Pub Date : 2023-05-14DOI: 10.24028/gj.v45i2.278339
R. Belevich, O. Andrianova, O. Batyrev, M. Skipa
The comparison of modern hydrophysical conditions in the Black Sea with the previously analyzed period of 1903—1982 was carried out based on the materials of the recently created (1991—2020) climate array of average monthly thermohaline characteristics of waters. The dynamic of processes in the upper 150-meter layer (halocline) of the Black Sea was evaluated based on the analysis of climatic materials on the vertical distribution of the depth of the maximum water salinity gradient, which is interpreted as the upper boundary of the hydrogen sulfide layer in the Black Sea. The comparison of state and seasonal fluctuations of this characteristic during the analysis of average monthly maps was carried out by their averaging. According to modern data(1991—2020), in the open part of the sea, a more intense intrusion of these waters up to a horizon of 40 m was found, as well as single cases of natural release of hydrogen sulfide from the depth to the surface. There is a clearly pronounced semi-annual cyclicity in temporal variability; however, in the modern period, the shift was for the whole season: in 1903—1982, the convection (the downwelling of these waters) occurred during autumn-winter, and intrusion (upwelling) — during spring-summer; in 1991—2020 according to the same climatic data, convection occurs during winter-spring, and intrusion occurs during summer-autumn, with the maximum depth of occurrence during the period of winter-spring convection and the minimum during the period of summer-autumn water intrusion. The axes of the northern and southern convergence zones laying near the corresponding coasts of the sea, and the axis of the zone of central divergence is close to open areas in its middle part. By these axes, the differences in the depth of occurrence between the period of convection and intrusion in the northern and southern convergence zones were 21.5 and 17.5 m, respectively; for the central divergence zone, it was 7.5 m.
{"title":"Features of the processes of convection and water intrusion at the boundary of the hydrogen sulfide contamination layer in the Black Sea in the climatic period 1991—2020","authors":"R. Belevich, O. Andrianova, O. Batyrev, M. Skipa","doi":"10.24028/gj.v45i2.278339","DOIUrl":"https://doi.org/10.24028/gj.v45i2.278339","url":null,"abstract":"The comparison of modern hydrophysical conditions in the Black Sea with the previously analyzed period of 1903—1982 was carried out based on the materials of the recently created (1991—2020) climate array of average monthly thermohaline characteristics of waters. The dynamic of processes in the upper 150-meter layer (halocline) of the Black Sea was evaluated based on the analysis of climatic materials on the vertical distribution of the depth of the maximum water salinity gradient, which is interpreted as the upper boundary of the hydrogen sulfide layer in the Black Sea. The comparison of state and seasonal fluctuations of this characteristic during the analysis of average monthly maps was carried out by their averaging. According to modern data(1991—2020), in the open part of the sea, a more intense intrusion of these waters up to a horizon of 40 m was found, as well as single cases of natural release of hydrogen sulfide from the depth to the surface. There is a clearly pronounced semi-annual cyclicity in temporal variability; however, in the modern period, the shift was for the whole season: in 1903—1982, the convection (the downwelling of these waters) occurred during autumn-winter, and intrusion (upwelling) — during spring-summer; in 1991—2020 according to the same climatic data, convection occurs during winter-spring, and intrusion occurs during summer-autumn, with the maximum depth of occurrence during the period of winter-spring convection and the minimum during the period of summer-autumn water intrusion. The axes of the northern and southern convergence zones laying near the corresponding coasts of the sea, and the axis of the zone of central divergence is close to open areas in its middle part. By these axes, the differences in the depth of occurrence between the period of convection and intrusion in the northern and southern convergence zones were 21.5 and 17.5 m, respectively; for the central divergence zone, it was 7.5 m.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48702599","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 : 2023-05-14DOI: 10.24028/gj.v45i2.278306
I. Logvinov, I. Gordienko, V. Tarasov, A. M. Logvinova
