Pub Date : 2022-11-04DOI: 10.24930/1681-9004-2022-22-5-612-623
V. Smirnov, K. Ivanov, A. Travin, A. Zakharov, Yu. V. Erokhin
Research subject. The pegmatites of Murzinka-Adui region (Ethtern sector of the Middle Urals), represented by three types of veins miarolitic pegmatites with topaz and beryl (mines Mokrusha, Kazennitsa, Semenovskaia), miarolitic rubillite-lepidolite pegmatites (Lipovka veins field) and rare metal pegmatites with Ta-Nb-Be mineralization (deposits Kvartal’noe and Lipovyi Log).Materials and methods. Isotope dating was carried out via the 40Ar-39Ar method by a mass spectrometer Micromass 5400 at the Institute of Geology and Mineralogy SB RAS for mica of different composition (muscovites, biotites and lepidolites).Results. 40Ar/39Ar ages for mica from dated pegmatite veins of the topaz-beryl type coincide within the measurement accuracy: mine Kazennitsa – 252.3 Ma, Mokrusha – 253.7 and Semenovskaia – 250.3 Ma. The average age of the two series of mica from rubillite-lepidolite pegmatites was found to be 254.1 Ma. The average age of four samples of muscovites from rare metal Ta-Nb-Be pegmatites equals 252.6 Ma.Conclusions. The closure of the isotope system of micas in pegmatites of all three studied types (topaz-beryllium, rubillite-lepidolite and rare-metal with Ta-Nb-Be mineralization) occurred almost simultaneously during the timeframe of 254 to 250 Ma years ago. The obtained age values, however, cannot be identified with the time of formation of pegmatites. The analysis of the available data suggests that the closure of the micas K-Ar isotope system of the studied pegmatites as well as previously dated schists and blastomylonites of the Bazhenovo suture zone and granites of the Murzinka-Adui block marks an important episode in the geological history of the eastern margin of the Urals and the basement of the adjacent part of the West Siberian plate: the change of the transpression regime prevailing during the collision stage of the region’s development to the regime of limited postcollision extension.
{"title":"40Ar-39Ar dating of pegmatites from Murzinka-Adui region (Middle Urals): Results and their geological interpretation","authors":"V. Smirnov, K. Ivanov, A. Travin, A. Zakharov, Yu. V. Erokhin","doi":"10.24930/1681-9004-2022-22-5-612-623","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-5-612-623","url":null,"abstract":"Research subject. The pegmatites of Murzinka-Adui region (Ethtern sector of the Middle Urals), represented by three types of veins miarolitic pegmatites with topaz and beryl (mines Mokrusha, Kazennitsa, Semenovskaia), miarolitic rubillite-lepidolite pegmatites (Lipovka veins field) and rare metal pegmatites with Ta-Nb-Be mineralization (deposits Kvartal’noe and Lipovyi Log).Materials and methods. Isotope dating was carried out via the 40Ar-39Ar method by a mass spectrometer Micromass 5400 at the Institute of Geology and Mineralogy SB RAS for mica of different composition (muscovites, biotites and lepidolites).Results. 40Ar/39Ar ages for mica from dated pegmatite veins of the topaz-beryl type coincide within the measurement accuracy: mine Kazennitsa – 252.3 Ma, Mokrusha – 253.7 and Semenovskaia – 250.3 Ma. The average age of the two series of mica from rubillite-lepidolite pegmatites was found to be 254.1 Ma. The average age of four samples of muscovites from rare metal Ta-Nb-Be pegmatites equals 252.6 Ma.Conclusions. The closure of the isotope system of micas in pegmatites of all three studied types (topaz-beryllium, rubillite-lepidolite and rare-metal with Ta-Nb-Be mineralization) occurred almost simultaneously during the timeframe of 254 to 250 Ma years ago. The obtained age values, however, cannot be identified with the time of formation of pegmatites. The analysis of the available data suggests that the closure of the micas K-Ar isotope system of the studied pegmatites as well as previously dated schists and blastomylonites of the Bazhenovo suture zone and granites of the Murzinka-Adui block marks an important episode in the geological history of the eastern margin of the Urals and the basement of the adjacent part of the West Siberian plate: the change of the transpression regime prevailing during the collision stage of the region’s development to the regime of limited postcollision extension.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"11 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74005221","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 : 2022-11-04DOI: 10.24930/1681-9004-2022-22-5-599-611
T. Beznosova, V. Matveev
Research subject. The article presents the results of studying traces of the global Late Aeronian biotic and isotopic (δ13Ccarb) events preserved in a new reference section of the Lower Silurian in the Subpolar Urals.Materials and methods. The samples of sedimentary rocks and microfauna, the results of isotope analysis, as well as the collections with remains of benthic fauna collected by the authors in different years during fieldwork were investigated. The studies were confirmed by sedimentological, biostratigraphic and chemostratigraphic data obtained by the authors.Results. The The event-stratigraphic interval, established in the upper part of the Lolashor stage (Aeronian) of the Silurian, is characterized by increasing regressive tendencies, decreasing biodiversity, disappearance of Pranognathus tenuis conodonts and brachiopods of the genus Pentamerus, as well as by δ13Ccarb anomalies in the upper strata of the Lolashor stage.Conclusions. The obtained data indicate a eustatic drop in the sea level, a major ecosystem restructuring, and a sedimentation gap at the end of the Lolashor time. The boundary between the Lolashor and Philippel stages (Aeronian and Telychian) records a sharp negative isotopic shift of δ13Ccarb, which was first observed in the Lower Silurian section in the European Northeast of Russia.
