A maturity map for Silurian rocks of Severnaya Zemlya: a combined study of conodont Colour Alteration Index and Rock Eval Pyrolysis

The Severnaya Zemlya Archipelago is located on the edge of the Arctic Ocean north of the Taimyr Peninsula, separating the Kara and Laptev seas, two potentially vast and apparently different hydrocarbon provinces. Conodont Colour Alteration Index (CAI) and organic geochemistry (Rock Eval Pyrolysis) data have been used to estimate the maximum temperature reached by the Silurianrocks of Severnaya Zemlya. The data were derived from about four hundred samples collected on October Revolution, Komsomolets, Pioneer islands and the Sedov Archipelago. Based on the data obtained, a thermal maturity map has been constructed for the region. Three areas, characterized by different CAI values are recognized on SevernayaZemlya. A clear trend indicating the thermal alteration increasing from west to east is most probably related to structural features; for example the main fault zone that separates the relatively simple structures in the western and the linear fold belt in the central parts from strongly faulted Early Palaeozoic sedimentary rocks that are intruded by magmatic rocks in the east of Severnaya Zemlya. These data and map will help in resource assessments and the development of burial/thermal history of the North Kara Basin.