scholarly journals GEODYNAMICS

GEODYNAMICS ◽  
2021 ◽  
Vol 2(31)2021 (2(31)) ◽  
pp. 92-101
Author(s):  
Anton Kushnir ◽  
◽  
Tatiana Burakhovych ◽  
Volodymyr Ilyenko ◽  
Bogdan Shyrkov ◽  
...  
Keyword(s):  
Upper Mantle ◽  
Deep Structure ◽  
Earth’S Crust ◽  
Joint Analysis ◽  
Homogeneous Layer ◽  
Conductivity Anomaly ◽  
Spatially Inhomogeneous ◽  
Axial Part ◽  
Geoelectrical Structure ◽  
Earth's Crust

In order to study the deep structure of the southwestern Ukrainian Carpathians, where the Carpathian conductivity anomaly is located, in 2015 and 2020, modern synchronous magnetotelluric studies were carried out on the profiles of Mukachevo-Skole, Seredne-Borynya and Karpatsky at twenty-three points and the spatiotemporal distribution and the electric field on the Earth's surface, which can be used to assess the conductivity and geoelectrical structure of the region, was obtained. Processing of experimental data was performed using the software PRC_MTMV, which provides a common noise-canceling impedance estimation for synchronous magnetotellurical recordings. Curves of apparent electrical resistivity (amplitude values and phases of impedance) from 10 to 10000 s were obtained reliably. A joint analysis of the apparent resistivity and impedance phases and the formal interpretation of the deep magnetotellurical sounding curves using the Niblett transformation indicate the presence of the spatially inhomogeneous conductor both in the earth's crust and in the upper part of the upper mantle. The chain of local conductive sections in the earth's crust coincides with the axial part of the Carpathian conductivity anomaly. High conductivity of the upper mantle was recorded in the Ukrainian Carpathians from the Transcarpathian Depression to the Skiba cover. It is shown that it is not a homogeneous layer, there is a general deepening of the upper edge to the northeast from 40-60 km (Transcarpathian depression) to 90-100 km (Krosno cover). Sharp deepening along the Porkulets and Dukla covers is revealed. Information about the existence of a deep conductor and its parameters should be the basis for quantitative interpretation and construction of the 3D deep geoelectrical model.

scholarly journals Structure of the Earth crust and upper mantle along seismological profile Mezen–Timan–Pechora (MEZTIMPECH)

LITOSFERA ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 517-527
Author(s):  
V. V. Udoratin
Keyword(s):  
Upper Mantle ◽  
Deep Structure ◽  
Structural Features ◽  
Earth’S Crust ◽  
Seismic Section ◽  
Crust And Upper Mantle ◽  
Research Results ◽  
The Earth ◽  
Geophysical Surveys ◽  
Earth's Crust

Object of study. The article was devoted to investigation of the depth structure of the Earth’s crust and upper mantle along the Mezen–Timan–Pechora seismic profile (MEZTIMPECH), crossing the southern parts of the Mezen syneclise, the Timan ridge and the Pechora syneclise. Total profile length was 525 km. Materials and methods. In the course of writing the article, the data obtained by performing seismic surveys using the earthquake exchange wave method were used. The processing involved seismic data using the methods of deep seismic sounding, reflected waves, a common depth point, a correlated method of refracted waves, and materials from well geophysical surveys. In interpreting the research results, generalizing models of the deep structure of the territory were employed. Research results. As a result of the interpretation of the records of the method of exchange waves of earthquakes and the subsequent mathematical modeling, a geological and geophysical section was constructed to a depth of about 100 km and a number of seismic boundaries were identified. The pivotal boundaries of the exchange were: Ф0 – the surface of the Riphean folded basement, Ф – the surface of the pre-Riphean crystalline basement, M – the surface of Mohorovich, identified with the roof of the upper mantle. Additionally, horizons K1–K4 – in the crust of the Earth, M1, M2 – in the upper mantle were traced. Four regional geoblocks were distinguished in the seismic section, differing in depth of the basement surface, the Moho sectionand the underlying structural features of the consolidated crust: the Kirov-Kazhim aulacogen, the Vychegda depression, the Timan ridge and the Pre-Ural downfold. Conclusions. The results of deep seismic studies reflected regional features of the structure of the Earth’s crust and were the basis for the construction of tectonic models of large geological objects.