{"title":"Manifestation of the Late Aeronian event in the Silurian section on the western slope of the Subpolar Urals","authors":"T. Beznosova, V. Matveev","doi":"10.24930/1681-9004-2022-22-5-599-611","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-5-599-611","url":null,"abstract":"Research subject. The article presents the results of studying traces of the global Late Aeronian biotic and isotopic (δ13Ccarb) events preserved in a new reference section of the Lower Silurian in the Subpolar Urals.Materials and methods. The samples of sedimentary rocks and microfauna, the results of isotope analysis, as well as the collections with remains of benthic fauna collected by the authors in different years during fieldwork were investigated. The studies were confirmed by sedimentological, biostratigraphic and chemostratigraphic data obtained by the authors.Results. The The event-stratigraphic interval, established in the upper part of the Lolashor stage (Aeronian) of the Silurian, is characterized by increasing regressive tendencies, decreasing biodiversity, disappearance of Pranognathus tenuis conodonts and brachiopods of the genus Pentamerus, as well as by δ13Ccarb anomalies in the upper strata of the Lolashor stage.Conclusions. The obtained data indicate a eustatic drop in the sea level, a major ecosystem restructuring, and a sedimentation gap at the end of the Lolashor time. The boundary between the Lolashor and Philippel stages (Aeronian and Telychian) records a sharp negative isotopic shift of δ13Ccarb, which was first observed in the Lower Silurian section in the European Northeast of Russia.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"25 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81143635","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 : 2022-11-04DOI: 10.24930/1681-9004-2022-22-5-579-598
A. Baluev, Y. V. Brusilovsky, A. Ivanenko
Research subject. The anomalous magnetic field of the southern part of the Barents Sea Shelf.Materials and methods. The research was based on a digital matrix (grid) of the anomalous magnetic field (AMP) compiled from the materials of magnetic surveys performed in 2002–2007 by a number of research organizations and research and production companies. A model describing the structure and formation of the magneto-active layer of the southern part of the Barentsevomorsk region was developed. An analysis of the radially averaged field spectrum made it possible to establish the confinement of the upper edges of the field sources to several structural horizons. Band filtering in the frequency domain in accordance with the allocated depth ranges allowed anomalies to be distinguished from other sources. To determine the nature of sources of magnetic anomalies at different levels of the earth’s crust, an integrated analysis of gravimagnetic fields, seismic profiling data and ground studies was conducted.Results. At least two levels of magnetic anomaly sources were found: the distribution of effective magnetization for the low-frequency component of AMP, reflecting the depth structure of the region, and the high-frequency component of AMP, reflecting the distribution of local intrusions in the upper part of the foundation and in the sedimentary cover. The lower level is represented by massive blocks of deep laying and corresponds to the SDR (Seaward Dipping Reflectors) complex, which is an alternation of tectonic plates of continental material with ultrabasite basites that were introduced into the crust at the post-rift stage of the continent’s split. The zone of positive linear anomalies of the magnetic field reflects the divergent boundary of the ancient continental plate of the Baltic, which arose during the fragmentation of the supercontinent of Colombia (Paleopangea) in the middle reef and the formation of the Rifean oceanic basin, which was then veiled by subsequent tectonic processes. The upper structural level indicates the introduction of the main composition into the upper layers of the earth’s crust in the zones of rift-forming faults of magma in late Devonian times during the process of continental rifting on the Svalbard Plate. This is confirmed by the presence of manifestations of the main magmatism within the propagation zone of the South Barents riftogenic depression into the body of the Baltic Shield.Conclusions. The conducted integrated analysis of the anomalous magnetic field and other geological and geophysical data allowed the authors to establish the nature of the sources of magnetic anomalies located at different structural levels of the earth’s crust in the southwestern part of the Barents Sea shelf. The magnetoactive layer of this region is characterized by a complex structure, the section of which includes at least two structural levels, each reflecting certain evolutionary stages of the earth’s crust.
