BARENTS SEA CRUSTAL ARCHITECTURE AND BASIN EVOLUTION

The Barents Sea continental shelf is characterized by a complex tectonic history and thus comprises a wide range of crustal and basin architectures that formed in response to different geological processes. Overlapping Paleozoic orogenies (Timanian, Caledonian, Uralian) preceded multiple rift episodes mainly affecting the western Barents Sea and eventual breakup with Greenland to the west and Lomonosov Ridge to the north. The eastern Barents Sea comprises a wide and deep sag basin that formed by rapid subsidence in Late Permian-Early Triassic times, most likely in response to basin-forming mechanisms other than rifting. In the western Barents Sea we find more typical rift basins formed in response to at least four major post-Caledonian rift phases: Carboniferous, Late Permian, Late Jurassic-Early Cretaceous, and Late Cretaceous-early Paleogene. The rifting activity migrated westwards through successive tectonic phases. Carboniferous rifting affected the entire western Barents Sea and gave rise to NE-SW to N-S trending horst and graben structures. Late Jurassic-Early Cretaceous oblique extension and formation of the deep SW Barents Sea basins was linked to the North Atlantic-Arctic plate tectonic evolution. Regional uplift associated with the Early Cretaceous High Arctic Large Igneous Province gave rise to a depositional system characterized by north to south progradation covering most of the Barents Sea. A Late Cretaceous-Early Paleogene mega-shear system along the western Barents Sea-Svalbard margin linked rifting, breakup and initial opening of the Norwegian-Greenland Sea and the Arctic Eurasia Basin. Narrow pull-apart basins formed within this dominantly shear system, in particular at a releasing bend in the margin SW of Bjørnøya. A restraining bend SW of Svalbard gave rise to the transpressional Spitsbergen Fold-and-Thrust Belt. Compressional structures of different styles are found widespread in the Barents Sea region, but the nature and timing of these are difficult to constrain in many areas due to later uplift and erosion. The entire Barents Shelf was uplifted and eroded during Neogene time and thick fans of mainly Plio-Pleistocene glacial sediments were formed in front of bathymetric troughs characteristic of both the western and northern Barents Sea.