NORWEGIAN JOURNAL OF GEOLOGY Vol 97 Nr. 1 https://dx.doi.org/10.17850/njg97-1-03 Facies development of the Upper Triassic succession on Barentsøya, Wilhelmøya and NE Spitsbergen, Svalbard Gareth Steven Lord1,2, Sondre Krogh Johansen1,2, Simen Jenvin Støen1,2 & Atle Mørk1 1Department of Geoscience and Petroleum, Norwegian University of Science and Technology (NTNU), Sem Sælands veg 1, 7491, Trondheim, Norway. 2Department of Arctic Geology, University Centre in Svalbard (UNIS), Longyearbyen, 9171, Norway. E-mail corresponding author (Gareth Steven Lord): [email protected] Field data collected from the northeasternmost Triassic exposures on the islands of Spitsbergen, Wilhelmøya and Barentsøya during 2015 are used for sedimentological facies analysis to improve our understanding of the stratigraphic development of the Upper Triassic strata. Results presented here build upon previous studies from the eastern areas of the Svalbard archipelago and seek to extend this understanding northward. Paralic deltaic sediments are recognised throughout the field area, and our analysis shows that the Upper Triassic De Geerdalen Formation is composed of three discrete units defined by the differences in gross depositional environments. The lower interval of early Carnian age is dominated by shallow-marine and delta-front/ shoreface deposits, the middle interval of mid Carnian age is dominated by delta-front to delta-top deposits, and the upper interval, corresponding to the Isfjorden Member, of a late Carnian to early Norian age, is dominated by delta-top deposits which include lagoonal and lacustrine deposits. These observations show that the De Geerdalen Formation represents a more distal depositional setting, than the depositional environments previously reported from the islands of Edgeøya and Hopen. We also document the presence of the Tschermakfjellet Formation and Isfjorden Member on Wilhelmøya, thus increasing our understanding of the northwestward development of the Upper Triassic succession in Svalbard. Keywords: Facies Development; Upper Triassic; Eastern Svalbard; Sedimentology Received 18. January 2017 / Accepted 6. February 2017 / Published online 28. March 2017 Introduction al., 2014, 2015). Recent sedimentological studies in the Upper Triassic of Svalbard have thus focused pri marily The Upper Triassic stratigraphy in Svalbard (Figs. on fluvial sandstone bodies seen in the southeastern 1A–B & 2A) was first described by Buchan et al. areas of the archipelago (Solvi, 2013; Klausen & Mørk, (1965). Preliminary facies studies were given for 2014; Lord et al., 2014b), as analogues to potential eastern Svalbard by Flood et al. (1971a) and Lock et al. reservoirs in the Snadd Formation. Mørk (2013) and (1978), whilst Mørk et al. (1982) covered much of the Anell et al. (2014a, b) discussed the Upper Triassic archipelago. Rød et al. (2014) provide the most extensive succession in relation to its potential as a CO2 storage sedimentological study covering Edgeøya and central reservoir in central Spitsbergen. However, in these cases Spitsbergen. The succession has largely been regarded as the northernmost parts of the Storfjorden area in eastern a useful analogue to the Triassic in the Barents Sea, and Spitsbergen have been somewhat disregarded. particularly the comparison to the fluvio-deltaic Snadd Formation, known for its reservoir potential, has received In the study area (Fig. 1B), the Carnian succession has some attention (e.g., Klausen & Mørk, 2014; Klausen et not been studied in detail since the earlier works of Lord, G.S., Johansen, S.K., Støen, S.J. & Mørk, A. 2017: Facies development of the Upper Triassic succession on Barentsøya, Wilhelmøya and NE Spitsbergen, Svalbard. Norwegian Journal of Geology 97, 33–62. https://dx.doi.org/10.17850/njg97-1-03. © Copyright the authors. This work is licensed under a Creative Commons Attribution 4.0 International License. 33 34FigureG.S. Lord et al. 1 A&B 20°00'E 20°30'E 21°00'E 21°30'E A A Kvitøya B Tumlingodden 10-1 Svalbard N 80° A’ Keisarkampen 15-1 N77°30’ Nordaustlandet Keisarkampen Tumlingodden WILHELMØYA Keisarkampen 13-1 Bjornøya N72°30’ Norway Bjørnbogen 79° Wilhelmøya 79°00'N E20° Alta Kong Karls Land Prins Spitsbergen Tumlingodden 15-1 Karls Forland Barentsøya Study Longyearbyen 78° Area Edgeøya 77° Kapp Payer Kongsfonna Hopen Storebrøme 1 H a n n b r e e n 15° 21° 27° 78°45'N78°45'N S o n Kvitbergetn 645 k e l e Kvitberget a Vasilievellet 662 r r Vasilievfjellet 38 b Hellwaldfjelletb 247 r 247 247 o e k Buchholz- e 30 Sonklarbreen n bukta n Hellwaldellet e š Legend 30 a d e Unconsolidated material: 1 P 3 Janusfjellet Sgp. (Callovian - Hauterivian) Hellwald- bukta Moraines kta Agardhfjellet Fm. (Callovian - Volgian) 20°00'E 20°30'E nbu 21°00'E 21°30'E Baka Marine