D. A. Novikov, A. Pyryaev, V. P. Sukhorukov, A. A. Maksimova, A. Derkachev, A. F. Sukhorukova, F. Dultsev, A. Chernykh, A. A. Khvashchevskaya, N. A. Medeshova
––We present the first results of comprehensive isotope-geochemical studies of mineral radon waters of the Tulinskoe field (Novosibirsk), aimed at identifying their stages of interaction with the host rocks. By geochemical coefficients Ca/Na, Ca/Mg, Ca/Si, Mg/Si, Na/Si, Si/Na, rNa/rCl, and SO4/Cl, the studied waters are assigned to fracture–vein waters of granitoids. The indices of carbonate mineral saturation of the radon waters show their oversaturation with aragonite, calcite, and dolomite. The waters are also saturated with diaspore, ferrohydrite, gibbsite, and kaolinite, which leads to the deposition of these minerals as secondary phases. In the thermodynamic diagrams, the points of the activities of the radon water components are localized mainly in the stability fields of clay minerals (kaolinite and Na-, Ca-, and Mg-montmorillonites), layered silicates (talc), and zeolites (laumontite). A few points fall in the stability field of silicates (Mg-chlorite). The studied waters of the Tulinskoe field are neutral fresh, with Si = 6.41–9.02 mg/dm3. According to the results of thermodynamic calculations, the radon waters of the Tulinskoe field are in equilibrium with carbonate minerals and hydromicas. Following the classification by S.L. Shvartsev, they are assigned to the Si-Na geochemical type.
{"title":"Role of the Water–Rock System in the Formation of the Composition of Radon Water of the Tulinskoe Field (Novosibirsk)","authors":"D. A. Novikov, A. Pyryaev, V. P. Sukhorukov, A. A. Maksimova, A. Derkachev, A. F. Sukhorukova, F. Dultsev, A. Chernykh, A. A. Khvashchevskaya, N. A. Medeshova","doi":"10.2113/rgg20244716","DOIUrl":"https://doi.org/10.2113/rgg20244716","url":null,"abstract":"\u0000 ––We present the first results of comprehensive isotope-geochemical studies of mineral radon waters of the Tulinskoe field (Novosibirsk), aimed at identifying their stages of interaction with the host rocks. By geochemical coefficients Ca/Na, Ca/Mg, Ca/Si, Mg/Si, Na/Si, Si/Na, rNa/rCl, and SO4/Cl, the studied waters are assigned to fracture–vein waters of granitoids. The indices of carbonate mineral saturation of the radon waters show their oversaturation with aragonite, calcite, and dolomite. The waters are also saturated with diaspore, ferrohydrite, gibbsite, and kaolinite, which leads to the deposition of these minerals as secondary phases. In the thermodynamic diagrams, the points of the activities of the radon water components are localized mainly in the stability fields of clay minerals (kaolinite and Na-, Ca-, and Mg-montmorillonites), layered silicates (talc), and zeolites (laumontite). A few points fall in the stability field of silicates (Mg-chlorite). The studied waters of the Tulinskoe field are neutral fresh, with Si = 6.41–9.02 mg/dm3. According to the results of thermodynamic calculations, the radon waters of the Tulinskoe field are in equilibrium with carbonate minerals and hydromicas. Following the classification by S.L. Shvartsev, they are assigned to the Si-Na geochemical type.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":"4 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141380288","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}
S. Bortnikova, O. Gaskova, A. Tomilenko, A. Makas, E.A. Fursenko, N. Pal’chik, I. V. Danilenko, N.A. Abrosimova
––We present results of studies of inclusions in secondary sulfates (antlerite and a mixture of copiapite and coquimbite) and arsenates (erythrite and picropharmacolite) formed on the surface of technogenic bodies, such as stored waste from the enrichment of sulfide (Belovo and Ursk waste heaps) and arsenide (disposal maps of the Tuvakobalt plant) ores. A wide range of components were identified in the gas–liquid inclusions, the main ones being water and carbon dioxide. Hydrocarbons, oxygen-containing organic compounds, and nitrogen- and sulfur-containing gases were found in smaller but measurable amounts. Arsine H3As was also detected in inclusions in picropharmacolite (calcium and magnesium arsenate–arsenite). The gas–liquid inclusions in secondary minerals reflect the composition of the interporous space in the waste body, filled with particular atmospheric gases entering the body in free form and with seasonal precipitation. The combination of in situ generated and penetrating gases determines the diversity of inorganic and biotic interactions in technogenic bodies. The presence of hydrocarbons and oxygen-containing organic compounds is, most likely, associated with bacterial transformations of organic matter (residual vegetation, wood, microalgae, and fungi). At the same time, carbon disulfide and sulfur dioxide are indicators of active inorganic reactions of decomposition of the sulfide matrix.
