Pub Date : 2023-08-30DOI: 10.24028/gj.v45i4.286283
V. Bakhmutov, O. Mytrokhyn, I. Poliachenko, S. Cherkes
A palaeomagnetic study of rocks for two Palaeoproterozoic anorthosite-mangerite-charnockite-granite (AMCG) complexes in the Ukrainian Shield was done to put additional constraints on the interpretation of palaeogeography of Fennoscandia and Volgo-Sarmatia in the Palaeoproterozoic. With this study, 5 sites of Korsun-Novomyrhorod and 3 sites of Korosten AMCG complexes in central and north-western parts of the shield, respectively, were chosen for palaeomagnetic sampling given the geological, modern geochronological and previous palaeomagnetic data. Primary remanent magnetization was isolated on samples of anorthosites, Gabbro, and monzonites within a narrow time interval of U-Pb geochronology dataset of 1.76—1.75 Ga. The palaeomagnetic poles calculated for Korosten and Korsun-Novomyrhorod complexes are almost identical, which indicates that the Volyn and Ingul Domains developed within a single structure of the Ukrainian Shield since at least 1.75 Ga. The new palaeomagnetic pole calculated for all 8 sites (Plat=22.7 °N, Plon=167.4 °E, A95=3.3°) agrees well with previous studies by Elming et al. [2001, 2010]. The selection of the most reliable palaeomagnetic poles for Fennoscandia and Volgo-Sarmatia of this time indicates that the present position of the Ukrainian Shield relative to Fennoscandia is not the same as for about 1.75 Ga, when Fennoscandia occupied a subequatorial position within palaeolatitudes of 5—20 °N, and Volgo-Sarmatia was located close to the equator and rotated relative to Fennoscandia counterclockwise by about 40° compared to its present position.
{"title":"New palaeomagnetic data for Palaeoproterozoic AMCG complexes of the Ukrainian Shield","authors":"V. Bakhmutov, O. Mytrokhyn, I. Poliachenko, S. Cherkes","doi":"10.24028/gj.v45i4.286283","DOIUrl":"https://doi.org/10.24028/gj.v45i4.286283","url":null,"abstract":"A palaeomagnetic study of rocks for two Palaeoproterozoic anorthosite-mangerite-charnockite-granite (AMCG) complexes in the Ukrainian Shield was done to put additional constraints on the interpretation of palaeogeography of Fennoscandia and Volgo-Sarmatia in the Palaeoproterozoic. With this study, 5 sites of Korsun-Novomyrhorod and 3 sites of Korosten AMCG complexes in central and north-western parts of the shield, respectively, were chosen for palaeomagnetic sampling given the geological, modern geochronological and previous palaeomagnetic data. Primary remanent magnetization was isolated on samples of anorthosites, Gabbro, and monzonites within a narrow time interval of U-Pb geochronology dataset of 1.76—1.75 Ga. The palaeomagnetic poles calculated for Korosten and Korsun-Novomyrhorod complexes are almost identical, which indicates that the Volyn and Ingul Domains developed within a single structure of the Ukrainian Shield since at least 1.75 Ga. The new palaeomagnetic pole calculated for all 8 sites (Plat=22.7 °N, Plon=167.4 °E, A95=3.3°) agrees well with previous studies by Elming et al. [2001, 2010]. The selection of the most reliable palaeomagnetic poles for Fennoscandia and Volgo-Sarmatia of this time indicates that the present position of the Ukrainian Shield relative to Fennoscandia is not the same as for about 1.75 Ga, when Fennoscandia occupied a subequatorial position within palaeolatitudes of 5—20 °N, and Volgo-Sarmatia was located close to the equator and rotated relative to Fennoscandia counterclockwise by about 40° compared to its present position.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42899438","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.24028/gj.v45i4.286288
I. Rokityansky, A. Tereshyn
Anomalous currents in a well-conducting body arise due to local electromagnetic induction inside the anomalous body, as well as due to conductive redistribution (and concentration) of currents induced in the host medium on a large territory equal to the external source size. The local induction generates the so-called anomaly of geomagnetic variations of the magnetic or inductive type. Its characteristic property is that the secondary anomalous field cannot be greater than the primary normal field of geomagnetic variations. However, in some places on the earth’s surface, the normalized anomalous fields are greater than 1. Analytical solution of the EM induction problem for circular cylinder yields the physical explanation of two types of anomalous geomagnetic fields. The first term (proportional to the normal electric field E0) describes the conductive anomaly type, the second term (proportional to the normal magnetic field B0) describes the inductive anomaly type. The conductive type usually is much greater than the inductive one. The normalized anomalous field of the conductive type is not limited to 1 or any other value. It is proportional to two functions: V(T) — the non-decreasing function of the period T (0≤V≤1, V=1 corresponds to DC) which describes the degree of filling of the conductor by anomalous currents (result of the skin effect inside the anomaly) and the normal impedance of inclosing cross-section — the decreasing function of the period. Product of these functions has a maximum at some period T0. The position T0 is closely related to the total lengthwise conductance G[S×m] of the anomalous body, that is, the scale of the anomaly. On the period T0, the anomalous fields and the induction vector become real C=Cu and the imaginary induction vector Cv passes through zero changing sign. Thus, the spectral properties of the geomagnetic response functions were studied for two-dimensional anomalies with a generalization to three-dimensional conductors with varying cross-section. 18 crustal electrical conductivity anomalies were considered and their integral lengthwise conductance G was obtained. At all anomalies, the G values turn out to be in a relatively narrow range G=(1—8)·108 S∙m; this has geophysical significance.
