Magnetic model for the earth's crust under the Ukrainian Shield

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.

2021 ◽  
Vol 11 (3) ◽  
pp. 375-385
Author(s):  
M.Y. Nilov ◽  
◽  
L.I. Bakunovich ◽  
N.V. Sharov ◽  
B.Z. Belashev ◽  
...  

An important task for the White Sea region, Russia’s second largest diamond-producing province, is the search for magmatic bodies overlapped by sedimentary cover via magnetometer survey. The models, linking local and magnetic anomalies with their sources, are essential for interpretation of search results. The aim of the study is to build a 3D magnetic model of the Earth’s crust for the White Sea region using aeromagnetic data and the modeling technologies of the Integro software package. The simulation is basing on a digital map of the pole-reduced anomalous magnetic field. The sources of magnetic anomalies are believed to be located in the Earth’s crust. The researchers obtained 3D distribution of the relative magnetic susceptibility of rocks by solving the inverse problem of magnetic prospecting. To separate the magnetic sources by spatial frequencies and depth, the model magnetic field was recalculated upward, as well as the TDR derivatives, which determine the lateral boundaries of the sources of positive magnetic field anomalies, were calculated. The researchers further analyzed 2D distributions of the magnetic sources of the model for vertical and horizontal sections with depths of 10, 15 and 20 km, thus proving the relationship between the surface and deep structures of the magnetic sources of the Earth’s crust in the region.


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

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.


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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