Geological Structure of the Neoproterozoic-Paleozoic Sequences in the North-East of Western Siberia

The model of the geological structure of the Neoproterozoic-Paleozoic deposits of the north-east of Western Siberia proposed by the authors is the first work where the obtained results and conclusions are based on regional mapping. This was made by using new highly informative 2D seismic data in the volume of large pre-Jurassic megasequences, including the adjacent large geostructures along the flanks of the Western Siberian basin. The study of the internal structure of megasequences includes sequence-stratigraphy analysis of the wave field tied-up to the geological data of drilling and geological surveys on the flanks of the Western Siberian basin (Yamal, Obsko-Laptevskaya ridge), as well as the on north-west of the Siberian platform within the Taymyr fold-thrust system. The article pays attention to the features of the geological structure of the Neoproterozoic-Paleozoic sequences, represented by the pre-cover (transitional) megasequence of the most ancient stratified deposits from metamorphosed rocks of the folded base to the sedimentary cover and Paleozoic (Vendian-Paleozoic?) orthoplatform structural-tectonic level (megasequence) of the sedimentary cover. The authors substantiate the development of the heavy (over 20–30 km) thick continental crust consisting of stratified Neoproterozoic and Phanerozoic deposits throughout Gydan and Taymyr. These deposits are typical for the north-east of Western Siberia. In the conclusion they describes the limited oil and gas prospects of Neo-Proterozoic and Paleozoic in the northeast of Western Siberia, which can only be associated with the most uplifted blocks of the northeastern parts of the inclined megaswells of the Obsko-Laptevskaya ridge and the flanks of the basin (South Taymyr, Western Taymyr, North Siberian monocline).