Auckland, and common risk segment (CRS) maps in the Private Bag 92019, Auckland 1142 offshore Great South Basin for the mid Cretaceous 2Volcanic Risk Solutions, Massey University, Private to Paleocene section. Bag 11222, Palmerston North 4442 [email protected] GDE maps are prepared based on the seismic character of reflection packages, isochron maps, The field of probabilistic volcanic hazard analysis is lithology observed in wells, wireline logs, rapidly expanding via the development of a range paleoenvironments, and biostratigraphic analysis. of statistical methods, many that include novel Source rocks identified in offshore wells in the approaches to incorporate geological information. basin are mainly marginal marine coals and coaly There is now a large number of potential methods mudstones within the Cretaceous interval. In the available to the hazard modeller and thus, a large syn‐rift sequences these source rocks are number of potential ‘answers’. Model selection is distributed throughout the basin whereas in the dependent on the information required (model post‐rift sequences they are restricted to the outputs), data availability (model inputs), any western margin of the basin. Within the Paleocene assumptions about the physics or chemistry of the section, Waipawa (Tartan) Formation shows high volcanic behaviour, and the goodness of fit to the organic carbon contents with very good potential observed data. For volcanic fields, information as for petroleum generation (Schiøler et al., 2009). to the likely location(s) and timing(s) of future Waipawa Formation displays a high amplitude and eruption(s) are frequently required for hazard and highly continuous seismic reflector character and risk assessments. To obtain this information, a is widely distributed in the basin. Potential spatio‐temporal model can be fitted to the reservoir rocks occur in a wide range of locations and timings of previous eruptive activity depositional environments. Cretaceous reservoirs

94 are mainly fluvial, coastal, shoreface, and shelfal modelling, preparation of virtual endocasts for sandstones. In addition to the above reservoir play comparative neuroanatomy, biomechanical types, the Paleocene submarine fan complexes analyses of bones and Finite Element Analysis that are recognised from the seismic character can (FEA), and skeletal and dental microanatomical act as potential reservoirs. Seal rocks are mainly research. shelfal and deepwater mudstones. Shelfal mudstones are developed in the Late Cretaceous and Paleocene section whereas deepwater mudstones are typically developed in the THE LITHOSPHERIC MANTLE BENEATH ZEALANDIA Paleocene section. AND ITS ROLE IN HIMU‐LIKE INTRAPLATE MAGMATISM

These GDE maps provide the main inputs for 1 1 2 1 preparing common risk segment (CRS) maps of J.M. Scott , M. Brenna , T.E. Waight , J.M. Palin , Q.H.A. Van der Meer2, A.F. Cooper1 & C. Münker3 source, reservoir, and seal rocks presence. These 1 maps show areas of high, medium and low risk for Department of Geology, University of Otago, PO Box 56, Dunedin 9054 each element, and are requisite in evaluating basin 2 prospectivity and play fairway analysis. Department of Geosciences and Natural Resource Management, Copenhagen University, Denmark 3Department of Geology and Mineralogy, A BRAVE NEW WORLD? THE USE OF COMPUTED University of Köln, Zülpicher Str. 49a, 50674 TOMOGRAPHY IN VERTEBRATE PALEONTOLOGY Köln, Germany [email protected] R.P. Scofield Canterbury Museum, Rolleston Ave, Christchurch There has been long debate on the asthenospheric 8130 versus lithospheric source for numerous intraplate [email protected] basalts with ocean island basalt (OIB) and high time‐integrated U/Pb (HIMU)‐like source Over the past 30 years, Computed tomography signatures that have erupted through the (CT) technology has progressed to reduce the Zealandia continental crust for the last 90 Ma. scanning speed, to improve the imaging Analysis of over 200 spinel facies peridotitic resolution, to simplify the overall operation, and to mantle xenoliths from localities across southern increase scanning resolution. Since the first fossil Zealandia permits the first comprehensive regional hominids were scanned in 1984 this technology description of the sub‐continental lithospheric has become increasingly common but only in the mantle (SCLM) and insights into whether it could last 2‐3 years, with increases in computing power be a source to the intraplate basalts. Intraplate and the availability of comparatively cheap basalts have sampled refractory craton‐like imaging software, have palaeontologists taken domains (West Otago, Westland, Chatham Islands) control of the imaging themselves. Because of the and moderately fertile domains (East Otago, North destructive processes that occur during Otago, Auckland Islands). Most domains have an fossilization, vertebrate fossils are usually early history decoupled from the overlying fragmented, distorted, and filled with heavily continental crust, and each domain has undergone calcified matrix when they are unearthed from varying degrees of depletion followed by re‐ sediments. Traditional preparation involves enrichment. Clinopyroxene grains reveal trace physically separating the fossil from the element characteristics (low Ti/Eu, high Th/U, high surrounding matrix and then repairing the missing LREE) consistent with enrichment through reaction parts with plaster or silica. Mechanical preparation with carbonatite. This metasomatic overprint has a and reconstruction is a highly invasive and composition that closely matches the HIMU potentially destructive process that is often mantle reservoir in terms of Sr, Pb and Nd isotopes irreversible; it is also highly subjective and [1,2]. Clinopyroxene Hf isotopes in most samples dependent upon the skills of the preparator. are more radiogenic than the intraplate basalts. Virtual CT preparation is reversible, repeatable and However, new Hf isotope analyses of the most can create files that allow 3D models to be highly depleted and strongly metasomatised produced for any future researcher anywhere else samples overlap with those of the intraplate in the world. Here I will talk about the use of CT to basalts. Batch melting models of highly depleted undertake virtual fossil reconstruction, 3D spinel facies peridotite enriched by carbonatite

95 can generate LREE‐enriched melts with trace and have the potential to act as fluid conduits that element profiles very similar to ocean island impact seal integrity in New Zealand petroleum basalt. The melting models do not require residual systems. Bulk permeability of PFSs is believed to garnet to generate the high LREE to low HREE increase with depth and to be highest at fault patterns observed in the Zealandia and other triple junctions, where the tendency for dilation is worldwide intraplate basalts. This would challenge greatest and, in some systems, there is evidence the current paradigm that attributes the intraplate for enhanced vertical fluid flow. magmatism to an asthenospheric source. [1] Cartwright (2011). Marine and Petroleum [1] Scott et al. (2014a) Contrib. Mineral. Petrol. Geology 28, 1593‐1610. 167, 963. [2] Scott et al. (2014b) Geochem. Geophys. Geosyst 15. MILANKOVITCH IN MUD: TESTING THE INFLUENCE OF ORBITAL FORCING ON GLOBAL

SEA‐LEVEL CHANGE USING A LATE PLIOCENE MARINE SEDIMENTARY RECORD FROM THE POLYGONAL FAULT SYSTEMS AND THEIR WANGANUI BASIN, NEW ZEALAND POTENTIAL IMPACT ON SEAL INTEGRITY J. Sefton1,2, T. Naish1, R. McKay1, G. Turner3, D. H. Seebeck1, A. Nicol1, T. Sahoo1, E. Tenthorey2 Seward2, B. Alloway2 & H. Morgans4 1GNS Science, PO Box 30368, Lower Hutt 5040 1Antarctic Research Centre, Victoria University of 2Geoscience Australia, GPO Box 378, Canberra ACT Wellington 6140 2601, Australia 2SGEES, Victoria University of Wellington, PO Box [email protected] 600, Wellington 6140 3 Polygonal fault systems (PFSs) are networks of School of Chemical and Physical Sciences, Victoria University of Wellington 6140 non‐tectonic normal faults that form in 4 hemipelagic sediments. They have been identified GNS Science, PO Box 30368, Lower Hutt 5040 in many sedimentary basins worldwide [1], [email protected] including Tertiary strata of the Taranaki, Milankovitch Theory directly links the waxing and Northland, Great South and Canterbury basins in waning of ice sheets to orbitally‐forced insolation New Zealand. In seismic section polygonal faults changes and suggests that variance in precession form layer‐bound arrays that extend vertically for (23 kyr) and obliquity (41 kyr) cycles should drive 100s of metres and accommodate small (< 100 m) ice volume changes. However, the globally‐ normal displacements. Many PFSs are tiered in integrated record of marine oxygen isotopes (δ18O) cross section and comprise segmented fault arrays during the Late Pliocene (3‐2.6 Ma) consists of that increase in degree of linkage, length and obliquity dominated signals, with an absence of displacement with depth. Fault maps constructed precession. Continuous, high resolution records using 3D seismic reflection data reveal polygonal can help assess whether ice sheets in the Late cells with maximum dimensions of several Pliocene responded to precession, obliquity or kilometres, which are defined by faults with no both. preferred strike or dip direction and many high‐ angle fault intersections or triple junctions. These Shallow‐marine sediment records are independent fault geometries are generally considered to of the δ18O record, and enable us to reconstruct develop in association with the dewatering and the frequency of Late Pliocene glacial‐interglacial compaction of mudstones. On individual variability via its effect on global sea‐level stratigraphic horizons fault displacement patterns recorded as cyclical water depth changes. The and cross‐cutting field relations indicate that faults Wanganui Basin, New Zealand, contains a high‐ forming high‐angle intersections slip resolution and well‐dated Neogene shallow‐ simultaneously with no dominant extension marine sedimentary succession. Consequently, this direction. Systematic up‐dip displacement basin is the perfect location to examine sea‐ variations in PFSs are similar to those of tectonic level/ice‐volume change. We aim to evaluate the faults and suggest that fault segments in different frequency and magnitude of Late Pliocene sea‐ tiers develop synchronously as kinematically level changes in the Mangaweka Mudstone (~3‐2.5 coherent arrays. Polygonal faults form slowly over Ma), where it is exposed between the Turakina timescales of millions to tens of millions of years

96 and Rangitikei Rivers. This will be achieved through and (b) the vertical and angular pressure an integrated analysis of sediment grain size, a distributions and the forces on the CS. The quantitative census of benthic foraminifera (both Influence of structure flexibility was investigated proxies for paleo‐water depth) and oxygen using four different types of the SPSs. Scouring isotopes (a proxy for ice volume). around the SPS and the CS was observed for different bore heights and velocities, using two Preliminary results show zircon fission track ages high‐definition video cameras positioned inside of tephra at 2.9±0.3 Ma, and the Gauss‐Matuyama the structures. Also, the impact of the tsunami paleomagnetic reversal at 2.58 Ma, which form the bore on elevated structures was observed using basis of an age model. Correlation of tephra the SPS, at elevations of 50mm, 70mm and 90mm geochemistry and paleomagnetic data within a above the flume floor. In addition to the bore regionally‐established chronostratigraphic impact on structures, the collision forces framework will place this record within the context associated with tsunami‐borne debris impact were of other records such as ODP 1123. It is anticipated investigated using a new measurement technique, that water‐depth changes corresponding to 23 kyr, utilising a smart debris device. The smart debris 41 kyr and/or 100 kyr orbital drivers of global ice device is an object with an attached impact volume will be resolved in the Late Pliocene record accelerometer, allowing direct measurement of and will provide insights into whether northern the impact acceleration and subsequently impact and southern hemisphere ice sheet responses to force. Milankovitch cycles are anti‐phased, synchronous or both.

3D INVERSION OF SHEAR WAVE SPLITTING FOR MODELLING ANISOTROPY IN CANTERBURY TSUNAMI RESEARCH AT THE UNIVERSITY OF AUCKLAND A. Shelley1 & M.K. Savage1 1SGEES, Victoria University of Wellington, PO Box S.R. Shafiei1, B.W. Melville1 & A.Y. Shamseldin1 600, Wellington 6140 1The University of Auckland, P O Box 92019, [email protected] Auckland 1142 [email protected] In order to understand the distribution and possible cause of elastic anisotropy (expressed as a The University of Auckland (UoA) is actively directional seismic velocity dependence) in the involved in research associated with tsunami crust, we have developed an inversion method impacts on inland‐structures. The research effort that produces 3D anisotropic models using shear is directed towards improving knowledge about wave splitting data. The method iteratively design of tsunami resilient structures. The employs a linearised least squares inversion hydraulic laboratory at the UoA is fully equipped technique, solving for the magnitude and to conduct experimental studies on the impact of a orientation of anisotropy for each element of a tsunami bore on structures, accompanying three‐dimensional model grid (where data is scouring around the structures, and impact of available). Love parameters and available velocity tsunami‐borne debris. The experiments are carried models are used to define an anisotropic elastic out in a 14m long, 1.2m wide and 0.8m deep large regime for each model elements, however any wave flume; the flume is connected to an 11m appropriate formulation of the elastic tensor can long, 7.3m wide and 0.6m deep reservoir with an be applied. We apply this method to a shear‐wave automatic gate across the full flume width. The splitting dataset of events from the aftershock gate consists of a sliding gate and a shutter gate, sequence of the 2011 Mw 7.1 Darfield Earthquake. allowing rapid release of water into the flume to The dataset covers a broad volume of the generate the tsunami bore. Canterbury region encompassing the Greendale fault group. We compare results from a number of Experiments have been successfully conducted to different starting models including an average investigate the fully‐developed bore impact on a starting model that takes into account ray square prism structure (SPS) and a cylindrical propagation direction, a uniform starting model structure (CS). The objectives were to investigate that represents regional maximum compressive (a) the vertical pressure distribution and the forces stress, and a model that uses previous calculated on the SPS for different orientations to the flow 2D delay time tomography results as an input. Our

97 results show a broad lateral heterogeneity in mid‐Waipara and Hampden sections [3]. We anisotropy for the region with areas of anisotropy examine how calcareous nannofossil assemblages that are orientated sub‐parallel to the regional change across the EECO, both in comparison with stress direction, indicating that the anisotropy is SST and with dinoflagellate cyst assemblages, and generally stress controlled. Other areas show we discuss how this event affected composition of anisotropy orientations that are rotated E‐W marine plankton communities and marine which may be attributed to fault controlled productivity in Canterbury Basin. anisotropy. [1] Bopp et al., (2005). Geophysical Research Letters 23, 1‐4. [2] Cermeño et al., (2008). PNAS 105, 20344‐ THE IMPACT OF GLOBAL WARMING ON 20349. CALCAREOUS NANNOFOSSILS: AN EOCENE CASE [3] Hollis et al., (2012) Earth and Planetary Science STUDY FROM CANTERBURY BASIN, NEW Letters 349‐350, 53‐66. ZEALAND

