UNIVERSITY OF GOTHENBURG Department of Earth Sciences Geovetarcentrum/Earth Science Centre

Characterizing provenances

of glacial sediments

in northeastern Svalbard

using in-situ

Rb-Sr systematics

Filip Johansson

ISSN 1400-3821 B932 Master of Science (120 credits) thesis Göteborg 2016

Mailing address Address Telephone Telefax Geovetarcentrum Geovetarcentrum Geovetarcentrum 031-786 19 56 031-786 19 86 Göteborg University S 405 30 Göteborg Guldhedsgatan 5A S-405 30 Göteborg SWEDEN Abstract 2 1. Introduction 3 2. Background 5 2.0. Glacial history of Svalbard 5 2.1. Bedrock geology of Svalbard 9 2.2. Rb-Sr systematics 17 3. Method 19 3.1. Laboratory work 19 3.2. ICP-MS procedures 19 3.3. Calculations 20 4. Results 21 4.1. SEM– backscattered electron images 21 4.2. Geochronology 28 4.4. Initial-87Sr signatures 38 4.5. 87Rb/87Sr signatures in the Kapp Ekholm stratigraphy 40 5. Discussion 42 5.1. Geochronology 42 5.2. Provenance potentials using initial-87Sr 44 5.3. Rb-Sr provenance signatures in the Kapp Ekholm stratigraphy 46 6. Conclusions 47 7. Acknowledgements 48 8. References cited 49 Appendix A: Geological maps with sample locations 54 Appendix B: LA-ICP-MS/MS Rb-Sr data 56

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Abstract Reconstructions of ice-sheet configurations in Svalbard inferred from geomorphological, isostatic and terrestrial exposure-dating are contradictory with regards to the structure of ice-domes and ice-flow. This identifies the need for accessing high resolution provenance data in the sedimentary archive as an additional proxy for ice-sheet reconstructions. While Sr-isotopic composition in glacial sediments has been demonstrated to reflect ice-sheet dynamics, this approach has remained relatively unexplored since technological limitations in conventional mass-spectrometry have restricted the acquisition of this data to bulk analyses. Recent developments in Laser Ablation-ICP-MS/MS facilitate in-situ determination of 87Sr/86Sr composition and Rb-Sr geochronology, circumventing the isobaric overlap between 87Sr and 87Rb with a reaction-gas chamber sandwiched between the double quadrupoles. This novel approach avoids the prior sample dissolution that has previously inhibited sediment source distinctions detailed enough to allow for ice-flow reconstructions. In-situ technology acquires 87Rb/86Sr and 87Sr/86Sr data for single detrital clasts, thus avoiding the problem of mixed geochemical signatures from unquantifiable contributions of petrogenic end-members associated with bulk analyses. Since the geomorphological archive in northeastern Svalbard produce contradictory reconstructions with regards to the ice-flow, there is a need for differentiating between the bedrock sources of glacial sediments in this area. By characterizing the Rb-Sr isotopic signatures in the bedrock, this study present a framework enabling future studies to differentiate between sources of glacial sediments in northeastern Svalbard. Geographically distinct regions are identified by the obtained initial-87Sr signatures, allowing for distinction between west Ny Friesland (0.8-1.13) and east Ny Friesland-Nordaustlandet (0.72-0.77) as sediment sources. The extremely high initial-87Sr signatures from west Ny Friesland (>0.8) appears to be restricted to the bedrock affected by the retrograde metamorphism associated with the Billefjorden fault zone. Since this shear zone extends along Wijdefjorden, which acted as an ice-stream conduit during periods of glaciation, glacial detritus derived from this source can be distinguished by its Sr-isotopic composition. The method was applied in the glacial stratigraphy of Kapp Ekholm in Billefjorden, a fjord located in connection to Ny Friesland. A subglacial till known to originate from an ice-flow emerging from Ny Friesland provided a testbed, where the in-situ 87Sr-signatures in granitic clasts successfully replicate those obtained from the bedrock located in the fjord head. Caledonian metamorphism has reset the Rb- Sr geochronometer in northeastern Svalbard, and is too synchronous to allow for provenance discrimination by bedrock ages. However, the Rb-Sr geochronology has contributed to constrain the timing of Caledonian metamorphism in northeastern Svalbard by revising the previously inconclusive Rb- Sr ages in this area. The Rb-Sr ages obtained agrees well with previous metamorphic ages from Ar-Ar and U-Pb titanite dating, supporting the robustness of in-situ Rb-Sr systematics applied in Svalbard.

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1. Introduction In recent years, our perception of ice-sheet behavior in Svalbard has profoundly changed with the concept of highly dynamic fast flowing ice-streams and inactive inter-ice-stream areas. Ice-sheet configurations in Svalbard are known to have differed considerably during the late Quaternary, where a shift towards a more channeled erosive flow-style constrained to fjord settings initiated in the mid- Pleistocene. Hence glacial sediments form a crucial archive for establishing a comprehensive account of the ice-sheet dynamics throughout multiple glacial cycles exhibiting different modes. Provenance studies in Svalbard however, are complicated by the recurrent tectonothermal activity that has affected Svalbard’s northeastern basement rocks. Repeated and partial resetting of the bedrock’s geochemical fingerprints causes inherited and mixed geochemical and geochronological signatures, making accurate pin-pointing of bedrock sources for glacial sediments with established lithological and heavy mineral provenance methods intricate. Hence there is a recognized need for a method non-prone to inheritance with microscale sample resolution that can avoid inclusions, zonations and alteration-zones of single sediment clasts. This study aims to explore the potentials of Rb and Sr isotopic signatures in bedrock as a method for deriving the provenance of glacial sediments in northeastern Svalbard, by utilizing novel laser- ablation ICP-MS in-situ Rb-Sr systematics. Within this scope an Rb-Sr isotopic map for Svalbard’s northeastern basement rocks was constructed to investigate the possibility to discriminate between bedrock sources for glacial sediments in this area, using the Rb-Sr system’s geochronometer and initial- 87Sr signatures. A detailed Rb-Sr isotopic description of northeastern Svalbard’s bedrock linked to glacial sedimentary archives in Svalbard and the Barents Sea would benefit reconstructions of Pleistocene glaciations with regards to ice-flow patterns and sources of ice-rafted debris. In addition, this study will add novel geochronological data to complement the tectonothermal history of Svalbard, since existing Rb-Sr ages of Ny-Friesland and Nordaustlandet are inconclusive. Ice-flow reconstructions in the Barents Sea and Svalbard archipelago are essential in order to disclose the configuration of ice-domes and channeling of ice-streams in the Svalbard-Barents ice-sheet (Hormes et al., 2011 & 2013; Gjermundsen et al., 2013; Platton et al., 2015). However, there is a need to establish a detailed provenance framework enabling discrimination between northeastern Svalbard’s bedrock regions in order to distinguish the bedrock sources of glacial sediments with the precision required to enable ice-flow reconstructions. Initial-87Sr signatures have previously been applied to shelf sediment to trace IRD deposits and reconstruct ice-sheet dynamics around Svalbard (e.g. Tütken et al., 2000; Farmer et al., 2003); however, lack of comprehensive bedrock descriptions and geological context with regards to the 87Sr-signatures leaves room for ambiguity in pin-pointing provenance. Geochemical and isotopic signatures as provenance tracers proves especially beneficial when individual grains can be coupled to geologically meaningful information, since petrogenic end-members are difficult to pinpoint with unquantifiable geochemical mixtures acquired from bulk samples (e.g. Faure & Taylor, 1983; Gwaizda et al., 1996; Hemming et al., 1998). Here we target the highly concerned Ny Friesland and Nordaustlandet regions in northeastern Svalbard, since these are flanking postulated ice-dome areas with conflicting ice-flow data (fig. 1) (Lambeck et al., 1995; Landvik et al., 2005; Dowdeswell et al., 2010; Hogan et al., 2010; Hormes et al., 2011). Geochronology can be used to distinguish between sediment sources provided a suitable bedrock context, and have proven very useful for tracing the definite sources for e.g. Heinrich events (Hemming et al., 1998). Utilizing the established method of heavy mineral geochronology is complicated in Svalbard by severe inheritance in both metamorphic and intrusive rocks (Johansson et al., 1995 & 2001). Varying degrees of inherited ages and associated geochemical signatures complicate provenance studies, especially since provenance studies commonly disposes of limited amount of sample material. The Rb-Sr system when applied in-situ is promising since it operates on major rock forming mineral phases and is less prone to preserve inherited ages, and is accompanied with the initial-87Sr signature which provides a

3 petrogenic indicator for the tectonic environment forming the rock. With new advancements in LA-ICP- MS it is now possible to couple single grains down to the sand-size fraction to metamorphic and magmatic ages and associated 87Sr signatures. An attempt to apply Rb-Sr systematics as a provenance tool for the late Weichselian till of the well documented Kapp Ekholm stratigraphy in inner Isfjorden provided a testbed for the method, since the area is one of the best constrained with regards to ice-flow and depositional history in Svalbard. This stratigraphy encompasses 4 complete glacial cycles of sedimentation, extending back to the Saalian glaciation. Provided that this method is successful, ice-flow data could also be obtained for the older units which currently lack ice-flow data due to obliteration from subsequent glaciations.

Figure 1: The Svalbard archipelago with compiled Late Weichselian ice-flow data by Dallman (2015) and ice-front position from DATED-1 (Hughes et al., 2015). Figure edited from Dallman (2015). Cross-cutting ice-flow has been observed around Kong Karls Land, making the area south of Hinlopen Strait a highly concerned site for understanding ice-sheet dynamics in the SBSIS during the last deglaciation.

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2. Background While marine glacial landforms provide constraints on the glacial dynamics of ice sheet disintegration, this archive is limited to the marine environment and only reflect the deglacial stage of the last present ice. Since the Svalbard archipelago have experienced repeated glaciation cycles of different modes during the last ~3.6 Ma (Knies et al., 2009; Gjermundsen et al., 2015), there is a need for utilizing archives enabling reconstructions extending further back in time. Recently our understanding of the ice sheet behavior has profoundly changed with the concept of highly dynamic ice-streams and stagnant inter-ice-stream areas. Cosmogenic-nuclide exposure dating and marine offshore data from Svalbard suggests a significant shift in ice sheet mode at ~1.1 Ma, when the erosive regimes of the ice shifted towards a channeled flow style constrained to fjords and lowland valleys (Gjermundsen et al., 2015), coincident with the formation of full scale glaciations of the Barents Sea reaching the shelf edge (Knies et al., 2009). 2.1. Glacial history of Svalbard The Svalbard archipelago has been repeatedly glaciated since the onset of the Quaternary and major northern hemisphere glaciation 3 - 2.6 million years ago (Spielhagen et al., 1997, Knies et al., 2009, Polyak et al., 2010). The build-up and disintegration of these ice sheets has distinctly shaped the landscape, leaving the characteristic fjord and U-shaped valley terrain. At its maximum extent the ice sheet - the Svalbard-Barents Sea ice sheet (SBSIS) - reached the shelf edge, covered most of the Barents Sea and so became confluent with the Scandinavian ice sheet. Although covering the entire Svalbard archipelago, the SBSIS was mainly situated below sea level and therefore classified as a marine-based ice sheet (fig. 1) (Hughes et al., 2015).

2.1.1. Last glacial maximum: The last glacial maximum (LGM) - also known as the marine isotope stage (MIS) 2 in the marine record - of the SBSIS occurred at ~ 24 000 years ago (Hughes et al., 2015), subsequent disintegration initiated at about 20 500 years ago, when interior ice sheet thinning on northern and western Svalbard had already begun (Hormes et al., 2013). While the interior thinning continued the ice margin remained at the inner shelf edge until 14 - 15 000 years ago, where after it rapidly retreated back to the fjord mouths.

2.1.2. Pleistocene glaciations The evolution of MIS 2 has through recent efforts has been reasonably well constrained by comprehensive compilation of temporal and spatial data (e.g. Hughes et al., 2015). However, data reflecting the dynamics and configurations of previous ice-sheets are sparse, since resolving the same features of earlier glaciations are complicated by the obliterative overlap of subsequent glaciations. With the advancements within cosmogenic-exposure dating, and sophisticated geochemical provenance studies on relict sediments, the scientific frontier is now beginning to access knowledge about the Quaternary glaciations with regards to erosive regimes, ice-flow patterns and ice-sheet thickness (e.g. Tütken et al., 2002; Rasmussen et al., 2012; Ingolfsson & Landvik, 2013; Gjermundsen et al., 2015). Geomorphologic data have yielded constraints on the penultimate major glaciation, which occurred during MIS 6 and was more extensive than the LGM (also MIS 2) (Svendsen et al., 2004). In southwestern Barents Sea, the only till overlying Eemian sediments is Late Weichselian, indicating that intermediate Weichselian glaciations were restricted to the archipelago. However, the isostatic depression as inferred by preserved marine terraces in Linnédalen (west Svalbard) suggests that the ice-sheet loading was similar to that of the LGM (Mangerud et al., 1998). In the inner fjords, relict glacial sequences are occasionally preserved. These sequences have been cross-correlated and make up the Svalbard glacier curve (fig. 2), which presents the most holistic account of the last 150 000 years of glacial history in Svalbard (Mangerud et al., 1998). One of the most

5 comprehensive glacial sequences is the Kapp Ekholm stratigraphy. Located ~15 km from the fjord head of Billefjorden, it has four complete glacial cycles of sedimentation preserved from MIS 6 to 2, representing the last 150 000 years of glacial-interglacial variability (Mangerud et al., 1998). This will be described in further detail below.