{"title":"Composition of Gases in the Interporous Space of Technogenic Bodies","authors":"S. Bortnikova, O. Gaskova, A. Tomilenko, A. Makas, E.A. Fursenko, N. Pal’chik, I. V. Danilenko, N.A. Abrosimova","doi":"10.2113/rgg20244709","DOIUrl":"https://doi.org/10.2113/rgg20244709","url":null,"abstract":"\u0000 ––We present results of studies of inclusions in secondary sulfates (antlerite and a mixture of copiapite and coquimbite) and arsenates (erythrite and picropharmacolite) formed on the surface of technogenic bodies, such as stored waste from the enrichment of sulfide (Belovo and Ursk waste heaps) and arsenide (disposal maps of the Tuvakobalt plant) ores. A wide range of components were identified in the gas–liquid inclusions, the main ones being water and carbon dioxide. Hydrocarbons, oxygen-containing organic compounds, and nitrogen- and sulfur-containing gases were found in smaller but measurable amounts. Arsine H3As was also detected in inclusions in picropharmacolite (calcium and magnesium arsenate–arsenite). The gas–liquid inclusions in secondary minerals reflect the composition of the interporous space in the waste body, filled with particular atmospheric gases entering the body in free form and with seasonal precipitation. The combination of in situ generated and penetrating gases determines the diversity of inorganic and biotic interactions in technogenic bodies. The presence of hydrocarbons and oxygen-containing organic compounds is, most likely, associated with bacterial transformations of organic matter (residual vegetation, wood, microalgae, and fungi). At the same time, carbon disulfide and sulfur dioxide are indicators of active inorganic reactions of decomposition of the sulfide matrix.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":"61 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141388884","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}
V. V. Vrublevskii, A. V. Chugaev, P. Tishin, A.D. Kotel’nikov, A. E. Izokh, F. Kazenova, I.O. Kremer
––We have studied the isotopic composition of Nd, Sr, and Pb in Permo–Triassic subalkaline dolerites and Late Cretaceous basanites of the northern part of the Minusa depression. The wide variations in the primary isotope parameters of dolerites (ɛNd = 6.6–8.5, 87Sr/86Sr = 0.7031–0.7061, 206Pb/204Pb = 18.13–18.72, 207Pb/204Pb = 15.51–15.55, 208Pb/204Pb = 37.88–38.07) and basanites (εNd = 5.3–9, 87Sr/86Sr = 0.7026–0.7054, 206Pb/204Pb = 18.63–19.09, 207Pb/204Pb = 15.54–15.56, 208Pb/204Pb = 38.40–39.01) indicate both heterogeneity of mantle mafic melts and their partial crust contamination. Doleritic magma was presumably generated predominantly from a substance from a moderately depleted mantle source, which is similar in isotopic composition to the PREMA component of sublithospheric plumes. The basanitic magma might have formed through the melting of the material of the subcontinental lithospheric mantle modified as a result of plume activity in the Paleozoic–early Mesozoic. The similar isotopic compositions of Pb in basanites and the derivates of the enriched lithospheric mantle (EM 2 type) are due to the mixing of different substances of the SCLM substratum.
