Main divide of the Russian Plain, its tectonic origin and glacioisostatic mechanism of its formation

Abstract

Formation of the main divide of the Russian Plain took place in Pleistocene and was connected with residual deformation of tectosphere resulting from repeated glacial iostatic subsidence and upheaval of the earthcrust due to growth and degradation of sheet glaciation. The main divide position is controlled by features of the basement block tectonics of the East European plate, first of all, by N. E. system of deep faults which outline the Mazur-Moscow linear megablock separating Baltic shield from Ukrainian, Voronezh and Volga-Uralian blocks. The Baltic megablock subsidence went along with the uplift of the Mazur-Moscow one, the latter being the frame of the main divide. Most active movements took place as long ago as during the first sheet (Varangian) glaciation, which preconditioned (together with lowering of the Black and Caspian Seas levels) the deep Pleistocene incision of the Kama, Oka, Volga and Dnieper Rivers at Pre-Solikamsk (Pre-Venedian) time.