Figure 2: The Svalbard glacier curve was originally compiled by Mangerud et al. (1998) and edited by Eccleshall et al. (2016) according to the new luminescence dates.

2.1.3. Ice sheet configuration & dynamics In recent time our understanding of ice sheet dynamics in Svalbard has increased profoundly with the concept of highly dynamic ice streams and sluggish, inactive inter-ice-stream areas (Ottesen et al., 2007, Landvik et al., 2012, Hormes et al., 2013; Platton et al., 2015). By 10Be exposure dating, transport pathways of erratics and sea floor bathymetry, it is suggested that the main erosion was focused to these topographically constrained pathways of fast flowing ice-streams. However, this flow style seems to have been initiated during the late Quaternary, prior to which the ice was actively eroding also the topographic highs in the alpine. This transition has been proposed to have been associated with the mid- Pleistocene transition (~ 1.1 Ma) (Gjermundsen et al., 2015). A long standing research question regarding the SBSIS concerns its large scale ice-dome and flow configuration. The mass-load center of the ice-sheet, as calculated from the isostatic rebound of the lithosphere (Lambeck 1995, Forman et al., 2004), was situated just south of the Hinlopenstretet (fig. 1), and has thus been suggested to represent a single dominant ice-dome governing a radiating flow of the SBSIS (Landvik et al., 1998). However cross-cutting glacial lineations in the Barents Sea, just south of Hinloppen Strait, infer a more complex and dynamic interplay of ice flow (fig. 1) (Dowdeswell et al., 2010). Sea floor geomorphology and transport pathways of erratics also suggest a flow configuration distinctly influenced by multiple ice-domes (Dowdeswell et al., 2011, Hormes et al., 2011 & 2013, Gjermundsen et al., 2013). Landvik et al., (2005) explains this by a time transgressive ice-sheet configuration with a single ice-dome dominating the flow, which subsequently disintegrated into multiple ice-domes with highly topographically constrained flow during deglaciation. This is contradictory to the theory of a steady multi-ice dome configuration supported by surface exposure dating of nunataks and distribution of erratics, which are absent in the higher alpine. High mountain peaks seems to have been covered by thin, cold based ice or alternatively been ice free during the LGM, indicating that fast flowing, erosive ice was constrained to fjords and valleys (Landvik & Ingólfsson, 2005, Hormes et al., 2013, Gjermundsen et al., 2015). By Sr and Nd isotopic signatures from glacial sediment on the Yermak Plateau, it appears that erosion of the Svalbard bedrock was concentrated during the build-up phase of the ice-sheet, while during maxima the erosion was predominantly occurring on the Eurasian shelf (fig. 3) (Tütken et al., 2002)

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87 86 Figure 3: Sediment delivery to the northern Svalbard shelf (Yermak plateau) exhibits variations in Sr/ Sr and Nd isotopic composition, corresponding to variations in ice-front positions. The 87Sr/86Sr signature increases when the ice-front recedes 87 86 inland and erosion is focused on the Svalbard bedrock which has a higher Sr/ Sr ratio than the Eurasian shelf (figure from Tutken et al., 2002). Core location is marked in fig. 4.

Although the glaciodynamical evolution of the SBSIS remains elusive, the consensual view is that of a complex and highly dynamic marine based ice sheet with fast flowing ice-streams and inactive inter-ice stream areas of sluggish ice. Fjords and lowland valleys acted as conduits that drained the interior of the ice sheet by a highly topographically constrained flow style, while the topographic highs of summits and mountain plateaus experienced little active flow and erosion (Hormes et al., 2013, Gjermundsen et al., 2015). The disintegration was characterized by early thinning and late but rapid punctuated retreat from the inner shelf to the fjord mouths (Landvik et al., 2005, Ottesen et al., 2007, Hormes et al., 2013, Jakobsson et al., 2014).

Core PS 1533 (Tutken et al., 2002)

Core PS1533

Figure 4: The full extent of the SBSIS at the last glacial maximum marked by the white line, major glacial deposits known as trough-mouth fans are illustrated in orange. The site of the core PS 1533 (fig. 3) used by Tutken et al., (2002) to reconstruct ice-sheet dynamics by 87Sr/86Sr isotope signatures is marked on the map. From Hughes et al., 2015. 7

2.1.4. The Kapp Ekholm glacial stratigraphy This key stratigraphic site comprises a corner stone for the Svalbard glacier curve (fig. 2) and is one of the most complete records of glacial interglacial cyclicality in Svalbard (Mangerud et al., 1998). The Kapp Ekholm stratigraphy is located within the coastal cliffs (fig. 5) on the southern shore in the inner reaches of Billefjorden about 15 km from the fjord head, which is occupied by the Nordenskiöldbreen tidewater glacier. Nordenskiöldbreen descend from the Lomonosovfonna ice cap, and is the only present-day active major glacial influence in Billefjorden. The glacier front is today located about 15 km from Kapp Ekholm. The stratigraphy comprises four sedimentation cycles characterized by diamicton beds followed by marine coarsening upward sequences, ending with gravel foresets. This is interpreted to represent four glacial advances with subsequent marine setting. The coarsening upward sequences reflect a dropping sea level due to isostatic rebound following deglaciation (Mangerud et al., 1998). The diamicton units are all interpreted as subglacial tills and the marine facies represent interglacial periods, when the glacier front probably receded to within ~14 km of its current position (Mangerud et al., 1998). Geochronological investigations of the Kapp Ekholm stratigraphy are presented in Mangerud & Svendsen (1992), Mangerud & Salvigsen (1984), Mangerud et al. (1998), Forman et al. (1999), and re-visited in Eccleshall et al. (2016).

Figure 5: Billefjorden is a tributary fjord to Isfjorden, located on the west coast of Svalbard. Nordenskiöldbreen is a tidewater glacier located in the fjord head, which at the last glacial maximum stretched occupied the entire fjord. Figure from Baeten et al., 2010.

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2.2. Bedrock geology of Svalbard The bedrock of the Svalbard archipelago comprises multiple accreted terranes of different tectonothermal backgrounds. The exposed pre-Devonian metamorphic and igneous rocks in the Northeastern basement province (fig. 6) are of primary concern in this thesis, since these should contain Rb-Sr geochronological data enabling provenance discrimination. The Northeastern basement province is further subdivided into the Nordaustlandet and Ny Friesland terranes, comprising a Paleoproterozoic (~1750 Ma) versus Grenvillian (~950 Ma) protolithic basement respectively (Gee et al., 1995; Witt- Nilsson et al., 1998). Granitoid complexes occur in the Northeastern province, associated with the Caledonian and Grenvillian orogenies. Both Caledonian and Grenvillian granitoids are identified on Nordaustlandet, and Caledonian on Olav V Land. The latter also belongs to the Nordaustlandet terrane although located adjacent to Ny Friesland and not the island Nordaustlandet (see map in fig. 6). (Gee et al., 1995; Tebenkov et al., 1996; Johansson et al., 2002). A comprehensive compilation listing available chronology of the investigated bedrock units are listed in table 1, with corresponding locations marked in fig. 6 below.

Figure 6: The northeastern basement province with its tectonic terranes. This study will focus on the northeastern basement province, comprising the Ny Friesland, Olav V land and Nordaustlandet terranes (areas encircled with dashed line). Orogeny associated magmatic activity is recognized as the intrusive complexes of granitoid batholiths featured both on Ny Friesland and Nordaustlandet. Detailed geological maps of marked zones are found in Appendix A. Map edited from Dallman (2015).

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Figure 7: Simplified compilation of available geochronological data edited from Dallman (2015), some data has been added from the original figure in order to establish a more comprehensive demonstration for the concerns of this study. Blue spots with corresponding bold names are bedrock areas also investigated in this study. Asterix (*) notes that the same sample is used in this study. Conclusive data for the Caledonian metamorphism on the Grenvillian basement on Nordaustlandet is only reported from the Nordmarka augen gneiss and the migmatized Duvefjorden complex. Detailed chronology with associated method is summarized in table 1 for the investigated areas (blue spots) and in Dallman (2015) for the not investigated geochronology. Detailed geological maps with sample locations are in Appendix A. Map edited from Dallman (2015).

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Table 1: Method: 1: U-Pb zircon (conventional), 2: U-Pb zircon (conventional, lower intercept), 3: U-Pb titanite (conventional), 4: 207Pb/206Pb monazite, 5: U-Pb monazite, 6: Ar-Ar muscovite plateau age, 7: Ar-Ar biotite plateau age, 8: Rb-Sr (whole rock). * = same sample as in this study. Study: 1: Johansson et al., 1995, 2: Johansson & Gee, 1999, 3: Larianov et al., 1995, 4: Johansson et al., 2001, 5: Johansson et al., 2002, 6: Gee et al., 1995, 7: Johansson et al., 2000, 8: Teben’kov et al., 1996, 9: Myhre et al., 2005. Location Article / Sampler Formation Sample Magmatic age Metamorphic age

Ny Friesland Johansson et al., 1995 Bangenhuk J91-17: 1720 - 17701,(1)* 404+/-93,(1)* (Spitsbergen) Granitic gneiss 1653 ±638, (1) ~4003,(1)* 79°13'35 16°11'10 Ny Friesland Johansson et al., 1995 Bangenhuk J91-13: 1766 +43/-351, (1)* No data (Spitsbergen) Granitic gneiss 1653 ±63 79°11'55 16°51'25 Ny Friesland Anne Hormes Bangenhuk Per-1 No data No data (Spitsbergen) Granitic gneiss 79°15'19 16°78'28 Ny Friesland Anne Hormes Flåen Bei-1 No data No data (Spitsbergen) Mica-schist 79°08'00 17°11'49 Ny Friesland Johansson & Gee, 1999 Eskolabreen J92-01: 1749 ± 91,(2)* 404 +/- 82,(2)* (Spitsbergen) Granitic gneiss ~4003,(3) 78°58'05 16°35'45 Ny Friesland Johansson & Gee, 1999 Eskolabreen J92-2: 1749 ± 91,(2)* 404 +/- 82,(2)* (Spitsbergen) Granitic gness ~4003,(3) 78°58'05 16°35'45 Olav V Land Anne Hormes Chydeniusbreen New-1 440 ±138,(8) Not applicable (Spitsbergen) (Newtontoppen) Granite 430 ±0.71,(9) 79°03'97 17°53'12 Nordaustlandet Johansson et al., 2000 Fonndalen G92-23 957 +30/-185, (7) No data Granitic augen gneiss 1048 +30/-241, (7) 80°05'94 23°23'36 Nordaustlandet Johansson et al., 2000 Laponia J92-03 961 ±171, (6) No data Granitic biotite gneiss 80°24'50 20°19'30

Nordaustlandet Johansson et al., 2000 Ringåsvatnet J92-07 956 ±79, (7)* No data Foliated augen gneiss 965 ±1810, (7)* 80°06'10 937 ±911, (7)* 22°57'40

Nordaustlandet Johansson et al., 2001 & 2002 Nordkapp 94048 440 ±24,(5)* Not applicable Two-mica granite 428 ±126,(4)* 80°45'33 19°97'73 Nordaustlandet Johansson et al., 2001 Winsnesbreen 94947 406 ± 56,(4)* Not applicable Two-mica granite ~420 - 4605,(5) 79°80'58 22°19'74

Nordaustlandet Johansson et al., 2001 & 2002 Rijpfjorden 28-1 410 ±151,(5)* Not applicable Two-mica granite 412 ±0.55,(4)* 80°27'77 399 ±56, (4)* 22°49'18 405 ±117,(4)*

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2.2.1. Nordaustlandet The pre-Caledonian bedrock of Nordaustlandet is comprised by a Grenvillian basement uncomformably overlain by metasedimentary units: Murchinsonfjorden and Hinlopenstretet supergroups; see fig. 7. A Grenvillian basement was first confirmed by Gee et al. (1995) who presented U-Pb zircon ages spanning 930-980. The basement is comprised of granites grading into augen-gneisses, which are intrusive into the Brennevinsfjorden-Helvetesflya metasedimentary unit (see stratigraphy fig. 7), thus confirming a Mesoproterozoic origin for these underlying stratigraphic units (Gee et al., 1995; Johansson et al., 2000). The crystalline magmatic rocks of Grenvillian and Caledonian origin are of prime interest in this study since corresponding samples were available.

The Caledonian rocks of Nordaustlandet features 3 intrusive complexes with associated migmatization (Duvefjorden complex). Known as the Nordkapp, Rijpfjorden and Winsnesbreen granitoids these plot as peraluminous I-type granites and are interpreted to originate from anatexis of Grenvillian crust by their Sm-Nd isotope characteristics (Johansson et al., 2002).

