scholarly journals Density inhomogeneity of the earth's crust along the latitudinal zones of the faults of the Ukrainian shield and the Dnieper-Donets basin

2012 ◽  
Vol 34 (6) ◽  
pp. 113-132
Author(s):  
V. I. Starostenko ◽  
P. Ya. Kuprienko ◽  
I. B. Makarenko ◽  
O.V. Legostaeva ◽  
A.S. Savchenko
2021 ◽  
Vol 43 (3) ◽  
pp. 205-226
Author(s):  
V. I. Starostenko ◽  
O. M. Rusakov ◽  
A. I. Yakimchik

The geological structure of the lithosphere of the main tectonic structures has been refined for the territory of Ukraine and adjacent regions of Slovakia, Poland, Romania, Russia, as well as Bulgaria, the Antarctic Peninsula (West Antarctica) and Southeast Asia, and new data have been obtained on geophysical impacts that can affect the environment. A geodynamic scenario has been developed for the formation of large-scale folding of the Fore- Dobrudzja Trough, the South Ukrainian monocline and the Ingul block of the Ukrainian Shield, caused by tectonic events associated with the closing of the Paleotethys and Neotethys oceans in the Mesozoic. In the Pripyat-Dnieper-Donets Basin, the structure of the earth’s crust and upper mantle can reflect different intensities of rifting, from its passive stage in the Dnieper Graben to active rifting in the Pripyat Trough. An analysis of the geoelectric structure of the Earth’s crust in the Ukrainian Eastern Carpathians indicates that seismic events occur mainly in resistive solid rock domainswhich surrounded by aseismic high conductive zones consisting of at least partially melted material. The present-day mutual position of the Ukrainian shield and Fennoscandia stabilized 1720—1660 Ma. The age, distribution, orientation and composition have been studied for the LatePalaeoproterozoicdykes in the Volyn, Ingul and Azov blocks of the Ukrainian Shield. Eastern Crimea and the Sorokin Trough are fragments of a tectonic wedge formed after the Paleocene. The geothermal conditions of the Intra-Carpathian region are due to subduction during the closure of the Pannonian sea basin and the collisional interaction of the Eurasian plate with the microplates system of this region. In Bulgaria, most earthquakes occur outside high-resistive domains. The tectonic stages are reconstructed for the formation of the northern part of the Antarctic Peninsula in the Mesozoic-Cenozoic. The relationship has been established between the geomagnetic field and climate change, with it being different for the Northern and Southern Hemispheres. The results have been obtained within the framework of 25 international projects and 6 temporary international target teams of S. I. Subbotin Institute of Geophysics, NAS of Ukraine consisting of researchers from 23 countries. The results are presented in 53 publications, 38 of which are indexed in the Web of Scienct database, and 32 papers are published in 20 international journals and special publications of 10 countries with different impact factors (from 0,101 to 4,214), whose average impact factor is 3,341, and the total one is 66,815.


1977 ◽  
Vol 14 (12) ◽  
pp. 2718-2728 ◽  
Author(s):  
Z. A. Krutikhovskaya ◽  
I. K. Pashkevich

A magnetic model for the crust under the Ukrainian Shield is proposed and the following aspects of its construction are discussed: (1) technique of separation of the regional component of the anomalous magnetic field; (2) estimation of rock magnetization and distribution of the sources of anomalies within the earth's crust; (3) Modelling of the crustal effect with the given distribution of magnetization; and (4) correlation of the regional component with crustal thickness and depth to Curie point isotherm of magnetite.Two ferromagnetic layers are established within the crust. Average magnetization of the upper crust ranges from 0.1 × 10−3 to 0.6 × 10−3 emu for different blocks. Magnetization maximum for the lower crust is 4 × 10−3 emu, the value being supported by different methods.Inhomogeneities with maximum magnetization of 6.5 × 10−3 emu are found within the lower crust.In the areas of regional highs the earth's crust is the thickest, the Moho discontinuity layered, and the distribution of magnetization anomalous for all depths.The stated correlation of regional component with crustal thickness may be of value in predicting the Moho topography.


