scholarly journals Inhomogeneities of the earth’s crust of the Aldan-Stanovoy shield along the 3-DV profile (Eastern Siberia, Russia

2021 ◽  
Vol 43 (3) ◽  
pp. 27-46
Author(s):  
V. V. Stogny ◽  
G. A. Stogny
Keyword(s):  
Gravitational Field ◽  
Deep Structure ◽  
Regional Metamorphism ◽  
Granite Gneiss ◽  
Earth’S Crust ◽  
Gneiss Dome ◽  
Proposed Model ◽  
Gravimetric Data ◽  
Juvenile Crust ◽  
Earth's Crust

Profile 3-DV (Skovorodino-Tommot) crosses in the sublatitudinal direction the Stanovoy and Aldan megablocks of the Aldan-Stanovoy shield. As the basic elements of the Earth’s crust section along the profile 3-DV, a technique was adopted for identifying regional inhomogeneities of the lithosphere based on the results of the analysis of seismic and gravimetric data with subsequent typification of their nature. According to the SRM-CMP data, in the upper part of the section (up to 35 km) of the Aldan megablock, the Yakokut and Chulman heterogeneities are distinguished, and the Stanovoy megablock — the Kalara-Dzhugdzhur heterogeneity. The Yakokut and Chulman seismic inhomogeneities in the gravitational field correspond to minima with an the amplitude of up to 25 mGal. The gravitational field of the Kalara-Dzhugdzhur heterogeneity is mosaic and reflects its block structure. It is shown that the deep structure of the Aldan megablock in the area of the 3-DV profile is determined by the Yakokut granite-gneiss dome and Chulman sublateral decompaction zone, and the upper part (0—25 km) of the Stanovoy megablock is represented by the Kalar-Dzhugdzhur structure, composed of the Stanovoy complex of rocks  and blocks of highpressure granulites. A significant (up to 10 km) increase in the thickness of the earth’s crust of the Aldan megablock is explained by the presence of the upper layer juvenile crust formed in the Paleoproterozoic as a result of regional metamorphism of igneous rocks. The Earth’s crust of the Stanovoy megablock is tectonically rebuilt for almost the entire thickness of up to 40 km during the Mesozoic collision of the Precambrian North Asian and Sino-Korean cratons. The Yakokut granite-gneiss dome, in accordance with the proposed model of the structure of the Earth’s crust of the Aldan megablock, is the ore-controlling structure of the Central Aldan gold-bearing region, and highpressure granulites of the Zverevsky block of the Kalara-Dzhugdzhur heterogeneity of the Stanovoy megablock served as a source of gold in the Chako-Berkakit ore cluster.

scholarly journals Improving of electrical channels for magnetotelluric sounding instrumentation

2015 ◽  
Vol 4 (2) ◽  
pp. 149-154 ◽  
Author(s):  
A. M. Prystai ◽  
V. O. Pronenko
Keyword(s):  
Electric Field ◽  
Electric Fields ◽  
Deep Structure ◽  
Experimental Tests ◽  
Magnetotelluric Sounding ◽  
Earth’S Crust ◽  
Geomagnetic Variations ◽  
The Earth ◽  
Wide Range ◽  
Earth's Crust

Abstract. The study of the deep structure of the Earth's crust is of great interest for both applied (e.g. mineral exploration) and scientific research. For this the electromagnetic (EM) studies which enable one to construct the distribution of electrical conductivity in the Earth's crust are of great use. The most common method of EM exploration is magnetotelluric sounding (MT). This passive method of research uses a wide range of natural geomagnetic variations as a powerful source of electromagnetic induction in the Earth, producing telluric current variations there. It includes the measurements of variations of natural electric and magnetic fields in orthogonal directions at the surface of the Earth. By this, the measurements of electric fields are much more complicated metrological processes, and, namely, they limit the precision of MT prospecting. This is especially complicated at deep sounding when measurements of long periods are of interest. The increase in the accuracy of the electric field measurement can significantly improve the quality of MT data. Because of this, the development of a new version of an instrument for the measurements of electric fields at MT – both electric field sensors and the electrometer – with higher levels relative to the known instrument parameter level – was initiated. The paper deals with the peculiarities of this development and the results of experimental tests of the new sensors and electrometers included as a unit in the long-period magnetotelluric station LEMI-420 are given.

scholarly journals Deep structure and geodynamic conditions of granitoid magmatism in the Eastern Russia