Grenvillian tectonothermal activity is recognized as granitoid bodies defined as the Laponia and Kontaktberget granites (northwest Nordaustlandet), and the Fonndalen and Ringåsvatnet granites (central Nordaustlandet), which were subsequently metamorphosed during the Caledonian (Johansson et al., 2000). By their geochemical signatures these units seem to originate from a volcanic arc or syn- collisional setting, with significant sedimentary input and crustal contribution. The metavolcanic Kapp Hansten unit is correlated to the same event (Johansson et al., 2000). However, Grenvillian ages are not recognized in the Nordaustlandet province by Ar-Ar dating, which instead register Caledonian metamorphism at ~400-430 Ma (Johansson et al., 2001). Allegedly Caledonian metamorphism on Nordaustlandet is generally in greenschist facies, however according to Johansson et al. (2001) it appears that eastern Nordaustlandet experienced Caledonian metamorphism at least exceeding the Ar-Ar closure temperature for hornblende, i.e. 500-550 °C (McDougall & Harrison, 1988). Signs of older crustal material has been inferred by zircons yield U-Pb ages dating back to 1650 Ma (Johansson et al., 2002). Caledonian migmatization is registered at c. 420-450 Ma (Teben’kov et al., 2002). Earlier Rb-Sr dating of Nordaustlandet (Hamilton et al., 1964; Gayer et al., 1966; summarized in Ohta et al., 1992) yields inconclusive ages spanning 370-700 Ma, which cannot be correlated to any geological event. Consequently, the eastern parts of Nordaustlandet seem to have experienced amphibolite facies metamorphism, while the metamorphic grade diminishes westward. Caledonian migmatization of Grenvillian basement is inferred to have occurred at c. 440-450 Ma (Johansson & Larianov, 1999; Johansson et al., 2002). The Caledonian granites can be divided into two age groups by Ar-Ar mica dating: 405 +/-11 Ma (Rijpfjorden & Winsnesbreen) and 428 +/- 12 Ma (Nordkapp). U-Pb monazite ages display the same tendency with 10-20 Ma delay, suggesting a cooling of 20-45 °C/Ma (Johansson et al., 2001). Detailed descriptions for all the bedrock units that are also analyzed in this study follows below.

2.2.1.1. Nordkapp granite The sample 94048 is from the Nordkapp granite pluton, which encompasses the Laponia peninsula with adjacent islands, and was thoroughly described in Johansson et al. (2002). It is described as a grey two- mica granite, and the sample “94048” is described as a light grey, medium grained, massive granite hosting quartz, K-feldspar and plagioclase with interspersed muscovite and biotite. The Nordkapp granite is defined as an anatectic granite crystallized during the main Caledonian orogeny phase, originating

12 from Grenvillian crust as inferred by Sm-Nd isotopic characteristics and U-Pb zircon data. Conventional 207Pb/206Pb monazite dating of sample 94048 define a discordia of 440±2 Ma, interpreted to represent intrusion age of the pluton. Zircons plot a discordant age of c. 750 Ma, interpreted to originate from crustal inheritance. Zircon Pb - evaporation ages also suggest Grenvillian crustal inheritance but some yields weighted average 207Pb/206Pb ages of 424±14 Ma. Analysis of zircons at NORDSIM in sample 94048 fails to define any precise Caledonian age, but inherited zircons span 800-900 Ma which is probably related to the adjacent Grenvillian rocks (Johansson et al., 2002).

2.2.1.2. Rijpfjorden granite The sample 28-1 is from the Rijpfjorden pluton, and is described as pink medium grained muscovite- normal granite. Associated migmatization of adjacent metasediments has been dated to 420-450 Ma (Teben’kov et al., 2002). The sample 28-1 is granitic in composition with muscovite, biotite and accessory apatite, calcite, monazite and zircon (Johansson et al., 2002). Comprehensive U-Pb and Ar-Ar geochronology of this granite was conducted by Johansson et al., 2001 & 2002. Conventional U-Pb dating on zircons identifies Grenvillian inheritance (c. 960 Ma) but also a Caledonian age of c. 410 Ma. Monazites however yields a well-defined weighted average 207Pb/206Pb-age of 412±0.5 Ma, interpreted to reflect the intrusion age of the granite. Pb-evaporation dating of zircons in the same samples yields a mean 207Pb/206Pb age of 423±6 Ma, and monazites define a slightly older age of 427+/-14 Ma. NORDSIM ion-microprobe zircon dating identifies a Caledonian age of 410±15 (Johansson et al., 2002). Ar-Ar dating of the same samples yields a muscovite/biotite plateau age of 399±5 Ma and 405±11 Ma respectively, corresponding to cooling ages (Johansson et al., 2001).

2.2.1.3. Winsensbreen granite The sample 94047 is from the Winsnesbreen granite, which mainly outcrops in central Nordaustlandet with possible southward extension under the Austfonna ice cap, and might itself represent a southern extension of the Rijpfjorden granite (Johansson et al., 2002). It is described as a muscovite rich two-mica granite (Ohta, 1982). A detailed petrographic description was conducted by Johansson et al. (2002), who observed plagioclase with dusty cores and albite rims, weakly perthitic microcline K-feldspar with inclusions of quartz and plagioclase. Zircon geochronology in the Winsnesbreen yields inconclusive results due to inheritance, with NORDSIM U-Pb ages ranging between 1675 Ma and 200 Ma. Conventional U-Pb monazite ages are spanning c. 420-460 Ma and fail to define any precise age (Johansson et al., 2002). Ar dating of the 94047 sample defines a plateau age of 406±5 Ma (Johansson et al., 2001).

2.2.1.4. Fonndalen augen gneiss The sample G92-23 was collected from the Fonndalen augen gneiss by Johansson et al. (2000), and is described as a coarse, light grey augen gneiss with large K-feldspar and smaller quartz phenocrysts together with a medium-sized matrix of quartz, feldspar, biotite and muscovite (Johansson et al., 2000). Conventional U-Pb zircon ages defines an upper intercept of 1048 +30/-24 Ma and monazites 957 +30/- 18. Single zircon Pb-evaporation defines a Grenvillian age of 949 ±4, but also an inherited age of 1822 ±9 Ma (Johansson et al., 2000). A granitic dike cross-cutting this unit has been dated to c. 410 Ma by U-Pb zircon dating, providing a minimum age for Caledonian metamorphism.

2.2.1.5. Laponia biotite schist Sample J92-3 is from the Laponia gneiss, outcropping on Laponiahalvöya on northwestern Nordaustlandet together with the Kontaktberget granite (not available for this study), this unit is

13 described as a coarse porphyritic granite that grade into an augen gneiss. The Laponiahalvöya granite has a transitional contact with the slightly younger Kontaktberget granite. The Laponia gneiss has been correlated to Grenvillian magmatism by conventional U-Pb zircon dating, which yields ages of 961 ±17 Ma (Gee et al., 1995).

2.2.1.6. Ringåsvatnet augen gneiss Sample J92-7 was retrieved from this bedrock unit by Johansson et al. (2000) and is described as grey foliated augen gneiss with medium K-feldspar and quartz phenocrysts (mm-size) within a fine- to medium grained matrix of quartz, feldspar, biotite and muscovite. Micas in the matrix are foliated and biotite is occasionally altered to chlorite or epidote (Johansson et al., 2000). Single zircon Pb-evaporation ages yield a plateau age of 956 ±7 Ma (Johansson et al., 2000).

2.2.2. The Chydeniusbreen graniotoid suite

The sample New-1 is from the Newtontoppen granite batholith, a part of the Chydeniusbreen granitoid suite, which encompasses a complex of one or more batholiths of post-tectonic granitoids, more precisely mapped as the Newtontoppen, Raudberget and Ekkoknausane bodies. The Newtontoppen granitoid body constitutes the largest exposed unit, revealed by its numerous nunataks that emerges through the northwestern part of the Lomonsovfonna ice cap (see map). The Raudberget body consists of 5 nunataks exposed close to the toe of Chydeniusbreen. The Ekkoknausane body outcrop just in the upper reaches of Nordenskiöldbreen and makes up the southernmost exposed unit. The Newtontoppen body constitutes the largest exposed massif, but the subglacial extent of the batholith is left to speculations since it is covered by the Lomonosovfonna ice cap. The Newtontoppen granitoid body has been thoroughly investigated by Teben’kov et al. (1996), who described them as transitionary I- to S-type granites. An Rb-Sr whole rock age is defined as 432±10 Ma with initial-87Sr of 0.715. When applying the new 87Rb decay constant from Villa et al. (2015) to the same whole-rock data however, the new isochron defines an age of 440±13 (MSWD=0.63). Myhre et al. (2005) re-visited the geochronology of Newtontoppen and presented an (ID-TIMS) U-Pb zircon and monazite age of 430±0.7. The Newtontoppen granite is by custom assigned to the Nordaustlandet terrane although it outcrops on Olav V land, located on the Spitsbergen Island. It should be noted however that the subglacial extent is largely unknown and the Ekkoknause granite outcrops in the head of Billefjorden, adjacent to the Atomfjella rocks which belongs to the Ny Friesland terrane. The Newtontoppen granite is relatively heterogeneous in composition as is believed to originate from a complex emplacement sequence, where melanozomes and dark grey granosyenites were incorporated at depth and large K-feldspar phenocrysts evolved later (Teben’kov et al., 1996). A mafic origin is also suggested by occurrence of clinopyroxene in some of the Newtontoppen rocks.

2.2.3. Ny-Friesland The succession of pre-caledonian basement rocks in the Northeastern basement province (fig. 7) is divided into three major tectonostratigraphic units: The Hinlopenstretet, Lomfjorden and Stubendorfbreen supergroups. Stubendorfbreen (fig. 7) constitutes the lower Hecla Hoek, and is the only stratigraphic unit containing the crystalline feldspathic rocks targeted in this study and will hence be described in further detail. The metamorphic succession is cut by a complex of Caledonian associated

14 post-tectonic intrusives exposed on Olav V Land: the Chydeniusbreen suite, comprising Newtontoppen, Raudberget and Ekkoknausane granitoid bodies. On Nordaustlandet the Grenvillian basement is more extensively cut by Caledonian intrusives, subdivided into the Rijpfjorden, Nordkapp and Winsnesbreen granite bodies (Johansson et al., 2001 & 2002).

The Ny Friesland terrane is characterized by an anticline composed of the Stubendorfbreen highgrade metamorphic rocks, flanked by Wijdefjorden and the Billefjorden fault zone in the west. This anticline is known as the Atomfjella complex and forms an asymmetric, N-S striking and slightly southward plunging orogeny with downward increasing metamorphic grade. East of the Atomfjella anticline is a syncline encompassing the eastern part of the Ny Friesland peninsula and Hinlopenstretet, which marks the transition to the Nordaustlandet terrane. Here, only the Neoproterozoic middle to upper Hecla Hoek (Lomfjorden & Hinlopenstretet supergroups) as well as Phanerozoic strata outcrop, covering the Stubendorfbreen basement units. Feldspathic gneisses have been recognized at four structurally distinct levels within the Stubendorfbreen supergroup, identified as the Eskolabreen, Instrumentberget-Flåtan, and Bangenhuken units, all yielding protolithic ages ~1750 Ma (U-Pb zircon) and metamorphic ages of ~410 Ma (U-Pb titanite (Witt-Nilsson et al., 1998). The western limb of the Atomfjella anticline hosts chloritized biotite, explained by retrograde metamorphism (Witt-Nilsson et al., 1998).

The isotopic homogeneity both internally and relative to the tectonostratigraphically lower Flåtan - Instrumentberget units is indicative of co-genesis and that the Bangenhuk granitoids represents one magmatic event ~1750 Ma (Carlsson et al., 1995), the Eskolabreen unit has also been suggested to belong to the same primal Proterozoic basement, explaining the tectonostratigraphic sequence by over thrusting (Witt-Nilsson et al., 1998). The Flåtan- Instrumenberget units are exposed only on the northernmost peninsula of Ny Friesland, although its thrusted emplacement in between the Polhem and Smutsbreen formations (Witt-Nilsson et al., 1998) could outcrop subglacially further south, since the boundary of these units continues underneath the Lomonsovfonna ice cap. Following are detailed descriptions for all the bedrock units also analyzed in this study.

Figure 7: a) Simplified lithostratigraphy of Hecla hoek stratigraphy in Ny Friesland from Harland (1992), investigated units in this study are marked in bold text with associated sample name in brackets. The units in the Stratigraphy are by custom referred to as formations, since they were originally thought to originate from sedimentary strata. Although this has been revised and refuted (Johansson et al., 1995; Witt-Nilsson et al., 1996; Johansson & Gee, 1999) this nomenclature has persisted. However, this thesis will refer to these as units rather than formations when discussed in the text. b) cross-section for the Northeastern Basement province’s tectonostratigraphy from Johansson et al., (2005).