1997 ◽  
Vol 269 (3-4) ◽  
pp. 269-278
Author(s):  
A.V. Chekunov ◽  
A.A. Tripolsky ◽  
O.M. Kharitonov

Author(s):  
O. Chalyi ◽  
M. Diaconescu ◽  
I. Gurova ◽  
Y. Lisovyi ◽  
P. Pigylevsky ◽  
...  

In the article, the earthquake near Sumy is considered in detail. According to the authors, this earthquake occurred under the influence of several stress regimes. At the regional level: it is related to the transfer of stresses from the Vrancea zone along the mantle lineament of Sollogub; a change in the local stress field, which is created by blocks with different thicknesses of the earth's crust, with the presence of subcrustal thermal anomalies. The area of the location of the earthquake focus near the town of Sumy in tectonic terms is on the southwestern slope of the Voronezh crystalline massif near the northeastern side of the Dnieper-Donets Basin (DDB). The epicenter is confined to the northern extension of the Krivyy-Rig-Kremenchug suture zone. The earthquake focus is confined to the tectonic node formed by the eastern edge fault of the Krivyy-Rig-Kremenchug suture zone and the northern side fracture of the DDB. The main deep faults near the source of the earthquake are the northern side fault of the DDB rift and the northern extension of the Krivyy Rig-Kremenchug fault. The hypocenter of the event is in the area with sharp change in the structural plan of the Moho surface accompanied by a negative mantle gravitational anomaly. In the relief of the Moho surface, a superimposition of the structural plan of the northwestern direction, connected with the Devonian rift of the DDV, on the ancient structural plan of the Ukrainian shield and Voronezh crystalline massive is clearly visible. Within the DDV, the isohypses of the Moho surface clearly delineate the ascent to ~ 35 km in the central part of the rift. The Krivyy-Rig-Kremenchug suture zone is expressed in the Moho surface by a narrow elongated depression with depths of more than 50 km in the central part. Here, in the lower part of the cortex, the development of the crust-mantle mixture is observed. The Krivyy-Rig-Kremenchug suture zone is also distinguished by the development of high-intensity deep magnetic inhomogeneities along it. In addition, here in the lower part of the crust and in the upper mantle a linear object of high electrical conductivity is isolated. Thus, the earth's crust of the region has a pronounced physic-geological heterogeneity, which creates instability of lithostatic stress, and this, in turn, is a prerequisite for the appearance of additional stresses.


Author(s):  
Y. Rozyhan ◽  
O. Trypilskiy ◽  
O. Topoliuk

A detailed comparative analysis of the velocity characteristics of the Earth's crust of the Korosten pluton, Volyn and Chopovitsky massifs of the basic rocks of the Volyn megablock of the Ukrainian Shield was carried out. In the interval of depths of 3–13 km in the Earth's crust of the Korosten pluton, five sections are fixed, where the speed on a short interval first decreases with depth, then, on the contrary, increases. This is due to the presence in the section of a series of layers composed of rocks with reduced or elevated speeds, which alternate with increasing depth. Such changes in velocity are considered to be the results of alternation of rocks of the basic and acidic composition. With depth, the rate of increase in velocity (vertical velocity gradient), which characterizes the features of rooting into the crust of an intrusion with increased basicity, significantly decreases. These features lie in the fact that the molten masses coming from the upper mantle were concentrated mainly in the upper and middle parts of the Earth's crust. The distinction between the features of the speed characteristics of the Earth's crust of the Volynsky and Chopovitsky massifs of the main rocks is revealed. The velocity characteristics of the compared structures reflect the characteristics of the rooting of igneous melts of the basic composition into the Earth's crust. Despite the territorial proximity of the massifs, the nature of the rooting of the melts between them is significantly different. For example, abrupt changes in velocity in the depth interval of 0–12 km of the Volynsky massif can be attributed to the presence of, at least, 10 layers of rocks, predominantly of acidic and basic composition, which alternate each other. It should be emphasized that at depths of 8–12 km maximum speeds (up to 0.17–0.18 km/s) between individual layers are observed. In the same depth interval in the Chopovitsky massif, only 5 layers stand out with a maximum differential velocity of 0.18 km/s.


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