{"title":"The nature of magnetic anomalies in the southern part of the Barents Sea shelf according to the results of an integrated analysis","authors":"A. Baluev, Y. V. Brusilovsky, A. Ivanenko","doi":"10.24930/1681-9004-2022-22-5-579-598","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-5-579-598","url":null,"abstract":"Research subject. The anomalous magnetic field of the southern part of the Barents Sea Shelf.Materials and methods. The research was based on a digital matrix (grid) of the anomalous magnetic field (AMP) compiled from the materials of magnetic surveys performed in 2002–2007 by a number of research organizations and research and production companies. A model describing the structure and formation of the magneto-active layer of the southern part of the Barentsevomorsk region was developed. An analysis of the radially averaged field spectrum made it possible to establish the confinement of the upper edges of the field sources to several structural horizons. Band filtering in the frequency domain in accordance with the allocated depth ranges allowed anomalies to be distinguished from other sources. To determine the nature of sources of magnetic anomalies at different levels of the earth’s crust, an integrated analysis of gravimagnetic fields, seismic profiling data and ground studies was conducted.Results. At least two levels of magnetic anomaly sources were found: the distribution of effective magnetization for the low-frequency component of AMP, reflecting the depth structure of the region, and the high-frequency component of AMP, reflecting the distribution of local intrusions in the upper part of the foundation and in the sedimentary cover. The lower level is represented by massive blocks of deep laying and corresponds to the SDR (Seaward Dipping Reflectors) complex, which is an alternation of tectonic plates of continental material with ultrabasite basites that were introduced into the crust at the post-rift stage of the continent’s split. The zone of positive linear anomalies of the magnetic field reflects the divergent boundary of the ancient continental plate of the Baltic, which arose during the fragmentation of the supercontinent of Colombia (Paleopangea) in the middle reef and the formation of the Rifean oceanic basin, which was then veiled by subsequent tectonic processes. The upper structural level indicates the introduction of the main composition into the upper layers of the earth’s crust in the zones of rift-forming faults of magma in late Devonian times during the process of continental rifting on the Svalbard Plate. This is confirmed by the presence of manifestations of the main magmatism within the propagation zone of the South Barents riftogenic depression into the body of the Baltic Shield.Conclusions. The conducted integrated analysis of the anomalous magnetic field and other geological and geophysical data allowed the authors to establish the nature of the sources of magnetic anomalies located at different structural levels of the earth’s crust in the southwestern part of the Barents Sea shelf. The magnetoactive layer of this region is characterized by a complex structure, the section of which includes at least two structural levels, each reflecting certain evolutionary stages of the earth’s crust.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"31 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86601369","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 : 2022-11-04DOI: 10.24930/1681-9004-2022-22-5-694-704
R. Mirnov, T. Alekseeva
Research subject. Paleosols discovered in the Kashira sequence of the Pennsylvanian in the southeastern part of the East European platform. Aim. To study the structure and composition of the paleosols.Materials and methods. Core material from wells was studied by X-ray analysis, scanning electron microscopy and a detailed description of the core and thin sections.Results. Four types of paleosols were identified, three of which are developed on a dolomite substrate. The dolomites are characterized by the following features: microcrystalline structure with a crystal size of 5–10 microns; predominantly euhedral form of crystals, high intercrystalline porosity (up to 38%), inclusions of in situ halite, gypsum and anhydrite, ubiquitous filaments of sepiolite. In paleosols based on a limestone substrate, beta-calcretes with Microcodium were found. The study of fossil roots (rhizoliths) revealed the correlation between their types and substrate composition. Thus, petrified rhizoliths and root casts filled with sedimentary rock and developed clay cutans were found on a dolomite substrate, while calcite tubules around root channels were developed on a limestone substrate. The latter show the presence of abundant Microcodium formations.Conclusions. The revealed morphological and compositional features of the paleosols under study, such as the presence of in situ halite and sulfates (anhydrite and gypsum), sepiolite, and beta calcretes, point to the semiarid climate during the Kashira age on the area under study.
