Evolution of the Central Tertiary Basin of Spitsbergen: towards a synthesis of sediment and plate tectonic history

The Central Tertiary Basin of Spitsbergen developed east of a strike-slip boundary between the Eurasian and Greenland plates in response to the initiation of rifting and later seafloor spreading in the Norwegian-Greenland Sea. Using a new plate model for the opening of the North Atlantic, we attempt to relate the sediment history of the Central Tertiary Basin to its plate tectonic framework and suggest a basin development in four phases. The Central Tertiary Basin was formed in the Early Paleocene during a right-lateral strike-slip phase, after the plate boundary between Greenland and Svalbard had jumped eastward to the Hornsund Fault Zone (phase 1). The onset of seafloor spreading between Greenland and Eurasia and a drastic counterclockwise change in spreading direction between Greenland and North America after chron 25 (Late Paleocene) induced compression-dominated transpression between Greenland and Svalbard until chron 24 (Lower Eocene) (phase 2). The first sedimentary evidence for tectonic uplift along the strike-slip zone is found in a wedge-shaped delta fan in the northwestern part of the basin. Strike-slip-dominated transpression prevailed from chron 24 to chron 21 (lower Middle Eocene), contemporaneous with successive basin narrowing and an eastward migration of the depocenter (phase 3). After chron 21 (lower Middle Eocene) the relative motion between Greenland and Svalbard first changed to strike-slip, terminating the transpressional phase, and then to transtension after chron 13 (Lower Oligocene) (phase 4).