A network of long-period magnetotelluric and magnetovariational data (124 sites) in the period range of 9—16 to 2500—6400 s made it possible to explore the geoelectric structure of the Erth’s crust and upper mantle of most of the Dniester-Bug and adjacent megablocks of the Ukrainian shield. Based on the resistivity cross-sections along the profiles (with 2D inversion), a three-dimensional matrix was created for the territory limited by coordinates 27.7—30.4° E and 47.7—49.4° N, which included the spatial coordinates of each grid node on each profile, the power of the model cells, and the resistance value in the cell. As a result, geoelectrical anomalous structures were identified at different depths from 3 to 100 km. The entire block of rocks 200×200 km down to a depth of 100 km is characterized by high resistivity, against which objects of reduced resistivity (LRO) are identified. The resulting distribution of high-resistivity rocks over the entire depth of the model is in good agreement with the laboratory dependencies obtained both for the rocks of the Ukrainian Shield and other data. Model data show a significant difference in resistivities in the upper 14—16 km (above 105 ohm), lower crust (about 104 ohm), and upper mantle (103 ohm). Against a general decrease in resistance with depth in the Earth’s crust, three regions were identified in which anomalously high (for a given depth) resistances extend to the entire thickness of the crust. These high-resistivity objects are consistent with positive Bouguer anomalies. Against the background of high-resistivity rocks, LROs stand out, the resistance of which does not exceed 120 ohm·m. The spatial dimensions of the LRO zones indicate their locality and do not form a continuous layer. An analysis of the distribution of LROs in space and depth suggests a genetic relationship between mantle LROs and crustal LROs. Comparison of mantle LROs with the Beltska zone of modern activation on the territory of Ukraine shows their good agreement both vertically and horizontally. To explain the lower LRO resistivity in the upper mantle, overheating of the rocks to solidus and 2—3 % melting and/or the presence of fluids is necessary [Gordienko, 2017]. In recent studies discussing the influence of thermobaric conditions and the fluid content necessary to explain the presence of increased conductivity in the upper mantle, the authors of [Blatter et al., 2022] concluded that an anomalously large amount of volatiles is needed with small amounts of melt. The assumption that mantle LROs are related to crustal LROs has been tested by comparing LROs with fault zones. The presence of LROs in the mantle, their vertical extent, and their connection with rejuvenated fault systems can serve as a basis for the deep migration of fluids enriched in volatiles.
{"title":"Geoelectric model of the Earth’s crust and upper mantle of the Dniester-Bug megablock of the Ukrainian Shield","authors":"I. Logvinov, I. Gordienko, V. Tarasov, A. M. Logvinova","doi":"10.24028/gj.v45i2.278306","DOIUrl":"https://doi.org/10.24028/gj.v45i2.278306","url":null,"abstract":"A network of long-period magnetotelluric and magnetovariational data (124 sites) in the period range of 9—16 to 2500—6400 s made it possible to explore the geoelectric structure of the Erth’s crust and upper mantle of most of the Dniester-Bug and adjacent megablocks of the Ukrainian shield. Based on the resistivity cross-sections along the profiles (with 2D inversion), a three-dimensional matrix was created for the territory limited by coordinates 27.7—30.4° E and 47.7—49.4° N, which included the spatial coordinates of each grid node on each profile, the power of the model cells, and the resistance value in the cell. As a result, geoelectrical anomalous structures were identified at different depths from 3 to 100 km. \u0000The entire block of rocks 200×200 km down to a depth of 100 km is characterized by high resistivity, against which objects of reduced resistivity (LRO) are identified. \u0000The resulting distribution of high-resistivity rocks over the entire depth of the model is in good agreement with the laboratory dependencies obtained both for the rocks of the Ukrainian Shield and other data. Model data show a significant difference in resistivities in the upper 14—16 km (above 105 ohm), lower crust (about 104 ohm), and upper mantle (103 ohm). Against a general decrease in resistance with depth in the Earth’s crust, three regions were identified in which anomalously high (for a given depth) resistances extend to the entire thickness of the crust. These high-resistivity objects are consistent with positive Bouguer anomalies. \u0000Against the background of high-resistivity rocks, LROs stand out, the resistance of which does not exceed 120 ohm·m. The spatial dimensions of the LRO zones indicate their locality and do not form a continuous layer. An analysis of the distribution of LROs in space and depth suggests a genetic relationship between mantle LROs and crustal LROs. Comparison of mantle LROs with the Beltska zone of modern activation on the territory of Ukraine shows their good agreement both vertically and horizontally. To explain the lower LRO resistivity in the upper mantle, overheating of the rocks to solidus and 2—3 % melting and/or the presence of fluids is necessary [Gordienko, 2017]. In recent studies discussing the influence of thermobaric conditions and the fluid content necessary to explain the presence of increased conductivity in the upper mantle, the authors of [Blatter et al., 2022] concluded that an anomalously large amount of volatiles is needed with small amounts of melt. The assumption that mantle LROs are related to crustal LROs has been tested by comparing LROs with fault zones. \u0000The presence of LROs in the mantle, their vertical extent, and their connection with rejuvenated fault systems can serve as a basis for the deep migration of fluids enriched in volatiles.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42561440","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 : 2023-05-14DOI: 10.24028/gj.v45i2.278310
