KINEMATIC OF THE INDENTATION OF THE SOUTHERN URALS BY THE EAST EUROPEAN CRATON

A previous study of the altitudes of the lowest part of the Upper Cretaceous–Eocene stratigraphic ensemble based on 458 drill holes evidenced for the first time the existence of an east-west elongated dome between N53° and N54° Lat. on the western slope of the Southern Urals. This ridge which results from the rejuvenation of the Sernovodsk–Abdullino Aulacogen and of the Belaya tear fault is interpreted as a positive flower structure. Slightly to the north, the southern Urals display a clear bend towards the East associated with a stress pattern typical of an indentation. Magnetic data follow the northern side of the indenter. Its southern side corresponds with the Belaya tear fault and with the flower structure. Field mappings at the intersection between the E-W flower structure and the N-S Belaya River Valley evidence: (1) two riverbeds more or less superimposed in the same valley, (2) the older riverbed is offset by east–west shear zones, (3) the shear zones extend the flower structure, (4) the actual riverbed is not affected by similar offsets. The vertical movements recorded along Belaya River by geodetic measurements are associated with karst collapses and diapers and don’t support a recent activity of the indenter. This conclusion is reinforced by the stratigraphic evolution of the fluvial sediments and confirms that the indentation of the Southern Urals did not continue after 10 ka.