Dynamics of the accumulation of the Mesozoic-Cenozoic sedimentary layer in the West-Siberian basin

Specific character of the formation of the West-Siberian basin has been considered, and dynamics of the sedimentation for the last 310 Ma has been traced. There are three tectono-sedimentation stages recognized for this period of geological history, which account for the present-day sizes and inner structure. Orogeny stage lasted 60 Ma, from Middle Carboniferous (Moscowian age) to Late Permian (Tatarian age). Rifting stage was expressed in the Early Triassic and took 12-13 Ma (Indian, Olenekian, and Anisian ages). Plate stage is involved with the post-rifting downwarping and accumulation of platform sediments. According to its features it is subdivided into three steps: early (Middle and Late Triassic, Early and Middle Jurassic), middle (Late Jurassic-Cretaceous, Pliocene, Eocene), and late, or neotectonic (Late Eocene--Holocene). The plate stage (200 Ma) is main, accumulation of oil- and gas-bearing complexes being confined to it. The neotectonic step (Late Eocene to Present, about 40 Ma) is due to lithosphere plate spreading in the Arctic part of the Earth, leading to the formation of the Arctic Ocean and, as a result, to the change of the sign of vertical movement in the north. Since the Late Eocene the northern side of the basin has elevated, and continental regime has built up, covering the basin territory and transformity it into an accumulation-denudation plain.