C.L. Shepherd1,2, D.K. Kulhanek3, E.M. Crouch2 & 2 C.J. Hollis SEISMIC DATA ANALYSIS ON WAYS TO MONITOR 1 SGEES, Victoria University of Wellington, PO Box ROCK‐CO2 REACTIONS AND FLUID SUBSTITUTION 600, Wellington 6140 IN SANDSTONES, POHOKURA FIELD, NEW 2 GNS Science, PO Box 30368, Lower Hutt 5040 ZEALAND 3Integrated Ocean Drilling Program, Texas A&M University, College Station, Texas, USA C. Y. Sim1, L. Adam1 & I. Pecher1 [email protected] 1School of Environment, University of Auckland, Private Bag 92019, Auckland 1142 The impact of global warming on the oceans is an [email protected] important issue for a maritime nation like New Zealand. Changes in ocean temperature and In recent years, geosequestration of circulation will affect nutrient availability, food anthropogenic carbon dioxide (CO2) into a changes and the composition of the marine biota. depleting oil reservoir, has become an increasingly Coccolithophores (calcareous nannoplankton) are popular process to store CO2 waste without important primary producers in the ocean that leakage for at least 1000 years. Geophysical play a fundamental role in the global carbon cycle. seismic methods are used to monitor subsurface Recent modelling studies predict that under variations in fluid pressure and saturation when warmer climates, ocean waters will become more CO2 is injected in a reservoir, as seismic wave stratified, leading to a reduction in nutrients in the velocities are highly sensitive to these changes. eutrophic zone. Under this scenario However, in the presence of CO2‐water mixtures coccolithophores become more abundant than (carbonic acid), besides saturations and pressures diatoms, resulting in a reduced efficiency of the change, the rock microstructure also alters due to biological pump and possible positive feedbacks in rock‐fluid reactions such as the dissolution of the carbon cycle [1, 2]. It is therefore important to carbonate minerals caused by carbonic acid. In this verify these modelling studies by examining how study, we first look at the effect of fluid climate change affects the productivity and substitution of water for CO2 alone has on wave assemblage composition of coccolithophores. speed. Secondly, we study how the sandstone’s carbonate cement dissolution changes the seismic One of the ways that this can be achieved is to velocities. As both fluid substitution and study global warming events that occurred during dissolution of carbonate cement decrease wave the geological past. Our study examines calcareous velocities, due to fluid compressibility and rock nannofossil assemblages from two Canterbury microstructure differences respectively, our goal is Basin sections spanning early to middle Eocene. Of to quantify these geophysical changes particular interest during this interval is the Early independently and combined. Up to now, how Eocene Climatic Optimum (EECO, ~50 Ma), a rock‐fluid reactions affect wave velocities and the warming event where global temperatures feasibility to monitor these with time‐lapse seismic increased by almost 5°C above background. interpretations is still unknown. Geochemical proxies for sea surface temperature (SST) have been used to identify the EECO in the

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The Pohokura Gas‐Condensate Field in New USING PALEOECOLOGICAL PROXIES TO Zealand is selected because the Mangahewa DETERMINE HOLOCENE formation sandstones have a variable range of ENVIRONMENTAL CHANGES: A CASE carbonate cement from less than 1% to up to 30%. STUDY AT ONAERO BEACH, NORTH Porosities range from 2 % to 12 % (with an average TARANAKI of 9%). We plan to use the suite of sonic logs, XRD 1 1 1 data and petrophysical analysis available at R. Skudder , R. Newnham & B. Alloway Pohokura Field for detailed characterization of the 1 SGEES, Victoria University of Wellington, PO Box reservoir rocks, where resulting rock physics 600, Wellington 6140 models can be used to generate 1D synthetic [email protected] seismogram and reflection coefficient models (AVO), in order to help better understand the A multi‐proxy paleoecological and effects on the seismic signatures in the Pohokura sedimentological record for the Holocene is Field when it is subjected to a CO2 sequestration extracted from a 2.5m coastal seacliff located at scenario. Onaero Beach, North Taranaki and used to infer changes in shoreline and coastal conditions. The tectonic, and especially postglacial, history of the North Taranaki coast is reviewed followed GLACIAL RAINFALL RECONSTRUCTION USING by analysis of diatom and pollen populations, TROPICAL SOUTH PACIFIC SPELEOTHEMS particle size, and loss on ignition. Paleoecological and sedimentological data will D. Sinclair be tied to a chronology determined through SGEES, Victoria University of Wellington, PO Box radiocarbon ages and tephrochronology. A 600, Wellington 6140 number of key tephras have already been [email protected] identified, tying the Onaero Beach seacliff to the Holocene. Key objectives of this study are: The South Pacific Convergence Zone (SPCZ) is the (1) To characterize changes in the relative largest component of the Intertropical position of the shoreline at Onaero Beach Convergence Zone (ITCZ), and its impact on global during the Holocene and, (2) Analyse results in climate rivals that of the deep convection at the the context of eustatic sea level change and the heart of the Western Pacific Warm Pool. Rapid tectonic history of North Taranaki. glacial climate fluctuations, such as Dansgaard‐ Carbonaceous sediments abundant in pollen Oeschger (D‐O) Events, would have triggered a record early Holocene vegetation changes after reorganization of tropical systems such as the which a transition into estuarine muds, SPCZ, manifesting as significantly altered rainfall abundant in diatoms, around the mid‐Holocene across the tropical south Pacific. However, a shows small changes between predominantly critical lack of high‐resolution glacial records from fresh and brackish water environments. this region means the dynamics of the SPCZ are largely unknown.

Recently, speleothems have proven to be effective GEOCHEMICAL VARIATIONS IN GLAUCONITIC recorders of tropical hydroclimate over the last MINERALS: APPLICATIONS AS A POTASSIUM several hundred thousand years. Stable oxygen FERTILISER RESOURCE isotopes ( 18O) and trace elements (Mg, Sr) respond to changing rainfall, while modern high‐ J. Smaill1, M.J Palin2, C. Oze1 & C.M Reid1 precision mass spectrometers allow U/Th dating of 1Department of Geological Sciences, University of speleothem calcite to an unprecedented precision. Canterbury, Private Bag 4800, Christchurch 8140 Speleothems are therefore ideal archives for 2 Department of Geology, University of Otago, PO studying glacial changes to atmospheric circulation systems such as the SPCZ. Box 56, Dunedin 9054 [email protected] In this poster, I present details of, and preliminary results from, an ongoing NSF/VUW funded Glauconitic clays display significant variation in research programme aimed at studying the glacial geochemical signatures, both structurally and in dynamics of the SPCZ using speleothems collected terms of their elemental proportions. The from the islands of Niue and Tonga. maturity of the green marine minerals is

99 influenced primarily by seafloor residence time, through time. But perhaps the most important role the parent materials’ physical properties and of the LAB is to facilitate plate tectonics by forming local chemical conditions on the seafloor. Here a low stress base to the tectonic plates. we use spatially resolved geochemical techniques including LA‐ICP‐MS and SEM with EDS to assess A serendipitous outcome from the SAHKE active‐ the geochemical variation of glauconite in three source seismic experiment across the lower North field areas: the Oamaru Basin; the Mid‐Waipara Island was the recording of very deep reflections section, North Canterbury; and the Oparara from the LAB. Here we deployed 887 seismographs Quarry, Karamea. Potassium contents are along a 85 km‐long line from coast to coast. 12 x consistently high, representing evolved to highly 500 kg dynamite shots were used as seismic evolved glauconite. Significant variations in trace sources. Although the main aim was imaging the elements exist between deposits and this subduction zone interface at about 7‐10 seconds appears to be related to the genetics of the (25 km‐deep), reflections between 25–35s (95‐120 proximal continental rocks. Concentrations of km‐deep) were also recorded. These deeper chromium, a known carcinogen, are consistently reflections define a ~ 10 km‐thick channel that dips high in all deposits (average 270 ppm). We also parallel to the top of the plate (i.e. ~ 12‐15 degrees measured the dissolution kinetics of glauconite in to west) and at a depth of 95‐105 km. We water using ICP‐MS. Potassium is released from interpret this channel as a low‐viscosity, low‐ glauconite, however the low concentrations in seismic‐velocity channel created by the ponding, solution and the potential to contaminate soil then strain localisation, of melt and/ or volatiles. through the addition of toxic trace elements raises questions regarding the application of glauconite as a standalone fertiliser resource. CONSTRUCTION OF SURTSEYAN VOLCANOES AT CAPE YOUNG AND MAUNGANUI BLUFF,

NORTHERN CHATHAM ISLAND

THE LITHOSPHERE‐ASTHENOSPHERE BOUNDARY 1 1 2 R.B. Stewart , K. Németh & Z. Pécskay (THE LAB): WHY IT’S IMPORTANT, AND IMAGING 1 Volcanic Risk Solutions, Massey University, Private IT BENEATH NZ WITH SEISMIC METHODS Bag 11222, Palmerston North 4442 2 T.A. Stern1, S.H. Henrys2, D.A. Okaya3, M.K. Institute of Nuclear Research of the Hungarian Savage1, H. Sato4, R. Sutherland1,2, T. Iwasaki4 & J. Academy of Sciences (ATOMKI), Debrecen, Louie5 Hungary 1Institute of Geophysics, SGEES, Victoria University [email protected] of Wellington, PO Box 600, Wellington 6140 Chatham Island is a rare subaerial part of 2GNS Science, PO Box 30368, Lower Hutt 5040 Zealandia 700 km to the east of New Zealand and 3Department of Earth Sciences, University of has been the locus of basaltic intraplate volcanism. Southern California, Los Angeles, CA 90210, USA Three major episodes of volcanism identified are a 4Department of Earth Sciences, Tokyo University, late Cretaceous (81‐70 Ma) shield volcano, late Tokyo, 12345, Japan Eocene (41‐36 Ma) Southern Volcanics, Red Bluff 5Seismological Observatory, University of Nevada, Tuff and Northern Volcanics, and Miocene – Reno, NA 90210, USA Pliocene (4 ‐ 5 Ma) Rangitihi Volcanics and [email protected] Rangiauria Breccia. We have recently completed a The LAB is the most pervasive, and arguably the radiometric dating field campaign in the northern most important, boundary within the Earth. It part of Chatham Island which included two separates the elastic crust and the cooled upper volcanic “centres”, Cape Young and Maunganui mantle lid (together called the lithosphere) from Bluff. The objective was to examine the age the more viscous and weaker asthenosphere relationships and preservation of these volcanic below. Typically the LAB is at a depth of ~ 100 km edifices. in the old oceans but can be as deep as 300 km Cape Young comprises proximal to distal, beneath continental cratons. The LAB is important pumiceous, eruption‐fed stratified pyroclastic because mechanical changes that occur across the density current deposits, suspension‐deposited boundary dictate how mountains become pyroclastic falls and minor syn‐eruptive elevated, how the earth rebounds after melting of remobilised pyroclastic sediments deposited in a ice caps and how and when sea levels change

100 relatively shallow marine environment. K‐Ar dates turn drove abrupt global warming, increased from basaltic clasts in the Cape Young pyroclastics weathering and supply of oceanic nutrients, are c. 40 Ma, placing them within the Northern enhanced plankton productivity, and stagnation in Volcanics. Some dykes cutting the pyroclastics of restricted ocean basins. One or more of these similar age probably represent feeders to the factors led to anoxia and ultimately euxinia, the source volcanoes while others are much younger build‐up of toxic H2S in the oceans. OAEs, recorded at c. 4Ma. Cape Young is preserved as a result of by seafloor sediments, strongly perturbed Earth’s the presence of numerous dykes rather than climate and ecosystems. However, the exact edifice structure and this appears to be true for a mechanisms driving OAEs remain uncertain number of other volcanic‐derived topographic because the evolution of the oceans during these features as well. events from oxic to anoxic and ultimately euxinic is poorly constrained. Maunganui Bluff comprises c. 4 Ma basal pillow lavas on shallow marine carbonates, succeeded by Our research uses a suite of new palaeo‐redox palagonitised kaesutite‐bearing volcaniclastics and tracers, based on the uranium (U), molybdenum capped by air‐fall lapilli tuffs, suggesting that (Mo), chromium (Cr) and iron (Fe) isotope Maunganui Bluff was emergent in its latter stages. signatures of seafloor sediments, to reconstruct the timing, duration and extent of anoxia across The facies architecture at both localities indicates known anoxic events of the Mesozoic Ocean. Our shallow subaqueous explosive and effusive research will also quantify the degree to which eruptions, confirming that the region was mostly oxygen depletion extended from the deep ocean submarine in Miocene – Pliocene time. The 4 Ma into the shallow photic zone, which currently eruptives, however, indicate that low tuff cones remains uncertain. Using high‐resolution records emerged above the sea level to form archipelagos from palaeogeographically widely separated of ephemeral volcanic islands a few tens of metres regions, we will aim to constrain the mechanisms high in a shallow marine environment. leading to extreme oxygen deprivation in the oceans. This, in turn, will provide information that

will have a direct bearing on assessing future GLOBAL OCEAN ANOXIA DURING ANCIENT climate‐change impacts, particularly given the ‘GREENHOUSE’ CLIMATES: CONSTRAINTS FROM rapid expansion of anoxic ‘dead zones’ in the METAL STABLE ISOTOPES modern oceans that has occurred in recent decades. C.H. Stirling1, M.O. Clarkson1, C.M. Moy2, J.S. Crampton3,4, D. Porcelli5 & H.C. Jenkyns5 1Department of Chemistry & Centre for Trace DEVELOPMENT OF MAGNITUDE‐FREQUENCY Element Analysis, University of Otago, Dunedin DISTRIBUTIONS FOR ACTIVE FAULTS IN NEW 9054 ZEALAND 2Department of Geology, University of Otago, PO M.W. Stirling1, M.C. Gerstenberger1, A. Nicol1, & Box 56, Dunedin 9054 1 3 R.J. Van Dissen GNS Science, PO Box 30368, Lower Hutt 5040 1 4SGEES, Victoria University of Wellington, PO Box GNS Science, P O Box 30368, Lower Hutt 5040 600, Wellington 6140 [email protected] 5Department of Earth Sciences, University of Development of the next generation of national Oxford, U.K. probabilistic seismic hazard model for New [email protected] Zealand is taking place within the “Rethinking Ocean oxygenation is crucial to marine life and, via PSHA” MBIE‐funded project. Initial efforts are a link with the carbon cycle, is a key regulator of being focused on developing new seismic source climate. During the warm “super‐greenhouse” models, evaluating ground motion prediction world of the Mesozoic, between ~250 and ~65 equations for application in New Zealand, and million years ago, the oceans underwent repeated updating the software platform for the national episodes of expanded anoxia, in which vast regions seismic hazard model. An important consideration were devoid of oxygen. These so‐called ‘oceanic in the development of fault source models is the anoxic events’ (OAEs) were closely linked to the assumed shape of the magnitude‐frequency distribution for the fault sources. A long standing rapid influx of CO2 into the atmosphere, which in debate in the seismological community surrounds