A. Murovskay, O. Verpakhovska, O. Hnylko, O. Chorna, T. Yegorova
Transcarpathian depression (TD) is located in the junction zone of the eastern margin of ALCAPA terrain and the northern part of Tisza-Dacia one, buried under thick Neogene molasses. The Earth’s crust structure of the TD is not clearly understood. The purpose of this work is to refine the TD crust structure and identify low-velocity zones by interpreting wave images obtained from WARR PANCAKE profile data using the finite-difference reflection/refraction migration method. The crustal domain beneath the TD is interpreted to be limited from southwest by a fault gently southwest dipping, traced from Pieniny Klippen Belt on the surface. Within domain two suture zones being the Alpine Tethys ocean remnants and cemented the European plate and ALCAPA microplate, were distinguished: Piemont-Liguria and PKB ones, as well as a rootless fragment of ALCAPA terrain. The Outer Carpathians thrust belt of 13 km depth borders the TD by subvertical Transcarpathian fault. The crust structure of the Pannonian segment is interpreted to be a pile of thick- and thin-skinned basement nappes of the Tisza terrain and cover nappes with superimposed younger extensional structures. High-reflectivity and low-velocity zone at depths of 10—20 km is identified. The zone follows the pattern of isotherms in the temperature range of 300—500°. On the deep seismic sounding (DSS) Chop—Velykiy Bychkiv profile, running along TD and crossing the PANCAKE line, two low-velocity zones were also distinguished. Published data on numerical and physical modeling, the deep well cores, as well as fault zones in natural outcrops suggest that the low-velocity zones have increased porosity, fracturing, and fluid saturation. Our results suggest a high hydrocarbon potential of the TD, associated with the low-velocity zones.
{"title":"Transcarpathian Depression: Study of Low-Velocity Zones in the Earth’s Crust Based on the Seismic Regional Profiles Data","authors":"A. Murovskay, O. Verpakhovska, O. Hnylko, O. Chorna, T. Yegorova","doi":"10.24028/gj.v45i2.278310","DOIUrl":"https://doi.org/10.24028/gj.v45i2.278310","url":null,"abstract":"Transcarpathian depression (TD) is located in the junction zone of the eastern margin of ALCAPA terrain and the northern part of Tisza-Dacia one, buried under thick Neogene molasses. The Earth’s crust structure of the TD is not clearly understood. \u0000The purpose of this work is to refine the TD crust structure and identify low-velocity zones by interpreting wave images obtained from WARR PANCAKE profile data using the finite-difference reflection/refraction migration method. \u0000The crustal domain beneath the TD is interpreted to be limited from southwest by a fault gently southwest dipping, traced from Pieniny Klippen Belt on the surface. Within domain two suture zones being the Alpine Tethys ocean remnants and cemented the European plate and ALCAPA microplate, were distinguished: Piemont-Liguria and PKB ones, as well as a rootless fragment of ALCAPA terrain. The Outer Carpathians thrust belt of 13 km depth borders the TD by subvertical Transcarpathian fault. The crust structure of the Pannonian segment is interpreted to be a pile of thick- and thin-skinned basement nappes of the Tisza terrain and cover nappes with superimposed younger extensional structures. \u0000High-reflectivity and low-velocity zone at depths of 10—20 km is identified. The zone follows the pattern of isotherms in the temperature range of 300—500°. On the deep seismic sounding (DSS) Chop—Velykiy Bychkiv profile, running along TD and crossing the PANCAKE line, two low-velocity zones were also distinguished. Published data on numerical and physical modeling, the deep well cores, as well as fault zones in natural outcrops suggest that the low-velocity zones have increased porosity, fracturing, and fluid saturation. Our results suggest a high hydrocarbon potential of the TD, associated with the low-velocity zones.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48287319","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 : 2023-05-14DOI: 10.24028/gj.v45i2.278322
V. A. Yentin, O. Gintov, M. Orlyuk, A. Marchenko