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2.2.3.1. Bangenhuken formation Samples J91-13, J91-17 and Per-1 are from this bedrock unit. The Bangenhuk granitic gneiss outcrops along the western limb of the Atomfjella, along the entire western wall of Wijdefjorden and is cut and vertically displaced by the Billefjorden fault zone close to the head of the fjord, exposing it on the western side of Petuniabukta as well (map).

The Bangenhuken unit defines a metamorphic unit composed of granites (lenses) and granitic gneisses, embedded in to the Atomfjella anticline. The unit is described as metaluminous, and shows A-type affinity from major and trace element distribution with negative initial εNd, suggesting some crustal contribution (Carlsson et al., 1995, Johansson et al., 1995). Johansson et al., (1995) performed the first and only extensive geochronological investigation of the Bangenhuken formation, reporting U-Pb zircon ages of 1720-1770 Ma, interpreted to reflect the crystallization of the plutonic protolith. U-Pb titanite ages of 408±9 Ma is reported from the same study, interpreted to reflect Caledonian metamorphism. Late Archean U-Pb Zircon ages (~2.7 Ga) has also been reported from the lower Bangenhuken thrust sheet, speculated represent intrusion of the 1.7 Ga basement into older crust (Hellman et al., 2001). The sample J91-17 was sampled by Johansson et al., 1995 from the western limb of the anticline (see table x. for location), and is described as a red medium-grained foliated granite with accessory apatite. U-Pb zircon dating of the sample yielded a well-defined discordia of 1724±14 Ma, and a U-Pb titanite age of ~410 Ma (see table x. for coordinates). Sample J91-13 was recovered from the eastern limb, at Reinsbukksbreen (see table x. for coordinates) in the same study, and is described to represent a more undeformed part of the Bangenhuken unit. 207Pb/206Pb zircon dating yields a discordia of 1766 +43/-35 Ma. The sample Per-1 was retrieved from Perriertoppen by Anne Hormes (20xx), and is a nappe, probably from the Bangenhuken unit emplaced on the Polhem-Rittervatnet formation during subsequent Caledonian overthrusting (Witt-Nilsson et al., 1996).

Using Rb-Sr whole-rock data from the study, applying the new 87Rb decay constant from Villa et al., (2015), defines an isochron of 1653±63 Ma, with an initial 87Sr of 0.7049±0.005 (MSWD=0.86). The low initial-87Sr suggests a mantle like origin and is discarded as an errorchron with the conclusion that the whole-rock Rb-Sr system has been disturbed (Johansson et al., 1995).

2.2.3.2. Eskolabreen formation Samples J91-1 and J91-2 are from this bedrock unit. J91-1 is from a low strain zone of the formation while J91-2 is from a more foliated zone. The Eskolabreen formation defines the tectonostratigraphically lowest exposed unit of the Hecla Hoek. It constitutes the core of the Atomfjella antiform, and outcrops in its central parts (see map). U-Pb zircon ages from the Eskolabreen formation reaches back to ~2.4 Ga, claimed to represent a metamorphic age (Balashov et al., 1993). These Early Proterozoic ages of the formation remains controversial however, since following work by Larionov et al. (1995) on granitic gneiss samples yielded U-Pb zircon upper intercept ages of 1766 ±10 Ma, placing the unit’s origin within the same time interval as the overlying Bangenhuk-Instrumentberget-Flåtan units. The accompanied U- Pb zircon lower intercept age 404 ±8 Ma, probably represents the timing of Caledonian metamorphism, which is further supported by U-Pb titanite ages of about 400 Ma (Larionov et al., 1995). Whole rock Rb- Sr dating of this unit was attempted by Johansson & Gee (1999) on sample J91-1 & 2. However, the

16 whole-rock isochron modeled after U-Pb zircon ages yields an impossibly low initial-87Sr value of 0.65- 0.69, indicating a disturbance of the Rb-Sr system in this unit.

2.2.3.3. Flåen formation Sample Bei-1 is from this bedrock unit. The Flåen formation is dominated by semipelitic schists and constitutes the Planetfjella Group (also referred to as the Mosselhalvöya Group) together with Vildalen formation (fig.7). This group lacks geochronological constraints, but is believed to originate from Proterozoic acid-volcano-clastics (Witt-Nilsson et al., 1996). The sample Bei-1 was retrieved by Anne Hormes (20xx) from the eastern massif of Neptunfjellet, located in the inner reach of Veteranen glacier (fig. 6).

2.3. Rb-Sr systematics Rb-Sr geochronology utilizes the β- decay of 87Rb to 87Sr, which has the half-life of about 48.8 billion years. 87Sr is a radiogenic isotope, and only occurs as produced by radioactive decay of 87Rb. Since Rb is preferentially incorporated into the earth’s crust, yielding a higher Rb/Sr ratio, chemical differentiation throughout Earth’s history has enriched the crust in 87Sr (87Sr/86Sr >0.71) and depleted the mantle (87Sr/86Sr ~0.7035) (Nebel, 2015). Sr isotopes do not fractionate by magmatic processes, hence at time of crystallization minerals will acquire the 87Sr/86Sr signature of their parental magma, which provides a good petrogenic indicator. Subsequent build-up of 87Sr by the decay of 87Rb will enrich minerals in 87Sr according to their abundance of Rb. Rb substitutes for K, while Sr substitutes for Ca, meaning that K-rich phases will become increasingly rich in 87Sr over time since crystallization. Plotting the 87Rb/86Sr and 87Sr/86Sr ratios of minerals with different Rb-affinity will hence produce a line (isochron), which inclination corresponds to the time the system has remained closed (i.e. not exceeded closure temperature) since time of crystallization or metamorphism (see fig. 8). This line will cross the y-axis at 87Rb = 0, which represents the 87Sr/86Sr ratio at time of crystallization or metamorphic event, and is known as the initial-87Sr signature. Two approaches can be employed to obtain an Rb-Sr isochron: whole- rock and mineral specific. As illustrated in figure 8 below, the whole-rock will ideally record the time and intial-87Sr at crystallization (i.e. protolith age and Sr-composition), while mineral specific isochrones reset at metamorphism that exceeds closure temperature for Rb-Sr. Mineral specific isochrones from metamorphosed rock will hence yield higher initial-87Sr signatures due to this enrichment process.

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Figure 8: The concept of Rb-Sr dating illustrated. A) High-Rb mineral phases will become progressively enriched in 87Sr by 87Rb decay, and increase the inclination of the line (isochron) as a function of time. B) Metamorphism will re-equilibrate the system by re-distributing Sr within the mineral phases according to their affinity for the element. Note that the 87 86 whole-rock (WR) line remains the same since this is the bulk Rb-Sr composition which will preserve the Sr/ Sr of the parental magma, assuming no external flux of Rb or Sr. From Nebel (2015).

Figure 9: The registered age differs between geochronometers. Rb-Sr represents cooling ages, normally around 350-500 °C for micas, unlike e.g. U-Pb zircon geochronometers which registers crystallization ages. From Nebel (2015).

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3. Method The decay constant of 87Rb has recently been revised by Villa et al. (2015) from 1.42 x 10-11 to 1.3972 x 10-11, which is used in this study. The closure temperature for the Rb-Sr system is complicated since it is dependent on multiple mineral phases with different response to temperature, pressure and fluids but usually range between 450-500 °C for muscovite and around 350 °C for biotite. The Rb-Sr system registers the cooling age, and thus differs from geochronology based on zircons which mostly registers crystallization ages (fig. 9).

Conventional (ex-situ) Rb-Sr dating requires prior separation of Rb and Sr, since 87Rb and 87Sr has the same mass over charge ratio which would inhibit distinction between these in mass-spectrometry, as with all β- decay systems. Prior Rb-Sr separtion is carried out on a liquid medium, which obligate complete sample dissolution for obtaining accurate Rb-Sr isotopic composition. Sample dissolution is accompanied with errors associated with unknown inclusions, zonations or mineral quaility. In-situ Rb-Sr dating is made possible by recent advancements in Laser ablation-ICP-MS (Zack & Hogmalm, 2016), which circumvents the isobaric overlap between 87Rb and 87Sr by a reaction gas, only reactive with Sr (detailed description in method chapther). This facilitates Rb-Sr dating directly on the sample by laser- ablation, allowing for micro-scale sample resolution and quality assessment prior to analysis. The laser- ablation recovers sample material by a microscale spot (50 μm in this study) while recording counts over time, allowing for monitoring of mineral variations and inclusions.

3.1. Laboratory work The laboratory procedures consisted of sieving the till bulk samples and subsequent hand-picking of crystalline grains under a binocular microscope. The sieving separated the 500 - 63 µm grain size in order to ease identification of smaller grains, larger grains were identifiable without prior sieving. The singled out crystalline grains were mounted in epoxy and polished.

The bedrock samples from Ny Friesland and Nordaustlandet were obtained by courtesy of the Natural History museum in Stockholm, by first curator Åke Johansson. Additional samples from the Newtontoppen batholith were retrieved by Anne Hormes during earlier field campaigns. These were also mounted in epoxy and polished. Sample locations are shown in fig. 6.

Prior to mass-spectrometry, all samples went through SEM (scanning electron microscope) analysis in order to identify and assess the quality of appropriate mineral phases.

3.2. ICP-MS procedures Rb-Sr isotopes were measured in the Agilent 8800 LA-ICP-MS/MS at Gothenburg University. The isobaric overlap associated with the beta decay system was circumvented by a reaction gas chamber sandwiched between the quadropoles, which shifts 87Sr to a higher mass while leaving 85Rb unaffected (Zack &

Hogmalm, 2016). N2O and SF6 were used as reaction gases in this study (details in Appendix A). LA-ICP- MS measurements were conducted over four days in total. The laser ablation set-up was a 213 nm Nd- YAG laser, with repetition rate set to 4Hz, yielding 5.7 J/cm2 with a spot size diameter of 50 µm.

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3.3. Calculations 87Rb/86Sr and 87Sr/86Sr ratios were calculated using raw counts, filtered and inspected by the Glitter data reduction software. Validation of the 87Rb/87Sr geochronology from each day’s analysis was assessed by a nano-powder tablet (Högsbo Ms), which acted as a data quality control with a constrained age of 1033 ±9 Ma (Karlsson et al., 2016). Geological Rb-Sr ages were calculated in the IsoPlot 4.1.2. excel plug-in client, using the new 87Rb decay constant of 1.3972 x 10-11 from Villa et al. (2015). Rb-Sr ages from the literature using the old decay constant were re-calculated in IsoPlot using the original values with the new decay constant. 85Rb was used as a proxy for 87Rb. The time resolved signals for 85Rb, 86Sr and 87Sr showing counts over time were used to represent the minimum analytical error for each analysis. However, if the internal signal error was lower than the runtime error for the corresponding standard, the runtime error replaced the signal error. Analyses were removed from the corresponding isochron if the signal was defective due to poor ablation, inclusions or apparent mineral alterations. NIST610 (Woodhead & Hergt, 2001) was used as a quantification-standard for high-Rb/high-Sr mineral phases, BCR-2G (Elburg et al., 2005) for low-Rb/high-Sr mineral phases, and the newly developed Mica- Mg (Karlsson et al., 2016) for high-Rb/low-Sr mineral phases. For the bedrock samples Per-1 and Bei-1 as well as the till grain “G2” only NIST610 and BCR-2G were used since the Mica-Mg standard was not developed at that time. Complete lists of standards used for corresponding analysis are found in Appendix B.

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4. Results

4.1. SEM– backscattered electron images

4.1.1. Bangenhuken granitic gneiss Major rock forming minerals are quartz, K-feldspar, plagioclase and biotite. Accessory mineral phases are iron-oxides (magnetite or hematite), fluorite, chlorite, apatite, zircon, titanite and allanite. All 3 samples show metamorphic textures with recrystallized grain boundaries. Sample J91-17 hosts highly dissolved grain boundaries and migration of K-feldspar, indicative of hydrothermal activity.

Sample J91-17:

Sample J91-13:

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Sample Per-1:

4.1.2. Flåen formation mica-schist Major rock forming minerals consists of muscovite, quartz, plagioclase, K-feldspar and minor amounts of biotite. Accessory minerals are chlorite, apatite and zircon. The sample exhibits schistose texture with aligned micas and feldspars, and recrystallized, dissolved grain boundaries. Chlorite appears secondary, and probably originates from biotite. Hydrothermal activity is thus indicated.

Bei-1:

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4.1.3. Eskolabreen granitic gneiss Two samples were appropriate for analysis from the Eskolabreen unit: J91-1 & 2. Major rock forming minerals are K-feldspar, quartz, plagioclase and biotite. Accessory minerals are chlorite, zircon, fluorite and allanite. Chloritization of biotite is extensive in rocks from this unit, although the samples J91-1 & 2 have very well preserved biotite and were hence chosen for Rb-Sr dating. Both samples show metamorphic texture from alignment of micas and recrystallized grain boundaries. Sample J91-1 show weakly dissolved grain boundaries, indicative of hydrothermal activity.

