Stages of Tectonic Reactivation of the West Siberian Platform (Based on K-Ar Dating)

摘要

As has been repeatedly pointed out in the literature on western Siberia [1 and others], only some traces of basement block motions can be detected in the sedimentary cover, although great importance is attached to such movements. Trofimuk and Karogodin deemed that the unconsolidation of rocks during the formation of the reservoir in the Bazhenovo Formation was related to a nonuniform lateral displacement of basement blocks. As early as 1940, A.D. Arkhangel'skii noted the relationship between the basement and cover structures. He emphasized that basement dislocations control the localization of arches and basins, which has been confirmed by recent data. For example, the folds in the platform cover are consistent with geological structures of the pre-Jurassic complex in the Shaim petroliferous district, where the pre-Jurassic rocks have been mapped in detail. The large Shaim Arch coincides (in plan view) with the Late Paleozoic granite-schist uplift. The Krasnoleninskii Arch, which is identified as a large fold in the cover, also represents the granite-schist ridge in the underlying Paleozoic rock association. The Visim and Khashgort arches correspond to the East Ural Uplift.