Deep Structure of the Junction Zones of the Chuya Tectonic Depression and Its Mountainous Frame in Gorny Altai according to Magnetotelluric Studies

2021 ◽  
Vol 62 (4) ◽  
pp. 474-485
Author(s):  
E.V. Pospeeva ◽  
V.V. Potapov
Keyword(s):  
Block Structure ◽  
Deep Structure ◽  
Sedimentary Cover ◽  
Internal Field ◽  
Kinematic Parameters ◽  
Magnetotelluric Data ◽  
Geoelectric Section ◽  
Sedimentary Deposits ◽  
Axial Part ◽  
Key Sites

Abstract ––Results of magnetotelluric studies (MTS) carried out along the SW–NE and W–E profiles across the Chuya depression are used to demonstrate the deep geoelectric structure of its internal field and the zones of transition to the northern (Kurai Ridge) and southern (South Chuya Ridge) mountainous frames. The Chuya depression is an area with small-block structure, with its axial part comprised of the thinnest sedimentary deposits (450–650 m). The key sites of the zones of transition from this depression to the Kurai and the South Chuya ridges manifest a complete geoelectric section of sedimentary deposits with a total thickness of 1000–1200 m. Subvertical conductive heterogeneous beds of abnormally low (<5 Ohm∙m) specific resistivity are mapped in the section of the sedimentary cover and the Paleozoic basement. They mark neotectonic faults and nodes of their intersection with the Paleozoic and Mesozoic faults. The kinematic parameters of the faults determined from the magnetotelluric data are generally consistent with the data of morphotectonic and geological studies.

scholarly journals Deep Structure of the Lithosphere in the Central Tien Shan along the Son-Kul Magnetotelluric Sounding Profile

2021 ◽  
Vol 496 (2) ◽  
pp. 101-106
Author(s):  
A. K. Rybin ◽  
E. A. Bataleva ◽  
V. E. Matiukov ◽  
Yu. A. Morozov ◽  
K. S. Nepeina
Keyword(s):  
Cross Section ◽  
Block Structure ◽  
Deep Structure ◽  
Tien Shan ◽  
Palm Tree ◽  
Localized Deformation ◽  
Magnetotelluric Data ◽  
Geological Interpretation ◽  
Quantitative Characteristics ◽  
Geological Substrate

Abstract New results of a detailed study of the deep structure of the Central Tien Shan along the Son-Kul magnetotelluric (MT) profile crossing the Son-Kul Lake are reported. Based on the results of magnetotelluric data modeling, the regional and local geoelectric anomalies in the lithosphere are studied and their quantitative characteristics are given. Geological interpretation of the geoelectric cross-section was carried out, which supported the existing ideas about the block–hierarchical structure of the upper part of the Earth’s crust. This corresponds to the tectonophysical concepts of the sequential inserted subordination of large and smaller elements of the zone–block structure consisting of stable blocks and limiting mobile zones, which are distinguished by the high dislocation of the geological substrate. The integral pattern of the distribution and morphology of zones of high electrical conductivity in this segment of the Central Tien Shan crust may reflect discretely localized palm tree–type structures associated with the evolution of transgressive suture zones of localized deformation during the Hercynian and Alpine tectogenesis.

scholarly journals Deep structure of the Anapa flexural-rupture zone, Western Caucasus

2019 ◽  
pp. 3-11
Author(s):  
E. A. Rogozhin ◽  
A. V. Gorbatikov ◽  
Yu. V. Kharazova ◽  
M. Yu. Stepanova ◽  
J. Chen ◽  
...  
Keyword(s):  
Deep Structure ◽  
Sedimentary Cover ◽  
Western Caucasus ◽  
Tectonic Structures ◽  
Deep Roots ◽  
Near Surface ◽  
North West ◽  
The North ◽  
Deep Faults ◽  
Tectonic Zones

In the period from 2007 to 2017 complex geological and geophysical studies were carried out in the three largest flexural-rupture fault zones in the North-West Caucasus (Anapa, Akhtyrka and Moldavan). The micro-seismic sounding (MSM) was used as the main geophysical method. Studies with the help of MSM allowed us to identify the features of the deep structure of the earth’s crust in the study area and to associate them with specific tectonic structures on the surface.The binding was carried out by harmonizing the results of the MSM and the parameters of the section of the sedimentary cover and crustal boundaries according to the drilling data and the work previously performed by the reflected wave method (MOVZ). It was found that the Anapa flexure and longitudinal tectonic zones have clear deep roots, and also separate the pericline of the North-Western Caucasus from the Taman Peninsula and from the lowered blocks of the Northern slope of the folded system.Faults in the study area are divided into: (1) deep faults of the Caucasian stretch, penetrating into the lower crust and even to the upper mantle, and (2) near-surface faults, do not extend to the depths beyond the thickness of the sedimentary cover. The seismogenic role of these tectonic disturbances in the studied seismically active region has been determined.