101 the question of whether the Gutenberg‐Richter Deepwater Taranaki, and possibly northern parts relationship or Characteristic Earthquake model of the proximal Taranaki Basin. This phase, with best describes the shape of the magnitude‐ approximately NE–SW‐orientated extension, was frequency distribution for the faults. The related to Tasman Sea rifting, and ceased roughly Gutenberg‐Richter relationship assumes a log‐ coincident with the onset of seafloor spreading, linear distribution of magnitude and frequency, which focused extension in the Tasman Sea. The whereas the Characteristic Earthquake model orientation and timing of this extensional event is assumes a very narrow range of magnitudes and comparable to that observed in the West Coast frequencies near a maximum magnitude that is and Great South‐Canterbury basins, consistent estimated from the physical dimensions of the with suggestions that this was a New Zealand‐wide fault. A hybrid Gutenberg‐Richter/Characteristic tectonic event associated with Gondwana magnitude‐frequency distribution has also been breakup. proposed (the “Youngs & Coppersmith” distribution). Our initial work on resolving this (2) A later, Late Cretaceous–Paleocene rift phase issue within the “’Rethinking PSHA” project is to (c. 80–55 Ma), with E–W to NW–SE‐oriented develop seismic moment‐balanced magnitude‐ extension, affected only proximal, especially frequency distributions for these three models, southern, parts of the Taranaki Basin. This rift and then evaluate them on the basis of: (1) phase, also observed in the basins of the West assessing how many earthquakes should have Coast and Western Southland, was mainly been observed in the historical period if the confined to western New Zealand and did not magnitude‐frequency distribution was correct, affect more distal areas, such as Deepwater and; (2) comparison of the predicted frequency of Taranaki. This second phase of minor extension the largest events to the available paleoseismic (<10%) led to the formation of a failed rift arm data. Issues such as non‐stationarity of associated with seafloor spreading in the area earthquakes, and uncertainties in event between the Ross Sea and Zealandia. completeness and magnitude are being carefully considered in the evaluation process. (3) The second rift phase was followed by passive thermal subsidence through much of the Eocene (c. 55–40 Ma), which formed part of a New Zealand‐wide marine transgression. Subsidence RIFT TO DRIFT ON THE EDGE OF GONDWANA: and transgression ceased in the Early Miocene CRETACEOUS–EOCENE PALEOGEOGRAPHIC with the onset of rapid plate convergence. EVOLUTION OF THE TARANAKI BASIN, NEW ZEALAND

1 1 1, 2 1 D.P. Strogen , K.J. Bland , J.R. Baur , A. Nicol , H. A NATIONAL TEPHRA GEOCHEMISTRY ONLINE 1 1 Seebeck & P.R. King DATA SET FOR NEW ZEALAND 1GNS Science, PO Box 30368, Lower Hutt 5040 2 Total Exploration and Production, Scientific and D.T. Strong1, G. Leonard1 & R.E. Turnbull2 Technical Centre Jean Feger, Pau, France 1GNS Science, P O Box 30368, Lower Hutt 5040 [email protected] 2GNS Science, Private Bag 1930, Dunedin 9054 [email protected] The Taranaki Basin, located predominantly offshore of western North Island, has had a PETLAB is New Zealand’s national rock and complex geological history. A regional geoanalytical database, and contains the locations reassessment of the evolution of the Taranaki and descriptions of over 191,000 rock and mineral Basin and surrounding areas, with a focus on the samples collected from on‐ and off‐shore New regional geodynamic implications, is presented in Zealand and worldwide. More than 50,000 of the form of 14 paleogeographic maps spanning the these samples have geochemical, geophysical mid‐Cretaceous to Late Eocene that synthesise and/or other analytical data. The PETLAB database paleobathymetric and paleofacies data. Three provides a number of powerful tools, including the main phases of basin evolution are recognised ability to customize search queries to specific through the Cretaceous–Eocene: research problems, and as such, is a valuable research tool across all avenues of earth science. (1) An early rift phase, of ‘mid’ to early Late Cretaceous age (c. 100–85 Ma), affecting mainly

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Tephrochronology plays an important role in many spectroscopy to provide valuable insights into earth science disciplines, where volcanic ash layers factors impacting public health. A significant are used to provide correlation and age control feature of these systems is that silicate adsorbed between sites. In 2012 the PETLAB team on oxide surfaces can be disposed towards augmented the PETLAB database with the addition condensation reactions if adjacent sorbed of a national tephra geoanalytical data set, monomers are orientated to allow insertion of a compiled primarily from old and new published solution H4SiO4 to bridge the sorbed monomers journal articles and unpublished university theses. and to form a linear trimeric silicate. This study Stage one of the tephra data entry is in progress has determined how the presence of non‐ and consists of entering geochemical analyses polymerizing ligands, such as arsenate, on the iron (modal analyses and mean major and trace oxide surface influences the propensity of the element analyses of tephra glass and silicate system towards silicate polymerization. From minerals), and allows users to search tephra which simple stochastic arguments we had anticipated match particular geochemical criteria. that sorbed arsenate would inhibit silicate Furthermore, the name of the tephra polymerization by blocking polymerization options horizon/eruptive episode is also listed where it is for monomeric sorbed silicate. Unfortunately in known (i.e. the regionally extensive Kaharoa Ash). situ infrared spectroscopy indicated that the Stage two will involve entering chronological data stochastic processes were not simple and the (i.e. the published accepted age for the tephra presence of sorbed arsenate promoted silicate horizon or radiometric ages). polymerization. This implies a much more dynamic approach to equilibrium which includes a The reasons for adding the tephra data set are spectrum of silicate polymerization probabilities many and varied, and include a) complementing with arsenate “pushing” silicate towards sites with the soon‐to‐be completed geology map of higher polymerization probabilities. Tongariro National Park; b) recovering value from old analyses by entering decades of unpublished university thesis data into one online database; and c) providing a source of readily accessible, pre‐ THE DISTANT INLAND NAGANO EARTHQUAKE compiled data for studies using tephra marker (M6.7) FOLLOWING THE 2011 TOHOKU‐OKI horizons. Potential applications of the tephra EARTHQUAKE geochemistry data set housed within PETLAB 1,2 2 2 include quaternary geology, climate change, T. Takeda , B. Enescu , K. Shimojo & S. 2 paleolimnology, archaeology, and paleoseismology Sekiguchi 1 studies. GNS Science, PO Box 30368, Lower Hutt 5040 2National Research Institute for Earth Science and Disaster Prevention, Japan 3Earth Evolution Sciences, University of Tsukuba, ARSENATE AND SILICATE INTERACTIONS ON IRON Japan OXIDE SURFACES: A DANSE MACABRE [email protected]

1 1 1 P.J. Swedlund , Salah‐ud‐Din , M.A.L. Airey , C. On 12 March 2011, an inland earthquake (M6.7) 1 1 1 Kuo , A.C. Van De Weg , J.L. Vella occurred 13 hours after the 2011 Tohoku‐Oki 1 School of Chemical Sciences, University of earthquake (Mw9.0). The hypocentre was about Auckland, Private Bag 92019 Auckland 400 km far from the Tohoku‐Oki one, and located [email protected] in a high‐strain‐rate and high‐seismicity area, called the HIZUMI zone. Reverse faulting was Iron oxides are important solid phases influencing expected to be suppressed due to extensive the distribution of trace elements in aquatic tension following the Tohoku‐Oki earthquake; systems. In particular sorption onto the surfaces of however the focal mechanism showed a reverse iron oxide particles is the principal process fault type. Therefore the relationship between the controlling arsenic in drinking water. Other inland earthquake and the Tohoku‐Oki megathrust sorbing ligands, in particular phosphate and event is not well known. silicate, can compete for these surfaces causing elevated solution arsenic concentrations. In this We used data of the dense seismograph network study we probe these interesting and important that had been temporarily deployed in the Nagano competitive surface reactions using in situ infrared region before the Tohoku‐Oki earthquake as part

103 of the HIZUMI project sponsored by a Japanese living Ganges River dolphin. Cladistic studies ministry, MEXT, and finally obtained the detailed confirm that Notocetus and the Squalodelphinidae hypocentral distribution and the velocity structure are not present in New Zealand. Other in and around the source area. The obtained undescribed and unnamed dolphins from the velocity model shows different velocities in the NE Otekaike Limestone include at least 4 species, and SW areas, and also reveals the existence of a some with exceptional skeletal preservation, plus 1 high Vp/Vs ratio structure below the inland species from the Kokoamu Greensand. These hypocentre. animals lived in the extensive shelf seas of later Oligocene Zealandia, along with baleen whales Based on the above results, we propose a (including Mauicetus and eomysticetids), penguins, schematic source fault model. This model contains billfish, and a diverse assemblage of invertebrates. two crustal blocks of the NE and the SW parts. The NE block includes the SE dipping mainshock fault, while the SW block has another fault. The high Vp/Vs ratio structure below the mainshock A NEW SPECIES OF PLIOCENE SHEARWATER hypocentre involves fluid existence. Therefore the (AVES: PROCELLARIIDAE) FROM TARANAKI inland earthquake may have been triggered by a A.J.D. Tennyson1 & A.A. Mannering2 pore pressure increase due to high‐amplitude 1 surface waves generated by the Tohoku‐Oki Museum of New Zealand Te Papa Tongarewa, P O Box 467, Wellington 6140 earthquake. Analysis of inland seismicity that 2 occurred in the Nagano region just after the 8 Roswell Place, Christchurch 8042 Tohoku‐Oki earthquake, suggests the inland [email protected] earthquake might have been delay‐triggered by A Pliocene (Waipipian) bird fossil from Taranaki, fluid migration from the deep source. New Zealand, represents a new species of seabird. It is a well‐preserved partial skeleton representing

the main wing elements and some legs elements. In structure these bones most closely resemble NEW ZEALAND OLIGOCENE DOLPHINS REVEAL those of a shearwater (Procellariiformes: THE EARLY HISTORY OF THE GANGES RIVER Procellariidae) but it is distinguished from all DOLPHIN GROUP (PLATANISTOIDEA) known living and extinct taxa by a combination of Y. Tanaka1 & R.E. Fordyce1 unique features. It was a gliding species as large as 1Department of Geology, University of Otago, P O the largest species of living shearwater. It Box 56, Dunedin represents the first pre‐Pleistocene record of a [email protected] new shearwater taxon from the Western Pacific and helps reveal the history of shearwater New Zealand's record of Oligocene marine evolution worldwide. Today New Zealand has the dolphins, especially from the Waitaki region, is greatest diversity of breeding shearwater species outstanding for temperate regions of the Southern in the world and the new fossil adds weight to Hemisphere. Important early finds involved Walter other evidence that shearwaters have a long Mantell in 1848, who recovered Phocaenopsis history in this region. mantelli, named by Huxley, and Alexander McKay in 1881, who collected a skull from the Otekaike Limestone, described as Microcetus hectori by THE GLEN MURRAY PENGUIN, AN OLIGOCENE Benham. More‐recently named key species based GIANT FROM THE NORTH ISLAND on skulls include “Notocetus” [now Otekaikea] marplesi, Waipatia maerewhenua, and Papahu 1 2 D.B. Thomas & D.T. Ksepka taitapu. Tanaka's PhD project has reviewed M 1 Massey University, Private Bag 102904, Albany hectori, O marplesi, W maerewhenua, and new 0745 species based on OU 22306 (Otekaikea), OU 22125 2 Bruce Museum, One Museum Drive, Greenwich, (cf. Waipatia) and others from the Waitaki region. CT, USA Morphological cladistic analyses are used to [email protected] establish phylogeny. Most of the Waitaki fossil dolphins represent basal species of the once‐ Paleogene tetrapods are rare discoveries in the diverse and now nearly extinct clade North Island of New Zealand. A particularly Platanistoidea, which includes the endangered

