The structure of the Earth’s crust of the central part of the Holovanivsk suture zone according to the reinterpretation of materials of IV geotraverse of DSS (PK 295—400)

The paper presents the results of reinterpretation of the materials obtained as a result of studies using the DSS method along the IV geotraverse at the site PK 295—400.Представлены результаты переинтерпретации материалов, полученных при исследованиях методом ГСЗ по IV геотраверсу на участке ПК295―ПК400.Представлені результати переінтерпретації матеріалів, отриманих при дослідженнях методом ГСЗ по IV геотраверсу на ділянці ПК295-ПК400

Crustal and Upper Mantle Velocity Model along the DOBRE-4 Profile from North Dobruja to the Central Region of the Ukrainian Shield : 2. Geotectonic Interpretation

Peer reviewe

Precambrian of the Ukrainian Shield and Plate Tectonics

By the example of the Ukrainian Shield Ingul megablock the reconstruction features of the plate tectonic development of the lithosphere in the Archean - Early Proterozoic have been shown. We analyze the geological model proposed by E. B. Glevassky in comparison with the tectonophysical data on the megablock. The proceedings of the independent studies are consistent with each other within the framework of the plate tectonic approach taking into account PT-conditions of the Early Precambrian. In contrast to the geological model providing the collision nature of the megablock granitoids, the tectonophysical model establishes that most granite massifs were formed in the process of microplates pushing apart

Scheme of periodization of faulting stages in the Earth's crust of the Ukrainian shield - new data

On the basis of petrological study and reference isotopic geochronological age determinations of Precambrian rocks of the Ukrainian shield (USh), published lately, a refined geochronological scale of stages of deformation (faulting) of the Earth's crust in this region has been made up. It is shown that the suture zones of the USh - Golovanevsk, Ingulets-Krivoy Rog and Orekhov-Pavlograd - were simultaneously formed in the Early Proterozoic. These data allowed us to clarify the scheme and the mechanism of geodynamic evolution of the central and eastern parts of the shield in the Early Precambrian. Plate tectonic mechanism of formation of the lithosphere structure of this part of the USh was provided with the action of two convection cells (or plumes) - regional and pulsating local ones

Geodynamic development of the Ingul megablock of the Ukrainian Shield for geological-geophysical and tectonophysical data. II

In the second part of the article (see [Gintov, Mychak, 2011а]) a structure of the Ukrainian Shield (USh) Ingul megablock as a result of about 40 phases of deformation that occurred more than one billion years ago (Neo Archaean-Late Proterozoic) has been described somehow in detail. It is shown that most of the time the megablock experienced compressive stress in shear, and the main phases of extension occurred within 2,05-1,7 billion years ago. The geodynamic interpretation of the materials has been done, according to which the Archaean basement of the USh was made of two microplates - Western and Eastern. In the Archean they were spaced at a considerable distance and developed independently, and on the border of the Archaean and early Proterozoic they came together. The collisional zone between the microplates was the scene of the most intensive processes of tectono-thermal activation, during which massifs of the Novoukrainian, Kirovograd granites and Korsun-Novomirgorodsky pluton of gabbro-anorthosites and rapakivi were formed

The ups and thrusts in the earth's crust of the Kirovograd ore region and the connection with them of uranium mineralization

In accordance with the data of tectonophysical studies of a set of uranium deposits of the central part of the Ukrainian shield it was shown that those deposits were formed on the stage of compression of the Earth's crust between two stages of stretching. The stretching prevented through passage of ore solutions to the day surface above the surface of erosion. In this case the structures of uplifts type with hanging flanks that served as a screen for ore solutions were formed. Ore mineralization was mainly concentrated in ruptures with oblique bedding (thrust faults) and were kinamatically conjugated with thrusts

Tectonophysical analysis and geodynamic interpretation of the three-dimensional geophysical model of the Ukrainian Shield

Geodynamic features of the Ukrainian Shield (USh) from Early Precambrian to Phanerozoic have been considered based on tectonophysical analysis of complex geophysical 3D model of the Shield, produced at the Institute of Geophysics of the National Academy of Sciences of Ukraine. In accordance with the materials of tectonophysical studies it has been established that fault zones of the USh with initial stages in Neo-Archean and Paleo-Proterozoic were the large shift zones appeared under the action of tangential forces. Kinematics of shift zones was different in the western and eastern megablocks of the Shield that was the basis for conclusion of the absence of connection between its western and eastern parts in Early Precambrian. Tectonophysical materials support the data of paleomagnetism on the clockwise 90 degrees rotation of the Shield together with the East European platform (EEP) as to rotation axis of the Earth during Phanerozoic. Large listric fault zones going to 100 and more km as well as low-angle crust faults which formation accompanied the process of collision of mega-structures of Fennoscandia and Sarmatia were established by deep seismic sounding. The data of seismotomography indicate the lowangle dipping of relatively high-velocity lithosphere of southwestern edge of EEP under relatively low-velocity lithosphere of the adjacent plates. The obtained data testify the fact that the processes of USh crust and mantle formation took place under the action of plate tectonics mechanisms. And it would be overbold at the same time to use the whole set of plate tectonics mechanisms, for example, spreading, formation of oceanic crust, island arches, subduction etc. to the narrow band of the shield as some geologists do. Predominant horizontally shearing type of the most steeply-falling Early Precambrian fault zones of the USh testify the fact that that these zones were transform ones and were formed as a result of the processes of spreading and collision happened outside the Ush