Routine 2D inversion of magnetotelluric data using the determinant of the impedance tensor

Geophysics ◽  
2005 ◽  
Vol 70 (2) ◽  
pp. G33-G41 ◽  
Author(s):  
L. B. Pedersen ◽  
M. Engels
Keyword(s):  
Inverse Modeling ◽  
Sedimentary Cover ◽  
A Priori ◽  
Synthetic Data ◽  
Impedance Tensor ◽  
Quality Of Data ◽  
Magnetotelluric Data ◽  
Strike Direction ◽  
Recent Developments ◽  
3D Elements

Recent developments in the speed and quality of data acquisition using the radiomagnetotelluric (RMT) method, whereby large amounts of broadband RMT data can be collected along profiles, have prompted us to develop a strategy for routine inverse modeling using 2D models. We build a rather complicated numerical model containing both 2D and 3D elements believed to be representative for shallow conductors in crystalline basement overlain by a thin sedimentary cover. We then invert the corresponding synthetic data on selected profiles, using both traditional MT approaches, as well as the proposed approach, which is based on the determinant of the MT impedance tensor. We compare the estimated resistivity models with the true models along the selected profiles and find that the traditional approaches often lead to strongly biased models and bad data fit, in contrast to those using the determinant. In this case, much of the bias is removed and the data fit is improved. The determinant of the impedance tensor is independent of the chosen strike direction, and once the a priori model is set, the best fitting model is found to be practically independent of the starting model used. We conclude that the determinant of the impedance tensor is a useful tool for routine inverse modeling.

scholarly journals Experience of working with the MTU-5 magnetotelluric complex for studying the deep structure of the Shanuch and Aginsky deposits in Kamchatka

2021 ◽  
pp. 91-99
Author(s):  
В.А. Джигимон ◽  
И.С. Улыбышев
Keyword(s):  
Deep Structure ◽  
Field Research ◽  
Magnetotelluric Data ◽  
Hardware Complex

Данная статья описывает методологию проведения полевых исследований, процесс обработки магнитотеллурических данных и особенности работы с аппаратным комплексом MTU-5. This article describes the methodology for conducting field research, the process of processing magnetotelluric data and the features of working with the MTU-5 hardware complex.

Geoelectric section of the Central Tien Shan: Sequential inversion of the magnetovariational and magnetotelluric data along the Naryn Line

2010 ◽  
Vol 46 (8) ◽  
pp. 698-706 ◽  
Author(s):  
M. N. Berdichevsky ◽  
N. S. Golubtsova ◽  
Iv. M. Varentsov ◽  
P. Yu. Pushkarev ◽  
A. K. Rybin ◽  
...  
Keyword(s):  
Tien Shan ◽  
Magnetotelluric Data ◽  
Geoelectric Section

scholarly journals MAGNETOTELURIC AND MAGNETOVARIATE RESEARCHES IN THE ENDOCONTACT AREA OF KORNINSKY GRANITE ARRAY

2020 ◽  
pp. 46-52
Author(s):  
V. Ilyenko ◽  
T. Burakhovich ◽  
A. Kushnir ◽  
S. Popov ◽  
O. Omelchuk
Keyword(s):  
Deep Structure ◽  
Low Rank ◽  
Geomagnetic Variations ◽  
Flow Paths ◽  
Deep Fault ◽  
Sedimentary Deposits ◽  
Wide Range ◽  
Rank One ◽  
Western Border ◽  
Natural Electromagnetic Field