A special class of local small sizes of subisometric magnetic field anomalies (AMF) of the Ukrainian Shield (USh) is considered here. Such AMF are united by the volcanogenic-intrusive-tubular origin of the sources associated with the assumed source-channel manifestations of pulsed plutonic-degassing processes of the Earth. The geological study of such anomalies indicates the enrichment of their sources with mineralization of dark, noble, non-ferrous and rare metals. Some of these AMF (Zhdanivska group, Rivnenska) in general contours coincide with local gravitational minima due to decompaction and grinding of the rocks that cause them, despite the basic-ultrabasic composition. Other anomalies, on the contrary, fully correspond to the maxima of gravity due to the enrichment of rocks with magnetite (Pischansk AMF) or ilmenite (Stremigorodsk AMF) on an industrial scale. In the section, all the studied sources of anomalies have a funnel-shaped (sometimes fungal-shaped) or stock-like shape, which indicates the focal-channel type of their genesis. A characteristic feature of some of the studied AMF are peculiarities of the magnetization vector of their sources, which has variable directions in the section and is often subhorizontal (Kalyniv group of anomalies, Rivne and Stremigorod AMF), which is unusual for the USh latitudes. This indicates a multiphase and separation in time formation of the sources of these anomalies from the Archean-Proterozoic time of formation of the surrounding USh rocks. This time may be either Proterozoic (Stremigorod AMF), or Phanerozoic (Rivnenska AMP — early Paleozoic). A number of similar in size and concentrically-zonal shape of Cenozoic AMF has been established, for example, within the TransCarpathian fault zone. The obtained results show that within the Ukrshield there is a certain number of small-sized structures associated with different-age focal-channel manifestations of pulsed intrusive and plutonic-degassing processes of the Earth, which are much more widespread than it has been supposed. This does not only extend the prospecting possibilities for new types of minerals associated with the processes of magmatism and degassing of the Earth, but also contains a new additional information in the context of the universal history of the Ukrshield formation and its ore potential
{"title":"Local magnetic anomalies of the Ukrainian Shield as indicators of the manifestation of different-age stages of focal-channel magmatism","authors":"V. A. Yentin, O. Gintov, M. Orlyuk, A. Marchenko","doi":"10.24028/gj.v45i2.278322","DOIUrl":"https://doi.org/10.24028/gj.v45i2.278322","url":null,"abstract":"A special class of local small sizes of subisometric magnetic field anomalies (AMF) of the Ukrainian Shield (USh) is considered here. Such AMF are united by the volcanogenic-intrusive-tubular origin of the sources associated with the assumed source-channel manifestations of pulsed plutonic-degassing processes of the Earth. The geological study of such anomalies indicates the enrichment of their sources with mineralization of dark, noble, non-ferrous and rare metals. Some of these AMF (Zhdanivska group, Rivnenska) in general contours coincide with local gravitational minima due to decompaction and grinding of the rocks that cause them, despite the basic-ultrabasic composition. Other anomalies, on the contrary, fully correspond to the maxima of gravity due to the enrichment of rocks with magnetite (Pischansk AMF) or ilmenite (Stremigorodsk AMF) on an industrial scale. In the section, all the studied sources of anomalies have a funnel-shaped (sometimes fungal-shaped) or stock-like shape, which indicates the focal-channel type of their genesis. \u0000A characteristic feature of some of the studied AMF are peculiarities of the magnetization vector of their sources, which has variable directions in the section and is often subhorizontal (Kalyniv group of anomalies, Rivne and Stremigorod AMF), which is unusual for the USh latitudes. This indicates a multiphase and separation in time formation of the sources of these anomalies from the Archean-Proterozoic time of formation of the surrounding USh rocks. This time may be either Proterozoic (Stremigorod AMF), or Phanerozoic (Rivnenska AMP — early Paleozoic). A number of similar in size and concentrically-zonal shape of Cenozoic AMF has been established, for example, within the TransCarpathian fault zone. \u0000The obtained results show that within the Ukrshield there is a certain number of small-sized structures associated with different-age focal-channel manifestations of pulsed intrusive and plutonic-degassing processes of the Earth, which are much more widespread than it has been supposed. This does not only extend the prospecting possibilities for new types of minerals associated with the processes of magmatism and degassing of the Earth, but also contains a new additional information in the context of the universal history of the Ukrshield formation and its ore potential","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47082697","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 : 2023-03-22DOI: 10.24028/gj.v45i1.275608
V. Starostenko
On January 1, 2023, Stella Borysivna Shekha Nova turned 60 years old! This is a respectable, but pleasant age for a person in general,including a woman, and especially for the most respected director of the Institute of Geological Sciences of the National Academy of Sciences of Ukraine, who is most respected in terms of age and with an unusually high scientific authority!
