Paleogeographic conditions in the West Siberian Basin during the Tithonian–Early Berriasian

Based on facies, structural, and general paleogeographic analyses, new models of the bottom topography and accumulation of the Tithonian–Early Berriasian Bazhenov Formation (West Siberian Basin) are proposed. According to these patterns, quite a low proportion of the terrigenous material in the high-carbon facies of the Bazhenov Formation can be explained by its accumulation in relatively deep troughs that frame the uplifted shallow-water central part of the West Siberian basin. In addition, the structure and dynamics of ocean currents are considered. During the Tithonian–Early Berriasian, these currents were related to the aeration stages of bottom waters enriched in hydrogen sulfide and carbon dioxide. As a result of the convection of the water mass suffocation periods occurred.