In 2018-2019, work was carried out to study the deep geoelectric structure of a complex system of intersection of the sub-latitudinal zone between the Andrushevsky and Masherinsky faults and the sub-meridional between Brusilovsky and Olshansky. Plane synchronous observations of the lowfrequency natural electromagnetic field of the Earth of ionospheric-magnetospheric origin in a wide range of periods are made. The transmission operators of MT/MV fields were evaluated using the PRC-MTMV software package. The obtained tipper estimates for periods of geomagnetic variations from 50 to 3100 s, curves of apparent resistance and impedance phases from 20 to 10000 s. According to the interpretation of the results of magnetotelluric studies, the Brusilovsky deep fault in the form of a subvertical surface lowresistance anomaly was clearly recorded. Analyzing these and previous works, it can be stated that within the Volyn megablock Ukrainian shield, the Brusilovsky deep fault is manifested by an anomalous highly conductive structure from the surface. Within the framework of the Rosinsky megablock, the Brusilov fault zone is not completely anomalous, and only its individual components (Velikoerchik fault) are anomalous, its conductivity decreases almost four times. The western border of the Korninsky massif is less clearly distinguished, as the relatively electrically conductive from the surface, which is most likely associated with the surface conductivity of minor sedimentary deposits or fracturing of rocks in the crystalline basement. It should also be emphasized that on pseudo-sections of magnetotelluric parameters, the SUS point (picket 14 km) did not appear to be anomalous, but the behavior of the curves for different polarizations, and especially low magnetovariational characteristics, may indicate that the deep structure of the region must be classified as heterogeneous. Moreover, this point is located near the zone of metasomatically altered rocks and multidirectional faults of low rank. One explanation of this may be that the processes of secondary changes in granitoids do not lead to an increase in porosity, the solutions which are filtered are immediately saturated with calcium and alkalis, filling the fluid flow paths.

scholarly journals Replenishment of oil deposits from the position of a new concept of oil and gas formation

Georesursy ◽  
2019 ◽  
Vol 21 (4) ◽  
pp. 40-48 ◽  
Author(s):  
Renat Kh. Muslimov ◽  
Irina N. Plotnikova
Keyword(s):  
Oil And Gas ◽  
Deep Structure ◽  
Sedimentary Cover ◽  
Crystalline Basement ◽  
The South ◽  
Gas Saturation ◽  
Oil Reserves ◽  
Long Term Study ◽  
The Earth ◽  
Deep Wells

The article is devoted to the problem of replenishing of oil reserves and considers it (the problem) in the aspect of deep degassing of the Earth. Based on an analysis of the results of a long-term study of the Precambrian crystalline basement in the territory of Tatarstan and adjacent areas, a number of new criteria are formulated that allow us to identify the processes of deep degassing of the Earth within the studied region. The article provides a brief overview of current views on the problem of replenishing oil reserves, considers options for possible sources and the mechanism of replenishment of hydrocarbons in the developed deposits. The arguments in favor of the modern process of deep degassing within the South Tatar arch and adjacent territories are examined, which are unequivocally confirmed by: the dynamics of the hydrochemical parameters of the deep waters of the crystalline basement obtained in the monitoring mode at five deep wells; uneven heat flux and its anomalies, recorded according to many years of research under the guidance of N.N. Khristoforova. The degassing processes are also confirmed by the dynamics of gas saturation of decompressed zones of the crystalline basement recorded in well 20009-Novoelkhovskaya, the dynamics of gas saturation of oil of the sedimentary cover and the composition of the gas dissolved in it, identified by oil studies in piezometric wells located in different areas of the Romashkinskoye field; the seismicity of the territory of Tatarstan, as well as its neotectonic activity. As criteria proving the existence of a process of replenishing the reserves of the developed oil fields of the South Tatar Arch, the features of the deep structure of the earth’s crust according to seismic data, as well as the results of geochemical studies of oils are considered.

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.

Tectonic structure and metallogeny of the Western Chukotka: insights from comprehensive geophysical dataset interpretation.

2020 ◽  
Author(s):  
Kseniia Antashchuk ◽  
Alexey Atakov ◽  
Kirill Mazurkevich ◽  
Oleg Petrov
Keyword(s):  
Potential Field ◽  
Deep Structure ◽  
Volcanic Belt ◽  
Structural Features ◽  
Geological Structure ◽  
Crystalline Basement ◽  
Magnetotelluric Data ◽  
Potential Field Data ◽  
Volcanic Deposits ◽  
Joint Interpretation

<p>Geological structure of western part of the Chukotka fold belt has been studied basing on the results of joint interpretation of geophysical data. The potential-field data, seismic and magnetotelluric data along two regional profile crossed the area and the off-shore seismic data obtained on the East Siberian sea were used in this study. The NE and NW oriented fault systems which control the mineragenous zones location were first detected and delineated. Joint interpretation of seismic and MT data along regional profiles allowed us to study: the deep structure of NW directed thrusts; the intrusion bodies morphology; the structural features of the Paleozoic and Mesozoic formations and the structure of volcanic deposits. The models of geological structure along regional profiles were used as a reference for potential field interpretation. Architecture of crystalline basement of the area was studied and several “steps” were detected. The depth of crystalline basement increases from north to south and reaches the largest depth under the volcanic deposits of Ochotsk-Chukotsk Volcanic Belt (OCVB).</p>

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