Paleohydrochemistry of Jurasic and Cretaceous deposits in arctic regions of Western Siberia

The Jurassic and Cretaceous paleohydrogeology of the Arctic regions of Western Siberia includes three hydrogeological cycles: Induan-Sinemurian, Pliensbachian-Cenomanian, Turonian-Serravallian. The paper presents results of the paleohydrological reconstructions of Jurassic and Cretaceous deposits. In the Triassic-Early Jurassic and Berriman-Cenomanian, the continental regime of sedimentation was prevalent within the study area, along with the processes of infiltration of fresh meteoric waters mainly hydrocarbonate calcium in composition with the TDS value not exceeding 5 g/dm³. Marine sedimentation conditions were dominant during the Pliensbachian-Hauterivian and Turonian-Bartonian elision stages, when the processes of sedimentation were accompanied by syngenetic burial of sodium chloride waters, locally rich in magnesium, with the TDS value reaching 35 g/dm³ in the deepest parts of the marine basin existing in the Volgian time. Modern chemistry of groundwaters of Jurassic and Cretaceous deposits in the Arctic regions of Western Siberia is a product of long-term geological evolution of the "water-rock-gas-OM" system.