{"title":"Paleosols in the Kashira deposits in the south of the East European Craton (Republic of Bashkortostan): characteristics, paleoecological and stratigraphic significance","authors":"R. Mirnov, T. Alekseeva","doi":"10.24930/1681-9004-2022-22-5-694-704","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-5-694-704","url":null,"abstract":"Research subject. Paleosols discovered in the Kashira sequence of the Pennsylvanian in the southeastern part of the East European platform. Aim. To study the structure and composition of the paleosols.Materials and methods. Core material from wells was studied by X-ray analysis, scanning electron microscopy and a detailed description of the core and thin sections.Results. Four types of paleosols were identified, three of which are developed on a dolomite substrate. The dolomites are characterized by the following features: microcrystalline structure with a crystal size of 5–10 microns; predominantly euhedral form of crystals, high intercrystalline porosity (up to 38%), inclusions of in situ halite, gypsum and anhydrite, ubiquitous filaments of sepiolite. In paleosols based on a limestone substrate, beta-calcretes with Microcodium were found. The study of fossil roots (rhizoliths) revealed the correlation between their types and substrate composition. Thus, petrified rhizoliths and root casts filled with sedimentary rock and developed clay cutans were found on a dolomite substrate, while calcite tubules around root channels were developed on a limestone substrate. The latter show the presence of abundant Microcodium formations.Conclusions. The revealed morphological and compositional features of the paleosols under study, such as the presence of in situ halite and sulfates (anhydrite and gypsum), sepiolite, and beta calcretes, point to the semiarid climate during the Kashira age on the area under study.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"19 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82551352","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 : 2022-11-04DOI: 10.24930/1681-9004-2022-22-5-624-643
S. Berzin, K. Ivanov, E. Pankrushina, N. Soloshenko
Research subject. Permian-Triassic flood basalts in the basement of the Arctic zone of the West Siberian Platform locate mainly in graben-rift structures. Flood basalts in this region remain to be understudied in comparison with other areas of its distribution, mainly due to the significant depth of their occurrence (4–6 km).Materials and methods. 36 core samples from 11 superdeep and deep boreholes were studied. Isotopic ratios were measured on mass spectrometers NEPTUNE PLUS (Nd, Sm) and TRITON PLUS (Rb, Sr). Bitumen were studied using a Raman spectrometer LabRAM HR800 Evolution. The Raman spectra were deconvoluted (“Peak fitting” procedure), and the bitumen conversion temperature was estimated.Results. About half of the samples of volcanic rocks underwent metamorphism of the prehnite-pumpellite and locally greenschist facies or intense low-temperature hydrothermal alteration. The studied basalts are close to typical flood basalts and are somewhat similar to island-arc volcanic rocks in terms of their geochemical characteristics. For the first time, thin inclusions of bitumen were found in the amygdalae of Permian-Triassic basalts in the superdeep borehole Tyumenskaya SG-6 at a depth of 7310.6 m. A high similarity of the studied volcanics by geochemical characteristics and the isotopic composition of Sr and Nd with the flood basalts of the Siberian platform is shown.Conclusions. The presence of a negative Ta, Nb, Ti anomaly, as well as a negative Ce anomaly, in some of the analyzed samples indicates a possible contamination of the basalts by island arc volcanics and volcanogenic-sedimentary rocks. The temperature of transformation of bitumen in inclusions in basalts from the well Tyumenskaya SG-6 according to Raman spectroscopy is estimated at 150–300°C and generally corresponds to the temperature of metamorphism of the host basalts. The presence of bitumen in the amygdalae may indicate the migration of hydrocarbons through the basalts.