{"title":"Electrical conductivity anomalies study","authors":"I. Rokityansky, A. Tereshyn","doi":"10.24028/gj.v45i4.286288","DOIUrl":"https://doi.org/10.24028/gj.v45i4.286288","url":null,"abstract":"Anomalous currents in a well-conducting body arise due to local electromagnetic induction inside the anomalous body, as well as due to conductive redistribution (and concentration) of currents induced in the host medium on a large territory equal to the external source size. The local induction generates the so-called anomaly of geomagnetic variations of the magnetic or inductive type. Its characteristic property is that the secondary anomalous field cannot be greater than the primary normal field of geomagnetic variations. However, in some places on the earth’s surface, the normalized anomalous fields are greater than 1. Analytical solution of the EM induction problem for circular cylinder yields the physical explanation of two types of anomalous geomagnetic fields. The first term (proportional to the normal electric field E0) describes the conductive anomaly type, the second term (proportional to the normal magnetic field B0) describes the inductive anomaly type. The conductive type usually is much greater than the inductive one. The normalized anomalous field of the conductive type is not limited to 1 or any other value. It is proportional to two functions: V(T) — the non-decreasing function of the period T (0≤V≤1, V=1 corresponds to DC) which describes the degree of filling of the conductor by anomalous currents (result of the skin effect inside the anomaly) and the normal impedance of inclosing cross-section — the decreasing function of the period. Product of these functions has a maximum at some period T0. The position T0 is closely related to the total lengthwise conductance G[S×m] of the anomalous body, that is, the scale of the anomaly. On the period T0, the anomalous fields and the induction vector become real C=Cu and the imaginary induction vector Cv passes through zero changing sign. Thus, the spectral properties of the geomagnetic response functions were studied for two-dimensional anomalies with a generalization to three-dimensional conductors with varying cross-section. 18 crustal electrical conductivity anomalies were considered and their integral lengthwise conductance G was obtained. At all anomalies, the G values turn out to be in a relatively narrow range G=(1—8)·108 S∙m; this has geophysical significance.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41899788","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.24028/gj.v45i4.286284
M. Orlyuk, M. Bakarzhieva, A. Marchenko, O. Shestopalova, V. Drukarenko
The article presents the results of a qualitative and quantitative analysis of the geomagnetic field of the Ukrainian Carpathians and 3D magnetic modeling along the PANCAKE geotransect and Transcarpathian Depression, as well as a comparison of the obtained results with fault-block tectonics, deep structure, and distribution of a number of types of endogenous ore deposits and hydrocarbon accumulations. It is shown that the overthrust northeastern part of the Carpathian arc lies on the magnetic crust, and the southwestern one — on its non-magnetic lower part, and between the Rava-Rus’ka and Krakovets and Pre-Carpathian faults, the Earth’s crust is magnetized throughout. For the territory of the Transcarpathian Depression, the regional and local components of the geomagnetic field were identified for the first time, geological and geophysical characteristics were provided, and their tectonic interpretation was proposed. A three-dimensional magnetic model of the Transcarpathian Depression was created taking into account the magnetization of rocks according to measurements. A detailed magnetic model of the upper part of the crustal section of the Transcarpathian Depression was developed. The connection of magnetic sources with fault zones was analyzed; the results were compared with the deep structure and distribution of ore deposits and hydrocarbon accumulations. The regional source with magnetism І=1.0 A/m is located within the Mukachevo Depression and is located at a depth of 6.0 km to 13 km. The local component of the geomagnetic field reflects the magnetic inhomogeneity of the Earth’s crust in the upper 3—4 km of the section and mainly reflects the volcano-tectonic structures and dike formations of the Vyhorlat-Gutyn Ridge, the Chop-Berehove Uplift, and the Velika Dobron’ Uplift. The maximum depths of magnetic sources (up to 3.5 km) and their magnetization (1.22 A/m) are characteristic of the structures of the Vyhorlat-Gutynsky Ridge, intermediate values of depths (2.0—3.0 km) and magnetization (up to 0.93 A/m) belong to the Chop-Berehove Uplift, and the minimum depths (up to 1.1 km) and magnetization (up to 0.7 A/m) are characteristic of the Velika Dobron’ Uplift. It is shown that the gas fields of Transcarpathia correspond to local positive magnetic anomalies and are localized above a deep magnetic source. Within the Berehove Uplift, positive anomalies and magnetic sources indicate andesiteporphyrite shafts and andesite domes of Sarmatian age associated with gold, gold-polymetallic and silver mineralization. A zone of antimony mineralization is associated with the Pannonian-Pontic volcanic structures along the southern foot of the Vyhorlat-Gutyn Ridge, and deposits and occurrences of bismuth and mercury correlate well with intrusive formations of the Dacian-Romanian age.