104 significant addition to our knowledge of the Subduction of the Cretaceous oceanic Hikurangi ancient biota was made in 1971, when hindlimb Plateau beneath the southern Kermadec arc and bones from a large Oligocene penguin were the North Island of New Zealand provides a collected from a Waikato farm near Glen Murray. modern example of this phenomenon. The The ancient marine bird was described by J.A. southern Kermadec arc has the highest magma Grant‐Mackie and G.G. Simpson in 1973, but with flux and the highest volcano density of the entire comparatively few fossil penguins known, the Glen Kermadec arc. Furthermore, Kermadec arc lavas Murray specimen was considered ‘unidentifiable south of c. 32˚S have high Pb and Sr and low Nd as to genus or species’. Subsequent fossil penguin isotope ratios. Combined with changes in seafloor discoveries from across the Gondwanic fragments morphology and a positive Bouguer gravity have generated renewed interest in the taxonomy anomaly (consistent with crustal thinning), this of the Glen Murray penguin. From a more suggests initial Hikurangi Plateau – Kermadec arc complete understanding of New Zealand stem collision c. 250 km north of the Hikurangi Plateau’s penguin taxonomy we may gain insight into giant present position. Oblique plate convergence penguin biogeography. Several broadly caused southward migration of the thick and contemporaneous Paleogene penguins are now buoyant large igneous province crust, which is known from both the North and South Islands of likely to create an H2O‐rich, buoyant ‘Hikurangi’ New Zealand, presenting an interesting mélange by tectonic erosion underplated beneath biogeographic question for the Glen Murray the arc crust (near the Moho) that interacts with penguin: was this rare Paleogene tetrapod a ascending arc melts. The combined dataset further member of a Zealandian radiation? Alternatively, indicates that a much larger portion of the was the Glen Murray penguin instead recruited Hikurangi Plateau (the missing Ontong Java‐Nui into the Paleogene avifauna from elsewhere? Here piece) than previously believed has already been we present phylogenetic data from the Glen subducted. Murray penguin and discuss the specimen in a Zealandian context. Located above the subducting Hikurangi Plateau, the two submarine volcanic centres Rumble II East and Rumble II West form a c. 22 km arc ‐ backarc transect across the southern Kermadec arc. EFFECTS OF HIKURANGI PLATEAU SUBDUCTION Although just c. 13 km apart, volcanic rocks from ON KERMADEC ARC VOLCANISM AND ELEMENT these two volcanic centres show fundamentally TRANSFER different geochemical compositions, posing the question whether these differences may be C. Timm1, B. Davy1, R.J. Wysoczanski2, Hauff, F.3, related to Plateau subduction. Whereas low 206 204 143 144 Hoernle, K.3, K. Haase4, M. Leybourne5, H. Pb/ Pb (< 18.75) and high Nd/ Nd isotope Seebeck1, M. Handler6, N. Mortimer7, J. Gamble6, values (> 0.51302) in Rumble II West lavas do not F. Caratori‐Tontini1 & C.E.J. de Ronde1 require input from a geochemically enriched 1GNS Science, PO Box 30368, Lower Hutt, 5040 source, some Rumble II East lavas show high 206 204 143 144 2 National Institute of Water and Atmospheric Pb/ Pb (> 18.8) and low Nd/ Nd (< Research, Private Bag 14901, Wellington 6241 0.51298), consistent with input from a 3GEOMAR Helmholtz Centre for Ocean Research, geochemically enriched source, such as the Wischhofstrasse 1‐3, 24148 Kiel, Germany Hikurangi Plateau and its associated seamounts. 4Geozentrum Nordbayern, Universität Erlangen‐ Nürnberg, Schlossgarten 5, 91054 Erlangen, Germany RECONSTRUCTION OF THE LARGEST ERUPTIONS 5Department of Earth Sciences, Laurentian OF MT. TARANAKI FROM PROXIMAL RECORDS: University, 935 Ramsey Rd, Sudbury, ON P3E 2C6, LITHOFACIES AND ERUPTIVE SCENARIOS Canada 6 SGEES, Victoria University of Wellington, PO Box 1 1 2 R. Torres‐Orozco , S.J. Cronin , N. Pardo & A.S. 600, Wellington 6140 1 7 Palmer GNS Science, Private Bag 1930, Dunedin 9054 1 Volcanic Risk Solutions, Massey University, Private [email protected] Bag 11222, Palmerston North 4442 2 The impact of large igneous province subduction Universidad Nacional de Colombia, Carrera 45 No on arc volcanism has rarely been studied. 26‐85, Edificio Uriel Gutiérrez, Bogotá D.C., Colombia

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R.Torres‐[email protected] debris‐avalanche deposits and a debris‐flow deposit that are exposed along seven major rivers The ca.150 ka Mt. Taranaki is an excellent example catchments currently or previously sourced from of an andesitic stratovolcano producing lava flows, Mount Ruapehu. The debris avalanches inundated domes, and explosive eruptions. In order to an area of > 1200 km2, and have volumes between reconstruct the largest eruptions through to the 1.35 km3 and 3 km3. Andesitic lavas within the Plinian range, spanning the last 5,000 yrs BP, a deposits were geochemically correlated with dated lithofacies stratigraphy of proximal pyroclastic lavas exposed on the cone, and indicate that the deposits within multiphase eruption periods was landslides occurred between 90 to 250 ka. Trace developed. Proximal deposits comprise the most element compositions of the debris‐flow deposit complete eruptive sequences at Mt. Taranaki, hint that the volcanic edifice is ≥ 340 ka old and is including onset‐phases and the intervening low‐ underlain by a hornblende‐bearing gabbroic layer level activity between the deadliest explosive at c. 40 km depth. Another hitherto unknown bursts. eruptive episode related to an initial intrusion event, which triggered a large flank collapse, Our detailed proximal stratigraphy suggests three occurred at c. 90 ka. Channelization of all mass plinian to sub‐plinian eruptive scenarios at Mt. flows within the steep river catchments resulted in Taranaki: 1) pumice‐rich, steady sustained extremely long run‐outs up to 90 km from source. convective columns, preceded by thin ash fallouts The corresponding deposits reveal “dry” debris‐ and/or pyroclastic density currents (PDCs), and avalanche features, e.g., jig‐saw jointing and ending with a gradual energy decrease (massive to hummock formation, alongside “fluid‐like” normal graded fallouts); 2) pumice‐ or lithic‐rich, properties, e.g., dish structures and strongly unsteady sustained columns (strongly stratified sheared rip‐up clasts. Incorporation of saturated fallout deposits), in some cases interrupted by river gravel and volcaniclastics en route potentially PDC‐forming partial collapses, and preceded and added vast amounts of interstitial fluids, which followed by thin ash fallouts and debris flows; and formed a highly mobile basal zone, and increased 3) pumice‐rich, steady sustained columns (massive the mobility of the flows by up to 2.5 times fallouts), following violent blast‐type PDCs and compared to unconfined avalanches. explosively decompressing lava domes. The largest eruptions of Mt. Taranaki are similar to some of the most explosive phases of the eruptions of Kelut in 2014 and 1990, Merapi in 2010, Mt. St. ORIGIN OF THE PETER PAN WHALE, CAPEREA Helens in 1980, and Vesuvius in 79 AD and 1631 MARGINATA (: MYSTICETI) AD. C. H. Tsai1 & R. E. Fordyce1 1Department of Geology, University of Otago, P O Box 56, Dunedin 9054 NEW ERUPTIVE EPISODES AND HAZARD FINDINGS cheng‐[email protected] REVEALED FROM DISTAL MASS‐FLOW DEPOSITS AT RUAPEHU VOLCANO, NEW ZEALAND ‘Descent with modification’ has been the essence of evolution since Darwin. Ideally, an M. Tost1, S.J. Cronin1, J.N. Procter1, R.C. Price2, understanding of biological evolution would be V.E. Neall1 & I.E.M. Smith3 based on ancestor‐descendant relationships (ADR) 1Volcanic Risk Solutions, Massey University, Private revealed by the fossil record. ADR is difficult to Bag 11222, Palmerston North 4442 recognise for groups with a sparse fossil record, 2School of Science, University of Waikato, Private but may be addressed using phylogenetic Bag 3105, Hamilton 3240 methods. An example here involves fossil and 3School of Environment, The University of modern pygmy right whales. Auckland, Auckland 1142 [email protected] We assessed the relationship between the relatively complete fossil , Flank failures of stratovolcanoes generate debris Miocaperea pulchra (7‐8 Ma, Miocene, Peru) and avalanches that pose a great risk to inhabited its sole living relative, the modern pygmy right areas, and may permanently reshape the whale, Caperea marginata (Southern Ocean). Two landscape. We examined the distal sedimentology, published matrices were used to include juvenile geochemistry, and petrology of six individual large and adult Caperea marginata as separate OTUs (in

106 total 25 and 46 taxa), involving 166 and 246 exhumation of the middle crust. The defining morphological characters respectively, analysed feature of metamorphic core complexes, a low using TNT (Tree analysis using New Technology). angle normal detachment fault juxtaposing brittle Results show Miocaperea as phylogenetically (cold upper plate) over ductile mid‐crust (hot bracketed between juvenile and adult Caperea. No lower plate), has not been identified in the vicinity autapomorphy (unique derived character) of Taranga‐1. However, support for a metamorphic occurred solely in Miocaperea to preclude core complex interpretation includes the location Miocaperea as the direct ancestor to Caperea. We of Taranga‐1 along strike from the Aotea Basin, thus interpret the Miocaperea‐Caperea and a 40Ar/39Ar K‐feldspar age of c.99 Ma that relationship as an ancestor‐descendant indicates rapid cooling during tectonic denudation relationship – the first so far identified within following granodiorite emplacement and baleen whales (Cetacea: Mysticeti). crystallisation at c.110 Ma.

Caperea marginata differs from other baleen In the Paparoa (Buller District) and Sisters (Stewart whales in having similar skull shape throughout Island) core complexes, steeply dipping transfer ontogeny, consistent with the idea of ‘Peter Pan’ ‐ faults cut detachment faults at a high angle, not growing up in terms of morphology. The striking sub‐parallel to the extension direction. similar skull morphology throughout ontogeny in Application of this orthogonal relationship to Caperea, with Miocaperea phylogenetically Taranaki Basin suggests a) that many of the north‐ bracketed between juvenile and adult Caperea, easterly trending faults can be regarded as suggests that the Miocaperea‐Caperea relationship Cretaceous transfer faults, and b) an original shows long‐term morphological stasis (7‐8 Ma to north‐westerly trend for postulated detachment Present). Given that punctuated equilibrium faulting. This orientation matches north‐westerly involves geologically rapid origination followed by strikes for detachment faults in the Paparoa core a long interval of morphological stasis, the complex and rift margins in the Aotea‐New Miocaperea‐Caperea may be the first possible Caledonia Basin. example of punctuated equilibrium in evolution. Phylogenetic and ontogenetic If correct, these interpretations indicate and/or studies can therefore indicate ancestor‐ predict a) that initial opening of the Aotea‐New descendant relationships in the absence of a dense Caledonia Basin was underway by c.99 Ma, some 6 fossil record. Ma before equivalent Paparoa exhumation, b) an original north‐westerly structural trend in basement and deepest sedimentary rocks may be more common than currently recognised in A POSSIBLE MID‐CRETACEOUS METAMORPHIC Taranaki Basin, and may have guided Late CORE COMPLEX UNDER TARANAKI BASIN Cretaceous fluvial pathways, and c) that north‐ westerly trending culminations of lower plate 1 2 1 A.J. Tulloch , T.L. Spell , N. Mortimer & J. rocks will likely define zones of relatively high Late 3 Ramezani Cretaceous heat flow and diagenesis. 1Regional Geology Dept, GNS Science, Private Bag 1930, Dunedin 9054 2Department of Geosciences, University of Nevada at Las Vegas, NV 89154, USA THE SOUTHERN SOUTH ISLAND GEOCHEMICAL 3Earth Atmospheric and Planetary Sciences, MIT, BASELINE SURVEY Cambridge, MA 02139, USA 1 1 2 [email protected] R.E. Turnbull , A.P. Martin & M.S. Rattenbury 1GNS Science, Private Bag 1930, Dunedin 9054 Basement granodiorite core in Taranaki Basin well 2GNS Science, PO Box 30368, Lower Hutt 5040 Taranga‐1 exhibits shallow dipping ductile shear [email protected] deformation of quartz that is overprinted by steeply dipping brittle deformation and associated Regional, national and trans‐national geochemical hydrothermal alteration. baseline surveys are recognised worldwide as important datasets for understanding normal These features are characteristic of the lower ranges of chemical element concentrations in the plates of cordilleran metamorphic core complexes earth, and monitoring and assessing any variation that represent rapid extensional tectonic with time. A pilot programme of soil collection

107 over an 8km‐spaced grid across south Otago and studies where onshore plutonic sources have been Southland, has so far collected 335 sites of the 400 well classified and mapped. planned. The area of the pilot study was chosen for the diversity of the underlying geology (e.g. Plagioclase and alkali feldspar from 38 samples of volcanic, sedimentary, crystalline igneous and plutonic igneous rocks representing the principal metamorphic rock, mineralised schist) and the igneous suites of Zealandia were analysed by laser variety of land uses (e.g. urban, agricultural, ablation inductively coupled plasma mass historic mining, pristine conservation estate). spectrometry (LA‐ICPMS) for a suite of 10 major Approximately five kilograms of soil was collected elements and 34 trace elements. Results show that at each site from both the A soil horizon and a feldspar grains from plutonic suites are mostly deeper sample (50‐70 cm) typically equal to the B readily distinguished on the basis of trace element soil horizon using hand augers, with the sieved concentrations such as Sr, CaO, and Rb. A strong <2mm fraction retained for chemical and isotopic correlation between the elemental composition of analysis. The survey sampling methodology is feldspar and whole‐rock compositions of Zealandia based on best‐practice, international geochemical plutonic suites indicates that distinctive chemical baseline surveys. signatures of the whole‐rock samples mirrored by individual feldspar grains from that sample. This collection will form the basis for a detailed chemical and isotopic study where a snapshot of Trace element fingerprinting of detrital feldspar the distribution and abundance of specific grains is a novel, world‐first, utilisation of the chemical components in the soil at the time of major framework mineral component of sampling will be established. The entire sample sandstones as a provenance tool (sources suite collection will be analysed for a suite of >60 trace proxy). As a complement to accessory zircon U‐Pb elements by aqua‐regia ICPMS. A sub‐set of ages (source rock age proxy), it has the potential to samples will also be analysed for major and some be a rapid and effective provenance tool than can trace elements using laboratory XRF, and isotopes be readily applied to Zealandia basins. This method (S, Sr, Pb). Data from this regional survey will be should prove a valuable new tool for unravelling freely available from the national rock and sediment source to sink pathways, allowing geoanalytical database (pet.gns.cri.nz), and will quantitative modelling of depositional have applications in fields as varied as paleogeography, petroleum reservoir distribution, environmental, agricultural, public health and and crustal evolution. The technique has also natural resources. shown potential as a tool for determining the provenance of mm‐sized seafloor dredge samples that comprise too few grains to represent a whole‐ rock sample. TO SEE THE WORLD IN A GRAIN OF SAND – A SINGLE GRAIN PROXY FOR SOURCE ROCK CHEMISTRY THE FUTURE OF PETROLEUM EXPLORATION IN R.E. Turnbull1, A.J. Tulloch1 & J.M. Palin2 NEW ZEALAND – A PERSONAL VIEW 1GNS Science, Private Bag 1930, Dunedin 9054

