GEODYNAMICS

Abstract

Aim of the work is tectonophysical identify the totality of the deformation structures of the collisional evolutionary stage, which determine the tectonic style of the Transition Zone between Dnieper-Donets Basin and the Donbas Foldbelt. Methods. For the research, we used the author's technique for reconstructing the fields of tectonic deformations and tectonophysical analysis of geostructures. The analytical base of the research was made up of new materials of geological mapping of the territory of the transition zone between the Basin and the Foldbelt. Results. Inversion deformations of the Dnieper-Donets Paleorift were controlled by lattices of tectonites of regionally stable submeridional directions of movements. An analysis of structural patterns of tectonites indicates over the riftogenic faults of the basement in the sedimentary cover of the transition zone, echeloned stages of plumage are formed, composed of thrusts with a significant component of horizontal displacement. The tectonic style of the Transition Zone is determined by the pushing on the low dislocation autochthonous of the Basin of the repeatedly deformed, crumpled into the folds of sedimentary geomas from the Foldbelt. The allochthon structural and tectonic framework consists of thrusts, coulisse-jointed structural ensembles of thrusts, folded covers of transverse extrusion of geomas from axial to side zones, and folded covers of longitudinal thrust towards the depression. All together its form the Western Donets Cover-folded Region, the main structural element of which is the Segment of the Tectonic Wedging of geomass. The north-eastern flank of the Segment is formed by linear anticlinal zones - Torsky-Drobishivska, North-Donets, Matrossko-Toshkovska, south-western - Petrovsko-Novotroitska. The structural apex of the Segment is a tectonic junction at the ends of dynamically conjugated thrusts in the area of the joint of the salt-dome shafts of the axial part of the Basin. Scientific novelty. The tectonic inversion is responsible for the formation of three folded structural floors - the Herzinian, Laramian and Attic. According to the dynamically coupled lattice, a cover-folding system of tectonic thrusting was formed in them, which was first diagnosed as a Segment of Tectonic Wedging of geomas by the Donbas Foldbelt. On the basis of this, within the Transtition Zone, a Western-Donetsk cover-folded Region was separated, covering two tectonic areas in intensity and style of deformation of the sedimentary cover - Kalmius-Toretsky area of scaly covering in the southwestern part, which is limited to the South Donbass Melange Zone in the south, and the Lugansk-Kamyshuvakhsky area of the coulisse-jointed uplift-folding on the northeastern part, which from the north is limited by the low-folded Mesozoic-Cenozoic cover. They are separated by the Central Zone of Strike-slip control along the axial folded zone of large stage-jointed uplift-folds, which include Great-Kamyshuvakhska, Novotroitska, Druzhkovsko-Konstantinovska and Main anticlines. Practical significance. Based on the actual geo-mapping data, it is proved the riftogenic structure in the southeast of the Dnieper-Donets Paleorift is destroyed by folding at the stages of platform activation. Allocation of territory of the Western Donetsk Сover-folded Region allow to correct the scheme of tectonic zoning of the Dnieper-Donets Basin, which is the basis for modeling the geodynamics of the Transition Zone formation.