{"title":"The geomagnetic field of the Ukrainian Carpathians and a 3D magnetic model of the Transcarpathian Depression","authors":"M. Orlyuk, M. Bakarzhieva, A. Marchenko, O. Shestopalova, V. Drukarenko","doi":"10.24028/gj.v45i4.286284","DOIUrl":"https://doi.org/10.24028/gj.v45i4.286284","url":null,"abstract":"The article presents the results of a qualitative and quantitative analysis of the geomagnetic field of the Ukrainian Carpathians and 3D magnetic modeling along the PANCAKE geotransect and Transcarpathian Depression, as well as a comparison of the obtained results with fault-block tectonics, deep structure, and distribution of a number of types of endogenous ore deposits and hydrocarbon accumulations. \u0000It is shown that the overthrust northeastern part of the Carpathian arc lies on the magnetic crust, and the southwestern one — on its non-magnetic lower part, and between the Rava-Rus’ka and Krakovets and Pre-Carpathian faults, the Earth’s crust is magnetized throughout. \u0000For the territory of the Transcarpathian Depression, the regional and local components of the geomagnetic field were identified for the first time, geological and geophysical characteristics were provided, and their tectonic interpretation was proposed. \u0000A three-dimensional magnetic model of the Transcarpathian Depression was created taking into account the magnetization of rocks according to measurements. A detailed magnetic model of the upper part of the crustal section of the Transcarpathian Depression was developed. The connection of magnetic sources with fault zones was analyzed; the results were compared with the deep structure and distribution of ore deposits and hydrocarbon accumulations. \u0000The regional source with magnetism І=1.0 A/m is located within the Mukachevo Depression and is located at a depth of 6.0 km to 13 km. The local component of the geomagnetic field reflects the magnetic inhomogeneity of the Earth’s crust in the upper 3—4 km of the section and mainly reflects the volcano-tectonic structures and dike formations of the Vyhorlat-Gutyn Ridge, the Chop-Berehove Uplift, and the Velika Dobron’ Uplift. The maximum depths of magnetic sources (up to 3.5 km) and their magnetization (1.22 A/m) are characteristic of the structures of the Vyhorlat-Gutynsky Ridge, intermediate values of depths (2.0—3.0 km) and magnetization (up to 0.93 A/m) belong to the Chop-Berehove Uplift, and the minimum depths (up to 1.1 km) and magnetization (up to 0.7 A/m) are characteristic of the Velika Dobron’ Uplift. \u0000It is shown that the gas fields of Transcarpathia correspond to local positive magnetic anomalies and are localized above a deep magnetic source. Within the Berehove Uplift, positive anomalies and magnetic sources indicate andesiteporphyrite shafts and andesite domes of Sarmatian age associated with gold, gold-polymetallic and silver mineralization. A zone of antimony mineralization is associated with the Pannonian-Pontic volcanic structures along the southern foot of the Vyhorlat-Gutyn Ridge, and deposits and occurrences of bismuth and mercury correlate well with intrusive formations of the Dacian-Romanian age.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47953630","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.24028/gj.v45i4.286285
I. Makarenko, O. Savchenko, J. Dérerová, A. Murovskaya, V. Starostenko, M. Bielik, O. Legostaeva
The presented research is devoted to the construction and calculations of the density model along the regional CMRV-DSS profile RP-17 (Chop–Velykyy Bychkiv), running along the Transcarpathian depression. Based on the results of density modeling, the distribution of density in the Earth’s crust was obtained in accordance with its seismic structure and gravity field as well as the density structure of individual layers. A tectonic interpretation of the obtained results was provided. The Mukachevo and Solotvyno parts of Transcarpathian depression have their own structural features, autonomous geological development and are distinguished by Neogene geodynamics. The analysis of density properties showed that in the Neogene sedimentary layer of both depressions there is a change in the density of various rocks in the depth intervals of 200—950; 950—1450; 1450—2050 m. In the Solotvyno depression in the depth intervals of 200—950 and 1450—2050 m, the density is greater than in Mukachevo, due to the presence of sandstones, tuffs, mudstones, and siltstones. In the interval 950—1450 m of Solotvyno depresson, on the contrary, the density is lower than in Mukachevo one, due to the presence of salt and clay. The Earth’s crust of Mukachevo depression is more compacted, as it contains a «basalt» layer. The Solotvyno depression consists of two parts and its average density corresponds to a diorite composition. The north-western block is of higher density and more homogeneous. The south-eastern one is of lower density and composed of a large number blocks of different densities separated by faults. The boundary of the lower density zone (PK 105—110) runs along the south-eastern branch of the Stryi-Latorytsia shear zone. This zone appears fragmentary on the density section, being similar to a mantle fault, with a lateral differentiation of density values, as well as the largest concentration of earthquakes, especially in the upper part of the Earth’s crust. The low-density area is probably associated with the transition from the Solotvyno depression to the structures located to the south-east of it. Thus, the block with the lowest density (2,38 g/cm3) of the Mesozoic-Paleozoic folded basement can be attributed to the Fore-Alkapa suture zone, represented by the Pieniny Klippen Belt and the Monastyrets nappe, which turns in the meridional direction in the zone of junction with the Tisza-Dacia terrane. The block located below with a density of 2,64 g/cm3 can be connected with the Marmarosh massif, or with the Rakhiv nappe. It was established that the crust of the Alkapa terrain along the profile is represented by three large blocks with a smaller block structure inside each one. The two more density blocks with different crust structure correspond to the Mukachevo depression. The lowest density third block belongs to the north-eastern part of the Solotvyno depression, the eastern border of which coincides with the area of clustering of earthquake hypocenters. The sout
{"title":"Depth structure of the Transcarpathian Depression (Ukrainian part) according to density modeling data","authors":"I. Makarenko, O. Savchenko, J. Dérerová, A. Murovskaya, V. Starostenko, M. Bielik, O. Legostaeva","doi":"10.24028/gj.v45i4.286285","DOIUrl":"https://doi.org/10.24028/gj.v45i4.286285","url":null,"abstract":"The presented research is devoted to the construction and calculations of the density model along the regional CMRV-DSS profile RP-17 (Chop–Velykyy Bychkiv), running along the Transcarpathian depression. Based on the results of density modeling, the distribution of density in the Earth’s crust was obtained in accordance with its seismic structure and gravity field as well as the density structure of individual layers. A tectonic interpretation of the obtained results was provided. The Mukachevo and Solotvyno parts of Transcarpathian depression have their own structural features, autonomous geological development and are distinguished by Neogene geodynamics. The analysis of density properties showed that in the Neogene sedimentary layer of both depressions there is a change in the density of various rocks in the depth intervals of 200—950; 950—1450; 1450—2050 m. In the Solotvyno depression in the depth intervals of 200—950 and 1450—2050 m, the density is greater than in Mukachevo, due to the presence of sandstones, tuffs, mudstones, and siltstones. In the interval 950—1450 m of Solotvyno depresson, on the contrary, the density is lower than in Mukachevo one, due to the presence of salt and clay. The Earth’s crust of Mukachevo depression is more compacted, as it contains a «basalt» layer. The Solotvyno