scholarly journals Deep structure and metallogeny of the earth's crust

1989 ◽  
Vol 20 (2) ◽  
pp. 37
Author(s):  
V.A. Erkhow
Keyword(s):  
Crustal Structure ◽  
Upper Mantle ◽  
Deep Structure ◽  
Earth’S Crust ◽  
Magnetic Data ◽  
Crust And Upper Mantle ◽  
Geophysical Field ◽  
Deep Crust ◽  
Deep Crustal Structure ◽  
Earth's Crust

Considerable experience with integrated geological and geophysical studies has enabled definition of deep crustal structures and, within limits, composition and processes within the deep crust, and to determine their association with metallogeny in the USSR.By means of seismic experiments, stratification of the Earth's crust and the upper mantle to a depth of about 100 km has been revealed. Numerous heat flow data have been compiled. Magneto-telluric soundings made it possible to determine the position of conductive strata in the crust and upper mantle for a number of areas. Gravity surveys coupled with the results of seismic profiling enabled the finding of a number of empirical laws that are useful for investigation into the deep crust. Magnetic data analysis has enabled evaluation of the magnetic layering of the deep crust. Kimberlite and ore provinces can be considered examples of these concepts.For more detailed studies of deep crustal structure the territory of the USSR is the subject of a system of regional investigation of the deep crust and upper mantle. This system is based principally upon a network of interconnected regional profiles (geotraverses) tied to deep and superdeep boreholes. The system includes predicted geophysical observations to control investigation of the geophysical field data. The geotraverse network is the basis for detailed studies within the bounds of petroleum and ore provinces.The most accurate data obtained allows the formation of a crustal model and reveals empirical relationships with metallogeny.Based on the deep crustal structure data a regional oregenesis prediction map has been made. The endogenous mineralization prediction was based on special features of the upper layering of the crust and on data relating to deep crustal permeability zones.

scholarly journals A model of the deep structure of the Earth’s crust and upper mantle in the area of the Karymshinsky gold-ore cluster according to geophysical data (South Kamchatka)

Georesursy ◽  
2020 ◽  
Vol 22 (1) ◽  
pp. 63-72
Author(s):  
Alexandr G. Nurmukhamedov ◽  
Mikhail D. Sidorov ◽  
Yury F. Moroz
Keyword(s):  
Upper Mantle ◽  
Deep Structure ◽  
Hydrothermal Systems ◽  
Earth’S Crust ◽  
The South ◽  
Converted Wave ◽  
Crust And Upper Mantle ◽  
Gold Ore ◽  
Dominant Feature ◽  
Earth's Crust

In the South of Kamchatka, modern geodynamic processes are actively taking place. A deep geological and geophysical model of the structure of the Earth’s crust and upper mantle along the regional profile of the Apacha Village-Mutnaya Bay in the zone of Tolmachevsky active magmatic center is presented. The profile passes near the South-Western border of the Karymshinskaya volcano-tectonic structure (VTS) and crosses the Ahomtenskaya VTS. The model created on the basis of integrated interpretation of materials of the earthquake converted-wave method (ECWM), gravity and magnetotelluric sounding (MTS). The thickness of the Earth’s crust along the profile varies from 30-33 km at the edges reaching 44-46 km, in its central part. The dominant feature of the model is a high-density formation – a block of the Earth’s crust, saturated with intrusions of the main and ultrabasic composition. The formation of the block is associated with a permeable zone between the crust and the upper mantle. In the block correlation of seismic boundaries is disturbed and in a density model the area with massive heterogeneity is allocated. A significant increase in depth to the M-Boundary in the center of the model is explained by the presence of a “bloated” transition layer between bark and mantle in this place. The thickness of the layer is about 10 km, and the density of the mantle reaches 3.4 g/cm3. It is assumed that this is a site of eklogization of breeds in a zone of paleosubduction of oceanic lithosphere under a continental. The area is favorable for the accumulation of meteor waters, which are in contact with high-temperature environment and postmagmatic solutions of intrusions, which leads to the formation of hydrothermal systems. The genetic connection of Karymshinsky gold-ore cluster with the intrusive array of medium-sour composition, allocated in the zone of the Tolmachevsky active Magmatic Center is shown.

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