Regional tectono-sedimentary development of the highs and basins of the northwestern Barents Shelf

Abstract

While many structural elements on the northwestern Barents Shelf initiated early and have remained influential on accommodation and sedimentation, detailed seismic interpretation attests to the development of new structural elements, shifting locus of influence, and burial, reactivation and inactivation at different times of various highs and basins. NE–SW-oriented structural elements such as the Gardarbanken and Hopen highs, and the Capria ridge (informally named herein), have old Carboniferous foundations and show signs of reactivation in the Early Triassic. Towards the southwest, the Capria ridge merges with the paleo-Stappen high, which is a N–S, tilted peneplaned, Late Carboniferous rift-shoulder which deeply erodes the Carboniferous deposits, and is onlapped by Permian and Early Triassic sediments. The paleosurface is overprinted by the dominantly post-Cretaceous development of the Stappen High, which has a maximum uplift and extent south of Bjørnøya. The Sørkapp basin is the main depocentre on the northwestern Barents Shelf; however, the Storjorden, Edgeøya and Ora (informally named herein) basins all formed around the same time in the Carboniferous. While the Sørkapp basin remained a sag basin until the Ladinian, the Edgeøya basin, a narrow rift basin, became largely inactive following infill. As a result, the Hopen high and Edgeøya platform, which bounded the Edgeøya basin, merged to form the Svalbard platform. The Storfjorden basin was reactivated around the Mid Jurassic when the Sørkapp depression, forming west of the Sørkapp basin, was initiated. Both basins are asymmetrical and bounded by gentle anticlinal features on one side implying formation associated with contraction. Cretaceous sediments, largely eroded from the area, are found in basins such as the Olga basin, which formed between two anticlines. One of these anticlines is the Sentralbanken high, which contrary to most other highs in the area shows no signs of initiation in the Carboniferous, but rather appears to have been a depocentre which was inverted around the Cretaceous.