LITHOLOGIC AND PALEOGEOGRAPHIC RECONSTRUCTIONS OF THE CALLOVIAN AND LATE JURASSIC WITHIN ARCTIC REGIONS OF THE WEST SIBERIAN PETROLEUM PROVINCE

G. G. Shemin, A. L. Beisel, L. G. Vakulenko, V. I. Moskvin, N. V. Pervukhina, A. A. Syurin

The Callovian and Late Jurassic in Western Siberia is the time of an extensive regional marine transgression associated with general borealic transgression throughout the northern hemisphere, which had begun at the very end of the Late Bathonian and reached the maximum at the turn of the Kimmeridgian and Volgian ages. The transgression occurred in several stages, which had an effect on the sections structure and served as the basis for a distinguishing of regional stratigraphic horizons (Vasyugan, Georgievka and Bazhenov). These horizons do not coincide with the stage division. A set of lithologic and paleogeographic maps has been compiled for the Early Vasyugan age (end of Late Bathonian – beginning of Early Oxfordian), the Late Vasyugan age (end of the Early Oxfordian – beginning of the Late Oxfordian), the Georgievka age (end of the Late Oxfordian – beginning of the Early Volgian), and the Bazhenov age (end of the Early Volgian – Early Berriasian) based on detailed correlation of Callovian – Upper Jurassic deposits and the results of their geological, lithofacies, geochemical and paleontological studies. The investigated area covers the northern and Arctic regions of the West Siberian petroleum province (Yamal-Nenets Autonomous District, adjacent districts of the Krasnoyarsk Territory and the Kara Sea aquatory). Erosion areas and sites of continental, transitional and marine sedimentation are highlighted on maps; territories of uncompensated subsidence and lateral filling of the basin are shown. Lithologic areas are distinguished and current thicknesses of deposits are given for the first time for similar developments as applied to the considered region. These data significantly increase reliability of paleogeographic reconstructions.

Key words: paleogeographic reconstructions, paleogeographic area, lithologic area, thickness, land, shallow water, shelf, deep-water region, uncompensated subsidence, lateral filling of basin, material composition, geochemical characteristics, macrofauna, microfauna.

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