{"title":"Isotopic (Nd, Sr, Pb) Composition of the Permo–Triassic and Late Cretaceous Basaltoids in the Minusa Depression (Southern Siberia, Kop’evo Uplift): Heterogeneity of Mantle Sources of Mafic Magmas","authors":"V. V. Vrublevskii, A. V. Chugaev, P. Tishin, A.D. Kotel’nikov, A. E. Izokh, F. Kazenova, I.O. Kremer","doi":"10.2113/rgg20244708","DOIUrl":"https://doi.org/10.2113/rgg20244708","url":null,"abstract":"\u0000 ––We have studied the isotopic composition of Nd, Sr, and Pb in Permo–Triassic subalkaline dolerites and Late Cretaceous basanites of the northern part of the Minusa depression. The wide variations in the primary isotope parameters of dolerites (ɛNd = 6.6–8.5, 87Sr/86Sr = 0.7031–0.7061, 206Pb/204Pb = 18.13–18.72, 207Pb/204Pb = 15.51–15.55, 208Pb/204Pb = 37.88–38.07) and basanites (εNd = 5.3–9, 87Sr/86Sr = 0.7026–0.7054, 206Pb/204Pb = 18.63–19.09, 207Pb/204Pb = 15.54–15.56, 208Pb/204Pb = 38.40–39.01) indicate both heterogeneity of mantle mafic melts and their partial crust contamination. Doleritic magma was presumably generated predominantly from a substance from a moderately depleted mantle source, which is similar in isotopic composition to the PREMA component of sublithospheric plumes. The basanitic magma might have formed through the melting of the material of the subcontinental lithospheric mantle modified as a result of plume activity in the Paleozoic–early Mesozoic. The similar isotopic compositions of Pb in basanites and the derivates of the enriched lithospheric mantle (EM 2 type) are due to the mixing of different substances of the SCLM substratum.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":"97 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141388963","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 main types of reservoir rocks have been identified within the Bazhenov-Abalak complex. To assess the geological resources of hydrocarbons, it is proposed to formally divide the entire set of lithological rock types comprising the Bazhenov-Abalak complex into two main varieties: fluid seals and reservoirs. We argue that it is possibile to distinguish between potentially productive and productive rocks, represented by siliceous and carbonate varieties, according to logging data. A possible mechanism for the formation of reservoir rocks within the Bazhenov-Abalak complex as a result of the tectonic-hydrothermal impact on these deposits has been reconstructed. An original methodology for identifying perspective zones of various categories of hydrocarbon accumulation in the Bazhenov-Abalak complex through integrating seismic data and tectonophysical modeling carried out on their basis has been proposed. For example, an assessment of the predicted geological resources of hydrocarbons contained in the Bazhenov-Abalak complex within the limits of 3D seismic exploration of the Yem-Yegovskaya area has been carried out. The necessity of assessing the prospects for oil content and calculating the predicted geological resources of hydrocarbons in the whole Bazhenov-Abalak complex, and not only in the Bazhenov Formation, is substantiated, based on a single mechanism of formation of reservoir rocks of tectonic-hydrothermal origin in them.
{"title":"Tectonic–Hydrothermal Processes and their Relationship with the Petroleum Potential of the Bazhenov-Abalak Complex of Western Siberia","authors":"M. Yu. Zubkov","doi":"10.2113/rgg20244644","DOIUrl":"https://doi.org/10.2113/rgg20244644","url":null,"abstract":"\u0000 ––The main types of reservoir rocks have been identified within the Bazhenov-Abalak complex. To assess the geological resources of hydrocarbons, it is proposed to formally divide the entire set of lithological rock types comprising the Bazhenov-Abalak complex into two main varieties: fluid seals and reservoirs. We argue that it is possibile to distinguish between potentially productive and productive rocks, represented by siliceous and carbonate varieties, according to logging data. A possible mechanism for the formation of reservoir rocks within the Bazhenov-Abalak complex as a result of the tectonic-hydrothermal impact on these deposits has been reconstructed. An original methodology for identifying perspective zones of various categories of hydrocarbon accumulation in the Bazhenov-Abalak complex through integrating seismic data and tectonophysical modeling carried out on their basis has been proposed. For example, an assessment of the predicted geological resources of hydrocarbons contained in the Bazhenov-Abalak complex within the limits of 3D seismic exploration of the Yem-Yegovskaya area has been carried out. The necessity of assessing the prospects for oil content and calculating the predicted geological resources of hydrocarbons in the whole Bazhenov-Abalak complex, and not only in the Bazhenov Formation, is substantiated, based on a single mechanism of formation of reservoir rocks of tectonic-hydrothermal origin in them.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":"160 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141388706","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}
––We summarize the results of geological, geochronological and petrochemical studies of the intrusive complexes of West Sayan, and on their basis analyze the scales, formation sequence, petrochemical characteristics and geodynamic environments of the formation of granitoid and gabbroid complexes. Geochronological data indicate that the formation of intrusive complexes (granitoids and gabbroids) of West Sayan ranged within 580–370 Ma at several age levels and in various geodynamic environments: island-arc – 580–570, 550–520 Ma, accretion-collision – 505–450 Ma, transform-shear of continental margins – 440–430 Ma, and active continental margin – 425–370 Ma. According to petrochemical characteristics, we distinguish the rocks of tholeiitic, calc-alkali and subalkaline series among the studied granitoid complexes. The study of xenogenic zircons from granitoid and gabbroid complexes indicate the age range of 650–440 Ma. Several age clusters are distinguished (~ 645, ~ 570, 555–520, 505–475, 455–440 Ma); this indicates heterogeneous composition of the West Sayan crust and participation of the Late Riphean, Vendian – Early Cambrian and Ordovician crust sources in granite formation.