Sample J91-1:

Sample J91-2:

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4.1.4. Newtontoppen granite Major rock forming minerals are quartz, K-feldspar, plagioclase and biotite. Accessory minerals are chlorite, apatite, zircon, titanite and allanite. The sample exhibits igneous texture. The texture of plagioclase is characterized by post-crystallization alteration such as chloritization of biotite. K-feldspar exhibits perthitic textures.

Sample New-1:

4.1.5. Fonndalen augen gneiss Major rock forming minerals are quartz, muscovite, plagioclase, biotite and K-feldspar. Accessory minerals are apatite and pyrite. The sample exhibits a metamorphic texture with recrystallization, aligned micas and feldspars and large augens of quartz. K-feldspar exhibit dissolved grain boundaries. Plagioclase occurs as euhedral grains that crosscut the muscovite, indicating that some plagioclase recrystallized during or after the metamorphic peak.

Sample G92-23:

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4.1.6. Laponia augen gneiss Major rock forming minerals are biotite, muscovite, quartz and plagioclase. Accessory minerals are apatite and zircon. The sample exhibit foliated texture with aligned micas. Grain boundaries are indicative of nearly complete recrystallization, suggesting a high metamorphic grade for the Laponia augen gneiss.

Sample J92-3:

4.1.7. Ringåsvatnet augen gneiss Major rock forming minerals are K-feldspar, plagioclase, quartz, muscovite and minor biotite. Accessory minerals are apatite, zircon, chlorite, titanite and allanite. The sample exhibits a metamorphic texture. Retrograde metamorphism facilitated by hydrothermal fluids appears significant for sample J92-7 with dissolved grain boundaries, embayment textures, widespread chloritization of biotite and seriticitic K- feldspar.

Sample J92-7:

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4.1.8. Nordkapp granite Major rock forming minerals are quartz, K-feldspar, plagioclase, muscovite and biotite. Accessory minerals are apatite and zircon. The sample exhibits an igneous texture, although some recrystallization in grain boundaries exists, indicating that some post-crystallization metamorphic activity has influenced this intrusive rock.

Sample 94948:

4.1.9. Winsnesbreen granite Major rock forming minerals are quartz, K-feldspar, plagioclase, biotite and muscovite. Accessory minerals are apatite, iron-oxide and zircon. Grain boundaries are recrystallized and weakly dissolved, indicative of some hydrothermal activity has occurred in this intrusive granite post crystallization. Perthitic K-feldspar however is preserved however, indicating that post-magmatic metamorphism was restricted.

Sample 94047:

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4.1.10. Rijpfjorden granite Major rock forming minerals are quartz, K-feldspar, plagioclase, biotite and muscovite. Accessory minerals are apatite, iron-oxide and zircon. The sample has igneous texture with indicators of post- crystallization hydrothermal activity. Plagioclase also occasionally exhibits sericitic alteration. K-feldspar is often perthitic.

Sample 28-1:

4.1.11. Kapp Ekholm till Major rock forming minerals are K-feldspar, plagioclase and biotite. Accessory minerals are chlorite, apatite, iron-oxide and zircon.

Sample G2:

K-feldspar

Quartz

Plagioclase

Biotite/chlorite K-feldspar Plagioclase

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Sample G3:

K-feldspar Biotite

Quartz

Plagioclase

4.2. Geochronology

4.2.1. Isochrons Isochrons were calculated by IsoPlot and are shown below for each sample. Analyzed mineral phases were plagioclase, K-feldspar, biotite and muscovite, where plagioclase and K-feldspar are shown in the zoomed in figure to the right of corresponding isochron. Removed points are shown in red, these are outliers from the best line of fit, but could not be excluded due to poor ablation or mineral attributes. The removal of these points neither changed the age nor the initial-87Sr by more than 1% but decreased the error range and MSWD to acceptable values. A statistically robust isochron for Winsnesbreen granite (sample 94047) could not be achieved. Sample locations with ages are shown in figure 10, compiled with pre-existing geochronological data. Tables for all values and corresponding quantification standard are shown in Appendix B.

Bangenhuken granitic gneiss: 3 samples were analyzed from the Bangenhuken unit, as shown below. Plagioclase, K-feldspar and biotite define the line. Sample J91-17 had 4 outliers removed since these did not confirm with the best line of fit.

Sample: J91-17 14 points Zoomed in

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Sample: J91- Zoomed in 13 10 points

Sample: Per-1 Zoomed in 11 points

Eskolabreen granitic gneiss: 2 samples were analyzed from the Eskolabreen unit, as shown below. Plagioclase, K-feldspar and biotite define the line. 4 points were removed from sample J91-1 and 3 points from J91-2 since these did not confirm with the best line of fit.

Sample: J91-1 Zoomed in 14 points

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Sample: J91-2 Zoomed in 13 points

Flåen formation mica schist 1 sample was analyzed from the Flåen formation, as shown below. Plagioclase, K-feldspar, muscovite and biotite define the line.

Sample: Bei-1 Zoomed in 10 points

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Newtontoppen granite 1 sample was analyzed from the Newtontoppen granite (Chydeniusbreen granitoid suite), as shown below. Plagioclase, K-feldspar and biotite define the line.

Sample: New-1 Zoomed in 13 points

Laponia granitic biotite gneiss: 1 sample was analyzed from the Laponia gneiss, as shown below. Plagioclase, muscovite and biotite define the line.

Sample: J92-3 Zoomed in 20 points

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Fonndalen augen gneiss: 1 sample was analyzed from the Laponia gneiss, as shown below. Plagioclase, K-feldspar, muscovite and biotite define the line. 2 points were removed since these did not confirm with the best line of fit.

Sample: G92-23 Zoomed in 16 points

Ringåsvatnet augen gneiss: 1 sample was analyzed from the Ringåsvatnet augen gneiss, as shown below. Plagioclase, K-feldspar, muscovite and biotite define the line.

Sample: J92-7 Zoomed in 7 points

Sample: G92-23 16 points

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Nordkapp granite: 1 sample was analyzed from the Nordkapp granite, as shown below. Plagioclase, K-feldspar, muscovite and biotite define the line. 1 point was removed since it did not confirm with the best line of fit.

Sample: 94048 Zoomed in 9 points

Winsnesbreen granite: 1 sample was analyzed from the Winsnesbreen granite, as shown below. Plagioclase, K-feldspar, muscovite and biotite define the line. Proper statistics (MSWD: 0.5-1.7) could not be achieved for this sample, possibly due to heterogeneity of the sample and/or underestimation of errors.

Sample: 94047 Zoomed in 10 points

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Rijpfjorden granite: 1 sample was analyzed from the Rijpfjorden granite, as shown below. Plagioclase, K-feldspar and muscovite define the line.

Sample: 28-1 Zoomed in 11 points

Kapp Ekholm till: 2 grains were analyzed from till unit G in Kapp Ekholm: “G2” and “G3”. Due to scarcity of biotite in “G3” an isochron could only be obtained from “G2”. This was a preliminary run with the ICP-MS, hence only 3 valid data points were obtained in order to save material, yielding a too low MSWD. Plagioclase, K- feldspar and biotite define the line.

Sample: G2 Zoomed in 3 points

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4.2.2. Summary of bedrock geochronology Table 2: Method: 1: U-Pb zircon (conventional), 2: U-Pb zircon (conventional, lower intercept), 3: U-Pb titanite (conventional), 4: 207Pb/206Pb monazite, 5: U-Pb monazite, 6: Ar-Ar muscovite plateau age, 7: Ar-Ar biotite plateau age, 8: Rb-Sr (whole rock), 9: Pb-evaporation zircon, 10: U-Pb zircon (NORDSIM), 11: 207Pb/206Pb zircon (NORDSIM) . * = same sample as in this study.

Study: 1: Johansson et al., 1995, 2: Johansson & Gee, 1999, 3: Larianov et al., 1995, 4: Johansson et al., 2001, 5: Johansson et al., 2002, 6: Gee et al., 1995, 7: Johansson et al., 2000, 8: Teben’kov et al., 1996, 9: Myhre et al., 2005, 10: Gee & Page, 1994.

Location Article / Sampler Formation Sample Magmatic age Metamorphic age This study (Ma) (Ma) Age (Ma)& Initial- 87Sr Ny Friesland Johansson et al., Bangenhuk J91-17: 1720 - 17701,(1)* 404+/-97,(10) 426.7 ±7.9 (Spitsbergen) 1995 Granitic gneiss 1653 ±638, (1) ~4003,(1)* 0.9579 ±0.002 79°13'35 ~4103,(1) 16°11'10 Ny Friesland Johansson et al., Bangenhuk J91-13: 1766 +43/-351, No data 411 ±12 (Spitsbergen) 1995 Granitic gneiss (1)* 0.7530±0.0021 79°11'55 16°51'25 Ny Friesland No article Bangenhuk Per-1 No data No data 409 ±11 (Spitsbergen) Granitic gneiss 0.7567±0.0015 79°15'19 16°78'28 Ny Friesland No article Flåen Bei-1 No data No data 403 ±11 (Spitsbergen) Mica-schist 0.7405±0.0022 79°08'00 17°11'49 Ny Friesland Johansson & Gee, Eskolabreen J92-01: 1749 ± 91,(2)* 404 +/- 82,(2)* 419 ±12 (Spitsbergen) 1999 Granitic gneiss ~4003,(3) 0.8417±0.0030 78°58'05 16°35'45 Ny Friesland Johansson & Gee, Eskolabreen J92-2: 1749 ± 91,(2)* 404 +/- 82,(2)* 417 ±11 (Spitsbergen) 1999 Granitic gness ~4003,(3) 1.1275±0.0037 78°58'05 16°35'45 Olav V Land No article Chydeniusbreen New-1 440 ±138,(8) Not applicable 418 ±10 (Spitsbergen) (Newtontoppen) Granite 430 ±0.71,(9) 0.7198±0.0012 79°03'97 17°53'12 Nordaustlandet Johansson et al., Fonndalen G92-23 957 +30/-185, (7) No data 431.9 ±6.2 2000 Granitic augen 1048 +30/-241, 0.7672±0.0019 gneiss (7) 80°05'94 23°23'36 Nordaustlandet Johansson et al., Laponia J92-03 961 ±171, (6) No data 431.4 ±6.1 2000 Tonalitic biotite 0.72938±0.00095 gneiss 80°24'50 20°19'30 Nordaustlandet Johansson et al., Ringåsvatnet J92-07 956 ±79, (7)* No data 425.1 ±8.5 2000 Foliated augen 965 ±1810, (7)* 0.7470±0.0032 gneiss 937 ±911, (7)* 80°06'10 22°57'40 Nordaustlandet Johansson et al., Nordkapp 94048 440 ±24,(5)* Not applicable 443.9 ±9 2001 & 2002 Two-mica 428 ±126,(4)* 0.7307±0.0024 granite 80°45'33 19°97'73

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Nordaustlandet Johansson et al., Winsnesbreen 94947 406 ± 56,(4)* Not applicable 453 ±10 2001 Two-mica ~420 - 4605,(5) 0.730±0.012 granite 79°80'58 22°19'74 Nordaustlandet Johansson et al., Rijpfjorden 28-1 410 ±151,(5)* Not applicable 420.6 ±7.7 2001 & 2002 Two-mica 412 ±0.55,(4)* 0.7182±0.0025 granite 399 ±56, (4)* 80°27'77 405 ±117,(4)* 22°49'18

Figure 10: Rb-Sr geochronology obtained in this study (table 2 for details) merged with existing geochronological data from figure 2 (Caledonian ages only). The Rb-Sr ages from Nordaustlandet appears slightly older but are within the statistical population (fig. 11), inhibiting discrimination between the terranes by geochronology. Map edited from Dallman (2015).

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Figure 11: The Caledonian overprint of the northeastern basement province is too synchronous to allow for differentiating between bedrock sources by geochronology, inhibiting Rb-Sr geochronology as a valid provenance tool for glacial sediments in northeastern Svalbard.

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4.3. Initial-87Sr Initial-87Sr ratios differ significantly between the samples analyzed, and may be appropriate for provenance discrimination. Most prominent is the abnormally high initial-87Sr from sample J91-1, J91-2 and J91-17, which exceeds 0.8. Figure 11 below shows initial-87Sr signatures for the northeastern basement province, plotted with 86Sr/87Sr ratios of plagioclase, which approximate the initial-87Sr derived from the isochron. Bedrock sample locations with corresponding age and initial-87Sr are shown in figure 12.

Figure 12: 87Sr/86Sr ratios in plagioclase with initial-87Sr of associated isochron. Only plagioclase with 87Rb/86Sr ratios <1 was plotted in order to avoid scatter from in-situ radiogenic 87Sr. The abnormally high initial-87Sr signature from the BFZ rocks can be seen in 87Sr/86Sr ratios in plagioclase as well. Locations are shown on map in figure 12. Cross-section edited from Dallman (2015).

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Figur 13: Provenance indicative framework for the northeastern basement province using initial-87Sr ratios. All 3 samples from the western Atomfjella limb investigated in this study shows abnormally high initial-87Sr ratios, perhaps related to the retrograde metamorphism associated with the BFZ. Map edited from Dallman (2015).

