Jurassic paleogeography and sedimentation in the northern West Siberia and South Kara Sea, Russian Arctic and Subarctic

Abstract

Abstract The study is focused on the depositional history of Jurassic oil- and gas-bearing sedimentary rocks, which currently occur at 3–6 km depth below the surface in the northern West Siberian Basin, the South Kara Basin and the western Yenisei-Khatanga Basin. Using data from deep wells, such as paleontological data and bedding geometries, lithology of rocks derived from cores and well log data, sediment thicknesses, results of detailed correlation of sedimentary cyclic units, and regional multichannel seismic reflection profiles, the authors produced 13 litho-paleogeographic maps of the studied region accompanied by W-E cross-sections. The maps present paleogeographic environments that existed during the deposition of each of 12 regional stratigraphic stages, namely: Lower Jurassic Zimniy (Hettangian – lowermost Upper Pliensbachian), Levinskiy (middle Upper Pliensbachian), Sharapov (uppermost Pliensbachian), Kiterbyut (lowermost Toarcian), Lower-Middle Jurassic Nadoyakh (uppermost Lower Toarcian – lowermost Aalenian), Middle Jurassic Laida (uppermost Lower Aalenian – lowermost Upper Aalenian), Vym (uppermost Aalenian – lowermost Bajocian), Leont'evskiy (uppermost Lower Bajocian – lowermost Upper Bajocian), Malyshev (uppermost Bajocian – lowermost Upper Bathonian), Middle-Upper Jurassic Vasyugan (uppermost Bathonian – lowermost Oxfordian), Upper Jurassic Georgiev (uppermost Oxfordian – lowermost Tithonian) and Bazhenov (uppermost Lower Tithonian – earliest Berriasian). The maps show the extent of exposed land, continental (alluvial plains), transitional (nearshore and coastal flood plains) and marine (water depth The presented results provide a more reliable framework for the re-evaluation of existing Jurassic hydrocarbon plays and identification of new plays in the West Siberian province.