{"title":"Evolution of Intrusive Magmatism in West Sayan","authors":"S. Rudnev, G. A. Babin, D. Semenova, A. Travin","doi":"10.2113/rgg20244704","DOIUrl":"https://doi.org/10.2113/rgg20244704","url":null,"abstract":"\u0000 ––We summarize the results of geological, geochronological and petrochemical studies of the intrusive complexes of West Sayan, and on their basis analyze the scales, formation sequence, petrochemical characteristics and geodynamic environments of the formation of granitoid and gabbroid complexes. Geochronological data indicate that the formation of intrusive complexes (granitoids and gabbroids) of West Sayan ranged within 580–370 Ma at several age levels and in various geodynamic environments: island-arc – 580–570, 550–520 Ma, accretion-collision – 505–450 Ma, transform-shear of continental margins – 440–430 Ma, and active continental margin – 425–370 Ma. According to petrochemical characteristics, we distinguish the rocks of tholeiitic, calc-alkali and subalkaline series among the studied granitoid complexes. The study of xenogenic zircons from granitoid and gabbroid complexes indicate the age range of 650–440 Ma. Several age clusters are distinguished (~ 645, ~ 570, 555–520, 505–475, 455–440 Ma); this indicates heterogeneous composition of the West Sayan crust and participation of the Late Riphean, Vendian – Early Cambrian and Ordovician crust sources in granite formation.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":"162 6","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141388566","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}
––Earthquake focal mechanisms that are atypical for the South Baikal basin, which is under the extension of the Earth’s crust in the NW-SE direction, are analyzed. Atypical mechanisms are understood as focal solutions of strike-slip and reverse fault types, as well as solutions with normal fault movements along NW-trending planes transverse to the main structures of the basin. Whereas normal faults along NE-trending planes dominate, 29% of solutions from the sample of focal mechanisms are of non-normal fault type, of which 18% account for strike-slip faults and their combinations with other types of displacements (with a normal or reverse component) and reverse faults (with a strike-slip component) – 11%. Such displacements occur predominantly along NW-trending planes, as well as along submeridional and sublatitudinal ones, and strike-slip movements are characterized by right-lateral displacement along NW and submeridional planes, and, accordingly, left-lateral displacement along sublatitudinal and some NE planes. Earthquakes with atypical mechanisms are distributed almost throughout the entire basin, but it is necessary to note an increase in their number on its southwestern termination (the Kultuk segment) and on the eastern side of the Central Basin. In the current field of crustal extension, transverse shears play the role of transfer faults, accommodating differences in the rates and vectors of deformation of local blocks within the basin, and on a regional scale between neighboring rift basins.