depression consists of two parts and its average density corresponds to a diorite composition. The north-western block is of higher density and more homogeneous. The south-eastern one is of lower density and composed of a large number blocks of different densities separated by faults. The boundary of the lower density zone (PK 105—110) runs along the south-eastern branch of the Stryi-Latorytsia shear zone. This zone appears fragmentary on the density section, being similar to a mantle fault, with a lateral differentiation of density values, as well as the largest concentration of earthquakes, especially in the upper part of the Earth’s crust. The low-density area is probably associated with the transition from the Solotvyno depression to the structures located to the south-east of it. Thus, the block with the lowest density (2,38 g/cm3) of the Mesozoic-Paleozoic folded basement can be attributed to the Fore-Alkapa suture zone, represented by the Pieniny Klippen Belt and the Monastyrets nappe, which turns in the meridional direction in the zone of junction with the Tisza-Dacia terrane. The block located below with a density of 2,64 g/cm3 can be connected with the Marmarosh massif, or with the Rakhiv nappe. It was established that the crust of the Alkapa terrain along the profile is represented by three large blocks with a smaller block structure inside each one. The two more density blocks with different crust structure correspond to the Mukachevo depression. The lowest density third block belongs to the north-eastern part of the Solotvyno depression, the eastern border of which coincides with the area of clustering of earthquake hypocenters. The sout","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43485848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The article presents an idea of the project that defines the development of a geothermal power plant methodology based on a single isolated well. It is planned to develop a technical and economic rationale and geological and geophysical aspects of the development of geothermal energy and to obtain data on deposits of geothermal water in the deep. Extraction of heat from hot rocks at the pits is to be carried out using a special energy carrier, construction of the operating column, and circulation mode. To create a model in the project, a well is needed with a depth of 4,702 m, temperature at the bottom of 130 °С, an unperforated casing string with a diameter of 245 mm to a depth of 4,500 m, and no formation fluids. The transfer and transformation of the energy carrier by the working body into electric and hydrogen energy is maintained by ORC (Organic Rankine Cycle). The development of the methodology includes two stages: The first stage of the project involves legal preparation at the local and state levels for the use of the land plot and technical means of the drilled well and obtaining licenses and permits for the implementation of the project. It is planned to develop a technical and economic feasibility study for the construction of a geothermal electric station that will generate electricity and hydrogen energy for consumers. The second stage of the project involves the technical preparation of the well for its use as part of a geothermal power station. Remediation of the well to a depth of 4,500 m is foreseen, as well as the implementation of industrial geophysical studies of the technical condition of the unperforated casing string; conducting preliminary geothermal studies on the stability and thermal productivity of hot rocks. The authors intend to use results in the oil-and-gas industry, which has deep wells that have completed their purpose for hydrocarbon extraction, as well as in the nuclear, metallurgical, chemical, and many other fields.
{"title":"Development of the methodology of energy and environmental safety of Ukraine based on own geothermics","authors":"Y.P. Starodub, V.M. Karpenko, A.P. Havrys, D.A. Behen","doi":"10.24028/gj.v45i4.286289","DOIUrl":"https://doi.org/10.24028/gj.v45i4.286289","url":null,"abstract":"The article presents an idea of the project that defines the development of a geothermal power plant methodology based on a single isolated well. It is planned to develop a technical and economic rationale and geological and geophysical aspects of the development of geothermal energy and to obtain data on deposits of geothermal water in the deep. \u0000Extraction of heat from hot rocks at the pits is to be carried out using a special energy carrier, construction of the operating column, and circulation mode. \u0000To create a model in the project, a well is needed with a depth of 4,702 m, temperature at the bottom of 130 °С, an unperforated casing string with a diameter of 245 mm to a depth of 4,500 m, and no formation fluids. \u0000The transfer and transformation of the energy carrier by the working body into electric and hydrogen energy is maintained by ORC (Organic Rankine Cycle). \u0000The development of the methodology includes two stages: \u0000The first stage of the project involves legal preparation at the local and state levels for the use of the land plot and technical means of the drilled well and obtaining licenses and permits for the implementation of the project. It is planned to develop a technical and economic feasibility study for the construction of a geothermal electric station that will generate electricity and hydrogen energy for consumers. \u0000The second stage of the project involves the technical preparation of the well for its use as part of a geothermal power station. Remediation of the well to a depth of 4,500 m is foreseen, as well as the implementation of industrial geophysical studies of the technical condition of the unperforated casing string; conducting preliminary geothermal studies on the stability and thermal productivity of hot rocks. \u0000The authors intend to use results in the oil-and-gas industry, which has deep wells that have completed their purpose for hydrocarbon extraction, as well as in the nuclear, metallurgical, chemical, and many other fields.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45665921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.24028/gj.v45i4.286287
O. Usenko
The study of the course of geodynamic processes in the lower crust and upper mantle proves that an additional energy contribution is made by a change in the phase state of matter with increasing pressure and temperature. The gas phase, composed of hydrogen, oxygen and carbon, turns into a fluid that combines the properties of a liquid and a gas. The result is a change in the behavior of fluid-crystal and fluid-melt systems which significantly accelerates melting and physicochemical interactions in the thermal asthenosphere. These conclusions are confirmed by numerous experimental studies and the results of the study of xenoliths representing the crust and mantle of cratons and active regions. Seismic tomography studies show distinct patterns of inhomogeneities in physical properties, reflecting inhomogeneities in the mantle structure. Many works hypothesize, with substantiation, that plumes or fluid flows arise at the boundary of the core and mantle and are factors of all geodynamic processes. Modern ideas about the composition of the Earth's core are based on the statement that it is composed of molten iron with minor impurities of other elements. However, calculations of the energy balance and physical modeling of the redistribution of matter in the core itself show that the removal of volatile components or convective currents do not provide enough energy for the formation of plumes. The assumption that the substance of the core is an electrically conductive ionic liquid in which chemical compounds have completely dissociatedand the electronic structure has no gapradically changes the idea of the energetics of the core and the possibility of initiating plume processes. The properties of a substance in a similar phase state are fundamentally different from the properties of a liquid.