deposits 247 Kapp Toscana Gp. (Carnian - Bathonian) Batesfjellet Bakanbukta Wilhelmøya Sgp. (Norian - Bathonian) Glaci-fluvial deposits Wilhelmøya Sgp. (Undifferentiated) Un-classified Material Hellwaldfjellet 15-1 Kvitberget (No Log) Svenskøya Fm. (Early Jurassic?) Geological Features Edlundfjellet Flatsalen Fm. (Norian) Rock Boundary Storfjorden Sgp. (Carnian - Early Norian) Fault (Inferred) De Geerdalen Fm. (Carnian - Early Norian) Normal Fault Tschermakfjellet Fm. (Early Carnian) Reverse Fault Unconformity Sassendalen Gp. (Induan - Ladinian) Farken 15-1 Botneheia Fm. (Anisian - Ladinian) Vikinghøgda Fm. (Induan - Olenekian) Farken Templefjorden Gp. (Late Permian) 0 5 10 km Grimheia Mistakodden 15-1 78°30'N Kapp Starostin Fm. (Late Artinskian - Kazanian) Contour Interval: 100 m Skrinnmulen Hahnfjella 15-3 Svartnosa 15-1 BARENTSØYA Vossebukta Barentsjøkulen Storfjorden SPITSBERGEN Hahnfjella Fault Zone Teistberget 15-1, 15-2 & 15-3 Gregoryfjellet Teistberget Krefftberget 15-1 OLAV V LAND STORFJORDEN Mohnbukta Nordmansfonna Andersonbukta Krefftberget 78°15'N Wallenbergfjellet Lomfjorden Fault Zone Domen Freemansundet Dunérbukta Raggfjellet 11-1 Snauheia Krapotkinfjellet Holmgardfjellet Friedrichfjellet 15-3 Leehovden Šmidtberget 15-2 Friedrichfjellet Dolomitneset Myklegardfjellet Klement’evfjellet 15-2 Timertfjellet Smidtberget 18°00'E Klement’ 18°30'E 19°00'E 19°30'E 20°00'E 20°30'E 21°00'E evfjellet Agardhbukta Figure 1. (A) Inset map showing an overview of the high Arctic position of Svalbard in relation to the Barents Sea and Norway. The study area is highlighted in red. Note the location of the seismic line, shown in Fig. 3B. (B) Geological map of the study area featuring the major strati- graphic units, structures and position of measured sections. The map is modified after Dallmann & Elvevold (2015). FigureNORWEGIAN JOURNAL 2 OFA&B GEOLOGY Facies development of the Upper Triassic succession on Barentsøya, Wilhelmøya and NE Spitsbergen, Svalbard 35 A Geological Time Svalbard Spitsbergen Stage Ma Wilhelmøya Barentsøya Edgeøya Hopen Era South Central East Group Period Sequence Sub-Group Boundaries Nordenskiöld Land Heer Land Sabine Land Olav V Land Tithonian Kimmeridgian Agardhfjellet Late Fm. Quaternary Erosion Janusfjellet Oxfordian Adventdalen 163 Callovian Marhøgda Bed* Bathonian Brentskardhaugen Bed Brentskardhaugen Bed Bajocian Middle Juriassic Aalenian 174 Kongsøya Toarcian Smal- Knorringfjellet Fm. egga Fm. ? Keisarkampen Mb. Fm. Teistberget mb. Pliensbachian Hellwaldfjellet Bed Early Sinemurian Svenskøya Fm. Hettangian 201 ? LFZ Sjögrenfjellet Mb. Quaternary Erosion Wilhelmøya Rhaetian oscana Svenskøya T Hiatus? Fm. ~208 Kapp Knorringfjellet ? Smal- Flatsalen egga Fm. Flatsalen Norian Fm. Tverrbekken mb. Fm. Fm. Mesozoic Slottet Bed Slottet Bed Slottet Bed Late ~227 Isfjorden Mb. Isfjorden Mb. Hopen Mb. Quaternary Erosion De Geerdalen Fm. De Geerdalen Fm. De Carnian Geerdalen Storfjorden Tschermakfjellet Fm. Tschermakfjellet Fm. Fm. ~237 riassic T Below Present Van Keulenfjorden Mb. Ladinian Sea Level Bravais- Blanknuten Mb. 242 Somovbreen Mb. Berget Botneheia Fm. Muen Mb. Middle Karentoppen Mb. Fm. Anisian 247 Passhatten Mb. Vendomdalen Mb. Olenekian Tvillingodden Fm. Sassendalen 251 Lusitaniadalen Mb. Vikinghøgda Fm. Early Hiatus Vardebukta Induan Fm. Deltadalen Mb. 252 B Hahnfjella 537 m asl Isfjorden Mb. De Geerdalen Fm. Tschermakfjellet Fm. Botneheia Fm. Botneheia Fm. Vikinghøgda Fm. SSE NNW Figure 2. (A) Stratigraphic chart of the Triassic to Middle Jurassic successions at various locations throughout Svalbard (modified after Mørk et al., 1999a, 2013). (B) An overview picture of the mountain of Hahnfjella (Fig. 1B) in eastern Spitsbergen with a well exposed section of the Middle–Upper Triassic succession. The Middle Triassic shales of the Vikinghøgda and Botneheia formations form steep cliffs along the base of the mountain. These are overlain by small upward-coarsening packages in the De Geerdalen Formation. The Isfjorden Member is partially exposed in the upper part of the mountain. 36 G.S. Lord et al. Flood et al. (1971a), Lock et al. (1978) and Pčelina (1983). Palaeozoic–Mesozoic platform area (Riis et al., 2008; These studies primarily focused on the establishment Worsley, 2008). The eastern areas of Spitsbergen are of a stratigraphic scheme and detailed dating. The dominated by flat-lying strata of Permian to Palaeocene work by Flood et al. (1971a) covered the main eastern age, intruded by Cretaceous (124.5 Ma; Corfu et al., islands of Barentsøya, Edgeøya and Hopen, defining 2013) dolerite sills and dykes (Dallmann & Elvevold, the Vardebukta, Kongressfjellet, Tschermakfjellet and 2015). The study area is located in this eastern platform De Geerdalen formations. A brief sedimentological area.