The Earth’s Crust Deep Structure in the North-eastern Eurasia on Evidence Derived from Deep Seismic Sounding

2012 ◽  
Author(s):  
A. Salnikov ◽  
A.S. Efimov ◽  
V.L. Kuznetsov ◽  
V.M. Solovyev
Keyword(s):  
Deep Structure ◽  
Earth’S Crust ◽  
Deep Seismic Sounding ◽  
The North ◽  
North Eastern ◽  
Seismic Sounding ◽  
Earth's Crust

scholarly journals COMPARATIVE ANALYSIS OF GEODYNAMIC PARAMETERS OBTAINED FROM ASTRONOMIC AND GPS OBSERVATIONS IN POLTAVA

2021 ◽  
pp. 11-16
Author(s):  
L. Halyavina ◽  
N. Zalivadnyj
Keyword(s):  
Deep Structure ◽  
Theoretical Explanation ◽  
Earth’S Crust ◽  
Plumb Line ◽  
Gps Data ◽  
The South ◽  
The North ◽  
Earth's Crust ◽  
Gps Station ◽  
Gps Observations

The functioning of the GPS station and regular astrometric observations with a prismatic astrolabe in Poltava provides series of local displacements of the earth's crust and plumb line in time, characterizing the changes in the gravitational field. The analysis of the N-component of the earth's crust movement and the displacement of the meridional projection of the plumb line was carried out on the basis of GPS data and from observations on the astrolabe, respectively, for the period 2002-2020. Comparison of the trends of these series showed that their shifts occur in opposite directions. It is noted that the movement of the point occurs in the northern direction at a speed of +0.3mm/yr, and the displacement of the plumb line - to the south, at a speed of -2.6mas/year. Similarly, an abrupt displacement of the N-component to the north by + 2mm at the turn of 2014 was accompanied by a displacement of the plumb line to the south by approximately -50 mas. These facts can be explained within the framework of the hypothesis of the existence of a deep structure in the vicinity of Poltava, in which a significant change in mass occurs. The spectra of both series show the presence of cyclicities with close periods: about 3.2, 2.8, 1.0, 0.5, and 0.3 yr. It is known that harmonics with those periods are present in many astrometric series. The geodynamic interpretation of the presented facts requires additional confirmation in observations of neighboring GPS stations, as well as a theoretical explanation and justification.

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.

scholarly journals IV.—The Glacial Deposits of Northern Pembrokeshire

1906 ◽  
Vol 41 (1) ◽  
pp. 53-87
Author(s):  
T. J. Jehu
Keyword(s):  
Igneous Rocks ◽  
Earth’S Crust ◽  
The West ◽  
Great Abundance ◽  
Glacial Deposits ◽  
North East ◽  
The North ◽  
Earth's Crust

The area embraced in this paper consists of that part of Pembrokeshire which lies to the north and north-east of St Bride's Bay. Bounded on the west by St George's Channel and on the north by Cardigan Bay, it extends to the north-east as far as the mouth of the river Teifi, near Cardigan.That part of the country which lies in the immediate neighbourhood of St David's has, through the laborious researches of the late Dr Hicks and others, become well-known to geologists, and may now be regarded as classic ground. The solid geology of this promontory has given rise to much discussion, and has, perhaps, attracted more attention than that of any other part of the Principality. The reason for this great interest is to be sought in the facts that the rocks of this area are of a very great antiquity, and that the sedimentary series contain the remains of some of the earliest organic forms yet found in the earth's crust, whilst the igneous rocks are also displayed in great abundance and variety, and present us, in the words of Sir Archibald Geikie, with “the oldest well-preserved record of volcanic action in Britain.”

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