{"title":"The effect of the mantle and core matter phase state on the course of geodynamic processes","authors":"O. Usenko","doi":"10.24028/gj.v45i4.286287","DOIUrl":"https://doi.org/10.24028/gj.v45i4.286287","url":null,"abstract":"The study of the course of geodynamic processes in the lower crust and upper mantle proves that an additional energy contribution is made by a change in the phase state of matter with increasing pressure and temperature. The gas phase, composed of hydrogen, oxygen and carbon, turns into a fluid that combines the properties of a liquid and a gas. The result is a change in the behavior of fluid-crystal and fluid-melt systems which significantly accelerates melting and physicochemical interactions in the thermal asthenosphere. These conclusions are confirmed by numerous experimental studies and the results of the study of xenoliths representing the crust and mantle of cratons and active regions. \u0000Seismic tomography studies show distinct patterns of inhomogeneities in physical properties, reflecting inhomogeneities in the mantle structure. Many works hypothesize, with substantiation, that plumes or fluid flows arise at the boundary of the core and mantle and are factors of all geodynamic processes. Modern ideas about the composition of the Earth's core are based on the statement that it is composed of molten iron with minor impurities of other elements. However, calculations of the energy balance and physical modeling of the redistribution of matter in the core itself show that the removal of volatile components or convective currents do not provide enough energy for the formation of plumes. \u0000The assumption that the substance of the core is an electrically conductive ionic liquid in which chemical compounds have completely dissociatedand the electronic structure has no gapradically changes the idea of the energetics of the core and the possibility of initiating plume processes. The properties of a substance in a similar phase state are fundamentally different from the properties of a liquid.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46425269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.24028/gj.v45i4.286292
V.P. Kyrylyuk
The name «Bug Series» was introduced into the Precambrian stratigraphic scheme of the Ukrainian Shield more than half a century ago. During this period, ideas about the composition and age of the series changed several times, but at the same time, until recently, the opinion of various studies about its stratigenic nature remained unchanged. In recent years, a number of publications have appeared in which other views on the origin of the «Bug series» are expressed. Initially, they concerned only individual petrographic groups, such as carbonate and magnetite-bearing rocks, which were attributed to endogenous (magmatic) origin. Later, an opinion was expressed about the nonstratigenic origin of the entire «Bug Series», and some authors propose to abandon the dismemberment of the Early Precambrian granulite complexes into suites altogether. These ideas are based only on the materials of the study of local objects obtained by drilling and geophysical methods, and they do not take into account the results of regional geological and stratigraphic studies. Simultaneously with new ideas about the genesis of the «Bug series», an attempt is being made to link its origin with faults and to revise its age. In order to discuss the problem of the «Bug series», a series of publications has been prepared, in which the main generalized data of many years of regional geological and thematic studies on the composition, structure, stratigraphic and structural position of the units belonging to the «Bug series» are presented. The cycle consists of three separate articles. The first article [Kyrylyuk, 2022a] characterizes the composition of subdivisions and rock associations included in the «Bug series» in the current Precambrian stratigraphic scheme of the Ukrainian Shield. In the second article of the series [Kyrylyuk, 2022б], the ideas about the structural position of the «Bug series» and its subdivisions are considered. This final article is devoted to consideration of ideas about the primary nature of the «Bug series» and its age. As for the Kosharo-Aleksandrovskaya and Khashchevo-Zavalyevskaya suites, the composition, structure, and structural-stratigraphic position of these suits in the stratotype region unambiguously testify to their original stratigenic nature. The problem is only the origin of the rock association of magnetic anomalies, which are erroneously included in the Khashchevo-Zavalievskaya suite. But this association, according to the sum of the signs that are given in the article, also has the most probable lithogenic origin. All subdivisions of the «Bug series» are part of the unified Pobug granulite-gneiss complex of the Lower Archean. Its «stratigraphic age» is not younger than 3.8 Ga, and all younger dates indicate a long-term granulite metamorphism of the complex up to 2.0—1.9 Ga.