{"title":"Congratulations to Stella Borysivna Shehunova, the youngest academician of the Department of Earth Sciences of the National Academy of Sciences of Ukraine, on the occasion of her 60th anniversary","authors":"V. Starostenko","doi":"10.24028/gj.v45i1.275608","DOIUrl":"https://doi.org/10.24028/gj.v45i1.275608","url":null,"abstract":"On January 1, 2023, Stella Borysivna Shekha Nova turned 60 years old! This is a respectable, but pleasant age for a person in general,including a woman, and especially for the most respected director of the Institute of Geological Sciences of the National Academy of Sciences of Ukraine, who is most respected in terms of age and with an unusually high scientific authority!","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49156749","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 : 2023-03-22DOI: 10.24028/gj.v45i1.275183
P. Zhyrnov, I. Solomakha
The scheme of engineering-construction assessment, which is created based on engineering geological zoning of the city’s territory is desirable among additional graphic materials in the design of master plans projects as determined by state building norms [State…, 2012]. Engineering geological zoning provides for different ranks’ selection of taxonomic engineering-geological (EG) units, which have a particular range of common engineering geological conditions that ultimately determine the construction sites’ affiliation to a specific suitability category. Geological-lithological structure and hydrogeological conditions of the Irpin city, Kyiv region are investigated, and the types and degrees ofgroundwater aggressiveness, chemical composition, and mineralization of groundwater, the depths of the first aquifers from the day surface are highlighted in this article. A variant of the creation of large-scale maps of groundwater depth and chemistry based on a hydrogeological survey conducting is presented. The analysis of hydrogeological circumstances of the city’s territory lays the foundations for the selection of engineering-geological sites based on the comparison of this information with geomorphological, engineering-geological and geodynamic data. Complexity assessment of hydrogeological conditions and accounting of hydrogeological factors for the construction assessment scheme and selection of corresponding measures of engineering training and protection of the problem construction sites has become an ultimate result.
{"title":"Hydrogeological conditions of Irpin and their influence on the city’s engineering protection and construction assessment","authors":"P. Zhyrnov, I. Solomakha","doi":"10.24028/gj.v45i1.275183","DOIUrl":"https://doi.org/10.24028/gj.v45i1.275183","url":null,"abstract":"The scheme of engineering-construction assessment, which is created based on engineering geological zoning of the city’s territory is desirable among additional graphic materials in the design of master plans projects as determined by state building norms [State…, 2012]. Engineering geological zoning provides for different ranks’ selection of taxonomic engineering-geological (EG) units, which have a particular range of common engineering geological conditions that ultimately determine the construction sites’ affiliation to a specific suitability category. Geological-lithological structure and hydrogeological conditions of the Irpin city, Kyiv region are investigated, and the types and degrees ofgroundwater aggressiveness, chemical composition, and mineralization of groundwater, the depths of the first aquifers from the day surface are highlighted in this article. A variant of the creation of large-scale maps of groundwater depth and chemistry based on a hydrogeological survey conducting is presented. The analysis of hydrogeological circumstances of the city’s territory lays the foundations for the selection of engineering-geological sites based on the comparison of this information with geomorphological, engineering-geological and geodynamic data. Complexity assessment of hydrogeological conditions and accounting of hydrogeological factors for the construction assessment scheme and selection of corresponding measures of engineering training and protection of the problem construction sites has become an ultimate result.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48461911","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 : 2023-03-22DOI: 10.24028/gj.v45i1.275179
M. Bondarenko, Z. Yevstakhevych, V. Kulyk, S. I. Diachenko, O. Dmytrenko, O. V. Kamilova