--分析了地壳向西北-东南方向延伸的南贝加尔湖盆地的非典型地震焦点机制。非典型机制可理解为走向滑动和逆断层类型的焦点解决方案，以及沿横向于盆地主要结构的西北走向平面的正断层运动解决方案。虽然沿 NE 走向的正断层占主导地位，但焦点机制样本中 29% 的解理属于非正断层类型，其中 18% 属于走向滑动断层及其与其他类型位移（具有正向或逆向成分）的组合，11% 属于逆断层（具有走向滑动成分）。这种位移主要沿着西北走向的平面以及水下和次纵向平面发生，走向滑动运动的特点是沿着西北和水下平面发生右侧位移，相应地，沿着次纵向平面和一些东北平面发生左侧位移。非典型机制的地震几乎遍布整个盆地，但有必要指出的是，其西南端（库尔图克地段）和中央盆地东侧的地震数量有所增加。在目前的地壳延伸领域，横向剪切起着转换断层的作用，可适应盆地内局部地块以及相邻裂谷盆地之间区域范围内变形速度和矢量的差异。
{"title":"Earthquake Focal Mechanisms of Non-Normal Type in the South Baikal Basin","authors":"N. Radziminovich","doi":"10.2113/rgg20244725","DOIUrl":"https://doi.org/10.2113/rgg20244725","url":null,"abstract":"\u0000 ––Earthquake focal mechanisms that are atypical for the South Baikal basin, which is under the extension of the Earth’s crust in the NW-SE direction, are analyzed. Atypical mechanisms are understood as focal solutions of strike-slip and reverse fault types, as well as solutions with normal fault movements along NW-trending planes transverse to the main structures of the basin. Whereas normal faults along NE-trending planes dominate, 29% of solutions from the sample of focal mechanisms are of non-normal fault type, of which 18% account for strike-slip faults and their combinations with other types of displacements (with a normal or reverse component) and reverse faults (with a strike-slip component) – 11%. Such displacements occur predominantly along NW-trending planes, as well as along submeridional and sublatitudinal ones, and strike-slip movements are characterized by right-lateral displacement along NW and submeridional planes, and, accordingly, left-lateral displacement along sublatitudinal and some NE planes. Earthquakes with atypical mechanisms are distributed almost throughout the entire basin, but it is necessary to note an increase in their number on its southwestern termination (the Kultuk segment) and on the eastern side of the Central Basin. In the current field of crustal extension, transverse shears play the role of transfer faults, accommodating differences in the rates and vectors of deformation of local blocks within the basin, and on a regional scale between neighboring rift basins.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":"102 5","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-06-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141389131","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}
––Integrated seismic, drilling, and generalizing scientific research in the southeastern Anabar–Khatanga oil and gas region (OGR) since the early 1930s led to discoveries of small oil and gas occurrences and one large Central Olgino oil field. However, the petroleum potential of the northwestern part of the region remains poorly investigated and evaluated. To assess the prospects for the oil and gas potential of this territory, all seismic and geological and geochemical information was used, including four new wells drilled in the Sopochnoe uplift and the Zhuravliny swell. The scales of oil and gas formation, accumulation and destruction of hydrocarbon accumulations in the Permian deposits, which are the most promising in terms of the initial potential of the source rocks included in their composition, is given. The source rocks of the Upper Kozhevnikovo, Lower Kozhevnikovo, and Tustakh formations have been characterized in terms of thickness, contents of organic carbon and chloroform bitumen, maturity (catagenesis) of organic matter, and density of oil migration and gas generation. The maximum possible estimates of oil and gas resources that can potentially accumulate in structural traps, without migration losses, are obtained for each of the three reservoir formations by basin modeling. Judging by geological and geochemical criteria, the Upper Kozhevnikovo Formation can preserve only a minor portion of initially accumulated hydrocarbons, while the oil and gas accumulations, as well as the petroleum generation potential of organic matter in the Lower Kozhevnikovo and Tustakh formations, were destroyed by late Permian–Early Triassic trap magmatism and Mesozoic–Cenozoic tectonic activity.
