scholarly journals Structural and geological studies in the Naryn and Atbashi depressions (Tien Shan) and geological interpretation of magnetotelluric data

2021 ◽  
Vol 929 (1) ◽  
pp. 012007
Author(s):  
E S Przhiyalgovskii ◽  
A K Rybin ◽  
Yu A Morozov ◽  
E V Lavrushina ◽  
M G Leonov ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Sedimentary Cover ◽  
Structural Features ◽  
Geological Structure ◽  
Tien Shan ◽  
Upper Crust ◽  
Seismic Profiles ◽  
Magnetotelluric Data ◽  
Geological Interpretation ◽  
Basement Structures

Abstract The article presents the results of complex geological and geophysical studies in the Naryn depression and Atbashi depression in the Middle Tien Shan. They included the geological interpretation of new magnetotelluric data along the detailed profile crossing the key segment of the Tien Shan, and the study of the morphology and spatial position of the sedimentary cover and basement structures. The compilation of the results of structural-geological and geophysical studies makes it possible to create a 2D model of the upper-crust geological structure, consistent with the structure of the electrical conductivity to depths of about 10 km and to analyze the structural features of deeper horizons. Two types of structural patterns of the electric conductivity, corresponding to the sedimentary complexes of the cover and the folded-metamorphic complexes of the basement, have been identified. Sedimentary rock complexes in depressions have a high electrical conductivity and subhorizontal structure. The upper crust above the K2 density layer is characterized by an alternation of rocks volumes with contrasting conductivity, elongated vertically. The recorded structure of the field confirms the presence of steep zones of fluid permeability and fragmentation, noted earlier in seismic profiles and probably corresponding to the Paleozoic structures of fragmentation of the Earth’s crust, activated during Alpine orogeny. Comprehensive research allow to characterize the deformations of the Cenozoic sedimentary complex and the surface of the Paleozoic basement associated with the Alpine activation of the key segment of the Tien Shan.

scholarly journals The structure of the sedimentary complex of the Middle and South Caspian depressions (Azerbaijan sector)

2021 ◽  
Vol 43 (4) ◽  
pp. 199-216
Author(s):  
N.P. Yusubov ◽  
I.S. Guliyev
Keyword(s):  
Seismic Data ◽  
Oil And Gas ◽  
Sedimentary Cover ◽  
Clay Content ◽  
Geological Structure ◽  
Point Of View ◽  
South Caspian Basin ◽  
Origin And Evolution ◽  
Geological Interpretation ◽  
High Degree

The high degree of knowledge of the upper horizons of the sedimentary cover of the Middle and South Caspian depressions, given an insufficient increase in hydrocarbon reserves, leads to the need for a detailed approach to the search for oil and gas deposits in deep-seated sediments (over 6 km). During the geological interpretation of new highly informative seismic data, as well as data of deep drilling and petrological core studies, there were revealed obvious shortcomings in the concepts of the origin and evolution of the Middle and South Caspian depressions. These ideas misinterpret evolution, especially the South Caspian Basin, which is characterized by a number of unique features: very thick sedimentary cover (up to 22 km), extremely high sedimentation rate, low heat flow and reservoir temperatures, abnormally high pore and reservoir pressures, high clay content of the section, etc. The main purpose of the study was to elucidate the regional structure and features of the dissection of the sedimentary cover of the Middle and South Caspian depressions, the conditions of occurrence and distribution of facies and thicknesses of individual complexes of deposits. The paper analyzes the results of some previous studies of the geological structure of the Middle and South Caspian depressions based on the data of deep seismic sounding, seismological and gravimetric observations. We consider the main conclusions of these studies, about the geological structure of the sedimentary complex of the region’s, very outdated and subject to revision. The results of seismic stratigraphic analysis of seismic data allowed the authors to identify new data about the tectonic structure and express a completely different point of view regarding the structure of the sedimentary cover in the region. The work also touches on the issue associated with the tectonics of the region and the alleged subduction zone here.