At the Institute of Geophysics of the National Academy of Sciences of Ukraine a modern technology for ground investigation has been created for solution of the engineering geological problems, including seismic microzonation. Technology is based on the methods and apparatus of radioactive logging (RL), which involves neutron-neutron logging (NNL), gamma-gamma density logging (DL) and gamma-ray logging (GR). The paper presents the results of the development of radioactive logging apparatus as an integral part of the new technology. Set of prototype dual-channel tools, namely 2NNL (dual-spacing NNL) and DL+GR, prototype three-component tool 2NNL+DL+GR, surface control and registration console were developed and produced on the basis of the modern elemental base. The 2NNL tool makes it possible to determine neutron porosity in two ways: single-sonde method and compensation method. Compensation neutron logging, in particular, aims to determine the porosity in the presence of anomalous neutron absorbers in the rock, and also, in combination with the single-sonde method, to estimate the content of anomalous absorbers. GR-channel of the DL+GR tool was equipped the same gamma-ray detector as the DL-channel. Here, the GR-detector performs a dual function: 1) integral registration of natural gamma-ray of ground, 2) account of natural background in the total readings of the DL-detector. The three-component radioactive logging tool combines three RL-methods and includes all the advantages of dual-channel tools. The obtaining a results in one trip by this tool is particularly important for relatively deep boreholes. According to the experimental results, the optimal intervals between sources and detectors of radiation in the created combined RL tools were established. The importance of adjustment and controlling the signals of sensors of the RL tools is shown; the new console allows to perform these procedures operational. The created apparatus increases the productivity and efficiency of logging operations by reducing the number of trips, digital recording, storage and transmission of information, and by using of a computer programs for processing and interpreting the results of borehole measurements. The effectiveness of the developed apparatus, together with the appropriate metrological and interpretation-methodical support, has been demonstrated on specific examples of borehole investigations and confirmed by independent laboratory data. The technology allows to determine the following engineering geophysical parameters: total density, dry ground density, content of shale, porosity, volume moisture, water saturation factor, groundwater level, etc.
{"title":"Geophysical technology for determining the ground parameters (methods and apparatus)","authors":"M. Bondarenko, Z. Yevstakhevych, V. Kulyk, S. I. Diachenko, O. Dmytrenko, O. V. Kamilova","doi":"10.24028/gj.v45i1.275179","DOIUrl":"https://doi.org/10.24028/gj.v45i1.275179","url":null,"abstract":"At the Institute of Geophysics of the National Academy of Sciences of Ukraine a modern technology for ground investigation has been created for solution of the engineering geological problems, including seismic microzonation. Technology is based on the methods and apparatus of radioactive logging (RL), which involves neutron-neutron logging (NNL), gamma-gamma density logging (DL) and gamma-ray logging (GR). \u0000The paper presents the results of the development of radioactive logging apparatus as an integral part of the new technology. Set of prototype dual-channel tools, namely 2NNL (dual-spacing NNL) and DL+GR, prototype three-component tool 2NNL+DL+GR, surface control and registration console were developed and produced on the basis of the modern elemental base. \u0000The 2NNL tool makes it possible to determine neutron porosity in two ways: single-sonde method and compensation method. Compensation neutron logging, in particular, aims to determine the porosity in the presence of anomalous neutron absorbers in the rock, and also, in combination with the single-sonde method, to estimate the content of anomalous absorbers. \u0000GR-channel of the DL+GR tool was equipped the same gamma-ray detector as the DL-channel. Here, the GR-detector performs a dual function: 1) integral registration of natural gamma-ray of ground, 2) account of natural background in the total readings of the DL-detector. \u0000The three-component radioactive logging tool combines three RL-methods and includes all the advantages of dual-channel tools. The obtaining a results in one trip by this tool is particularly important for relatively deep boreholes. \u0000According to the experimental results, the optimal intervals between sources and detectors of radiation in the created combined RL tools were established. The importance of adjustment and controlling the signals of sensors of the RL tools is shown; the new console allows to perform these procedures operational. \u0000The created apparatus increases the productivity and efficiency of logging operations by reducing the number of trips, digital recording, storage and transmission of information, and by using of a computer programs for processing and interpreting the results of borehole measurements. The effectiveness of the developed apparatus, together with the appropriate metrological and interpretation-methodical support, has been demonstrated on specific examples of borehole investigations and confirmed by independent laboratory data. \u0000The technology allows to determine the following engineering geophysical parameters: total density, dry ground density, content of shale, porosity, volume moisture, water saturation factor, groundwater level, etc.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42461314","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 : 2023-03-22DOI: 10.24028/gj.v45i1.275178