{"title":"Conditions for Generation, Accumulation, and Preservation of Oil and Gas in Permian Strata, Northwestern Anabar–Khatanga Oil and Gas Region","authors":"A. Larichev, O. Bostrikov, A.N. Khabarov","doi":"10.2113/rgg20244669","DOIUrl":"https://doi.org/10.2113/rgg20244669","url":null,"abstract":"\u0000 ––Integrated seismic, drilling, and generalizing scientific research in the southeastern Anabar–Khatanga oil and gas region (OGR) since the early 1930s led to discoveries of small oil and gas occurrences and one large Central Olgino oil field. However, the petroleum potential of the northwestern part of the region remains poorly investigated and evaluated. To assess the prospects for the oil and gas potential of this territory, all seismic and geological and geochemical information was used, including four new wells drilled in the Sopochnoe uplift and the Zhuravliny swell. The scales of oil and gas formation, accumulation and destruction of hydrocarbon accumulations in the Permian deposits, which are the most promising in terms of the initial potential of the source rocks included in their composition, is given. The source rocks of the Upper Kozhevnikovo, Lower Kozhevnikovo, and Tustakh formations have been characterized in terms of thickness, contents of organic carbon and chloroform bitumen, maturity (catagenesis) of organic matter, and density of oil migration and gas generation. The maximum possible estimates of oil and gas resources that can potentially accumulate in structural traps, without migration losses, are obtained for each of the three reservoir formations by basin modeling. Judging by geological and geochemical criteria, the Upper Kozhevnikovo Formation can preserve only a minor portion of initially accumulated hydrocarbons, while the oil and gas accumulations, as well as the petroleum generation potential of organic matter in the Lower Kozhevnikovo and Tustakh formations, were destroyed by late Permian–Early Triassic trap magmatism and Mesozoic–Cenozoic tectonic activity.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":"41 18","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140662925","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 paper presents data on a granulite xenolith from the Zarnitsa kimberlite pipe (Yakutia, Russia), which stores a record of two metasomatic events in addition to the main stage of metamorphism. The granulitic mineral assemblage consists of garnet, clinopyroxene, and plagioclase as main phases. The granulite xenolith contains kyanite–clinopyroxene and later orthopyroxene–plagioclase symplectites. Kyanite–clinopyroxene symplectites appear as short veins inside or between grains of rock-forming minerals. Orthopyroxene–plagioclase symplectites form kelyphite rims in all garnets or occur as veins in garnet grains. The P–T conditions for granulite in the lower crust reconstructed by Perple_X phase equilibrium modeling are 700–750 ℃ and 1.2–1.3 GPa. According to TWQ thermodynamic calculations, the kyanite–clinopyroxene symplectites were produced by Si-metasomatism at invariable Р–Т parameters. The growth of orthopyroxene–plagioclase symplectites after garnet was maintained by Ca inputs upon heating and decompression (200 ℃ temperature increase and 0.6 GPa pressure decrease) while the xenolith was transported by ascending kimberlite melt.
{"title":"Two Types of Symplectites in a Lower Crust Granulite Xenolith from the Zarnitsa Kimberlite (Yakutia): A Record of Si-Metasomatism and Decompression","authors":"A. Sapegina, A. Perchuk, V.S. Shatsky","doi":"10.2113/rgg20244684","DOIUrl":"https://doi.org/10.2113/rgg20244684","url":null,"abstract":"\u0000 ––The paper presents data on a granulite xenolith from the Zarnitsa kimberlite pipe (Yakutia, Russia), which stores a record of two metasomatic events in addition to the main stage of metamorphism. The granulitic mineral assemblage consists of garnet, clinopyroxene, and plagioclase as main phases. The granulite xenolith contains kyanite–clinopyroxene and later orthopyroxene–plagioclase symplectites. Kyanite–clinopyroxene symplectites appear as short veins inside or between grains of rock-forming minerals. Orthopyroxene–plagioclase symplectites form kelyphite rims in all garnets or occur as veins in garnet grains. The P–T conditions for granulite in the lower crust reconstructed by Perple_X phase equilibrium modeling are 700–750 ℃ and 1.2–1.3 GPa. According to TWQ thermodynamic calculations, the kyanite–clinopyroxene symplectites were produced by Si-metasomatism at invariable Р–Т parameters. The growth of orthopyroxene–plagioclase symplectites after garnet was maintained by Ca inputs upon heating and decompression (200 ℃ temperature increase and 0.6 GPa pressure decrease) while the xenolith was transported by ascending kimberlite melt.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":"8 9","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140660543","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}
E.O. Malysheva, M. S. Doronina, L. N. Kleschina, V.A. Nikitina, A.S. Popov, N. Vasilyeva
—The Permian–Triassic (P–T) boundary records the most dramatic events in Phanerozoic history. The character of the boundary differs greatly, so it has been the subject of great discussion. The Barents Sea separates regions having markedly different expressions of the P–T boundary, and it can give an insight into the conditions of formation of this boundary in different parts of the European North. This contribution is based on a combination of regional projects from the Russian and Norwegian sectors, including seismic data across the Barents Sea and well data in marginal zones. Application of new seismic data and the sequence stratigraphy concept provides a novel approach to correlation and interpretation of the P–T boundary beneath the Barents Sea. The study has revealed a distinct regional sequence boundary corresponding to the P–T boundary with conformable and unconformable bedding. Three major types of this stratigraphic boundary are recognized. The distinct “erosional” type of the P–T boundary, with a significantly reduced Permian section, exists in the southeast (Timan–Pechora Basin). The conformable “overcompensated” type of boundary with an additional Lower Triassic section is interpreted in the central part of the Barents Sea. Westward, beneath the Norwegian sector, a relatively conformable “condensed” type of P–T boundary predominates. In addition to these types associated with regional paleostructural and depositional trends, the superposed “structural” subtype caused by local growth of structures at the Permian–Triassic boundary is identified.