2Department of Geology, University of Otago, PO C. Uruski Box 56, Dunedin 9054 OMV New Zealand Limited, Brandon Street,

[email protected] Wellington 6011 [email protected] We have successfully calibrated a new micro‐ geochemical method that is capable of Taranaki is New Zealand’s only producing determining the provenance of individual detrital petroleum province. Discovery rates and size feldspar grains from sedimentary basins on the continue to decline. Ten years ago, one well in basis of trace element characteristics. Zealandia’s seven was a commercial success, while today, that plutonic suites are largely compositionally and figure is one in ten. A new prolific Taranaki play is chronologically distinct, and represent major first a receding possibility. cycle detrital components of Cretaceous‐Cenezoic sedimentary basins. As the dominant mineral New Zealand is a by‐product of collision between group their varied trace element compositions the Pacific and Australian plates. Associated make them an ideal target for use in provenance tectonism created numerous potential petroleum

108 traps and then breached them. Testing the change. We will show that there have been many hypothesis that the best place to find large examples in which palaeoclimate studies have volumes of petroleum is where Neogene helped evaluate our confidence in climate change tectonism is minor means taking the plunge into models. These examples can be drawn from many deep water. different time periods including the Quaternary, Pliocene, and earlier times. But there are also Our first deep‐water exploration wells were drilled weaknesses with palaeoclimate studies and it has in the Great South Basin, where a sub‐commercial been rare that climate models have been changed gas‐condensate field, Kawau, was discovered in and improved because of palaeoclimate research. 1977. In 1999 Waka Nui‐1 in the Northland Basin This is often because of uncertainties in the was followed recently by Romney‐1 in Deep‐water quantitative interpretation of the climate proxies. Taranaki and Caravel in the Canterbury Basin. Therefore the talk will finish by showing some new Anadarko operates in Deep‐water Taranaki, methodologies of model‐data comparisons which Pegasus and Canterbury basins. Shell, OMV and can fully embrace these uncertainties and open up Mitsui are exploring the Great South Basin. Statoil considerable further opportunities for has a permit in the Northland Basin and Woodside, palaeoclimate research to contribute towards with New Zealand Oil and Gas, operate permits improving our confidence in future climate change across the slopes of Taranaki and the Great South predictions. Basin. The recent licensing round offers further acreage in all of these basins.

Current exploration resulted largely from SEDIMENT FINGERPRINTING IN THE MANAWATU Government reconnaissance 2D seismic surveys RIVER CATCHMENT that allowed companies to assess the potential of New Zealand’s frontier basins. New speculative S.S Vale1, J.N. Procter1 & I.C. Fuller1 surveys have been acquired in the Pegasus and 1Institute of Agriculture & Environment, Massey East Coast basins, others are about to start, and University, Private Bag 11222, Palmerston North Shell, Anadarko and CNOOC are investigating the 4442 vast New Caledonia Basin. The large volume of [email protected] new data available and to be acquired will re‐draw the petroleum prospectivity map of New Zealand. Suspended sediment contributes to the chemical The future for petroleum exploration in New and ecological character of fluvial channels and is a Zealand is already happening. product of the contributing catchment. It is therefore important to understand rates of suspended sediment delivery, transport and deposition in the fluvial system. In the Manawatu THE ROLE OF PALAEOCLIMATE IN PREDICTING River Catchment, extensive landuse conversion THE FUTURE from indigenous forest to pastoral agriculture has occurred following European settlement of New 1 1 P.J. Valdes & D. Lunt Zealand. This has influenced slope stability and 1 School of Geographical Sciences, University of caused widespread mass movements, soil erosion Bristol, University Road, Bristol. BS8 1SS. UK and an increased sediment supply to the river. [email protected] Catchment scale identification of erosion processes and geomorphically active areas The study of past climates is frequently motivated contributing sediment have often been poorly by efforts to improve our understanding of future understood and quantified. Sediment climate change. However, it is often difficult to fingerprinting provides an approach capable of demonstrate that such knowledge of the past has directly quantifying sediment delivery through truly helped improve the predictions of future differentiating between sediment sources based climates. In part, this is because there are no direct on their inherent geochemical signature. In this palaeo‐analogues for the coming century. Instead research step‐wise discrimination function analysis knowledge of past climates have to be used to test and principal component analysis of bulk and improve the climate models used for future geochemical concentrations (SiO2, TiO2, Al2O3, climate change predictions. The talk will review Fe2O3, MnO, MgO, CaO, Na2O, K2O, P2O5, Sc, V, Cr, the role that palaeoclimate has played in Co, Ni, Cu, Zn, Ga, Rb, Sr,Y, Zr, Nb, Cs, Ba, La, Ce, improving our understanding of future climate Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Hf,

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Ta, Pb, Th & U) has been employed to differentiate reaching consequences, and can be measured (in between and understand key sediment sources in classrooms) around the world. This is one reason the Manawatu River Catchment. why different versions of “seismometer in schools” projects thrive around the world. Our New Zealand network is named “Ru” after the Maori God of Earthquakes and Volcanoes. ENVIRONMENTAL RESEARCH, ENVIRONMENTALLY CONCIOUS? Ru uses a cheap, robust and easy‐to‐build seismometer –called the TC1— to measure seismic D. Van Walt displacements in the vertical direction. Assembling Van Walt Ltd, Unit A, 21 Gordon Road, Wanaka and running the system naturally introduces 9305 students to a number of concepts in physics and [email protected] engineering, while we hope that upon completion seismic recordings trigger discussions about the The world is slowly waking up to the concept of dynamics and internal structure of the Earth. preserving natural resources and monitoring the effects of our actions. We are torn between our This presentation will be an update of our immediate need for food and fuel vs the future experiences with the roughly 10 schools in the welfare of the world as we know it. Billions of network. Dollars a year are invested in environmental research but are we conscious of the effects of this research on the very resources that are so precious to us. As an example, every day I supply PALEOTEMPERATURE CONSENSUS kilometres of sample tubing to environmental RECONSTRUCTIONS FROM LIPID BIOMARKERS, consultants. The situational irony is not lost on me POLLEN AND CHIRONOMIDS: IS THIS A DUMB that this tubing is used once to determine IDEA? contamination and then disposed of as a 1 1 2 2 M. Vandergoes , K. Zink , A. Rees , R. Newnham , consumable item. Is there a better way? YES! 1 3 4 X. Li , J. Wilmshurst , A. Dieffenbacher‐Krall , L. From equipment installation to sample acquisition 5 Schwark there is progress in the industry to design and 1 GNS Science, PO Box 30368, Lower Hutt 5040 manufacture equipment that is more sensitive to 2 SGEES, Victoria University of Wellington, PO Box our environmental needs. The following 600, Wellington 6140 presentation will highlight some of the traditional 3Landcare Research, PO Box 40, Lincoln, methods of using a sledge hammer to crack a nut Canterbury 7640 vs recent developments that can offer better 4School of Biology and Ecology, University of results with less impact on the immediate Maine, Orono, USA. environment. 5Institute of Geoscience, University of Kiel, Germany [email protected] RU: THE NEW ZEALAND NETWORK FOR SEISMOLOGY IN SCHOOLS New Zealand temperature reconstruction models, based on biological indicators preserved in lake K. van Wijk1, L. Adam2 & D. Hikuroa3 sediments, are essential for defining the temporal 1Department of Physics, University of Auckland, and spatial magnitudes of paleoclimate variability Private Bag 92091, Auckland 1142 in the Southern Hemisphere and for providing 2School of Environment, University of Auckland, quantitative temperature reconstructions for Private Bag 92091, Auckland 1142 constraining and testing paleoclimate model 3Ngā Pae o te Māramatanga, University of simulations. Common proxies include pollen, Auckland, Private Bag 92091, Auckland 1142 insect remains and lipid biomarkers from bacteria [email protected] (branched isoalkyl Glycerol Dialkyl Glycerol Tetraethers: GDGTs). The interpretation of Earthquakes are some of the more dramatic temperature estimates derived from a proxy is expressions of the dynamics of our planet. The highly dependent on that organism’s biology, and sudden release of stress, built up slowly by extrapolating these individual reconstructions to tectonic or volcanic processes, often has far‐ regional temperature signals, rather than non‐

110 climatic local environmental controls, remains an with notably different depth penetration scales important consideration. and seismic resolutions.

We present a consensus reconstruction of lipid, The Waihemo Fault System can be seen to extend chironomid and pollen‐based temperature from the basement through the overlying Tertiary estimates, covering the glacial‐interglacial cycle, sedimentary units, with the Shag Point Anticline from two climatically sensitive sites in southern visible on the northern side. The new high‐ New Zealand. The consensus reconstruction resolution data, as well as the older exploration approach is designed to smooth local, site‐specific data, appear to confirm previously created signals by combining several lake sediment cores, offshore segment models, and potentially extend and by the same logic, we hope to smooth local, the fault system further offshore. Strands of the proxy‐specific signals by amalgamating the three Waihemo Fault System are shown to continue proxies and two sites into a single temperature from onshore to offshore away from the coast reconstruction. This consensus is developed by with an approximate northwest‐southeast strike. normalising and smoothing each record and then At least one of these main strands is confirmed, combining all of the data into a single temperature while the two others are not seen in the new high‐ profile. We both discuss the validity of this resolution data. A previously inferred extension of approach as a means to provide robust the Titri Fault System in the area, running parallel interpretations of multi‐proxy data and ask the to the coastline and extending from south of question, “Is it a dumb idea?” Dunedin, has not been proven and remains a possibility.

SEISMIC IMAGING OF THE WAIHEMO FAULT SYSTEM IN THE SOUTHERN CANTERBURY BASIN THE ROOTS OF A MONOGENETIC VOLCANO: OFF HYALOCLASTITES, DYKES AND DIATREMES COASTAL OTAGO REVEAL A COMPLEX HISTORY OF PLIOCENE

1 1 VOLCANISM ALONG THE WAIKATO COAST, NEW L. N. van Haastrecht & A.R. Gorman ZEALAND 1Department of Geology, University of Otago, PO Box 56, Dunedin 9054 R. van Niekerk1, K. Németh1, G. Lube1 [email protected] 1Volcanic Risk Solutions, Massey University, Private Bag 11222, Palmerston North 4442 The Waihemo Fault System is a major crustal‐scale [email protected] structure that forms the northern boundary of the active north‐east striking ranges of Otago. The Monogenetic volcanic fields have been drawing fault system on the east coast of the South Island growing research interest ‐ Auckland City is but is orthogonal to the coast but its offshore one example of a major settlement on or near a geometry is still poorly understood. The Waihemo dormant volcanic field. Many questions remain Fault System originated in the Cretaceous as a set about the catastrophic nature of hazards of crustal‐scale northeast trending normal faults associated with this type of volcanism. Recent that reactivated as reverse faults in the Late literature has demonstrated the need for a Cenozoic. This study aims to investigate the thorough understanding of subsurface geology as offshore extent of the Waihemo Fault System, how to comprehend the triggers, scales and impacts of it changes further away from the coast, and how eruptions in monogenetic volcanic fields. As such, this compares to the known nature of the onshore a section at Ngatutura Bay along the Waikato coast fault system. offers a rare opportunity to observe the roots of a monogenetic volcano that are thoroughly exposed Three multichannel seismic data sets were used in and extraordinarily well preserved. The volcanic a comparison study to comprehensively features observed include hyaloclastite piles and characterise the offshore section of the Waihemo lava domes with pillows and peperitic margins, as Fault System. Petroleum industry exploration data well as at least one diatreme structure. Diatremes from the 1980s were compared to recent seismic are subsurface structures, often associated with data from 2012 (RV Kaharoa 48‐channel data with maar volcanoes. They are filled with fragmented a generator‐injector airgun source) and 2014 (RV magma and country rock that originated from Polaris II 24‐channel data with a boomer source), numerous phreatomagmatic explosions. The

