Early Hercynides of the Baikal-Vitim Fold System, western Transbaikal region

摘要

New data on the composition, age, structure, and geodynamic settings of the Upper Silurian-lower Middle Carboniferous rocks in the Baikal-Vitim Fold System (BVFS) are reported. These rocks make up the Early Hercynian structural stage of the BVFS, within which the Uda-Vitim, Vitimkan-Tsipa, and Turka-Kurba lithotectonic zones are recognized. The Early Hercynian stage combines rocks of two stratigraphic levels: Upper Silurian-Upper Devonian (S-2-D-3) and Upper-Devonian-Middle Carboniferous (D-3-C-2 (1)). On the basis of lithostratigraphic and spatiotemporal relationships between sedimentary and volcanic-sedimentary complexes of the Early Hercynian stage three formations are identified, which characterize the main tectonic regimes of the early half of the Late Paleozoic. It has been established that a common paleobasin that evolved through consecutively changing geodynamic settings at the passive and active continental margins existed in the Silurian (?)-early Middle Carboniferous in the northeastern part (in present-day coordinates) of the western Transbaikal region.