scholarly journals FEATURES OF THE GEOLOGICAL STRUCTURE OF SEDIMENTARY COVER OF FROLOVSKAYA MEGADEPRESSION DERIVED FROM THE RESULTSOF GENERALIZATION OF GEOLOGICAL AND GEOPHYSICAL DATA

2018 ◽  
pp. 7-16
Author(s):  
S. R. Bembel ◽  
V. G. Kobzov ◽  
R. M. Bembel ◽  
F. Z. Khafizov
Keyword(s):  
Sedimentary Cover ◽  
Geophysical Methods ◽  
Geological Structure ◽  
Geophysical Data ◽  
Seismic Profiles ◽  
Gravity And Magnetic ◽  
Drilling Data ◽  
Entire Complex ◽  
Cretaceous Deposits

The article is devoted to the features of the geological structure of Jurassic-Cretaceous deposits of Frolovskaya megadepression. These features are derived from the results of the generalization of the materials of regional seismic profiles, maps of gravity and magnetic prospecting, drilling data. The main petroleum prospects are associated with Jurassic deposits and pre-Jurassic basement. We conclude that it is necessary to intensify further researches with carrying out the entire complex of geophysical methods, including magnetic and gravity prospecting with an increased density of observations.

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.

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>

scholarly journals Constraints of nonseismic geophysical data on the deep geological structure of the Benxi iron-ore district, Liaoning, China

2020 ◽  
Vol 12 (1) ◽  
pp. 887-903
Author(s):  
Chun-Hui Xu ◽  
Lin-Fu Xue ◽  
Chong Peng
Keyword(s):  
Iron Ore ◽  
Sedimentary Cover ◽  
Geological Structure ◽  
Ore Deposits ◽  
Geophysical Data ◽  
Liaoning Province ◽  
Magnetotelluric Data ◽  
Iron Ore Deposits ◽  
Iron Bearing ◽  
Ore District

AbstractThe Benxi area in Liaoning Province is one of the most important iron-ore districts in China. This study uses nonseismic geophysical data (in the form of gravity–magnetic–magnetotelluric data) and based on the section modeling method to model the deep, three-dimensional geological structure of the Benxi area. Based on the modeling results and deep geological structure characteristics, the Benxi area can be divided into three first-order deep geological tectonic units. A close relationship is between tectonic unit and iron-ore concentrations. First, high-quality iron-ore deposits occur within the tectonic boundary and sedimentary boundary zone of the Jiao–Liao–Ji Belt, reflects the protective effect of sedimentary cover on the iron-bearing formation. Second, enriched iron-ore deposits are mainly developed in Mesozoic granitic intrusion zone, reflects the hydrothermal leaching of silicon in host iron-bearing formations during magma intrusion. Thus, the findings of this study have important implications for future prospecting in the Benxi iron-ore district.

The role of airborne geophysics for detecting hydrocarbon microseepages and related structural features: The case of Remanso do Fogo, Brazil

Geophysics ◽  
2012 ◽  
Vol 77 (2) ◽  
pp. B35-B41 ◽  
Author(s):  
Julia B. Curto ◽  
Augusto C.B. Pires ◽  
Adalene M. Silva ◽  
Álvaro P. Crósta
Keyword(s):  
Gamma Ray ◽  
Sedimentary Cover ◽  
Structural Features ◽  
Magnetic Data ◽  
Gamma Ray Spectrometry ◽  
Horizontal Gradient ◽  
Near Surface ◽  
Residual Values ◽  
Basement Structures ◽  
New Occurrences