111 presence of a diatreme indicates subaerial expulsion to occur at shallower burial depths than explosive activity. In contrast, pillow lavas and would otherwise be required. dykes represent non‐explosive volcanism in a subaqueous environment. Local stratigraphy is The Waipawa Formation is an organic‐rich, marine well defined and helps to explicate the eruption source rock that occurs in many New Zealand history of the region. The base of the section sedimentary basins. Weathered exposures comprises Oligocene‐Miocene marine sediments frequently display sulphur oxide coatings suggest ‐ of the Te Kuiti Group that is overlain by the the presence of reduced sulphur species (e.g. HS , Pliocene Kaawa Formation and Late Quaternary polysulphides) in the rock matrix. Preliminary Awhitu sandstone, the latter being of terrestrial analyses of twelve outcrop samples from the provenance. Non‐explosive features are found Raukumara Peninsula, Hawke’s Bay, and within the Kaawa Formation, indicating a shallow Wairarapa suggests sulphurisation of OM may marine environment. A rapid shift to subaerial have been an active preservation pathway that conditions is envisaged with the diatreme forming impacted the quantity, quality and maturity of OM in close association with the terrestrial Awhitu within the Waipawa Formation. To verify these sands. Furthermore, the facies architecture of the observations the freshly exposed Upper Angora diatreme is complex; highly varied volcaniclastic Road (Taylor–White) section in southern Hawke’s domains pertain to the vibrant nature of diatreme Bay is currently being analysed. The ~70 m thick formation. The significance of such dynamic Waipawa Formation in this section has transitional volcanism, and applicability to the Auckland boundaries with the underlying Whangai Volcanic Field are elucidated by unravelling the Formation and the overlying Wanstead Formation. processes behind the spatially and temporally The section consequently offers a rare opportunity confined volcanism at Ngatutura Bay. to evaluate the bottom water geochemistry during sediment deposition and the potential impacts sulphurisation of OM may have played on the petroleum potential and generation history of this EFFECTS OF ORGANIC MATTER SULPHURISATION formation. ON THE PETROLEUM GENERATION CHARACTERISTICS OF THE LATE PALEOCENE WAIPAWA FORMATION OF THE EAST COAST BASIN, NEW ZEALAND INTERSEISMIC, COSEISMIC, AND SLOW SLIP EVENT DEFORMATION ABOVE A SHALLOW G.T. Ventura1, B.D. Field1, K.J. Bland1, D.P. SUBDUCTION THRUST IN THE WESTERN Strogen1, C.J. Hollis1 & R. Sykes1 SOLOMON ISLANDS 1GNS Science, PO Box 30368, Lower Hutt 5040 1 1 2 [email protected] L. M. Wallace , F. W. Taylor , M. Bevis , D. Phillips3, E. Kendrick2 & J. Walter1 In this study we examine whether sulphurisation 1University of Texas, Institute for Geophysics, of organic matter (OM) has enhanced the Austin, TX, USA petroleum generation characteristics of the Late 2School of Earth Sciences, Ohio State University, Paleocene Waipawa Formation of the East Coast Columbus, OH, USA Basin, New Zealand. Kerogen, the non‐extractable 3UNAVCO, Boulder, CO, USA OM in sedimentary rocks, typically forms by the [email protected] decomposition and condensation of biogenic polymers. Within Fe‐limiting, sulphidic The western Solomon Islands are a remarkable environments the sulphurisation of OM plays an natural laboratory to investigate processes important role in kerogen formation. Under these occurring on a shallow subduction interface. conditions even highly labile compounds, such as Islands within the New Georgia Group are located carbohydrates, can be reduced and bound to <15 km from the San Cristobal Trench, with the sulphur radicals to form organosulphur subduction thrust located only a few km beneath compounds that are in turn joined together by the southwest coast of islands like Rannonga and relatively weak intermolecular carbon‐sulphur and Rendova. This offers a globally unique opportunity sulphur‐sulphur cross‐linkages. Cleavage of these to use GPS to monitor deformation processes very weaker bonds and the ensuing release of sulphur close to the trench at a subduction zone. We radicals can enable petroleum generation and present results from a campaign GPS network in the western Solomons that was operated from

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1996‐2007. The data from 1996‐2002 indicate character of SSEs at Hikurangi also undergoes interseismic coupling on the shallow portion of the strong along‐strike variations. At central interface, at a rate of nearly 100% of the relative Hikurangi, the majority of the megathrust between plate motion. Coupling does not appear to extend <10‐50 km depth undergoes SSE slip of varying deeper than ~20 km depth, and the relatively durations (weeks to > 1 year), indicating that the shallow down‐dip limit of coupling is consistent physical conditions conducive to SSE slip may be with subduction of young (<6 Ma) oceanic crust of inherently broad. SSEs also appear to dramatically the Woodlark Basin. We also show evidence for a impact seismicity rates in the North Island: the slow slip event in late 2000, observed at a GPS site large (Mw > 7.0) 2013/2014 Kapiti SSE and many of near Gizo that was running continuously from the east coast, shallow SSEs are excellent examples 1999‐2002. In April 2007, an Mw 8.1 earthquake of this. We will also discuss interactions between occurred on the subduction thrust beneath the the 2013 Kapiti SSE and the January 2014 network, resulting in large coseismic Eketahuna Mw 6.3 intraslab earthquake. The displacements at nearby campaign GPS sites. The Eketahuna earthquake was consistent with being earthquake caused widespread coastal uplift and triggered by the Kapiti SSE, while stress changes on subsidence in the region, as revealed by studies of the interface induced by the Eketahuna coral microatolls following the earthquake (Taylor earthquake may have abruptly halted the Kapiti et al., 2008). We invert displacements of the cGPS SSE. This is the first‐ever example of a local sites jointly with vertical displacements of coral earthquake halting an SSE. microatolls to evaluate the coseismic slip during the earthquake. The area of the interface that The marked along‐strike changes in subduction underwent slip in the earthquake matches well interface slip behaviour at Hikurangi have sparked with the region that was interseismically coupled much international interest in the Hikurangi just prior to the 2007 earthquake. The data also margin as a natural laboratory to understand require large coseismic slip on the shallow subduction megathrust slip behaviour. SSEs interface near the trench, which likely contributed offshore Gisborne are the shallowest well‐ to the generation of a large, damaging tsunami documented SSEs on Earth, making them an following the earthquake. excellent locale to undertake investigations of the SSE source area. Offshore Gisborne is the target of a variety of marine geophysical studies including seismological and seafloor geodetic investigations, INVESTIGATING SPATIAL AND TEMPORAL as well as proposals to use scientific drilling to VARIABILITY OF SLIP BEHAVIOUR ON THE understand the origin of SSE behaviour. HIKURANGI SUBDUCTION THRUST

L. M. Wallace1, N. Bartlow2, S. Bannister3, B. Fry3, USING SEISMICITY TO DETECT THE OCTOBER 13TH I. Hamling3 & C. Williams3 2012 TE MAARI LAHAR 1University of Texas, Institute for Geophysics, Austin, TX, USA B. Walsh1, J. Procter1, S. Cronin1 & A. Jolly2 2Scripps Institution of Oceanography, University of 1Volcanic Risk Solutions, Massey University, Private California, San Diego, CA,USA Bag 11222, Palmerston North 4442 2 3GNS Science, Lower Hutt, NZ GNS Science, Wairakei Research Centre, Private Bag 2000, Taupo 3352 [email protected] [email protected]

Over the last decade, campaign and continuous Volcanic mass flows are a major concern for GPS measurements in the North Island have populated areas on and around volcanic revealed marked along‐strike variations in slip mountains. Being able to detect these flows is of behaviour of the Hikurangi subduction thrust. The most importance for the safety of lives, southern Hikurangi interface undergoes deep communities, and industry. Many instruments and interseismic coupling (down to 30 km depth) and techniques have been used to detect, measure, deep (>30 km), long‐term (>1 year) episodic slow and record mass flows, but none have been more slip events (SSEs), while much of the interface at promising then seismic techniques. The benefits the northern and central Hikurangi margin is seismic techniques have over other techniques dominated by aseismic creep and SSEs. The include the fact that seismic instruments can

113 collect data at a safe distance from the event and into a depth‐integrated tsunami run‐up and most importantly seismic methods can work in any inundation simulation. In this model, the tsunami weather and during the day and night. Here we simulation provides information on temporal and present the seismic recordings for the October spatial evolution of tsunami currents and the 13th‐14th 2012 Te Maari lahar as a possible dispersals of waterborne debris and pollutants are stepping‐stone to seismic lahar detection. Seismic simulated as passive agents with RWPT. Scenario recordings of the October 2012 event are studies show that the coupled model can provide particularly important because the lahar occurred indicative and quantitative information with overnight with no eyewitnesses. The seismic data respect to this type of environmental influences of from the October 2012 event were collected from tsunami impact, including dispersal pathways, and three broadband 3‐component seismometers the distribution and extent of hazardous material located on and around Mt. Tongariro. The seismic in tsunami events. This information will benefit data were processed, and spectra were created. land‐use planning and evacuation mapping for From the spectra, spectrograms were generated to improved tsunami hazard mitigation. determine where in the seismic records the lahar occurred. From the spectrograms it was determined that the lahar occurred at approximately 11:30 UTC on October 13th and THE WAIHAPA OILFIELD – WHAT 25 YEARS OF lasted for about 40.0 minutes, with a frequency EXPLORATION AND PRODUCTION DATA TELLS US range between 3‐15Hz. The use of spectrograms is ABOUT THE INTERNAL PLUMBING OF NEW especially important when there is a lot of ZEALAND’S ONLY FRACTURED CARBONATE OIL background noise. Noise can cause the seismic RESERVOIR signal of the lahar to get lost in the overall seismic 1 1 1 recording and the lahar can be almost impossible S. Ward , D. Hoke and R. Kellett 1 to detect just from the record. Furthermore, lahars New Zealand Energy Corp, PO Box 8440, New are more likely to be found in spectrograms Plymouth 4342 because lahars occur in a distinctive frequency [email protected] range. Detecting the frequency outputs produced by lahars has much potential for identifying future The Waihapa Oilfield is one of a number of events, and may lead to a real time lahar warning hydrocarbon accumulations along the Tarata system. Thrust foldbelt located in eastern Taranaki. The field has produced 24 million barrels of oil and 28 BCF of gas since 1998, mostly from 8 wells. Reservoir comprises fracture porosity in the TRACKING POLLUTANT AND DEBRIS DISPERSAL Oligocene Tikorangi Limestone which developed as DURING TSUNAMI EVENTS a result of Pliocene extensional faulting. Successful wells are characterised by extensive X. Wang1 & W.L. Power1 fluid losses and hydrocarbon shows while drilling, 1GNS Science, PO Box 30368, Lower Hutt 5040 though total produced oil volumes are strongly [email protected] controlled by the timing of water influx. Artificial lift has been used to maintain oil production, with Dispersals of debris and hazardous material are economic limits being controlled by water cut and recognized among others as major environmental oil price. Unusually, many wells exhibit apparent aftermaths of the 2004 Indian Ocean Tsunami and recharge over weeks to months when shut in, the 2011 Tohoku event, in addition to direct losses indicating that mobile oil is still present in the of property and human lives. In these events, fracture system. Pressure measurements indicate dislocated and contaminated waste and debris water has replaced oil up to the level of the posed immediate threats to tsunami evacuation highest producing well in the main Waihapa and became one of major obstacles in structure. reconnaissance actions and recovery process following the tsunami disasters. Hydrocarbon column pressure measurements indicate that there was an initial oil column in the In order to investigate the dispersal of debris and Tikorangi Limestone covering 900+ vertical metres pollutants during tsunami events, we develop a and extending along strike through the Waihapa, coupled simulation model in which Random Walk Ahuroa and Tariki structures. Despite this, only 1 Particle Tracking (RWPT) schemes are integrated additional well in the far north has produced

114 modest volumes of oil from the Tikorangi Southern Lakes to examine this apparent along‐ Limestone. Many wells have failed to intersect strike change in exhumation pattern. Our results sufficient connected fracture systems to sustain show the width of the apatite HEZ in the commercial production. Southern Lakes has been previously over‐ estimated. Instead, fully reset AFT ages are In late 2013, New Zealand Energy Corp and its limited to within ~30 km of the Alpine Fault partner L&M Energy acquired the Waihapa (comparable to the Central Alps), whilst the Production Station and the Waihapa, Ngaere and transition to Cretaceous ages though partially Tariki Mining Licences. NZEC has reactivated 6 reset AFT ages occurs over a wider area than Tikorangi production wells, using gas lift and a high further north. volume downhole electric pump to extract reservoir fluids and increase pressure drawdown, Combining this new exhumation profile with in order to mobilise oil trapped in tighter fractures. inverse modelling techniques we are able to Total NZEC production to date is over 51,000 impose constraints on the sub‐surface geometry barrels. NZEC also continues to evaluate further of the Alpine Fault underneath the Southern drilling opportunities within the wider Tikorangi Lakes. Limestone oil column. [1]J. Tippett Kamp (1993). J.G.R. 98, 16119‐16148.

RE‐INTERPRETATION OF THE EXHUMATION PROFILE OF THE SOUTHERN LAKES REGION, NEW GRAIN SIZE ANALYSIS OF CATACLASITES WITHIN ZEALAND, FROM APATITE AND ZIRCON FISSION‐ THE OTAGO SCHIST TRACK AGES C. Webster1 & V. Toy1 1 1 1 E. Warren‐Smith , D. Seward , S. Lamb , T. A. 1Geology Department, Otago University, PO Box 1 2 Stern & F. Herman 56, Dunedin 9054 1 SGEES, Victoria University of Wellington, P O Box [email protected] 600, Wellington 6140 2Institute of Earth Surface Dynamics, Université de We discuss the deformation mechanisms and Lausanne, Lausanne, Switzerland Emily.Warren‐ microstructure which form during earthquake [email protected] rupture. Three main processes are identified as being important in forming cataclasites: Apatite and zircon fission‐track (AFT and ZFT) mineralogic alteration, constrained comminution, ages from New Zealand’s South Island show that and selective fragmentation of particles. Together displacement on the Alpine Fault largely controls these result in increasing irregulatity of particles Cenozoic vertical kinematics of the Pacific [1]. In and mean size reduction. Such microstructures the Central Alps, AFT ages within ~25 km of and evidence that result from these processes can the Alpine Fault are fully reset as a result of be identified and used to estimate the conditions late Neogene exhumation of the hanging wall. under which the cataclasis occurred. The degree of These young AFT ages (<5 Ma) define a high particle size reduction may be directly related to exhumation zone (HEZ) which transitions the energy released within a fault zone. While through partially reset ages to background there have been numerous studies investigating Cretaceous AFT ages with increasing distance particle size distribution within fault zones, we from the Alpine Fault. examine the relationship of grain size and shape to the processes observed during cataclasis. Samples However, in the Southern Lakes this HEZ appears have been examined from three brittle fault zones to widen, with very young (0 Ma) AFT ages found at Loch Laird Reserve, Otematata. The up to 60 km from the Alpine Fault. These ages displacement along the fault planes ranges from are inconsistent with geological observations, 0.6 – 6.8m. High‐resolution backscatter images and we believe are artificially young as a result of were taken using a scanning electron microscope a low uranium concentration in the apatite used from which particle maps were produced for age calculation. distinguishing grains according to their size and shape. Mineral phases can be separated by Here we present new AFT and ZFT ages for 29 manipulating the contrast and brightness to samples from the Haast Schist around the investigate the size and shape of each phase

115 separately. Comparison of this data allows us to Ba, K, Cs) show the highest mobilities, but also in determine the conditions at the time of cataclasis. some changes in the concentration of major Future work is intended to compare the particle elements (e.g. Ca, Si) and the volatile components distribution with the mechanisms of deformation (e.g. CO2, S). Mobility of elements is traceable on to assess the energy released during fault rupture. microscopic scale, too. For example, during the replacement of calcite by ankerite, Mg and Fe, the light and medium REE are added and Ca removed.