{"title":"About the so-called «Bug series» of the Middle Bug region (Ukrainian Shield). Article 3. Problems of origin and age.","authors":"V.P. Kyrylyuk","doi":"10.24028/gj.v45i4.286292","DOIUrl":"https://doi.org/10.24028/gj.v45i4.286292","url":null,"abstract":"The name «Bug Series» was introduced into the Precambrian stratigraphic scheme of the Ukrainian Shield more than half a century ago. During this period, ideas about the composition and age of the series changed several times, but at the same time, until recently, the opinion of various studies about its stratigenic nature remained unchanged. In recent years, a number of publications have appeared in which other views on the origin of the «Bug series» are expressed. Initially, they concerned only individual petrographic groups, such as carbonate and magnetite-bearing rocks, which were attributed to endogenous (magmatic) origin. Later, an opinion was expressed about the nonstratigenic origin of the entire «Bug Series», and some authors propose to abandon the dismemberment of the Early Precambrian granulite complexes into suites altogether. These ideas are based only on the materials of the study of local objects obtained by drilling and geophysical methods, and they do not take into account the results of regional geological and stratigraphic studies. Simultaneously with new ideas about the genesis of the «Bug series», an attempt is being made to link its origin with faults and to revise its age. \u0000In order to discuss the problem of the «Bug series», a series of publications has been prepared, in which the main generalized data of many years of regional geological and thematic studies on the composition, structure, stratigraphic and structural position of the units belonging to the «Bug series» are presented. The cycle consists of three separate articles. The first article [Kyrylyuk, 2022a] characterizes the composition of subdivisions and rock associations included in the «Bug series» in the current Precambrian stratigraphic scheme of the Ukrainian Shield. In the second article of the series [Kyrylyuk, 2022б], the ideas about the structural position of the «Bug series» and its subdivisions are considered. This final article is devoted to consideration of ideas about the primary nature of the «Bug series» and its age. As for the Kosharo-Aleksandrovskaya and Khashchevo-Zavalyevskaya suites, the composition, structure, and structural-stratigraphic position of these suits in the stratotype region unambiguously testify to their original stratigenic nature. The problem is only the origin of the rock association of magnetic anomalies, which are erroneously included in the Khashchevo-Zavalievskaya suite. But this association, according to the sum of the signs that are given in the article, also has the most probable lithogenic origin. All subdivisions of the «Bug series» are part of the unified Pobug granulite-gneiss complex of the Lower Archean. Its «stratigraphic age» is not younger than 3.8 Ga, and all younger dates indicate a long-term granulite metamorphism of the complex up to 2.0—1.9 Ga.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68826937","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-30DOI: 10.24028/gj.v45i4.286290
T. Akhmedov, M.A. Aghayeva
The article is devoted to the study of the geological structure of the lower parts of the Productive Series of the Lower Pliocene of the Kurovdagh field. It consists of an introduction, problem statement, research questions, research methodology, results, conclusion and list of references. The introduction provides basic information about the field under study, its geographical location, the history of geological and geophysical studies, the lithology of the section, the structure of the Kyurovdag fold and the oil and gas potential of the field. Oil and gas presence inthefield is related to the Absheron stage of Pleistocene, Akchagyl stage and Productive Series (horizons PS01—PS23) of Neogene. Despite the long-term production from the field, the lower parts of the Productive Series and underlying sediments have not been recovered and sufficiently studied by deep drilling due to the complicated surface and deepseismo-geological environment. It has been recommended to carry out a 3D seismic survey due to a high level of lateral one-fold reflections on seismic records. The major goals of the 3D seismic survey were studyingthe Kurovdagh field's geologic setting, obtaining characteristics previously unknown to geoscientists, and providing detailed research on velocity section to derive prognostic time-depth dependence. It was noted that thePetroalliance Services Company Limited geophysical company has performed a field seismic survey on request «The Caspian Energy Group» company. Processing of the acquired data used the FOCUS 5.4 software package manufactured by Paradigm Geophysical. For repeated interpretation of 3D seismic survey data, the 3D CDP data acquired from the field were used. The kinematic analysis by use of the 3 D cubes revealed the difference by the time shift, frequency spectrum, and amplitude range. The 3 D cubes were brought to a single formby time, phase, and amplitude. The further kinematic interpretation displayed the good quality of the data acquired from Kurovdagh area. The study applied PANGEYA® software for a multi-attribute geological and geophysical data analysis and the standard interpretation. For volumetric modeling of the productive layers of the Kurovdagh oil field, we used the PETREL.10.2 software package. The study targets included complex, lithologically, and tectonically sealed deposits of Productive Series PS01—PS09 and Akchagyl stage (AKCH). Productive layers are attributed to Neogene's Pliocene stage within the Caspian basin's limits. It is represented by a thick series of continental, coastal, and marine sediments (sand, clay, coarsely fragmented depositions) of 1600 m thickness and is unconformity laying over the Pontian stage and covered by the Akchagyl layers in a transgressive form. The Akchagyl stage is one of the stages of the Upper Pliocene which is made of clay, limestone, marl, sandstone, sand, and conglomerates. It became clear that the Kurovdagh field is characterized by a block type structure