The first direct indication of hydrocarbon occurrence in Remanso do Fogo area (Minas Gerais State, Brazil) was the existence of microseepages. However, Quaternary sedimentary cover in the area made the identification of new occurrences and associated controlling structures quite difficult. This study investigated the spatial distribution of hydrocarbon related gases in shallower to intrasedimentary depths in Remanso do Fogo area, using airborne gamma-ray spectrometry and magnetic data. The geophysical data were processed using techniques designed to suppress the influence of regional geological signatures. Known and possible new occurrences of microseepages were detected by mapping low residual potassium values and high uranium residual values in relation to potassium, termed as DRAD values, which resulted from the subtraction of potassium from uranium residual values, using a Thorium (Th)-normalizing approach. The validation of these occurrences was done based on existing gas geochemistry data in the soil. For the magnetic data, the amplitude of the analytic signal, combined with the total horizontal gradient of the subtraction between the 1200- and 400-meter upward continuations, enhanced the northwest–southeast and east–west magnetic lineaments, which are partially related to the microseepages and the drainage of the area. The distinction of near-surface and deep signatures also allowed the general identification of intrasedimentary and basement structures, which are potentially controlling the occurrences of seepages in the area.

scholarly journals THREE-DIMENSIONAL DENSITY MODEL OF THE UPPER CRUST AT THE JUNCTION OF THE LOSEVSKY AND DONSKOY TERRANES (VORONEZH CRYSTALLINE MASSIF)

2021 ◽  
pp. 24-35
Author(s):  
T.A. Voronova ◽  
◽  
O.M. Muravina ◽  
V.N. Glaznev ◽  
S.I. S.I. Berezneva ◽  
...  
Keyword(s):  
Sedimentary Cover ◽  
Three Dimensional ◽  
Geological Structure ◽  
Crystalline Basement ◽  
Density Model ◽  
Upper Crust ◽  
Southeastern Part ◽  
Voronezh Crystalline Massif ◽  
Gravitational Fields ◽  
Anomalous Field

The results of detailed three-dimensional density modeling of the upper crust of the area located in the southeastern part of the Voronezh crystalline massif at the junction of the Losevsky and Donskoy terranes and, partially, the Vorontsovsky terrane are presented. The resulting model was built based on the inversion of local anomalies of the gravity field into anomalous density values, taking into account all available geological and geophysical information. The field inversion was implemented within the framework of the starting model developed on the basis of the regional density model and corresponding gravitational field of the East European platform lithosphere, generalized information on the density of rocks of the sedimentary cover and crystalline basement, the thickness of the «gravitational» layer obtained by statistical analysis of the anomalous field, and geological data and topography. The resulting model shows density distribution of the crystalline basement rocks to a depth of 16 km, and provides thus fundamentally new information about the geological structure of the upper crust of the area. The model makes it possible to trace geological objects, which are most expressive in terms of density, at deep levels, and allows interpreting the relationship between the Losevsky and Donskoy terranes in the upper-middle crust. The consistency of the model and observed gravitational fields indicates the reliability of the obtained results.

scholarly journals Tectonic structure and development of the “depression/ uplift” transition zones, Northern Tien Shan

2020 ◽  
Vol 65 (4) ◽  
Author(s):  
Eugeny S. Przhiyalgovskii ◽  
◽  
Yuriy A. Morozov ◽  
Mikhail G. Leonov ◽  
Anatoliy K. Rybin ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Lateral Pressure ◽  
Sedimentary Cover ◽  
Tectonic Setting ◽  
Structural Features ◽  
Tien Shan ◽  
Vertical Movements ◽  
Transition Zones ◽  
Basement Rocks ◽  
Northern Tien Shan