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4.4. 87Rb/87Sr signatures in the Kapp Ekholm stratigraphy Insufficient sample quantities and quality from the till units prevented adequate provenance analysis for the sediment in the Kapp Ekholm stratigraphy. However, using the initial-87Sr signatures from the bedrock units investigated in this study a provenance map could be inferred (fig. 13), enabling distinction between west Atomfjella, east Atomfjella and the Caledonian intrusive rocks (fig. 12). Furthermore, this enables distinction of granitic clasts from Adolfbukta since these has significantly lower initial-87Sr signature, which is also expressed by 87Sr/86Sr ratios in plagioclase (fig. 11). Rb-Sr data for the 2 analyzed clasts can be seen in table 3 below.

Figure 14: Initial-87Sr signatures differ between the Paleoproterozoic Atomfjella rocks and the Caledonian intrusive rocks, with the latter being significantly lower in initial-87Sr ratios. Plagioclase 87Sr/86Sr ratios approximates the initial-87Sr signature for the bedrock units investigated (fig. 12), and provides a mineral specific provenance tracer especially useful in Kapp Ekholm since lack of biotite here inhibits isochrones to be made. G2 and G3 are both granitic clasts from till unit G, which was deposited during the LGM by the extended Nordenskiöldbreen (Eccleshall et al., 2016). Map edited from Dallman (2015).

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Table 3: LA-ICP-MS data for the 2 analyzed clasts from the Kapp Ekholm. SF6 was used as reaction gas. An isochron may be obtained from G2 but not G3 since this lacks data from biotite. Plagioclase and K-feldspar show two groups however; G2 has normal 87Sr/86Sr in plagioclase and low 87Rb/86Sr in K-feldspar, G3 has extremely high 87Sr/86Sr in plagioclase and high 87Rb/86Sr in K-feldspar.

Sample Mineral 87Rb/86Sr Error 87Sr/86Sr Error G2 Biotite 376.00478 1.20% 2.876755 0.24% G2 K-feldspar 1.7537896 1.20% 0.727447 0.24% G2 Plagioclase 0.0356567 1.20% 0.717126 0.24% G3 K-feldspar 19.40937 1.20% 0.952254 0.24% G3 Plagioclase 0.615074 1.20% 0.800181 0.24% G3 Plagioclase 0.227012 1.20% 0.846711 0.24%

K-feldspar may also serve as a provenance proxy in this area (fig. 14), since the bedrock of Ny Friesland and Olav v land differs significantly in initial-87Sr as well as 87Rb/86Sr ratios in K-feldspar. This proves especially valuable for provenance analysis in the Kapp Ekholm till, where scarcity of biotite inhibits proper isochrones to be made.

Figure 15: 87Rb/87Sr ratios in K-feldspar differs significantly for the provenance groups West Atomfjella, East Atomfjella and the Newtontoppen granite (Chydeniusbreen suite). The initial-87Sr value from corresponding isochrones are used to define the 87Sr/86Sr ratio when 87Rb/86Sr = 0. The trendlines hence represents the 87Sr evolution as a function of 87Rb content. Two granitic grains from the Kapp Ekholm was analyzed and plots according to the K-feldspar 87Rb/87Sr trends of the Newtontoppen granite (G2) and Eskolabreen granitic gneiss (G3).

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5. Discussion In this study new metamorphic data for Svalbard’s northeastern basement province was produced by Rb-Sr dating. Accompanied initial-87Sr signatures for the bedrock units investigated show significant differences between geographically distinct areas, and hence offer potentials for distinguishing provenances in glacial geological studies.

5.1. Geochronology The Caledonian overprint encompasses the entire Northeastern terrane, demonstrating that the closure temperature for the Rb-Sr system has been exceeded for all mineral phases analyzed, rendering 87Rb/87Sr geochronology alone as an intricate provenance tool for distinguishing between the Ny Friesland and Nordaustlandet terranes. Hence, provenance distinctions rather rely on the associated initial-87Sr signature, which will be discussed further in section 5.2. The Rb-Sr ages obtained in this study appears to best correspond to the monazite and titanite geochronology reported in the literature (table 2). The Rb- Sr system seems to predate the Ar-Ar ages reported from the literature by ~10-20 Ma, which agrees well with other studies (e.g. Nebel, 2015). Caledonian tectonothermal activity on Nordaustlandet seems to precede Ny Friesland with syn-tectonic intrusions at ~435-460 Ma represented by the Nordkapp and Winsnesbreen granites. Concerns should also be taken to the possibility of some heterogeneity within all the bedrock units investigated, since the ages presented from each bedrock unit are extrapolated from 1-2 samples.

5.1.1. Ny Friesland: Rb-Sr geochronology of the Atomfjella complex The Rb-Sr system has been completely reset by Caledonian tectonothermal activity across for all the bedrock units investigated on the Ny Friesland peninsula. However, pre-existing metamorphic data for Ny Friesland is restricted to the western limb, where Ar-Ar dating registers Caledonian cooling ages at about 404 ±9 Ma, and U-Pb titanite at ~400 Ma for the Eskolabreen and Bangenhuken units (Johansson et al., 1995; Johansson & Gee, 1999). The Rb-Sr ages obtained in this study is ~10-20 Ma older, which is in the same range as for the Ar-Ar versus Rb-Sr discrepancy shown on Nordaustlandet. The abnormally high initial-87Sr of the units from these samples has to be considered however, since this suggests a disturbance of the Rb-Sr system as also postulated by Johansson et al. (1995) and Johansson & Gee (1999). Textural evidence supports presence of fluids by dissolved grain boundaries, which could also explain the high initial-87Sr by gain of radiogenic Sr and cause an apparent older Rb-Sr age, however textures indicating activity of hydrothermal fluid are not unique to this area, since the sample Bei-1 from Flåen formation also exhibits these textures but yields a significantly lower initial-87Sr. 87Sr gain for both Bangenhuken and Eskolabreen units in the western Atomfjella is indicated by plagioclase 87Sr/86Sr ratios, which falls in the same range of 0.8-1.13. This initial-87Sr signature persists even when the plagioclase is removed from the isochron. The Rb-Sr system of the eastern side, as inferred by Bangenhuken unit and Flåen formation, seems more robust and yields ages similar to the existing metamorphic data previously mentioned, pointing towards that the Rb-Sr system closed at about 410 Ma in the Atomfjella antiform’s eastern limb.

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5.1.2. Chydeniusbreen suite: Rb-Sr geochronology of the Newtontoppen batholith The analyzed sample New-1 yielded an isochron of 418 ±10 Ma (13 points, MSWD = 0.74), with an initial- 87Sr of 0.7198 (±0.0012). This age compares well with the U-Pb zircon age from Myhre et al. (2005) of 430±0.5 Ma, with the Rb-Sr age from this study representing the slightly younger cooling age rather than the crystallization age. The whole-rock Rb-Sr age (432 ±10 Ma) from Teben’kov et al. (1996) was adjusted with the new 87Rb decay constant and then yielded an age of 440±13 Ma. Although within the error of the zircon age, the Rb-Sr age from this study fits better with the crystallization age inferred by U-Pb zircon reported by Myhre et al., (2005) since the Rb-Sr system should register the time of cooling subsequent to crystallization. The age of 440±13 is also contradictory to its postulated post-tectonic origin (Teben’kov et al., 1996). However, Teben’kov et al. (1996) sampled the entire Newtontoppen batholith to obtain a composite whole-rock date, while this study only analyzed a single sample from the central massif. Thus the discrepancy in age between these studies might relate to geochronological heterogeneity in the batholith. It should also be noted that all geochronological data available for Chydeniusbreen granitoid suite is based on analyzes on the Newtontoppen batholith, leaving room for uncertainties regarding the adjacent minor granitoids Ekkoknause and Raudberget since the tectonic relationships are disclosed by the Lomonosovfonna ice-cap. Accepting the age of 418 ±10 Ma, the Newtontoppen batholith appears to originate from the younger, post-tectonic magmatic event also recognized on Nordaustlandet from the Rijpfjorden granitoid body (420 ±7.9 Ma).

5.1.3. Nordaustlandet: Rb-Sr geochronology Rb-Sr geochronology on Nordaustlandet exclusively yields Caledonian ages, showing that the Rb-Sr system has been completely reset during this time for the investigated bedrock units. Caledonian tectonothermal activity seems to have abated earlier on Nordaustlandet than on Ny Friesland as inferred by the Rb-Sr system, this is supported by the Ar-Ar age on the Nordmarka augen gneiss of 420 ±12 Ma (Johansson et al., 2001 & 2002). Ar-Ar ages from Ny Friesland on the other hand infers cooling at 404 ±9 Ma, although it should be noted that the metamorphic ages of the basement rocks investigated are within overlapping errors. The Rb-Sr system appears intact and robust for Nordaustlandet using in-situ methodology, with no indicators of the indefinite ages reported by earlier Rb-Sr whole-rock data (Ohta et al., 1982; Hamilton, 1966).

5.1.3.1. The metamorphic basement of Nordaustlandet Rb-Sr dating of the Grenvillian basement as represented by the Laponia, Fonndalen and Ringåsvatnet gneisses, constrain Caledonian metamorphism to about 415-440 Ma. Previous metamorphic data for Nordaustlandet was not available for any of the bedrock units analyzed in this study, making these results contributing to new geochronological data for Caledonian metamorphism on Nordaustlandet. Pre-existing metamorphic data on the Grenvillian basement was limited to the Nordmarka augen-gneiss from Johansson et al. 2001 & 2002, presenting a U-Pb monazite age of ~440 Ma and an Ar-Ar muscovite age of 420 ±12 Ma, which fits well with the Rb-Sr ages obtained in this study which falls approximately in the middle of this age span (c. 430 Ma). The migmatization ages available also agrees well with this time of Caledonian tectonothermal activity (see fig. 7). The initial-87Sr of the investigated bedrock of this category is high, which would be expected from their metamorphic history. However, the Fonndal and especially Ringåsvatnet augen gneisses both exhibit textural signs of retrograde metamorphism, fasciliated by hydrothermal fluids.

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5.1.3.2. The Caledonian granitoids of Nordaustlandet The Rb-Sr ages of the Caledonian granitoid bodies obtained by this study show an age division similar to that proposed by Johansson et al. (2001), with Nordkapp yielding an Rb-Sr age of 443.9 ±9 Ma and Rijpfjorden (420.6 ±7.7 Ma) as shown by Ar-Ar mica and U-Pb monazite dating, supporting the hypothesis of a two-stage tectonothermal evolution of Caledonian magmatism on Nordaustlandet. However, the obtained Rb-Sr age for the Winsnesbreen granite (453 ±10 Ma) places this intrusion in the older syn-tectonic age division together with the Nordkapp intrusion, while Johansson et al. (2001) obtained an Ar-Ar muscovite age for the intrusion placing it in the younger, post-tectonic generation together with Rijpfjorden. The Rb-Sr age falls within the range of the poorly defined U-Pb monazite age of 420-460 Ma (Johansson et al., 2002) and is similar to the Nordkapp Rb-Sr age. Accepting the results from this study this would infer that the Winsnesbreen granite is not the speculated southward extension of the Rijpfjorden granite (Ohta et al., 1984, Johansson et al., 2002), but instead related to the syn-tectonic generation of intrusives as the Nordkapp granite. The initial-87Sr of the Winsnesbreen granite is more similar to the Nordkapp granite, although associated with large errors which also overlap with the Rijpfjorden granite. The Rijpfjorden granite is more similar to the Newtontoppen granite, which is also considered a post-tectonic intrusive. It should be noted however, that the Winsnesbreen granite isochron lacks statistical robustness (MSWD = 5.1 on 10 points), originating from an apparent off-set between K-feldspar and the best-fit line. The texture also suggests that the sample has been subject to heavy post-magmatic alteration, which might be the source for this off-set. The initial-87Sr signature of 0.71-0.72 for these Caledonian intrusives agrees with the general crustal evolution of 87Sr/86Sr, supporting a crustal anatectic origin as proposed by Johansson et al. (2001).