O. Rusakov, V. Starostenko, I. Pashkevich, R. Kutas
We present an integrated analysis of the geophysical parameters of the lithosphere of Black Sea basin obtained as a result of the interpretation of magnetic, gravity, thermal, deep seismic sounding and seismic-tomographic data. It first demonstrates inherent significant differences in geophysical parameters of lithosphere in the Western and Eastern Black Sea subbasins existing from the prerift stage. The set of reviewed parameters responsible for formation of the present-day lithosphere includes types of crust, depths to acoustic basement, configuration of subbasins, depths to Moho, heat flow and relief of the thermal-asthenosphere boundary (LAB), trends of main deep faults of the crystalline crust, their kinematic types, occurring linear magnetic anomalies, velocity pattern of subcrustal mantle. The above-mentioned parameters of the lithosphere are indicators of the age, geodynamics and driving mechanisms for opening of a subbasins. Oblique trends of the subbasins and the topography of Moho discontinuity in the west and east domains, oblique striking of pre-rifting Istanbul zone and the Shatsky Ridge and different trends of deep faults in the crystalline crust suggest distinct lithospheric structure existing from pre-opening of the Black Sea subbasins and different geodynamical conditions of its formation. The Odesa-Sinop-Ordu deep fault zone as a direct continuation of the Golovanivskaya suture zone of the Ukrainian shield and its slope, probably is of the Precambrian age. So it could be the tectonic boundary between two segments of pre-rift continental crust and between future subbasins. The examples illustrate how indicated parameters of the lithosphere can geophysically confirm the basic ideas of available models for geodynamics of the Black Sea.
我们对通过磁、重力、热、深地震测深和地震层析成像数据的解释获得的黑海盆地岩石圈的地球物理参数进行了综合分析。它首先证明了从预抬升阶段开始存在的黑海西部和东部次盆地岩石圈地球物理参数的内在显著差异。负责现今岩石圈形成的一组已审查的参数包括地壳类型、声学基底深度、次盆地构造、莫霍面深度、热软流圈边界（LAB）的热流和起伏、结晶地壳主要深部断层的趋势、它们的运动学类型、发生的线性磁异常，地壳下地幔的速度模式。岩石圈的上述参数是时代、地球动力学和次盆地打开驱动机制的指标。西域和东域的次盆地的倾斜趋势和莫霍不连续地形、裂谷前伊斯坦布尔带和沙茨基山脊的倾斜走向以及结晶地壳中深层断层的不同趋势表明，黑海次盆地开放前存在着不同的岩石圈结构，其形成的地球动力学条件也不同。Odesa Sinop Ordu深层断裂带是乌克兰地盾及其斜坡的Golovanivskaya缝合带的直接延续，可能属于前寒武纪。因此，它可能是裂谷前大陆地壳两段之间以及未来次盆地之间的构造边界。这些例子说明了岩石圈的指示参数如何在地球物理上证实黑海地球动力学可用模型的基本思想。
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Pub Date : 2023-03-22DOI: 10.24028/gj.v45i1.275176
V. Gordienko
Some problems of the formation and development of oceanic regions with various variants of endogenic regimes (with the exception of island arcs, which, in the author’s opinion, belong to late Alpine geosynclines) are considered. Calculated geological events and anomalies of physical fields within them are determined by heat-mass-transfer schemes in the tectonosphere. The reliability and accuracy of the latter is related to the quantity and quality of information about the content of the regimes. In the oceans, such data is scarce. The article attempts to attract additional information about the formation of the Earth’s crust of a typical oceanic basin. It was presented in the form of oceanization (destruction and basification) of the continental crust with a slightly increased basicity. The process included the uplift and denudation of the upper block up to 10 km thick, the intrusion of mafic and ultrabasic rocks from the mantle in a concentration increasing with depth into the lower approximately 20—30 km of the crust. Seismic wave velocity and density in the crustal basement were almost equal to the properties of the warmed mantle rocks. The final stage of magmatism was presented in a large part of the region during the period of recent activation by the removal of partially molten matter from the shallow asthenosphere up to the surface. Similar models have also been constructed for other endogenous regimes. In all cases, significant scatter in the ages of the process stages and the order of formation of asthenolite sources rising from different depths of the upper mantle were unavoidable. The resulting thermal models were averaged effects for the considered variants of heat and mass transfer. The control of the reality of these constructions was carried out according to the correspondence of known events of geological history, allowing a quantitative description, and anomalies of physical fields. In this work, the second part is considered. The calculated velocity sections of the upper mantle regions, the heat flow distribution, and the values of mantle gravity anomalies were compared with the experimental data. In all cases, the agreement reached is satisfactory. The discrepancies can be explained by errors in observations and calculations
