Variations in depositional environments of the Paleogene Firkanten Formation across Adventdalen, from Operafjellet to Breinosa

• Main Author: Guðmundsdóttir, Anna Stella
• Other Authors: University of Gothenburg/Department of Earth Sciences, Göteborgs universitet/Institutionen för geovetenskaper
• Format: Text
• Language: English
• Published: 2021
• Subjects: Adventdalen; Spitsbergen
• Online Access: http://hdl.handle.net/2077/68092

The lowermost Paleogene clastic infill of the Central Spitsbergen Tertiary Basin, the coal bearing Firkanten Formation, has been the subject of study for researchers in the past but little focus has been on the northeast edge of the basin until now. Due to the economic potential of the coal seams in the formation, the Norwegian mining company, Store Norske Spitsbergen Grubekompani (SNSG), has for several years conducted core drilling in key locations in basin, and for decades, they have given an access to their core material to researchers. Drill cores and laboratory results from SNSG is used for sedimentological and geochemical investigation for the purpose of comparing the depositional environment in the Operafjellet and Breinosa mountains, to give a better understanding of the depositional setting at the northeast edge of the basin. Six cores from each mountain were chosen as they characterized the overall lithology of the area, with a complementary field log and observations from Operafjellet mountain. All cores were logged in detail (1:20), and special attention was put on the coal where lithotyping was done on cores with intact coal seams. Furthermore, laboratory results from SNSG, containing ash and sulphur results from the coal seams, were used to support correlation and to investigate the quality of the coal at the basin edge. In the past, 5 coal seams have been recognised in the Todalen Member, the lowermost member of Firkanten Formation. Two new coal seams, one from the top of Todalen Member and another from the uppermost Endalen Member of the formation are presented with detailed description and names to distinguish them from other seams. Results show that the Firkanten Formation is deposited in coastal plain to shallow-marine setting and significant lithological differences are observed in the two areas despite their relatively short distance from each other, this is especially noticeable in the Todalen Member where there are coal deposits of higher quality and greater thickness and relatively ...