本文研究了库洛夫达油田上新世下统生产系列下部的地质构造。它包括引言、问题陈述、研究问题、研究方法、结果、结论和参考文献列表。引言提供了有关所研究油田的基本信息、地理位置、地质和地球物理研究历史、剖面岩性、Kyurovdag褶皱的结构以及油田的油气潜力。该区油气的存在与更新世Absheron期、Akchagyl期和新近系生产系列（层位PS01～PS23）有关。尽管该油田进行了长期生产，但由于复杂的地表和深部地震地质环境，生产系列的下部和下层沉积物尚未通过深部钻探进行回收和充分研究。由于地震记录上存在高水平的横向一次褶皱反射，因此建议进行三维地震勘测。三维地震勘探的主要目标是研究Kurovdagh油田的地质环境，获得地球科学家以前未知的特征，并对速度剖面进行详细研究，以得出预测时间-深度的相关性。据指出，Petroalliance Services Company Limited地球物理公司应“里海能源集团”公司的要求进行了现场地震勘测。采集数据的处理使用Paradigm Geophysical制造的FOCUS 5.4软件包。对于三维地震勘探数据的重复解释，使用了从现场获得的三维CDP数据。使用三维立方体进行的运动学分析揭示了时间偏移、频谱和振幅范围的差异。三维立方体通过时间、相位和振幅形成单一形式。进一步的运动学解释显示了从Kurovdagh地区获得的数据的良好质量。该研究应用PANGEYA®软件进行多属性地质和地球物理数据分析和标准解释。对于Kurovdagh油田生产层的体积建模，我们使用了PETREL.10.2软件包。研究对象包括生产系列PS01-PS09和Akchagyl阶段（AKCH）的复杂、岩性和构造封闭矿床。生产层归属于里海盆地范围内的新近纪上新世。它由一系列1600米厚的大陆、海岸和海洋沉积物（沙子、粘土、粗碎沉积物）组成，是位于庞蒂阶之上的不整合面，并以海侵形式被阿克恰吉尔层覆盖。阿克恰吉尔阶是上新世晚期的一个阶段，由粘土、石灰石、泥灰岩、砂岩、沙子和砾岩组成。很明显，Kurovdagh油田的地质剖面具有块状结构。块体大小几乎没有变化，证明了构造阶段的一致性和构造运动的继承性。泥火山和底辟褶皱及其大小是该地区的主要特征。
{"title":"Detailed study of geology of the lower parts of Pliocene in Kurovdagh area by use of 3D seismic survey","authors":"T. Akhmedov, M.A. Aghayeva","doi":"10.24028/gj.v45i4.286290","DOIUrl":"https://doi.org/10.24028/gj.v45i4.286290","url":null,"abstract":"The article is devoted to the study of the geological structure of the lower parts of the Productive Series of the Lower Pliocene of the Kurovdagh field. \u0000It consists of an introduction, problem statement, research questions, research methodology, results, conclusion and list of references. The introduction provides basic information about the field under study, its geographical location, the history of geological and geophysical studies, the lithology of the section, the structure of the Kyurovdag fold and the oil and gas potential of the field. \u0000Oil and gas presence inthefield is related to the Absheron stage of Pleistocene, Akchagyl stage and Productive Series (horizons PS01—PS23) of Neogene. Despite the long-term production from the field, the lower parts of the Productive Series and underlying sediments have not been recovered and sufficiently studied by deep drilling due to the complicated surface and deepseismo-geological environment. It has been recommended to carry out a 3D seismic survey due to a high level of lateral one-fold reflections on seismic records. \u0000The major goals of the 3D seismic survey were studyingthe Kurovdagh field's geologic setting, obtaining characteristics previously unknown to geoscientists, and providing detailed research on velocity section to derive prognostic time-depth dependence. \u0000It was noted that thePetroalliance Services Company Limited geophysical company has performed a field seismic survey on request «The Caspian Energy Group» company. Processing of the acquired data used the FOCUS 5.4 software package manufactured by Paradigm Geophysical. \u0000For repeated interpretation of 3D seismic survey data, the 3D CDP data acquired from the field were used. The kinematic analysis by use of the 3 D cubes revealed the difference by the time shift, frequency spectrum, and amplitude range. The 3 D cubes were brought to a single formby time, phase, and amplitude. The further kinematic interpretation displayed the good quality of the data acquired from Kurovdagh area. The study applied PANGEYA® software for a multi-attribute geological and geophysical data analysis and the standard interpretation. \u0000For volumetric modeling of the productive layers of the Kurovdagh oil field, we used the PETREL.10.2 software package. The study targets included complex, lithologically, and tectonically sealed deposits of Productive Series PS01—PS09 and Akchagyl stage (AKCH). Productive layers are attributed to Neogene's Pliocene stage within the Caspian basin's limits. \u0000It is represented by a thick series of continental, coastal, and marine sediments (sand, clay, coarsely fragmented depositions) of 1600 m thickness and is unconformity laying over the Pontian stage and covered by the Akchagyl layers in a transgressive form. The Akchagyl stage is one of the stages of the Upper Pliocene which is made of clay, limestone, marl, sandstone, sand, and conglomerates. \u0000It became clear that the Kurovdagh field is characterized by a block type structure","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48697496","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.24028/gj.v45i3.282419
M. Kozlenko, Y. Kozlenko
In order to investigate the deep structure and tectonics of the central part of the South Ukrainian monocline (SUM), a detailed study of this structure was carried out using a network of gravimetric profiles. It is shown that on the part of the SUM, which belongs to the southern edge of the East European Platform (EEP), the basement is split into separate blocks with different characteristics of the consolidated crust. The crust of the Scythian Plate (SP) within the SUM has undergone considerable changes as a result of tectonic activation and significant complications of its structure. The distribution into the areas with different density characteristics of the basement of EEP and SP does not coincide, indicating that the development of the latter has not been fully inherited from the former. The obtained results, compared with data from other researchers in Prydobrydzha and Crimea, show that the northwestern shelf is an intermediate link between these terranes. A tectonic scheme of the research area based on the hypsometry of the surface of the second layer of the basement was built on the basis of the simulation. It was shown that the southern edge of the platform has undergone rather insignificant transformations, which are manifested in the emergence of an elongated intracrustal graben system along the EEP/SP boundary, divided by sublatitudinal faults into three blocks with different parameters. At the northern margin of the SP within the SUM, in addition to the grabens and horsts in the basement, there are sags and uplifts with boundary faults without vertical crustal displacements along them. Areas of the heterogeneous-heterochronous structure of the crust of the Baikal, Hercynian, and Kimmerian generations have been identified within SUM part of the SP. It has been determined that the Golitsyn fault system and the northern flank of the Karkinit trough were further restructuring during the Alpine tectogenesis phase. A variant of the Scythian Plate origin scenario based on the Mobilist ideas is proposed and substantiated by the results of the conducted studies and the available geological and geophysical information as a discussion.
