Finnmark Platform Composite Tectono-Sedimentary Element, Barents Sea

Abstract

Abstract The Finnmark Platform Composite Tectono-Sedimentary Element (CTSE), located in the southern Barents Sea, is a northward-dipping monoclinal structural unit. It covers most of the southern Norwegian Barents Sea where it borders the Norwegian mainland. Except for the different age of basement, the CTSE extends eastwards into the Kola Monocline on the Russian part of the Barents Sea. The general water depth varies between 200 and 350 m, and the sea bottom is influenced by Plio-Pleistocene glaciations. A high frequency of scour marks and deposition of moraine materials exists on the platform areas. Successively older strata sub-crop below the Upper Regional Unconformity (URU), which was formed by several glacial periods. Basement rocks of Neoproterozoic age were heavily affected by the Caledonian Orogeny, and previously by the Timanide tectonic compression in the easternmost part of the Finnmark Platform CTSE. Depth to crystalline basement varies considerably and is estimated to be from 4–5 to 10 km. Following the Caledonian orogenesis, the Finnmark Platform was affected by Lower–Middle Carboniferous rifting, sediment input from the Uralian Orogen in the east, the Upper Jurassic–Lower Cretaceous rift phase and the Late Plio-Pleistocene isostatic uplift. A total of eight exploration wells drilled different targets on the platform. Two minor discoveries have been made proving the presence of both oil and gas, and potential sandstone reservoirs of good quality identified in the Visean, Induan, Anisian and Carnian intervals. In addition, thick sequences of Permo-Carboniferous carbonates and spiculitic chert are proven in the eastern Platform area. The deep reservoirs are believed to be charged from Paleozoic sources. A western extension of the Domanik source rocks well documented in the Timan–Pechora Basin may exist towards the eastern part of the Finnmark Platform. In the westernmost part, charge from juxtaposed downfaulted basins may be possible.