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Pub Date : 2023-03-22DOI: 10.24028/gj.v45i1.275181
Yu.O. Fomin, Y. Demikhov, V. Verkhovtsev, V. Pokalyuk, O. Buglak, N. Borisova
The aim of the study, the results of which are presented in this article, is to study changes in the composition of hydrothermal fluid ore systems of the early Precambrian on the example of gold and uranium ore deposits of the Ukrainian shield in connection with the evolution of exo- and endogenous processes in the outer shells of the Earth. The method used is a complex isotope-geochemical study of the composition of gas-liquid inclusions of hydrothermal fluid of ore systems. Based on experimental isotope-geochemical studies of the fluid of gas-liquid inclusions in the minerals of Precambrian deposits of uranium and gold of the Serednoprydniprovsky and Ingul megablocks of the Ukrainian Shield, a consistent change in the quantitative and isotopic composition of hydrothermal fluids of mineral formation from Mesoarchean to Paleoproterozoic was established. The content of H2O and CO2 was investigated and the isotopic composition of carbon CO2 fluids in quartz, pyrite, and feldspar were studied. The age range of the studied deposits is 3200—1750 million years. A decrease in the carbon dioxide content in the hydrothermal mineral-forming fluid of the Precambrian occurred in the Neoarchean, that is, before the Great Oxygen Event (Great Oxidation Event) — an increase in the oxygen content in the atmosphere in the Paleoproterozoic and is probably associated with the processes of exogenous and endogenous hydration of ultramafic rocks during the formation of the protocontinental crust. Molar fraction of CO2 in the mineral-forming fluid, in the Precambrian correlates to some extent with atmospheric pressure. The increase in the content of the carbon-12 isotope in the Paleoproterozoic in the mineral-forming fluid occurred due to the oxidation of organic matter with an increase in the oxygen content in the atmosphere.
{"title":"Evolution of the composition of hydrothermal mineral-forming fluid of ore deposits in early Precambrian of the Ukrainian Shield","authors":"Yu.O. Fomin, Y. Demikhov, V. Verkhovtsev, V. Pokalyuk, O. Buglak, N. Borisova","doi":"10.24028/gj.v45i1.275181","DOIUrl":"https://doi.org/10.24028/gj.v45i1.275181","url":null,"abstract":"The aim of the study, the results of which are presented in this article, is to study changes in the composition of hydrothermal fluid ore systems of the early Precambrian on the example of gold and uranium ore deposits of the Ukrainian shield in connection with the evolution of exo- and endogenous processes in the outer shells of the Earth. The method used is a complex isotope-geochemical study of the composition of gas-liquid inclusions of hydrothermal fluid of ore systems. Based on experimental isotope-geochemical studies of the fluid of gas-liquid inclusions in the minerals of Precambrian deposits of uranium and gold of the Serednoprydniprovsky and Ingul megablocks of the Ukrainian Shield, a consistent change in the quantitative and isotopic composition of hydrothermal fluids of mineral formation from Mesoarchean to Paleoproterozoic was established. The content of H2O and CO2 was investigated and the isotopic composition of carbon CO2 fluids in quartz, pyrite, and feldspar were studied. The age range of the studied deposits is 3200—1750 million years. A decrease in the carbon dioxide content in the hydrothermal mineral-forming fluid of the Precambrian occurred in the Neoarchean, that is, before the Great Oxygen Event (Great Oxidation Event) — an increase in the oxygen content in the atmosphere in the Paleoproterozoic and is probably associated with the processes of exogenous and endogenous hydration of ultramafic rocks during the formation of the protocontinental crust. Molar fraction of CO2 in the mineral-forming fluid, in the Precambrian correlates to some extent with atmospheric pressure. The increase in the content of the carbon-12 isotope in the Paleoproterozoic in the mineral-forming fluid occurred due to the oxidation of organic matter with an increase in the oxygen content in the atmosphere.","PeriodicalId":54141,"journal":{"name":"Geofizicheskiy Zhurnal-Geophysical Journal","volume":" ","pages":""},"PeriodicalIF":0.5,"publicationDate":"2023-03-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42190198","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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