Stratigraphy and sedimentary environments for cretaceous deposits in the southern part of the Var’egansk Megabar (Western Siberia)

Results of comprehensive studies of the Var’egansk Megabar sections in boreholes which penetrated the upper part of the Pokur Formation and the lower part of the Kuznetsovo Formation are presented. The stratigraphic range of the studied deposits spans the upper Albian-lower Turonian. Palynological and lithofacies studies resulted in the refinement of sedimentary paleoenvironments in the region under study. It has been confirmed that the upper part of the Pokur Formation was formed under coastal-marine conditions; it characterizes mainly different deltaic facies. Sandy rocks of the Pokur Formation upper part mostly formed in delta channels, whereas silty-clayey rocks, in marshy-swamp environments. Deposition of the Kuznetsovo Formation is confined to a major sea transgression, and it proceeded under normal sea conditions.