Eastern Barents Sea Late Palaeozoic setting and potential source rocks

Abstract

The Late Palaeozoic basins of the Eastern Barents Sea are in general controlled by three orogenic lineaments, the Baikalian, the Caledonian and the eastern plate boundary. The Baikalian in the south includes the onshore Timan–Kanin Ridge which turns from a northerly to a northwest direction seaward of the Kola Peninsula. The trend appears to be cut by the Vyalozero and the Tuloma fracture zones. Similar northwesterly lineaments including the Tiddlybanken Basin occur on the west side of these fracture zones towards northern Norway. The Caledonides extend from the Norwegian mainland to Svalbard and probably eastward to Franz Josef Land. A northeasterly Caledonian trend is shown by a number of structures like the Nordkapp Basins, Sentralbank High, a nameless basin east of Svalbard and to some degree the Olga Basins. During Devonian and Early Carboniferous the eastern plate boundary was characterized by subduction of oceanic crust along volcanic arcs which were located parallel with the present-day Urals and Novaya Zemlya. The distribution of potential source rock facies in the Eastern Barents Sea during Late Palaeozoic can be represented by palaeogeographic maps for the Late Devonian (Fransnian–Famennian), Early Carboniferous (Late Visean–Serpukhovian) and Early Permian (Sakmarian) periods. The Late Devonian basin in the Eastern Barents Sea was probably a northward extension of the onshore Timan-Pechora, Volga-Ural and North Caspian basins. The palaeogeographic map shows the restricted Domanik facies and the bordering open shelf carbonate facies and their continuation from the Pechora area and into the Barents Sea. During the Late Visean to Serpukovian a wide low relief shelf existed between the continental setting of the western Barents Sea and the open basinal facies at the eastern plate boundary. On this platform the only basins present were reactivations of Caledonian structures. An equivalent to the Devonian basin was not present at this time. An open shelf facies existed in the east. Towards the west marine conditions may have been more restricted and favourable for source rock deposition. The Sakmarian period coincided with the early stage of the Uralian continent collision. Much of the Barents Sea was in an open shelf setting. However, areas of restricted circulation and source rock potential occurred locally as a function of topography.