5.2. Provenance potentials using initial-87Sr The initial-87Sr from the metamorphic Bangenhuken and Eskolabreen unit in the western Atomfjella limb (bordering Austfjorden-Wijdefjorden) is between 0.8 - 1.13, indicating that the Rb-Sr system here has been disturbed. This is in agreement from Johansson et al. (1995) and Johansson & Gee (1999) who by whole-rock Rb-Sr dating concluded that the system has been disturbed. The whole-rock Rb-Sr isochron from Eskolabreen presented by Johansson & Gee (1999), which was modeled after the U-Pb zircon age yielded an impossibly low initial-87Sr 0.65-0.7. Johansson & Gee (1999) explained this by Rb-gain, Sr-loss or change in Sr isotopic composition. It should be noted however, that these are model ages based on geochronology from a system with significantly different thermobarometric sensitiveness. A re- calculation of the whole-rock 87Rb/87Sr isochron from the Bangenhuken unit by Johansson et al. (1995), using the new decay constant from Villa et al. (2015) yields an isochron of 1653±63 Ma, with an initial- 87Sr of 0.705. This initial-87Sr ratio suggests a mantle source for the protolith of the Bangenhuken unit, and Rb-Sr characteristics similar to the Transcandinavian Igneous Belt (Johansson et al., 1995). Thus both Eskolabreen and Bangenhuken granitic gneisses from the western Atomfjella (i.e. BFZ) exhibits the same Rb-Sr characteristics; whole-rock data yielding Paleoproterozoic protolith ages associated with impossibly low intial-87Sr ratios, while mineral specific isochrones yields Caledonian metamorphic ages associated with abnormally high initial-87Sr ratios. Increase of initial-87Sr ratios in mineral specific isochrones should be expected by repeated metamorphism, and may have been further facilitated by the extensive retrograde metamorphism associated with the movements along the BFZ (Witt-Nilsson et al., 1998). Textural evidence for retrograde metamorphism by hydrothermal fluids also exists in samples

44 from east Atomfjella and Nordaustlandet, which are not associated with initial-87Sr ratios in this range (0.8-1.13). Especially the sample J92-7 and G92-23 from Ringåsvatnet and Fonndalen augen gneiss appears to have experienced extensive alteration by fluids, which might explain their extremely high initial-87Sr of 0.7470±0.0032 and 0.7672±0.0019 respectively. However, samples from Bangenhuken granitic gness in the eastern Atomfjella unit appears unaffected by any retrograde processes and still yield initial-87Sr ratios in the range of 0.753-0.757.

The western limb of Atomfjella thus appears to have experienced some disturbance in the Rb-Sr system which produces extremely high initial-87Sr values using mineral specific Rb-Sr systematics. By textural observations in SEM, presence of fluids is suggested by dissolved grain boundaries between plagioclase, K-feldspar and quartz. The chloritization of biotite that is characteristic of the samples from this area also suggests some post-tectonic alteration. Witt-Nilsson et al. (1998) explained this extensive chloritization in the western Atomfjella limb by retrograde greenschist facies metamorphism related to the movements of the Billefjorden Fault Zone (BFZ). The sample J91-13 and Per-1 is from the Bangenhuken unit’s eastern limb, in central Ny-Friesland and yields an initial-87Sr of about 0.75, which falls in the same range as the other metamorphic bedrock units investigated. Accepting the assumption that these units are relatively homogenous, the extremely high initial-87Sr signatures should be limited to the Austfjorden-Wijdefjorden area and provide a provenance signature enabling distinction of material originating from this area. However, it has to be noted that this hypothesis suffers from a high level of extrapolation, which is accompanied with uncertainties, especially since some samples exhibit textures indicative of post-crystallization hydrothermal alteration. Since the Rb-Sr system is sensitive to fluid interaction this might produce initial-87Sr ratios not suitable for extrapolating from. However, the 2 analyzed grains from the Kapp Ekholm till in Billefjorden correlates well to this provenance framework and so add to the robustness of this supposition, having initial-87Sr signatures of 0.7171 and ~0.82. These are correlated to the post-tectonic intrusions (Newtontoppen and Rijpfjorden granites), and east Atomfjella (BFZ) granitic gneisses respectively. This correlation agrees well with textural evidence in the grains and ice-flow data for the till unit they derive from. Further investigations on the bedrock along the BFZ would benefit the reliability of the hypothesis that BFZ affected rocks are associated with an abnormally high initial-87Sr. 87Sr/86Sr analysis of the sedimentary units cropping out on the western flank of the BFZ would also greatly add to the comprehensibility of the initial-87Sr signatures that could be expected for sediment deriving from the Wijdefjorden area. The possibility of intermediate hosting by the adjacent metasedimentary and sedimentary units must also be considered, since these could contain recycled material from the bedrock units investigated.

Input of sediment originating from the eastern slope of Austfjorden-Wijdefjorden should show abnormally high initial-87Sr signatures, since the background value for shelf sediments in this area is significantly lower (about 0.713-0.719) (Tütken et al., 2002). This provides a discriminatory framework for IRD and glacial sediment on the northern Svalbard shelf and the Yermak plateau, which has already been shown to exhibit variations in initial-87Sr coupled to the Pleistocene ice-front position in Svalbard (Tütken et al., 2002). The Rb-Sr provenance framework presented here could thus be applied within the same context to distinguish between the relative contribution from the Wijdefjorden and Hinlopen Strait respectively, significantly improving the resolution for these sediments’ provenance. Since both hosted

45 ice-streams draining different ice-dome areas during glaciation, identification of ice-dome influences may potentially be obtained from the initial-87Sr signature in sediment from the northern Svalbard shelf and the Yermak plateau.

Since the 87Sr/86Sr ratio in plagioclase closely corresponds to the initial-87Sr (fig. 12), plagioclase could be used as a proxy for the initial-87Sr, providing a mineral-specific provenance tracer. This is especially valuable for the the eastern Atomfjella provenance, where extensive chloritization of biotite and thus lack of high-Rb mineral phases often inhibits robust isochrons to be made.

5.3. Rb-Sr provenance signatures in the Kapp Ekholm stratigraphy The applicability of in-situ 87Rb/87Sr on the till units from Kapp Ekholm has not been fully established by this study due to scarce amount of crystalline fragments obtained from the till samples. Rb-Sr geochronology cannot differentiate provenances in this area since the ages are too similar. However, using the initial-87Sr provenance signature appears promising for provenance analysis in this stratigraphy, with the possibility to discriminate between the metamorphic units of the west Atomfjella, the east Atomfjella, and the Chydeniusbreen batholith (Newtontoppen granite). Since 87Sr/86Sr in plagioclase closely corresponds to the initial-87Sr for the investigated bedrock units, plagioclase should serve as a proxy for the initial-87Sr signature, providing a mineral-specific provenance tracer. The grain G2 from till unit G (deposited during the last glacial maximum) yielded a 3-point isochron defining an initial-87Sr of 0.7171 (±0.0049), which is significantly lower than the obtained 87Sr initials from the Atomfjella metamorphic units (~0.74-1.11), but correlates well with the initial-87Sr signature from Newtontoppen of 0.7198 (±0.0012). The grain G3 could not yield a meaningful isochron since biotite was not analyzed for this sample, however using average 87Sr/86Sr in plagioclase low in 87Rb/86Sr (<1) the initial-87Sr may be approximated to ~0.82. This extremely high value is similar to the bedrock from east Atomfjella (along the BFZ) and infers that these initial-87Sr signatures also may be used as a provenance discrimination factor in the Billefjorden area, but also adds robustness to the supposition that the extremely high initial- 87Sr signatures are widespread along the western Atomfjella limb. Since the ice-flow that deposited this till is known to have originated from the Nordenskiöld glacier, Nordaustlandet could be excluded as a likely provenance.

The K-feldspar may also be used as a provenance tracer in this area, since the 87Rb/87Sr ratios divide into the same provenance groups concluded by initial-87Sr signatures (fig. 14), and hence provides a supplementary provenance signature for improving robustness and detail in provenance analysis in this area. The K-feldspar 87Rb/87Sr provenance discrimination differentiate bedrock areas as a function of the initial-87Sr and 87Rb/86Sr contents, which defines distinguished trendlines enabling distinction between west Atomfjella (BFZ), east Atomfjella, and Newtontoppen granite (Chydeniusbreen suite). This framework correlates G2 and G3 to the same provenances as the 87Sr/86Sr signatures in plagioclase. Grain G3 falls on the same line as the low strain-zone Eskolabreen granitic gneiss (sample J91-1), which agrees well with its outcropping location close to the Nordenskiöld glacier.

Future provenance studies in this area would be recommended to excess the sample quantity, since limestone constitutes the majority of the till and crystalline fragments are relatively rare, hence bulk samples are also ill-advised. The problem of intermediate hosting within sedimentary units is not within

46 the scope of this study, but should likewise be considered however, since some of the bedrock flanking Billefjorden hosts sandstones.

6. Conclusions  Initial-87Sr ratios provide a provenance tool enabling discrimination between selected bedrock areas within Svalbard’s northeastern basement province, since some geographically adjacent areas group together. 4 areas may be discerned by this framework: Laponiahalvöya (~0.73), Fonndalen & eastern Atomfjella (0.74-0.77), western Atomfjella (0.8-1.13), and the Newtontoppen-Rijpfjorden granites (~0.72). The overlap of initial-87Sr signatures of Fonndalen and Rijpfjorden with east Atomfjella and Newtontoppen, intricate all-encompassing distinction between Ny Friesland and Nordaustlandet. However, distinction between west Atomfjella (i.e. west Ny Friesland) and Nordaustlandet is possible, enabling distinction between Wijdefjorden and Hinlopen Strait as sources for glacial sediments on Svalbard’s northern shelf and the Yermak plateau. The utility of this framework appears most relevant for terrestrial glacial deposits in Svalbard and glacimarine deposits on the northern shelf edge, the Yermak plateau, the area south of Hinlopen Strait, and the Billefjorden-Isfjorden area.  Rb-Sr systematics in plagioclase and K-feldspar provide a promising tool for the Kapp Ekholm stratigraphy since it enables distinction between the west Atomfjella, east Atomfjella and Newtontoppen granite (Chydeniusbreen suite). 2 grains (G2 & G3) from till unit G was analyzed, providing a testbed since the ice-flow depositing this till is well constrained. Low initial-87Sr signatures (~0.72) should be confined to a source from the Nordenskiöld glacier, supplied by the post-tectonic intrusives (i.e. Chydeniusbreen suite). Extremely high initial-87Sr signatures (>0.8) should also be expected from this source since the Eskolabreen granitic gneiss outcrops adjacent to the Nordenskiöld glacier as well. This prediction is exactly replicated by the G2 and G3 granitic clasts, yielding initial-87Sr signatures of 0.717 and ~0.82 respectively. This further supports the supposition that the extremely high initial-87Sr signatures are widespread in the granitic gneisses of western Atomfjella. Measuring 87Rb and 87Sr simultaneously, as facilitated by reaction gas LA- ICP-MS, also gives the advantage that the initial-87Sr signature can be approximated from plagioclase and K-feldspar by considering the 87Rb content.  The Rb-Sr geochronology obtained in this study has added novel data for Caledonian metamorphism in Svalbard’s northeastern basement province. Closure temperature for the Rb- Sr system has been exceeded by Caledonian metamorphism for the entire Northeastern basement province. Previous attempts with Rb-Sr dating on Nordaustlandet yielded ages spanning 370-700 Ma (summarized in Ohta et al., 1992). The Rb-Sr ages for Nordaustlandet with in-situ mineral specific dating however ranges between 415-450 Ma, which is in agreement with available U-Pb and Ar-Ar dating. According to the Rb-Sr system Caledonian metamorphism appears to have subsided earlier on Nordaustlandet than on Ny Friesland, although most ages are within overlapping errors and all ages obtained in this study could be considered the same statistical population (fig. 11). The Rb-Sr age obtained for the Winsnesbreen granite should be considered inconclusive however, since it is associated with inadequate statistics and partly disagrees with previous geochronology.

47

 Initial-87Sr provides the most promising single factor provenance tracer as inferred by the results in this study. The 3 samples from the western Atomfjella limb yields abnormally high initial-87Sr ratios, suggesting a disturbance in the Rb-Sr system by gain of radiogenic Sr. The retrograde greenschist facies metamorphism associated with the Billefjorden fault zone could offer an explanation for this disturbance in the Rb-Sr system. Textural evidence for retrograde metamorphism facilitated by hydrothermal fluids exists in all samples from the BFZ, but also in samples with significantly lower initial-87Sr signatures. This could also be applied in the Kapp- Ekholm stratigraphy, since the east and west Atomfjella rocks as well as Chydeniusbreen granites outcrop in the reaches of the fjord head. Further studies to test this supposition would be beneficial, since an elaborate geochemical explanation for the initial-87Sr behavior nor were adequate sample points attained for this study, leading to large extrapolation and assumptions of homogeneity in the rock units investigated. However, the till from Kapp Ekholm, known to originate from an ice-flow emerging from southernmost Ny Friesland and Olav V land, exhibits the same 87Sr-signatures obtained from the bedrock units investigated, supporting the claim of homogeneity and consistency in the extrapolated initial-87Sr signatures.

7. Acknowledgements I would like to express my sincere gratitude to the supervisors of this project: Anne Hormes1, Thomas Zack1 and Ólafur Ingólfsson2 for guidance, management and inspiration throughout this project. Greatest gratitude is also expressed to Andreas Karlsson1 for expertise counselling regarding ICP-MS, SEM and petrology. Thank you Åke Johansson at the natural history museum providing the bedrock samples analyzed in this thesis. For indispensable field assistance and complementary sampling, gratitude goes to Daniel Ben-Jehoshua, Nína Aradóttir, Andreas Alexander and Helena Håkansson. Finally I would like to recognize the help from the students of AG-332/832 at the University centre in Svalbard for assisting the excavation and sampling of the Kapp Ekholm stratigraphy.