{"title":"Permian–Triassic Boundary in Sedimentary Succession of the Barents Sea","authors":"E.O. Malysheva, M. S. Doronina, L. N. Kleschina, V.A. Nikitina, A.S. Popov, N. Vasilyeva","doi":"10.2113/rgg20244648","DOIUrl":"https://doi.org/10.2113/rgg20244648","url":null,"abstract":"\u0000 —The Permian–Triassic (P–T) boundary records the most dramatic events in Phanerozoic history. The character of the boundary differs greatly, so it has been the subject of great discussion. The Barents Sea separates regions having markedly different expressions of the P–T boundary, and it can give an insight into the conditions of formation of this boundary in different parts of the European North. This contribution is based on a combination of regional projects from the Russian and Norwegian sectors, including seismic data across the Barents Sea and well data in marginal zones. Application of new seismic data and the sequence stratigraphy concept provides a novel approach to correlation and interpretation of the P–T boundary beneath the Barents Sea. The study has revealed a distinct regional sequence boundary corresponding to the P–T boundary with conformable and unconformable bedding. Three major types of this stratigraphic boundary are recognized. The distinct “erosional” type of the P–T boundary, with a significantly reduced Permian section, exists in the southeast (Timan–Pechora Basin). The conformable “overcompensated” type of boundary with an additional Lower Triassic section is interpreted in the central part of the Barents Sea. Westward, beneath the Norwegian sector, a relatively conformable “condensed” type of P–T boundary predominates. In addition to these types associated with regional paleostructural and depositional trends, the superposed “structural” subtype caused by local growth of structures at the Permian–Triassic boundary is identified.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":" 10","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140683345","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}
V. Seleznev, A. V. Liseikin, I. Kokovkin, V. M. Solovyov
—This work is devoted to the development of the engineering seismic monitoring method created in Geophysical Survey of the Russian Academy of Sciences (GS RAS). In previous years, the “method of standing waves” was created and put into practice. It helps to separate natural oscillation modes of buildings and other engineering structures. The natural oscillations of hundreds of various objects (buildings, bridges, dams, etc.) had been studied and identified. We assumed that the physical condition of studied constructions could be controlled during exploitation by measuring the changes of natural oscillation frequencies. That would help to identify the appearance of defects in constructions, to prevent the risk of their destruction. However, it turned out that not everything is that simple: changes in frequency values are logically affected by changes in the environment around the studied objects. This article provides examples of these relations, influence of changes in environmental temperature, mass of objects and precipitation on the frequencies of natural oscillations.
{"title":"Change of Natural Oscillation Frequencies of Buildings and Structures Depending on External Factors","authors":"V. Seleznev, A. V. Liseikin, I. Kokovkin, V. M. Solovyov","doi":"10.2113/rgg20244703","DOIUrl":"https://doi.org/10.2113/rgg20244703","url":null,"abstract":"\u0000 —This work is devoted to the development of the engineering seismic monitoring method created in Geophysical Survey of the Russian Academy of Sciences (GS RAS). In previous years, the “method of standing waves” was created and put into practice. It helps to separate natural oscillation modes of buildings and other engineering structures. The natural oscillations of hundreds of various objects (buildings, bridges, dams, etc.) had been studied and identified. We assumed that the physical condition of studied constructions could be controlled during exploitation by measuring the changes of natural oscillation frequencies. That would help to identify the appearance of defects in constructions, to prevent the risk of their destruction. However, it turned out that not everything is that simple: changes in frequency values are logically affected by changes in the environment around the studied objects. This article provides examples of these relations, influence of changes in environmental temperature, mass of objects and precipitation on the frequencies of natural oscillations.","PeriodicalId":506591,"journal":{"name":"Russian Geology and Geophysics","volume":" 13","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140684174","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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