Tromsø–Bjørnøya Composite Tectono-Sedimentary Element, Barents Sea

Abstract

Abstract The Tromsø–Bjørnøya Composite Tectono-Sedimentary Element (CTSE) in the southwestern Barents Sea comprises strata of Late Paleozoic–Paleocene age. Since the Paleozoic Caledonian Orogeny, the structural evolution of the CTSE is mainly related to extension, culminating in Late Jurassic–Early Cretaceous hyperextension. Some compressive deformation observed during Late Cretaceous–Paleogene times may relate to activity in the North Atlantic prior to the Early Eocene onset of seafloor spreading between Norway and Greenland. The sedimentary succession may be up to 14 km thick. It comprises Late Paleozoic continental facies, followed by carbonates, evaporites, and eventually cherts and marine clastic material. The overlying Triassic–Paleocene succession is entirely siliciclastic, reflecting Triassic–Middle Jurassic deltaic and shallow-marine conditions followed by deeper-marine conditions during Late Jurassic–Paleocene times. Primary reservoirs are encountered in the latest Triassic–Middle Jurassic succession, with secondary reservoirs found in the Late Jurassic–Early Cretaceous synrift succession, and in Paleocene strata. The primary source rock for petroleum is of Late Jurassic–Early Cretaceous age. Other source rocks include strata of Triassic and Barremian age, and a recently observed unit of Cenomanian–Early Turonian age.