Morphotectonic of the Baikal rift zone (U.S.S.R.)

Abstract

The Bajkal rift zone is the northern wing of the Mongolo-Siberian rejuvenated orogenic belt. Longitudinal faults and transverse transformal faults usually being dextral displacements are of great importance in its recent structure. The Baikal rift zone and that located south-eastward the Selenga-Vitim zone of linear warping have the common systems of transverse faults. The rift zone consists in subzones: (1) rift valleys, uplifted interbasins and large tectonic steps, (2) systems of inclined horsts – rift shoulders, (3) inner block uplifts and (4) arch curve of the south-eastern wing. The rift zone structure has high symmetry and paragenetic link with the deep-seated structure. Cenozoic geodynamics of the south of East Siberia is characterized by: (1) tension of lithosphere in the Baikal rift zone above the anomalous mantle protrusion; (2) displacement of lithospheric blocks to the south-east above subhorizontal layer of anomalous mantle; (3) compression of lithosphere, linear warping of its undersurface parts and formation of thrusts in the Selenga-Vitim zone.