1: University of Gothenburg , 2: University Centre in Svalbard.

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Appendix A: Geological maps with sample locations

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Appendix B: LA-ICP-MS Rb-Sr data

ICP-MS data: 87Rb/86Sr & 87Sr/86Sr ratios with errors Eliminated analyses due to poor ablation or mineral qualities are crossed over. Analyses not included in isochron calculations are in italic.

Raised digit on the mineral specifies quantification standard used: 1: Mica Mg (Karlsson et al., 2016) 2: NIST SRM610 (Woodhead and Hergt, 2001) 3: BCR-2G (Elburg et al., 2005)

Sample J91-1 Reaction gas: N2O Sample J91-2 Reaction gas: N2O Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Bt1 6314.81 5.08% 39.19 4.89% Bt1 13149.55 5.02% 80.19 4.95% Bt1 7109.25 3.52% 43.46 3.45% Bt1 13044.48 4.04% 79.86 4.09% Bt1 4006.77 2.54% 24.48 2.42% Bt1 10566.58 3.91% 64.19 3.85% Bt1 7117.42 3.19% 42.91 3.11% Bt1 8428.15 2.72% 51.16 2.72% Bt1 10092.47 4.19% 61.23 4.03% Bt1 5762.64 2.37% 36.04 2.43% Bt1 7333.77 2.89% 45.38 2.97% Kfs1 29.96 1.30% 1.30 0.32% Bt1 7545.33 3.05% 46.33 3.08% Kfs1 30.30 1.30% 1.30 0.30% Bt1 8328.25 5.47% 51.64 5.33% Kfs1 73.64 1.68% 1.50 1.45% Kfs1 20.30 1.30% 0.94 0.26% Kfs1 55.56 1.30% 1.40 0.72% Kfs1 46.98 1.87% 1.10 0.56% Kfs1 29.11 1.30% 1.29 0.31% Kfs1 29.73 1.30% 1.00 0.41% Kfs1 30.57 1.48% 1.30 0.44% Kfs1 18.04 1.40% 0.92 0.33% Kfs1 33.07 1.40% 1.33 0.34% Kfs1 19.30 1.40% 0.93 0.29% Pl3 0.08 25.18% 1.13 0.54% Pl3 0.01 7.22% 0.85 0.54% Pl3 0.14 10.24% 1.14 0.34% Pl3 0.04 4.56% 0.84 0.38% Pl3 0.40 4.78% 1.11 0.42% Pl3 1.99 6.44% 0.86 0.50% Pl3 0.43 4.13% 1.12 0.43% Pl3 1.11 6.52% 0.86 0.41% Pl3 0.28 7.67% 1.13 0.40% Pl3 0.36 9.89% 0.85 0.43% Pl3 0.04 9.64% 1.13 0.33% Pl3 0.13 4.54% 0.84 0.40% Pl3 0.06 5.51% 0.84 0.46% Pl3 3.50 7.25% 0.86 1.39% 3 Pl 0.04 5.37% 0.84 1.05%

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Sample J91-17 Reaction gas: N2O Sample J91-13 Reaction gas: N2O Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Bt1 6742.08 2.26% 42.99 2.33% Bt1 1591.07 2.35% 9.87 2.27% Bt1 4539.18 2.11% 28.53 2.12% Bt1 2356.87 3.10% 13.79 2.72% Bt1 4402.56 2.58% 27.03 2.58% Bt1 1134.05 2.47% 7.55 2.39% Bt1 4184.06 1.34% 25.93 1.31% Bt1 2064.50 2.54% 12.46 2.69% Bt1 3188.62 1.66% 19.34 1.72% Bt1 840.83 2.19% 5.72 1.97% Bt1 2273.30 1.93% 14.95 1.88% Bt1 579.72 2.52% 4.01 2.36% Bt1 1582.11 2.91% 10.46 2.66% Kfs2 3.51 1.30% 0.77 0.22% Bt1 882.29 3.55% 6.16 3.14% Kfs2 3.81 1.30% 0.77 0.31% Bt1 312.63 2.50% 2.64 1.94% Kfs2 4.03 1.30% 0.78 0.25% Kfs1 22.88 1.40% 1.08 0.45% Pl3 0.02 16.79% 0.75 0.31% Kfs1 18.58 1.40% 1.07 0.25% Pl3 0.09 4.92% 0.75 0.40% Kfs1 16.69 1.30% 1.05 0.25% Pl3 0.11 8.68% 0.75 0.46% Kfs1 16.45 1.30% 1.06 0.25% 1 Kfs 15.34 1.30% 1.04 0.25% 1 Kfs 14.72 1.40% 1.05 0.25% 3 Pl 1.56 3.22% 0.93 0.28% 3 Pl 0.47 9.30% 0.96 0.25% Pl3 0.31 8.19% 0.95 0.26% Pl3 0.03 8.24% 0.96 0.26% 3 Pl 0.03 4.78% 0.96 0.25% 3 Pl 0.79 2.64% 0.95 0.31%

Sample Per-1 Reaction gas: SF6 Sample Bei-1 Reaction gas: SF6 Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Bt2 1505.13 2.15% 9.37 2.78% Bt2 158.79 3.63% 1.63 2.57% Bt2 2262.17 4.78% 13.83 0.28% Bt2 120.37 1.73% 1.40 1.46% Bt2 1461.89 4.99% 9.07 0.38% Kfs2 1.64 2.45% 0.74 0.45% Kfs2 3.24 1.58% 0.78 0.25% Kfs2 2.66 1.60% 0.76 0.37% Kfs2 3.49 1.30% 0.77 0.25% Kfs2 3.60 0.42% 0.76 0.22% Kfs2 3.31 1.55% 0.78 1.63% Kfs2 3.25 1.08% 0.76 0.30% Kfs2 3.26 1.31% 0.78 1.44% Ms2 93.27 1.55% 1.27 1.06% Pl3 0.18 3.57% 0.76 0.42% Ms2 103.23 0.61% 1.33 1.11% Pl3 0.20 5.48% 0.76 0.32% Ms2 107.89 1.37% 1.35 0.99% Pl3 0.36 1.30% 0.75 0.26% Pl3 1.31 1.60% 0.75 0.63% Pl3 0.06 1.30% 0.76 0.22% Pl3 0.58 3.77% 0.73 0.41% Pl3 2.03 1.93% 0.75 0.44% 3 Pl 0.80 3.39% 0.75 0.45% Pl3 1.47 1.28% 0.75 0.38% Pl3 0.56 2.90% 0.75 0.73%

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Sample G92-23 Reaction gas: N2O Sample J92-3 Reaction gas: N2O Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Mineral3 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Bt1 1215.48 1.26% 8.03 1.16% Bt1 87.64 1.30% 1.24 1.22% Bt1 602.51 1.96% 4.51 1.86% Bt1 572.00 1.38% 4.29 1.38% Bt1 1196.84 2.77% 7.95 3.01% Bt1 569.86 1.30% 4.24 1.22% Bt1 3772.45 6.74% 21.64 6.65% Bt1 471.14 1.73% 3.63 1.79% Bt1 1390.91 1.86% 8.73 1.84% Bt1 585.79 1.40% 4.15 1.06% Bt1 456.02 1.75% 3.35 1.51% Bt1 717.11 1.57% 4.97 1.46% Bt1 1497.47 4.63% 9.30 4.48% Bt1 622.93 1.40% 4.52 1.32% Kfs2 8.82 1.20% 0.81 0.25% Ms1 16.96 1.40% 0.83 0.41% Kfs2 7.46 1.20% 0.81 0.24% Ms1 403.46 8.92% 3.27 2.37% Kfs2 7.63 1.20% 0.81 0.25% Ms1 128.99 6.32% 1.44 3.39% Kfs2 7.29 0.90% 0.81 0.25% Ms1 12.69 1.30% 0.81 0.32% Kfs2 8.66 0.90% 0.81 0.25% Ms1 12.53 48.11% 0.81 4.44% Ms1 236.12 1.40% 2.21 0.87% Ms1 780.61 6.06% 5.47 4.35% Ms1 156.68 1.40% 1.75 0.82% Ms1 10.03 1.30% 0.80 0.36% Ms1 92.75 8.76% 1.35 2.12% Ms1 11.52 1.30% 0.79 0.28% Ms1 155.02 1.30% 1.71 0.90% Ms1 11.66 1.40% 0.80 0.43% Ms1 143.34 1.30% 1.62 0.75% Ms1 8.31 1.30% 0.78 0.53% Ms1 155.78 1.30% 1.72 0.83% Ms1 12.02 1.30% 0.80 0.35% Pl3 0.02 7.73% 0.77 0.25% Ms1 12.71 1.40% 0.81 0.96% Pl3 0.22 1.91% 0.76 0.34% Pl3 0.01 5.45% 0.73 0.20% Pl3 0.48 1.27% 0.74 0.25% Pl3 0.01 7.29% 0.73 0.18% Pl3 0.15 14.66% 0.76 3.15% Pl3 0.02 5.76% 0.73 0.28% Pl3 0.13 6.28% 0.76 0.41% Pl3 0.04 2.83% 0.73 0.19% Pl3 0.68 17.54% 0.74 0.83% Pl3 0.00 5.92% 0.73 0.19% Pl3 0.03 6.21% 0.73 0.16% Pl3 0.00 67.68% 0.73 0.88% Pl3 0.01 16.22% 0.73 0.19% Pl3 0.02 7.36% 0.73 0.21%

Sample New-1 Reaction gas: N2O Sample: 94048 Reaction gas: N2O Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Bt1 338.50 1.82% 2.59 1.34% Bt1 4083.68 1.85% 24.50 1.46% Bt1 107.92 1.82% 1.31 0.76% Bt1 5717.69 3.96% 34.25 3.90% Bt1 61.20 5.72% 1.07 3.86% Bt1 38.78 9.19% 0.92 4.80% Bt1 431.90 2.69% 3.32 2.54% Bt1 11466.56 3.13% 70.58 3.05% Bt1 792.77 1.89% 5.35 1.60% Kfs2 10.37 1.40% 0.79 0.44% Bt1 1100.89 1.82% 6.94 1.64% Kfs2 9.32 1.40% 0.78 0.32%

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Bt1 98.30 3.64% 1.24 1.45% Kfs2 10.33 1.40% 0.79 0.23% Bt1 1726.18 1.94% 11.10 1.96% Kfs2 8.92 1.40% 0.79 0.23% Bt1 1549.71 1.82% 9.88 1.85% Ms1 151.54 1.40% 1.68 0.74% Bt1 41.31 3.14% 0.95 2.65% Ms1 139.26 1.40% 1.61 0.65% Bt1 98.22 3.84% 1.30 3.14% Ms1 159.38 1.40% 1.71 0.69% Bt1 532.96 3.71% 3.95 3.26% Pl3 0.07 6.78% 0.73 0.27% Bt1 323.58 3.60% 2.58 3.13% Kfs2 1.70 1.54% 0.73 0.14% Kfs2 1.40 1.43% 0.73 0.25% 2 Kfs 1.35 1.43% 0.72 0.41% 3 Pl 0.12 2.22% 0.72 0.25% 3 Pl 0.09 1.34% 0.72 0.25% 3 Pl 0.25 1.51% 0.72 0.25% Pl3 0.46 1.69% 0.72 0.31% Pl3 0.62 1.33% 0.72 0.28% 3 Pl 1.21 1.33% 0.73 0.25% 3 Pl 0.03 5.43% 0.72 0.27% 3 Pl 0.11 4.06% 0.71 0.25% 3 Pl 0.06 6.45% 0.71 0.34%

Sample: 94047 Reaction gas: N2O Sample: 28-1 Reaction gas: N2O Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Mineral 87Rb/86Sr 1 sigma 87Sr/86Sr 1 sigma Bt1 24195.95 3.87% 150.87 3.84% Kfs2 32.79 1.43% 0.91 0.36% Bt1 23716.00 7.41% 148.29 7.24% Kfs2 15.64 1.43% 0.81 0.39% Bt1 17487.61 5.91% 109.91 5.96% Kfs2 15.69 1.43% 0.81 0.19% Kfs2 25.60 1.40% 0.88 0.28% Ms1 1012.99 1.82% 6.74 0.73% Kfs2 41.40 1.40% 0.97 0.28% Ms1 1454.21 1.82% 9.33 1.13% Ms1 391.63 1.40% 3.26 0.59% Ms1 1040.05 1.82% 6.82 0.81% Ms1 492.77 1.40% 3.85 0.68% Ms1 686.91 1.82% 4.78 1.06% Ms1 1727.26 1.40% 11.76 1.18% Pl3 0.03 6.45% 0.72 0.46% Pl3 0.24 9.42% 0.75 0.37% Pl3 0.77 7.50% 0.73 0.40% Pl3 1.20 6.06% 0.75 0.45% Pl3 0.85 6.86% 0.73 0.85% Pl3 1.15 8.12% 0.74 0.35% Pl3 0.11 3.57% 0.72 0.40% Pl3 0.31 8.00% 0.74 0.24%

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