CHEMISTRY OF CARBONATE VEINS, THE ORIGIN OF THEIR COMPONENTS AND THE ALTERATION HALOES AROUND THEM ‐ A CASE STUDY FROM GLACIER MONITORING IN 3D USING STRUCTURE WESTERN OTAGO FROM MOTION (SfM)

1 1 1 1 A.K. Wellnitz , J.M. Scott , J.M. Palin , D. Craw , 1 1 1 2 1 2 & 3 J. Welter , H. Horgan , B. Anderson , A. Lorrey , T. C.E. Martin , G.J. Holk F. Wombacher 3 2 1 1 Chinn , A. Willsman and A. Mackintosh Department of Geology, University of Otago, PO 1Antarctic Research Centre, Victoria University of Box 56, Dunedin 9054 2 Wellington, P O Box 600, Wellington 6140 Department of Geological Sciences, Californian 2National Institute of Water and Atmospheric State University, Long Beach, CA, USA 3 Research, Private Bag 99940, Auckland 1010 Universitätzu Köln, Geologie und Mineralogie, 3Lake Hawea Institute of Cryodynamics, 20 Muir Greinstr. 4‐6, 50939 Cologne, DE Rd, LGM Hawea, RD2 Wanaka 9382 [email protected] [email protected]

In Otago's Southern Alps, Miocene tectonics have The end of summer snowline (EOSS) dataset, caused the formation of faults and joints. In places, comprising oblique aerial photographs of glaciers these structures served as pathways for fluids that in the New Zealand Southern Alps dating back to produced the Shotover gold deposits and for the 1978, has proved a valuable resource for glacier alkaline intrusives of the Alpine Dike Swarm. monitoring. Here we outline a method for Additionally, Fe‐carbonate veins and alteration extracting additional quantitative information zones are found connected to these structures. from these data using newly developed The goal of this study is to trace back the origin of photogrammetric techniques. the different components of the carbonate and whether there could have been a connection The technique of ‘structure from motion’ (SfM) between the CO2 bearing fluids in the enables the creation of 3D digital models without mesothermal gold system of the Shotover and the laser scanning or conventional stereoscopic carbonatites of the Alpine Dike Swarm. photogrammetry. Digital models made with SfM from oblique photos have a higher resolution than Radiogenic isotopes (Sr, Nd) reveal that the conventional DEMs, and can be created more isotopic signature of fluids and precipitating frequently resulting in a more accurate carbonates are highly influenced by the representation of the landform. This makes SfM immediately surrounding host rock. Trace element ideally suited for extracting metrics from changing concentrations seem to be mostly dependent on glaciers, such as snowline, terminus position, and their structural position of the carbonate, eg. volume, from existing and future photo datasets. whether it is in a silicified breccia, veins or disseminated in the wall rock. However, As a proof of concept, we present the photo sets carbonates at the southern end of the Alpine Dike of Brewster Glacier covering the years from 1985 Swarm do show mixed signals regarding their to 2012. Photoscan software was used to generate chemical and isotopic compositions, which can be models, which enabled orthophoto construction explained as the result of the interaction of for most years within that period. Coregistration of magmatic and crustal sourced fluids. the orthophotos allowed visual and quantitative analysis of the snowline and terminus positions. The CO2‐rich fluids not only form carbonate in veins, but also infiltrate the wall rock. This causes Adequate photo coverage also enables the the breakdown of metamorphic epidote, chlorite, generation of accurate 3D point clouds. Brewster actinolite and titanite and the formation of Glacier elevation models were directly compared carbonates. During this alteration the LILEs (Sr, Rb, at the point‐cloud level using CloudCompare

116 software. Future goals include determining a remaining cold, and the glacier progressively method for quantifying volume changes and the ablated such that its surface had lowered 390 m by establishment of ground control points (GCP’s) to the start of MIS 2 and by >600 m by ca. 18 ka. The increase the accuracy of terminus and snowline culmination of the gLGM in NZ occurred in MIS 3 positions, and volume change estimates. about 12 000 years before global ice volume reached its peak. By the time global ice was at a maximum (19 ka) glaciers had almost disappeared from major Fiordland valleys in New Zealand. A REVIEW OF NEW ZEALAND PALAEOCLIMATE FROM THE LAST INTERGLACIAL TO THE GLOBAL TSUNAMI AND CYCLONE DEPOSITS: THE SAMOAN LAST GLACIAL MAXIMUM CASE

1 2 3 P.W. Williams , M. McGlone , H.L.Neil & J.‐X. S. Williams1,2, C. Chagué‐Goff3,4, J. Goff3, T.R. 4 Zhao Davies1, A. Zawadzki4, G. Jacobsen4, P. Gadd4, H. 1 School of Environment, University of Auckland, PB Heijnis4 92019, Auckland 1142 1Department of Geological Sciences, University of 2 Landcare Research, PO Box 40, Lincoln, Canterbury, Private Bag 4800, Christchurch 8140 Canterbury 7640 2GEOL Geomanage Environ Oceania Limited, 31 3 National Institute of Water and Atmospheric Blake Street, Christchurch 8061 Research, Kilbirnie, PB 14901, Wellington 6241 3School of Biological, Earth and Environmental 4 Radiogenic Isotope Laboratory, University of Sciences, UNSW Australia, Sydney Queensland, Brisbane, Queensland 4072, Australia 4Institute for Environmental Research, ANSTO, [email protected] Kirrawee DC, Australia [email protected] Results from terrestrial and marine palaeoclimate proxies are integrated to reconstruct We report on geochemical and sedimentary palaeoclimate variations in New Zealand from the proxies used to identify and distinguish tsunami Last Interglacial to the global Last Glacial from cyclone deposits on Savai’i, Upolu, and Ta’u Maximum (gLGM). The MIS 5e thermal maximum islands in the Samoan archipelago. Subtle in New Zealand was around 128‐122 ka BP. differences in the elemental ratios, loss on Temperatures in parts of the North Island may ignition, and grain size characteristics between the have been 2‐3C warmer than present and sea preserved 2009 South Pacific Tsunami deposits, level 3‐5 m above modern. In MIS 5d and 5b cool and the identified 1990—1991 Cyclones Ofa and conditions with glacial advances occurred in the Val deposits, provide analogues for distinguishing South Island, but from about 87‐73 ka in MIS 5a probable tsunami from cyclone deposits deeper in warmth within 2C of present characterised most the stratigraphic record. 210Pb and 14C of the Otamangakau Interstadial. Conditions then geochronological indicators help to corroborate cooled rapidly and culminated in a MIS 4 glacial the identified historical events, and constrain the advance that was the greatest of the Last Glacial timing of identified palaeo‐events, respectively. An Cycle (nzLGM). Conditions that followed during approximately 3,000‐year‐long baseline tsunami MIS 3 were very variable. The climate in Hawke and cyclone chronology is developed for this Bay and the Bay of Plenty at the start of MIS 3 was region, and directions for future research are similar to the Holocene, and the period 61‐43 ka proposed. was relatively mild overall and is termed the Aurora Interstadial, although it contained a short interval of mountain glacier expansion around 49‐ 47 ka. After 43 ka conditions cooled again with a NUMERICAL MODELS OF THE HIKURANGI glacial advance from 42‐38 ka, before a return to MARGIN ‐ THE ROLE OF DIFFERENT LITHOSPHERIC milder, but still cool conditions during the BLOCKS IN THE SUBDUCTION DYNAMICS Moerangi Interstadial from 37 ‐ 31 ka. The D. Willis1 & L. Moresi2, P. Betts1 & L. Ailleres1 maximum glacial advance occurred in late MIS 3 1School of Geosciences, Monash University, around 31 ka. The glacial onset was abrupt, with Clayton Campus, VIC 3800, Australia the Te Anau Glacier in Fiordland taking only about 2Department of Earth Sciences, University of 2000 years to achieve its maximum gLGM height, Melbourne, Melbourne VIC 3001, Australia probably because conditions were wet as well as [email protected] cold. The climate then became drier, while

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The role of different lithospheric blocks along the passive data collected during the SAHKE Hikurangi margin has been investigated using deployment provides an excellent opportunity to Underworld models setup to mimic northern New measure seismic anisotropy at the Hikurangi Zealand’s lithospheric setting. Using free‐slip margin from shear wave splitting analysis. We plan boundary conditions, the models rely on the to build a model of azimuthal shear wave buoyancy contrast of the subducting lithosphere to anisotropy and from this infer the orientation of create a slab pull force that drives deformation in compressional stresses across the southern North visco‐elastic models. By including and excluding Island. Preliminary results from a subset of seven equivalents of the Chatham Rise, Hikurangi Plateau seismometers recording earthquakes of magnitude and South Fiji Basin, as well as altering their greater than 3 returned fast directions parallel to relative strengths, we have explored dynamic role the NE/SW regional maximum horizontal stress each of the lithospheric blocks plays in the direction determined by focal mechanism studies. complex tectonic setting. The models have shown From a larger set of anisotropy measurements we it is possible that the Alpine Fault and Hikurangi will model the upper crustal stress field, and if Trough once formed a continuous, linear plate time permits calculate focal mechanisms for local boundary and that slab pull is driving the Chatham earthquakes collected by the passive array and Rise further into the overriding plate. Velocity compare them to the stress model. outputs from passive tracers in the near surface of the models have been compared with GPS and schematic displacement diagrams of New Zealand. The velocities show that rotation of the North NEW ZEALAND’S IMPROVED VERTICAL DATUM Island only requires the presence of the Chatham 1,2 2 1, Rise driving into the overriding plate and an area R. Winefield , M. Amos , J. McCubbine E. 1 3 opening up above a subduction zone in roll back. Smith & F. Caratori Tontini 1 The rotation seen in the Pacific Plate is only SGEES, Victoria University of Wellington, PO Box matched when a buoyant plateau enters the 600, Wellington 6140 2 subduction zone, creating differential velocities of Land Information New Zealand, National subduction and trench roll back along the Geodetic Office, Wellington 6145 3 subduction zone. Once introduced, the thin weak GNS Science, PO Box 30368, Lower Hutt 5040 lithosphere of the oceanic South Fiji Basin allows [email protected] quicker back‐arc extension in the over‐riding plate, this velocity increase results in a quickening of The most timely and cost effective means of subduction roll back to the north of New Zealand determining heights is to use technologies such as and increasingly asymmetric subduction rollback. GNSS. However, GNSS heights are related to an ellipsoid: a mathematical figure used to approximate the shape of the Earth. As they are not related to the Earth’s gravity field, they may CRUSTAL SEISMIC ANISOTROPY AT THE not accurately predict the direction which water HIKURANGI SUBDUCTION MARGIN, LOWER will flow. NORTH ISLAND, NEW ZEALAND An ellipsoidal height can be converted to a normal‐ T.D. Wilson1 & M. K. Savage1 orthometric height or “height above sea‐level” 1Institute of Geophysics, SGEES, Victoria University through the application of a geoid model: a of Wellington, PO Box 600, Wellington 6140 hypothetical surface that describes the irregular [email protected] shape of the Earth’s gravity field. Normal‐ orthometric heights can then be used in surveying, The Seismic Array Hikurangi Experiment (SAHKE) hydrology, agricultural and other land was a large seismic acquisition project undertaken management applications. from late 2009 until mid 2011, across the southern North Island of New Zealand. The SAHKE data set Land Information New Zealand is halfway through provides high spatial resolution of the Pacific Plate a four‐year project to improve the New Zealand subducting beneath the Indo‐Australian plate. Vertical Datum 2009 (NZVD200), the national SAHKE consisted of two phases: A series of active reference surface for elevations. Much of this source seismic lines, and a five month passive improvement will be realised through the seismometer deployment consisting of 57 short‐ integration of data from a national airborne gravity period & 10 broad band seismometers. The survey with existing terrestrial gravity

118 observations. The final result will be a more HAVRE 2012: THE LARGEST HISTORIC SUBMARINE accurate geoid and national vertical datum. ERUPTION THE WORLD HAS NEVER SEEN

1 2 3 This presentation investigates the role of gravity R.J. Wysoczanski , C. Timm , M.R. Handler & R.J. 4 observations in height system definition and the Carey 1 benefits of easier access to more accurate and National Institute of Water and Atmospheric comparable heights in New Zealand. Research, Private Bag 14901, Wellington 6241 2GNS Science, PO Box 30368, Lower Hutt 5040 NEW INSIGHTS INTO WELLINGTON HARBOURS' 3SGEES, Victoria University of Wellington, PO Box TECTONIC SETTING FROM MARINE GEOPHYSICAL 600, Wellington 6140 & SEDIMENTOLOGICAL DATA 4CODES, University of Tasmania, Sandy Bay,

