Limitotipes of Lower Sakmarian and Artinskian stages boundary in the Urals

The section Usolka and duplicating its section Dal’ny Tulkas (Bashkortostan) are proposed as the stratotypes of the Lower Sakmarian stage boundary and Lower Artinskian stage boundary of the International Stratigraphic scale. We give the description of sections with the indication of conodont, fusulinid and ammonoid level findings and the results of studying U-Pb geochronology as well as Sr, C, O isotopes

Dynamics of near-surface structures of Ural area in Upper Perm-Triassic time and tectonic division of crystal crust of the West Siberian geosyneclise

The provision of early mesozoic grabens (rifts) filled with terrigenous deposits and basalts of the Triassic in tectonic volume model of crystal crust is considered. Taking into account the similar analysis on the Upper Paleozoic granitization and arrangement of fields of hydrocarbons, which were made earlier, the causation of tectonics and magmatism with a deep structure of upper part of a lithosphere of Uural area of the West Siberian geosyneclise is emphasized. The common source of these phenomena caused by joint activity of a deep underearth in a Upper Permian-Triassic stage of development of the studied geological environment is offered

Devonian organogenic buildings of the Urals and adjacent regions of East-Europian Platform and West Siberian

Several reef-building systems occurred during Cambrian-Devonian on the Urals and adjacent regions of the East-European Platform. The first phase was manifested in the Lower Cambrian within a limited area of the western slope of the Urals. The next stage occured on the western slope of Urals during Early to Middle Devonian as a result of Caledonian orogeny. This reef complex is traced on the western slope of the Urals from the Ural River latitude on the south to Barents Sea on the north. Late Devonian bioherms on the territory of the East-European Platform are distributed over a wide area from the Western Urals to the Volga basin. On the east slope of the Urals and in West Siberia bioherms are attributed to marginal structures of depressions