Tectonic inversion of the Dnipro-Donets basin. Part 3. Tectonic style of deformations

Abstract

The purpose. The peculiarities of the spatial distribution and tectonic style of collisional deformations of the riftogenic structure of the Dnipro-Donets Basin were investigated. Method. Kinematic and paragenetic analyses were used, structural drawings were studied, kinematic models of alpine-type deformations in the folded floors of the southeastern segment of the Basin were compiled. The results. It was found that the riftogenic structure along the strike different style and intensity of inversion complications was been undergone. The structural border between the weakly and significantly located territory along the meridian of the city of Balaklia was determined. To the west of the border the rift downthrows acquired arc-shaped contours and a pendulum structure due to horizontal movements. Zones of Hercynian folding are divided into separate branches by echelon systems of landslides located diagonally to their axes. To the east of the border, at first the regional board faults bend to the west, and then to the east of the city of Donetsk, the northern ones bend to the east, and the southern ones - to the southeast. The zones of nearboard and axial regional faults are destroyed, and because of this, the lines of the Kochubiyivsko-Volvenkivskyi and Sosnivsko-Stepkivskyi axial salt dome shafts are interrupted. The relic is the Axial fault with the Druzhkiv-Komyshuva shaft adapted to it. Instead of a reset rift, a shear-thrust inversion frame of orocline form was formed. Alpinotype dislocations on most of the territory of the Basin are weakly pronounced (scattered, low-amplitude faults and uplifts), but the southeastern segment significant fault-folding and cover-thrust deformations has undergone. The analysis of the structure of the Oligocene-Miocene sediments shows that neotectonic structures in the sole of the Cenozoic cover and the daytime relief are reflected. On the northern board of the Basin, a number of arc-like elongated uplands that located in the hanging wings of the Hercynian thrusts were formed. A sign of uplands` formation in the geodynamic environment of transpression is oscillating articulation and diagonal placement relative to shear-thrust zones. Scientific novelty. By the analysis of structural pictures of Elements of tectonics characteristic of transpression zones was identified. For the first time the nature of alpine-type deformations on kinematic models was identified. The Cenozoic movements along the re-mobilized zones of the Hercynian thrusts formed dynamically coupled ensembles of neotectonic structures was established. The hinged-jointed structural parageneses were formed by the mechanism of longitudinal elongation of the geological space due to the horizontal movements of right kinematics over the zones of dynamic influence of shear-thrusts of the foundation. It was found the tectonic style of the latest deformation ensembles is inherent in the platform fold-thrust geostructures of the tectonic breakaway. For the first time the newest platform structure - the West-Donetsk tectonic orocline of cover-folding deformations was identified. Practical significance. Data on the distribution of alpine-type complications of the West-Donets Graben for paleogeodynamic reconstructions and improvement of the regional scheme of tectonic zoning of the Dnipro-Donetsk Basin can be used.