Structural evolution of the Earth crust of the East European platform: evidence from the Sarmatian plate. 1. Intra-plate tectonic and stages of the evolution of the Earth’s crust

Abstract


 
 
 The problems of intra-plate tectonics and geodynamics of the East European plat- form are analyzed. It is shown that the current status and tectonic position of regional structures on its territory changed during the Phanerozoic as a result of radical inversion rearrangements of the earth’s crust structure. The sources of forces and deformations and the influence of the anisotropy of the lithosphere on the evolution of the Earth’s crust based on evidence from the Sarmatia plate are considered. It is assumed that collision stress in the crust of the plate during the epochs of platform activation in the Mesozoic and Cenozoic caused the movements of Arabia and Africa and the spreading of the crust in the North Atlantic ridge. The platform is characterized by stable meridional collision compression, except for Sarmatia, where the stress axis is oriented to the north-northwest. This is related to the initial anisotropy of the plate lithosphere and its modern longitudinal structural differentiation. The stress from the boundaries of the platform was transmitted inward and absorbed in the mobile belts, which determined their overall plate mobility. The structure-forming role of collision belts in the evolution of the Earth’s crust has been clarified based on data from the Dnipro-Donetsk Paleorift Belt. A model of the evolution of the belt is proposed, according to which the rift was laid by splitting of the «cold» continental crust with displacement by the Pull-apart basin mechanism. The «built-in» anisotropy of the lithosphere of the Sarmatian plate and the lack of a direct connection between the modern segmentation of the Precambrian consolidated crust and the relief of the sole of the seismic lithosphere are considered. Due to the overall plate collision, the basin underwent inversion uplift and folding. As a result of the change in the mode of deformation along the extension of the belt, two heterogeneously deformed segments were distinguished in its structure. The western segment contains the relics of the rift, but in the eastern segment, the structure of the Graben is destroyed by cover-folding deformations. The modern longitudinal structural and material differentiation of the Sarmatian lithosphere has been established. The general orientation and phasing of the structural rearrangements of the Earth’s crust of the Precambrian Craton have been determined. It was found that the processes of evolution of the structure of the East European platform were caused by changes in geodynamic conditions and tectonic deformation regimes. Initial geotectonic data were obtained, and a rational methodology was chosen for further geodynamic interpretation. The distribution and nature of the inversion rearrangements of the Earth’s crust on the terrain of Sarmatia were clarified by reconstructing the stress field in the Phanerozoic epochs using indirect methods of Geomechanics analysis of discontinuous and folding deformations.