The article presents data on the structure of transition zones from areas of relative downwarping (intramountain depressions) to anticlinor uplifts dividing them. The geological and geophysical data obtained by the authors in recent years in different areas of the Northern Tien Shan are considering and discussing to compare the structure and tectonic evolution of key objects. A comparative analysis of the depression / uplift tectonic zones in different regions indicates a fundamental similarity in their structure. These areas of gradient vertical movements are zones of concentrated deformation. We described ensembles of structures formed at the same time in the sedimentary cover and in the basement rocks. Similar structural features are due to the common tectonic evolution of basins and ridges as parts of a unified activation structure of the Paleozoic folded belt. Over a long period of time, from the Oligocene to the Pliocene inclusive, the depressions of the Northern Tien Shan had developed under conditions of sedimentary subsidence, probably by the type of pool-apart structures in a latitudinally oriented region of plastic shear deformation. The relatively quiet tectonic setting of this stage is reflected in the lithological features of the sedimentary complexes. The next stage, which began about 3 Ma b.p., was marked not only by the emergence of a high-altitude relief and the accumulation of molasses, but also by a change of tectonic regime to transpression. The generally flexible bending of the foundation surface in the steep sides of the depressions, to some extent complicated by uplifts, was accompanied by the formation of extensive detachments and thrust-folded structural ensembles in the sedimentary cover of the depressions. Contrary to popular point of view volumes of disintegrated basement rocks demonstrate significant plasticity. The lateral pressure of the side ledges inside the sedimentary cover was transmitted for many kilometers towards the depression’s center. At the same time, contrary to traditional ideas, the volumes of disintegrated rocks of the basement demonstrate significant plasticity, while the lateral pressure of the side ledges was transmitted for many kilometers into the depressions inside the sedimentary cover.

Application of Eddy Currents in Processed Materials Structural Evaluation

2012 ◽  
Vol 730-732 ◽  
pp. 715-720
Author(s):  
Telmo G. Santos ◽  
João Faria ◽  
Pedro Vilaça ◽  
R.M. Miranda
Keyword(s):  
Electrical Conductivity ◽  
Solid State ◽  
Eddy Currents ◽  
Microstructural Analysis ◽  
Structural Features ◽  
Crystal Defects ◽  
Electrical Currents ◽  
Friction Stir ◽  
Characterization Technique ◽  
Physical Phenomena

Eddy currents are based on electromagnetic induction and analysis of electrical currents on conductive materials. This method is used for thickness measurements, corrosion and defects detection, electrical conductivity and magnetic permeability measurements. Recently, it has been exploited as a materials characterization technique, namely in solid state welding, since, compared to hardness, it is based in distinct physical phenomena. Electrical conductivity is controlled by electronic mobility, while hardness depends on crystal defects and thus a scale factor exists. This paper presents results of this characterization technique applied to multipass solid state friction stir processing (FSP) of AA1100 alloy. These results were compared to microstructural analysis and hardness measurements and show that eddy current is a feasibly, reliable and expedite technique to characterize processed materials. The electrical conductivity measured by eddy currents, maps more precisely structural features, while hardness does not. Measurement of electrical conductivity field suggests having potential to constitute an alternative and/or complement to hardness evaluation with the further advantage of being a non-destructive method.

scholarly journals The Osservatorio Geofisico Sperimentale marine magnetic surveys in the Antarctic Seas

1999 ◽  
Vol 42 (2) ◽  
Author(s):  
E. Lodolo ◽  
F. Coren ◽  
C. Zanolla
Keyword(s):  
Tectonic Evolution ◽  
Ross Sea ◽  
Austral Summer ◽  
Geological Structure ◽  
Seismic Profiles ◽  
Scotia Sea ◽  
Geophysical Surveys ◽  
Scientific Results ◽  
The Antarctic ◽  
Derived Data

About 40 000 km of marine magnetic and gradiometric data have been collected during eight geophysical surveys conducted since the Austral summer 1987/1988 in the circum-antarctic seas, by the research vessel OGS-Explora. For the most surveyed areas (Ross Sea, Southwestern Pacific Ocean, and Southern Scotia Sea), the analysis of the acquired data have contributed to clarify important aspects of their geological structure and tectonic evolution. The main scientific results, obtained combining other available geophysical data (multichannel seismic profiles and satellite-derived data), will be briefly illustrated.

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