研究课题。西西伯利亚地台北极带基底二叠纪—三叠纪洪水玄武岩主要位于地堑-裂谷构造中。与其他地区的洪泛玄武岩分布相比，该地区的洪泛玄武岩研究仍然不足，主要是由于其出现深度较大(4-6 km)。材料和方法。研究了11个超深和深钻孔的36个岩心样品。用质谱仪NEPTUNE PLUS (Nd, Sm)和TRITON PLUS (Rb, Sr)测量同位素比值。采用LabRAM HR800 Evolution拉曼光谱仪对沥青进行了研究。对拉曼光谱进行反卷积(“峰拟合”程序)，并估计沥青转化温度。近一半的火山岩样品经历了前亚花岗岩-泵状岩和局部绿片岩相的变质作用或强烈的低温热液蚀变。研究的玄武岩接近典型的洪泛玄武岩，在地球化学特征上与岛弧火山岩有些相似。在深7310.6 m的Tyumenskaya SG-6超深钻孔中，首次在二叠系—三叠系玄武岩杏仁核中发现了薄包裹体沥青。从地球化学特征和Sr、Nd同位素组成来看，所研究的火山岩与西伯利亚地台洪水玄武岩具有较高的相似性。部分分析样品中存在负Ta、Nb、Ti异常和负Ce异常，表明玄武岩可能受到岛弧火山和火山-沉积岩的污染。根据拉曼光谱估计，Tyumenskaya SG-6井玄武岩包裹体沥青的转化温度在150 ~ 300℃之间，与主玄武岩变质温度基本一致。杏仁核中沥青的存在可能表明碳氢化合物通过玄武岩迁移。
{"title":"Permian-Triassic flood basalts in the pre-Jurassic basement of the Arctic zone of the West Siberian platform","authors":"S. Berzin, K. Ivanov, E. Pankrushina, N. Soloshenko","doi":"10.24930/1681-9004-2022-22-5-624-643","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-5-624-643","url":null,"abstract":"Research subject. Permian-Triassic flood basalts in the basement of the Arctic zone of the West Siberian Platform locate mainly in graben-rift structures. Flood basalts in this region remain to be understudied in comparison with other areas of its distribution, mainly due to the significant depth of their occurrence (4–6 km).Materials and methods. 36 core samples from 11 superdeep and deep boreholes were studied. Isotopic ratios were measured on mass spectrometers NEPTUNE PLUS (Nd, Sm) and TRITON PLUS (Rb, Sr). Bitumen were studied using a Raman spectrometer LabRAM HR800 Evolution. The Raman spectra were deconvoluted (“Peak fitting” procedure), and the bitumen conversion temperature was estimated.Results. About half of the samples of volcanic rocks underwent metamorphism of the prehnite-pumpellite and locally greenschist facies or intense low-temperature hydrothermal alteration. The studied basalts are close to typical flood basalts and are somewhat similar to island-arc volcanic rocks in terms of their geochemical characteristics. For the first time, thin inclusions of bitumen were found in the amygdalae of Permian-Triassic basalts in the superdeep borehole Tyumenskaya SG-6 at a depth of 7310.6 m. A high similarity of the studied volcanics by geochemical characteristics and the isotopic composition of Sr and Nd with the flood basalts of the Siberian platform is shown.Conclusions. The presence of a negative Ta, Nb, Ti anomaly, as well as a negative Ce anomaly, in some of the analyzed samples indicates a possible contamination of the basalts by island arc volcanics and volcanogenic-sedimentary rocks. The temperature of transformation of bitumen in inclusions in basalts from the well Tyumenskaya SG-6 according to Raman spectroscopy is estimated at 150–300°C and generally corresponds to the temperature of metamorphism of the host basalts. The presence of bitumen in the amygdalae may indicate the migration of hydrocarbons through the basalts.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"50 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84640460","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 : 2022-09-04DOI: 10.24930/1681-9004-2022-22-4-536-547
Y. Ezimova, V. Udoratin, A. Magomedova
{"title":"Detailed geophysical studies of the Ilych-Chikshinskaya fault system (Izyma-Pechora Monocline)","authors":"Y. Ezimova, V. Udoratin, A. Magomedova","doi":"10.24930/1681-9004-2022-22-4-536-547","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-4-536-547","url":null,"abstract":"","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"18 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78803461","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 : 2022-09-03DOI: 10.24930/1681-9004-2022-22-4-497-511
V. Lysenko, S. Sadykov, T. V. Mikhailichenko