1 1 1 1 Tasmania, Australia S. Woelz , S.D. Nodder , P.M. Barnes , A.R. Orpin [email protected] 1National Institute of Water and Atmospheric Research, Private Bag 14901, Wellington 6241 The July 2012 eruption of Havre caldera volcano [email protected] was likely to have been the largest submarine eruption documented. The eruption, reported to After the experience of several damaging coastal be a one in a century event, produced an earthquakes in New Zealand in the last three atmospheric plume that penetrated at least 900 m years, the importance of locating and of seawater, and a pumice raft reported to have characterising the earthquake potential of active had an aerial extent similar to Canterbury. Pumice faults close to urban areas has become more from this raft has since dispersed and is still obvious, especially when cities lie in complex washing up on beaches across the Pacific. The tectonic settings as it is the case for Wellington. To estimated volume of the eruption is at least 1.5 assess the earthquake and tsunami potential and km3. the associated hazard posed by such faults, it is necessary to characterise fault geometry, slip rate, Multibeam echosounder data was collected over earthquake history and earthquake potential. In the volcano during the R/V Tangaroa Nirvana the marine environment, we have the advantage expedition (TAN1213) 3 months after the eruption. that faults can be assessed cross‐sectionally Comparison with previously collected data in 2002 through the application of high‐resolution allowed changes in the seafloor resulting from the geophysical data without having to excavate eruption to be established. These show (i) the trenches across the active fault trace. growth of a new c. 250 m high cone on the We present new marine data from Wellington southeast flank of the caldera rim thought to be Harbour that helps to characterise three faults; the the main eruption conduit; (ii) a field of 8 small Wellington Fault at Kaiwharawhara, the Evans Bay cones on the southern rim; and (iii) a bulged area Fault, and a newly discovered fault off Oriental on the western wall of the caldera. The 5 km wide Bay, informally referred to as the Mount Victoria caldera floor itself was in places 50 m higher in Fault (see paper by Nodder et al. this conference). relief than before the event, but it was not the New marine geophysical data has better source of the eruption itself. delineated the location and characteristics of these faults. High‐resolution multi‐beam Samples collected from the caldera range include bathymetric data (50 cm grid‐cell size), covering dark dense rhyodacite, light to dark grey pumice, the entire Wellington Harbour, were also used to and white pumice clasts. Pumice dispersed from determine the occurrence of seafloor scarps the raft is all white pumice. The 2012 eruption associated with surface ruptures on the faults. products show a range of chemical compositions Sediment cores from either side of the Wellington with little change in chemistry by pumice colour. Fault off Kaiwharawhara Stream, in about 17.5 m Despite the large range, the sample suite shows a water depth, provide insight into the late well‐defined fractionation trend and geochemical Quaternary‐Holocene stratigraphy and age of composition that differs from other caldera sediments that have been deformed by activity on volcanoes of the Kermadec arc, which generally the faults delineated in Wellington Harbour. The show fractionation trends unique to themselves. stratigraphy reveals details of the post‐glacial These distinct compositions can be used to marine flooding of the harbour that occurred fingerprint the source volcano of pumice rafted about 10,000 years ago. from the Kermadec arc.

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A STRUCTURALLY‐CONTROLLED HYDROTHERMAL RAPID ASCENT OF APHYRIC MANTLE MELTS SYSTEM IN THE MANUHERIKIA FAULT ZONE, THROUGH THE OVERRIDING CRUST IN ALEXANDRA, CENTRAL OTAGO SUBDUCTION ZONES: EVIDENCE FROM VARIABLE U‐SERIES DISEQUILIBRIA, AMORPHOUS HYDROUS S. Yeo1 & D. Craw1 & D. MacKenzie1 & J. Scott1 ALTERATION MICROTEXTURES IN CRYSTAL RIMS, 1University of Otago, Geology Department PO Box AND TWO‐PYROXENE PSEUDO‐DECOMPRESSION 56, Dunedin PATHS [email protected] G.F. Zellmer1, H. Freymuth2, H.‐H. Hsieh3, S.‐L. A zone of brittle faults, hosted within Hwang4, Y. Iizuka3, C.A. Miller5, K.H. Rubin5, quartzofeldspathic Otago Schist, occurs along the N. Sakamoto6 & H. Yurimoto6 NE‐trending margin of the Manuherikia valley in Central Otago. The faults were initiated in the 1Institute of Agriculture and Environment, Massey Cretaceous with predominantly normal sense of University, Private Bag 11222, Palmerston North motion. Some faults have been reactivated as 4442 reverse structures since the Miocene, offsetting 2School of Earth Sciences, University of Bristol, Cenozoic sediments. There is also evidence for Wills Memorial Building, Queens Rd., Bristol BS8 strike‐slip motion on some fault strands. 1RJ, UK Quaternary reactivation has resulted in stepped 3Institute of Earth Sciences, Academia Sinica, 128 topography adjacent to the Manuherikia River. Academia Road Sec. 2, Nankang, Taipei, Taiwan Cretaceous fault activity was accompanied by 4DMSE, National Dong Hwa University, No. 1, Sec. hydrothermal fluid flow and minor alteration of 2, Da Hsueh Rd., Shoufeng, Hualien 97401, Taiwan fault rocks and adjacent wall rocks. There are 5Geology & Geophysics, SOEST, University of three different styles of hydrothermal alteration: Hawaii at Manoa, 1680 East West Road, Honolulu, narrow silicified zones, wide silicified cataclasite HI, USA zones, and carbonitic shear zones. The narrow 6Isotope Imaging Laboratory, University of silicified zones have 5‐10 cm wide silicified Hokkaido (HokuDai), Sapporo 060‐0810, Japan cataclasites along the fault plane, and these [email protected] dominate the southern end of the area. Some of these zones host veins with euhedral crystals of Volcanic hazard mitigation at subduction zones calcite and quartz. The narrow zones have a wide critically depends on knowledge of magma range of orientations, and are traceable for only generation and ascent processes and timescales. short distances (<100 m) along strike. Some are Two diametrically opposite scenarios are presently north‐striking, whereas many of the smaller faults debated: One paradigm is the generation of low‐ are predominately orientated east‐west. Farther silica (basaltic) melts in the mantle wedge, north in the area, wide resistant, silicified slabs of followed by protracted sub‐liquidus magma ascent cataclasite, up to 5 metres across, form resistant and evolution through crystal growth and ridges across topography. These zones are well‐ fractionation in crustal reservoirs, which are exposed, with prominent fault planes containing tapped during volcanic eruptions. The contrasting slickenlines which predominately show a dip‐slip model favours the generation of higher silica melts sense of motion. These large resistant faults range in the mantle or in a lower crustal hot zone, from moderately to steeply dipping and are largely followed by rapid decompression to the surface orientated NE‐SW. Carbonitic shear zones are under super‐liquidus conditions. In the latter case, prominently orange‐stained where ferroan calcite crystals are picked up during magma ascent and has been altered to limonite, and form easily‐ are in the process of dissolving. We present eroded lower topographic features within the area multiple lines of evidence that point to crystal such as gullies or saddles between ridges. Some uptake as the principal processes by which mafic carbonitic shear zones occur along the same strike to intermediate arc melts acquire their crystal 234 238 as the wide silicified cataclasite zones. Scattered cargo: (i) variable U‐ U disequilibria in mineral pyrite occurs in some silicified rocks, and there are separates; (ii) hydrous mineral rims with low but anomalous levels of arsenic and gold in amorphous alteration textures; and (iii) two‐ some fault rocks. pyroxene pseudo‐decompression paths; cf. Zellmer et al. (2014a,b,c), doi: 10.1144/SP385.3 and 10.1144/SP385.9 and 10.1144/SP410.1. These observations point to a scarcity of true phenocrysts in many arc magmas, and thus to

120 decompression of aphyric melts that take up their faults work together to accommodate relative crystal cargo during ascent. The data imply that plate motions. many hydrous wedge melts are more silica‐rich than basalts and achieve super‐liquidus conditions during rapid ascent from great depth. THE HOLOCENE TEPHRA RECORD OF MARINE CORE MD06‐3017, BAY OF PLENTY A. Zohrab1,2, R.J. Wysoczanski2, A. Orpin2, H. Neil2, ANALYSIS OF NEWLY ACQUIRED HIGH‐ 3 3 2 RESOLUTION LIDAR DIGITAL TOPOGRAPHIC DATA A. Kent , F. Tepley & M.R. Handler 1National Institute of Water and Atmospheric ALONG THE MARLBOROUGH FAULT SYSTEM, SOUTH ISLAND, NEW ZEALAND Research, Private Bag 14901, Wellington 6241 2SGEES, Victoria University of Wellington, PO Box R. Zinke1, J.R. Grenader1, J.F. Dolan1, E.J. Rhodes2, 600, Wellington 6140 3 R. Van Dissen3, R.J. Langridge3, C. McGuire4, A. College of Earth, Ocean, and Atmospheric Nicol3 Sciences, Oregon State University, Oregon, USA 1University of Southern California, 3651 Trousdale [email protected] Pkwy, Los Angeles, CA, USA 90089 2University of Sheffield, Western Bank, Sheffield The volcanic record preserved in terrestrial S10 2TN, UK deposits in the Bay of Plenty is reasonably well 3GNS Science, PO Box 30368, Lower Hutt 5040 established, especially for larger eruptions where 4 University of California, Los Angeles, 595 Charles thick deposits allow the eruptive events to be well Young Drive East, Box 951567, Los Angeles, CA, characterised. Smaller eruptions, or smaller phases USA 90095 of larger eruptive events, however, may not be as [email protected] well preserved as a consequence of the small amount of erupted material, differential erosion, We analyze newly acquired lidar high‐resolution burial by subsequent events or lack of exposure. digital topographic data to measure offset By contrast, these events may be better preserved geomorphic markers along the Wairau, Awatere, in the marine record, particularly where Clarence, and Hope faults in the Marlborough sedimentation rates are sufficient to create an Fault System, northern South Island, New Zealand. expanded, high resolution record to be preserved. With an average shot density of ≥ 12 shots/m2, these lidar data, which were acquired for us by the Marine core MD06‐3017 was collected during the US National Center for Airborne Laser Mapping R/V Marion Dufresne MD152 (MATACORE) voyage (NCALM) and New Zealand Aerial Mapping, offer a in early 2006. It was recovered in 150 m water uniquely detailed view of the topography along depth just 20 km from the coast in the Whakatane ~250 km of fault parallel imagery. We identify and Trough. This near‐shore setting has a high measure offset geologic features ranging in size sedimentation rate (1000 yrs/m of core), with the from ~1 m to 100s of meters to constrain the style 10 m recovered core spanning the Holocene and distribution of surface slip along each of these epoch. This high sedimentation rate has allowed a four faults, and present examples of the lidar data number of tephras to be preserved, ranging from at several key study sites including the well‐known small eruptions that deposited < 5mm of ash, to Branch River and Saxton River sites on the Wairau the large well‐known eruptives of the Taupo, and Awatere faults, respectively. The precise fault Mamaku and Rotoma events. offsets we measure at these sites, combined with post‐IR IRSL (225˚C) single‐grain K‐feldspar dating We will present 6 carbon ages, and major (EPMA) of fluvial terrace sediments, will provide the basis and trace (ICP‐MS) element data for 35 tephra for determining incremental slip rates on these units, both primary and reworked, from MD06‐ faults at a range of latest Pleistocene to late 3017. These data will add to the terrestrial record Holocene timescales. This project is part of a of the Holocene volcanic depositional history of broader effort to generate incremental slip rates, the offshore Bay of Plenty. We will also examine and paleoearthquake ages and displacements from the temporal evolution of larger volcanic events the four main faults that comprise the found in the core, as well as processes that rework Marlborough Fault System with the goal of further and redeposit the tephras in the marine record understanding how mechanically complementary through the comparison of glass shards in reworked units with primary pristine tephras.

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Unravelling these deposits could yield a more method has a factor two higher quartz yields, contiguous eruption history for the region. while visual inspection suggests that quartz purities are similar to those obtained via HF etching.

IMPROVING CAPABILITIES OF SURFACE [1] Gosse & Phillips (2001). Quaternary Science EXPOSURE AGE DATING WITHIN NEW ZEALAND Reviews 20, 1475‐1560. [2] Putnam et al., (2013). Quaternary Science 1 1 2 A. Zondervan , B. Ditchburn , K. Norton , M. Reviews 62, 114‐141. 3 3 3 Vandergoes , R. McDonnell , R. Tremain , D. [3] Talvitie (1951). Analytical Chemistry 23, 623‐ 4 2 5 5 Barrell , R. Jones , J. Schaefer & A. Putnam 626. 1 Environment and Materials Division, GNS Science, [4] Mifsud et al. (2013). Nuclear Instruments and PO Box 30368, Lower Hutt 5040 Methods in Physics Research B 294, 203‐207. 2 SGEES, Victoria University of Wellington, PO Box 600, Wellington 6140 3 Geological Resources Division, GNS Science, PO Box 30368, Lower Hutt 5040 4 Natural Hazards Division, GNS Science, PO Box 30368, Lower Hutt 5040 5Lamont‐Doherty Earth Observatory, Columbia University, New York, USA [email protected]

For the most commonly used terrestrial cosmogenic nuclides, 10Be and 26Al, quartz is the target mineral of choice [1]. Alongside improvements of in situ production rate calibrations and of AMS measurement techniques, many labs continue to refine the technique to extract pure quartz from various rock types. New Zealand contains extensive areas of quartz‐bearing rocks. In particular, the greywacke and schist lithologies of the Southern Alps have proved to be well‐suited to surface exposure dating [e.g. 2], despite low abundance of sand‐sized quartz grains. Victoria University of Wellington and GNS Science have started a collaboration to refine the analytical capabilities within New Zealand. At present, the focus is on establishing practical limits of key parameters for 10Be, such as minimum sample size and AMS detection limit, for different lithologies with low quartz concentration and/or small quartz grain size. We will present preliminary results from a replication study in which we sampled and analysed greywacke boulders from Last Glaciation moraines in the Southern Alps. These boulders have previously been surface exposure dated by the LDEO Cosmogenic Nuclide Group [2]. Part of our study aims to achieve a more efficient and safe implementation of the hot phosphoric acid (HPA) technique to separate quartz from other minerals [3,4]. We compare degrees of purity and recovery against those of the more widely employed etching method using hydrofluoric acid. Initial results show that the HPA

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