{"title":"Deep structure and tectonics of the South Ukrainian monocline in the zone of juncture of the East European platform and the Scythian plate (according to gravimetric data)","authors":"M. Kozlenko, Y. Kozlenko","doi":"10.24028/gj.v45i3.282419","DOIUrl":"https://doi.org/10.24028/gj.v45i3.282419","url":null,"abstract":"In order to investigate the deep structure and tectonics of the central part of the South Ukrainian monocline (SUM), a detailed study of this structure was carried out using a network of gravimetric profiles. It is shown that on the part of the SUM, which belongs to the southern edge of the East European Platform (EEP), the basement is split into separate blocks with different characteristics of the consolidated crust. The crust of the Scythian Plate (SP) within the SUM has undergone considerable changes as a result of tectonic activation and significant complications of its structure. The distribution into the areas with different density characteristics of the basement of EEP and SP does not coincide, indicating that the development of the latter has not been fully inherited from the former. The obtained results, compared with data from other researchers in Prydobrydzha and Crimea, show that the northwestern shelf is an intermediate link between these terranes. A tectonic scheme of the research area based on the hypsometry of the surface of the second layer of the basement was built on the basis of the simulation. It was shown that the southern edge of the platform has undergone rather insignificant transformations, which are manifested in the emergence of an elongated intracrustal graben system along the EEP/SP boundary, divided by sublatitudinal faults into three blocks with different parameters. At the northern margin of the SP within the SUM, in addition to the grabens and horsts in the basement, there are sags and uplifts with boundary faults without vertical crustal displacements along them. Areas of the heterogeneous-heterochronous structure of the crust of the Baikal, Hercynian, and Kimmerian generations have been identified within SUM part of the SP. It has been determined that the Golitsyn fault system and the northern flank of the Karkinit trough were further restructuring during the Alpine tectogenesis phase. A variant of the Scythian Plate origin scenario based on the Mobilist ideas is proposed and substantiated by the results of the conducted studies and the available geological and geophysical information as a discussion.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":"1 1","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68827310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-07-03DOI: 10.24028/gj.v45i3.282411
S. Stovba, R. Stephenson, A. Tyshchenko, P. Fenota, D. Vengrovych, S. Mazur
Regional seismic investigations have made it possible to obtain new knowledge on the geological history of the Ukrainian sector of the Black Sea during rifting from Albian to Cenomanian, post-rift subsidence (Turonian¾Maastrichtian and Paleocene¾Middle Eocene), tectonic compression at the end of the middle Eocene and post-rift subsidence interrupted by a series of short-lived, compressional events (late Eocene ¾ the beginning of the Early Miocene). Rifting occurred simultaneously in the entire area of study and formed three long rift basins, each of which consisted of a system of (half)grabens, separated from each other and their margins by faults with amplitudes of up to3 km. The intensity of Cretaceous rifting was significantly less than would be required to produce continental lithosphere break-up and oceanic crust formation, or through-going «oceanisation» of continental lithosphere. Sedimentation during the pre-Late Eocene post-rift phase took place in relatively shallow marine conditions. Eocene compression caused a strong deformation of the sedimentary cover, partial and complete inversion of rift faults and the formation of three largely separate sea basins, between which a large landmass arose. The primary area of deposition of sedimentary sequences was significantly reduced due to strong deformations caused by compressional phases in the Late Miocene. That which is now the deep Black Sea was a relatively shallow basin until the beginning or even the end of the Pleistocene. Only thereafter did the water depth increase rapidly to more than 2 km. Research results indicate that modern tectonic reconstructions of the Western Black Sea and Eastern Black Sea basins, which are based on assumptions about the formation of the (sub)oceanic crust in these basins and/or different times of their formation, look unreliable. It also follows that any view of back-arc basins as small oceanic basins is not universally applicable.
{"title":"History of the geological development of the Ukrainian sector of the Black Sea from the middle Early Cretaceous to the beginning of the Late Miocene","authors":"S. Stovba, R. Stephenson, A. Tyshchenko, P. Fenota, D. Vengrovych, S. Mazur","doi":"10.24028/gj.v45i3.282411","DOIUrl":"https://doi.org/10.24028/gj.v45i3.282411","url":null,"abstract":"Regional seismic investigations have made it possible to obtain new knowledge on the geological history of the Ukrainian sector of the Black Sea during rifting from Albian to Cenomanian, post-rift subsidence (Turonian¾Maastrichtian and Paleocene¾Middle Eocene), tectonic compression at the end of the middle Eocene and post-rift subsidence interrupted by a series of short-lived, compressional events (late Eocene ¾ the beginning of the Early Miocene). Rifting occurred simultaneously in the entire area of study and formed three long rift basins, each of which consisted of a system of (half)grabens, separated from each other and their margins by faults with amplitudes of up to3 km. The intensity of Cretaceous rifting was significantly less than would be required to produce continental lithosphere break-up and oceanic crust formation, or through-going «oceanisation» of continental lithosphere. Sedimentation during the pre-Late Eocene post-rift phase took place in relatively shallow marine conditions. Eocene compression caused a strong deformation of the sedimentary cover, partial and complete inversion of rift faults and the formation of three largely separate sea basins, between which a large landmass arose. The primary area of deposition of sedimentary sequences was significantly reduced due to strong deformations caused by compressional phases in the Late Miocene. That which is now the deep Black Sea was a relatively shallow basin until the beginning or even the end of the Pleistocene. Only thereafter did the water depth increase rapidly to more than 2 km. Research results indicate that modern tectonic reconstructions of the Western Black Sea and Eastern Black Sea basins, which are based on assumptions about the formation of the (sub)oceanic crust in these basins and/or different times of their formation, look unreliable. It also follows that any view of back-arc basins as small oceanic basins is not universally applicable.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42365334","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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