Research subject. For the first time, the results of a study of hydrothermal-bacterial carbonate structures and a shell bank of brachiopods on the surface of the effusive sequence of the Late Triassic Tessel paleovolcano are presented. Methods. Petrographic thin sections were studied using an Olympus BX 5 microscope with an Olympus DP 12 camera. Geochemical investigations were performed according to the conventional methodology by an inductively coupled plasma mass spectrometer (ICP-MS). The isotopic composition of carbon was determined by isotope ratio mass spectrometry (IRMS) by a Deltaplus Advantage instrument. The mass spectrometer was paired with an EA Flash1112 analyzer and a TC/EA convector. When measuring, the NBS-19, NBS-18, and IAEA-C-3 standards were used. Results. The data obtained on the geology, geochemistry, and isotopic composition of the studied materials confirm the existence of a symbiosis between brachiopods and protozoa. The primary formation of organic matter and carbonate of bacterial structures occurred due to the processing of paleofluids by the community of bacteria and archaea. These organisms created carbonate, sulfide and organic matter in a suboxide environment of hydrogen sulfide and methane. The biocenosis of the shell bank of brachiopods was characterized by a poor taxonomic composition and a high biological productivity. The formation of a shell bank of brachiopods with bacterial carbonate edifices took place during the period of volcanic activity and continued during breaks in eruptions. The results of geochemistry and the carbon isotopic composition of the carbonate of bacterial buildups confirm the deep nature of the paleofluids. The Norian age of paleovolcanism was determined from finds on the surface of the terrigenous- volcanic sequence of brachiopods Worobiella ex gr. caucasica Dagys and ammonite Megaphyllites insectus (Mojsisovics). Conclusions. According to geological features, the material of the shell bank of brachiopods with bacterial carbonate structures on the surface of the Tessel paleovolcano belongs to the ancient hydrocarbon seeps-carbonate. Based on their genesis and formation material, these formations should be referred to as Triassic methanoliths. Signs of allocation of similar formations in other time intervals and regions are given. Emissions of fluids with hydrogen sulfide and methane by the Tessel paleovolcano in the Late Triassic may have been related to the causes of the “global extinction”.
研究课题。本文首次报道了晚三叠世Tessel古火山喷涌层序表面的热液细菌碳酸盐岩构造和腕足类壳群的研究结果。方法。采用Olympus bx5显微镜和Olympus DP 12照相机对岩石薄片进行研究。采用电感耦合等离子体质谱仪(ICP-MS)进行地球化学研究。碳的同位素组成采用Deltaplus Advantage型同位素比质谱法(IRMS)测定。质谱仪与EA Flash1112分析仪和TC/EA对流器配对。测量时采用NBS-19、NBS-18和IAEA-C-3标准。结果。研究材料的地质、地球化学和同位素组成数据证实了腕足动物和原生动物之间存在共生关系。细菌结构的有机质和碳酸盐的初步形成是由于细菌和古细菌群落对古流体的加工作用。这些生物在硫化氢和甲烷的亚氧化环境中产生碳酸盐、硫化物和有机物。腕足类贝壳群生物群落的特点是分类组成差，生物生产力高。在火山活动期间形成了带有细菌碳酸盐结构的腕足类贝壳滩，并在火山喷发间歇期间继续形成。地球化学结果和细菌堆积碳酸盐的碳同位素组成证实了古流体的深层性质。古火山作用的挪威时代是根据陆源-火山序列中腕足类Worobiella ex gr. caucasica Dagys和菊石类Megaphyllites昆虫(Mojsisovics)的表面发现确定的。结论。根据地质特征，特塞尔古火山表面具有细菌碳酸盐构造的腕足类壳滩的物质属于古烃类渗漏-碳酸盐。根据其成因和地层物质，这些地层可称为三叠纪甲烷岩。给出了在其他时间间隔和区域中类似地层的分配标志。晚三叠世Tessel古火山喷发的含硫化氢和甲烷的流体可能与“全球灭绝”的原因有关。
{"title":"Hydrothermal-bacterial structures with a brachiopod fauna on the surface of Tessel paleovolcano (South coast of Crimea)","authors":"V. Lysenko, S. Sadykov, T. V. Mikhailichenko","doi":"10.24930/1681-9004-2022-22-4-497-511","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-4-497-511","url":null,"abstract":" Research subject. For the first time, the results of a study of hydrothermal-bacterial carbonate structures and a shell bank of brachiopods on the surface of the effusive sequence of the Late Triassic Tessel paleovolcano are presented. Methods. Petrographic thin sections were studied using an Olympus BX 5 microscope with an Olympus DP 12 camera. Geochemical investigations were performed according to the conventional methodology by an inductively coupled plasma mass spectrometer (ICP-MS). The isotopic composition of carbon was determined by isotope ratio mass spectrometry (IRMS) by a Deltaplus Advantage instrument. The mass spectrometer was paired with an EA Flash1112 analyzer and a TC/EA convector. When measuring, the NBS-19, NBS-18, and IAEA-C-3 standards were used. Results. The data obtained on the geology, geochemistry, and isotopic composition of the studied materials confirm the existence of a symbiosis between brachiopods and protozoa. The primary formation of organic matter and