2020 ◽  
Vol 243 ◽  
pp. 259
Author(s):  
Viktor Alekseev
Keyword(s):  
Deep Structure ◽  
Gravity Anomalies ◽  
Federal District ◽  
Heat Fluxes ◽  
Earth’S Crust ◽  
Granitoid Magmatism ◽  
The Pacific ◽  
Earth's Crust ◽  
Far Eastern ◽  
Eastern Russia

We investigated the deep structure of the lithosphere and the geodynamic conditions of granitoid magmatism in the Eastern Russia within the borders of the Far Eastern Federal District. The relevance of the work is determined by the need to establish the geotectonic and geodynamic conditions of the granitoids petrogenesis and ore genesis in the Russian sector of the Pacific Ore Belt. The purpose of the article is to study the deep structure of the lithosphere and determine the geodynamic conditions of granitoid magmatism in the East of Russia. The author's data on the magmatism of ore regions, regional granitoids correlations, archive and published State Geological Map data, survey mapping, deep seismic sounding of the earth's crust, gravimetric survey, geothermal exploration, and other geophysical data obtained along geotraverses. The magma-controlling concentric geostructures of the region are distinguished and their deep structure is studied. The connection of plume magmatism with deep structures is traced. The chain of concentric geostructures of Eastern Russia controls the trans-regional zone of leucocratization of the earth's crust with a width of more than 1000 km, which includes the Far Eastern zone of Li-F granites. Magmacontrolling concentric geostructures are concentrated in three granitoid provinces: Novosibirsk-Chukotka, Yano-Kolyma, and Sikhote-Alin. The driving force of geodynamic processes and granitoid magmatism was mantle heat fluxes in the reduced zones of the lithospheric slab. The distribution of slab windows along the Pacific mobile belt's strike determines the location of concentric geostructures and the magnitude of granitoid magmatism in the regional provinces. Mantle diapirs are the cores of granitoid ore-magmatic systems. The location of the most important ore regions of the Eastern Russia in concentric geostructures surrounded by annuli of negative gravity anomalies is the most important regional metallogenic pattern reflecting the correlation between ore content and deep structure of the earth's crust.

The deep structure of the earth’s crust beneath the White Sea based on seismic data

2011 ◽  
Vol 66 (3) ◽  
pp. 213-219
Author(s):  
V. B. Piip ◽  
L. P. Tsydypova ◽  
N. V. Shalaeva ◽  
E. A. Teplyakova
Keyword(s):  
Seismic Data ◽  
White Sea ◽  
Deep Structure ◽  
Earth’S Crust ◽  
The White Sea ◽  
Earth's Crust

scholarly journals ANALYSIS OF THE DEEP SEISMIC STRUCTURE AND SEISMICITY OF THE TRANSBAIKALIA (ALONG THE 1-SB PROFILE)

2019 ◽  
Vol 2 (2) ◽  
pp. 224-233
Author(s):  
Victor Solovyev ◽  
Alexander Salnikov ◽  
Viktor Seleznev ◽  
Vladimir Chechelnitsky ◽  
Nadezhda Gilyova ◽  
...  
Keyword(s):  
Rift Zone ◽  
Velocity Structure ◽  
Deep Structure ◽  
Baikal Rift Zone ◽  
Earth’S Crust ◽  
Seismic Structure ◽  
Elastic Parameters ◽  
S Waves ◽  
Close Proximity ◽  
Earth's Crust

An analyzing on the seismicity and the deep structure of Transbaikalia along the 1-SB profile is presented. Determined that areas of high seismicity associated with the blocks of the Earth's crust with a heterogeneous velocity structure. The site of the Baikal rift zone which is located in close proximity to the Muya earthquake (1957, M=7.6) is characterized by increased heterogeneity according to the values of P- and S-waves and of elastic parameters in the Earth’s crust upper part.

Deep structure of the earth's crust in the vicinity of the Streltsovsky uranium ore field (Eastern Transbaikalia) from the data of microseismic sounding

2010 ◽  
Vol 2 (6) ◽  
pp. 33-37
Author(s):  
A. P. Aleshin ◽  
V. I. Velichkin ◽  
A. V. Gorbatikov ◽  
M. Yu. Stepanova ◽  
Vik. B. Komarov ◽  
...  
Keyword(s):  
Deep Structure ◽  
Earth’S Crust ◽  
Uranium Ore ◽  
Microseismic Sounding ◽  
Eastern Transbaikalia ◽  
Earth's Crust
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