carbonate of bacterial structures occurred due to the processing of paleofluids by the community of bacteria and archaea. These organisms created carbonate, sulfide and organic matter in a suboxide environment of hydrogen sulfide and methane. The biocenosis of the shell bank of brachiopods was characterized by a poor taxonomic composition and a high biological productivity. The formation of a shell bank of brachiopods with bacterial carbonate edifices took place during the period of volcanic activity and continued during breaks in eruptions. The results of geochemistry and the carbon isotopic composition of the carbonate of bacterial buildups confirm the deep nature of the paleofluids. The Norian age of paleovolcanism was determined from finds on the surface of the terrigenous- volcanic sequence of brachiopods Worobiella ex gr. caucasica Dagys and ammonite Megaphyllites insectus (Mojsisovics). Conclusions. According to geological features, the material of the shell bank of brachiopods with bacterial carbonate structures on the surface of the Tessel paleovolcano belongs to the ancient hydrocarbon seeps-carbonate. Based on their genesis and formation material, these formations should be referred to as Triassic methanoliths. Signs of allocation of similar formations in other time intervals and regions are given. Emissions of fluids with hydrogen sulfide and methane by the Tessel paleovolcano in the Late Triassic may have been related to the causes of the “global extinction”.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"29 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77788705","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 : 2022-09-03DOI: 10.24930/1681-9004-2022-22-4-526-535
V. Bakhterev
Research subject. Chromite ores and massive chromitites with alumina (low chromium) chrome spinelide (the Podennoye deposit deposit) and chromite ores with high-chromium chrome spinelide (Kurmanovskoye deposit) of the Alapaevsky hyperbasite massif. Materials and methods. Samples of chromite ores and massive chromitites collected during field research were studied in transparent sections using chemical analysis and electrical methods (electrical conductivity, dielectric losses). Results. The temperature dependences of electrical resistance and dielectric losses in the temperature range of 20‒800°C were obtained. The electrical parameters lgRₒ and Eₒ were determined, and the inverse linear relationship bet-ween them was revealed. The electrical parameters for the three groups of samples were found to differ depending on the degree of metamorphic changes. It was established that an increase in metamorphism leads to an increase in lgRₒ and a decrease in Eₒ. For the studied samples of chromite ore from the Podennoye deposit, Eₒ and lgRₒ vary from 0.61 to 0.96 and from 2.5 to –0.41, respectively. In the Kurmanovskoye field, these parameters vary from 0.81 to 1.35 and from 0.95 to –2.8, respectively. For the studied samples of chromitites from the Podennoye deposit, Eₒ varies from 0.21 to 0.41, while lgRₒ varies from –0.08 to 1.67. In this case, the coefficients a and b are different for each group of samples. For some samples, the chemical composition was determined, and for six samples (two samples from each group), the content of ferrous and trivalent iron oxides in the original sample and a duplicate sample after calcination at temperature of up to 800 °C was determined. Relative change in the ratio of ferrous and trivalent iron oxides in the initial sample (FeO/Fe2O3)* and a duplicate sample (FeO/Fe2O3)** H = [(FeO/Fe2O3)*/(FeO/Fe2O3)**] was compared with the position of the maximum of dielectric losses on the temperature scale. In the coordinates H–T, °C, the studied samples, depending on the metamorphic changes, occupy a certain place. Conclusions. The study indicates the potential of the obtained information to be used as petrogenetic indicators of chromite deposits with a simultaneous assessment of the degree of metamorphic changes.
{"title":"High-temperature electrical conductivity of chromite ores from the Alapaevsky hyperbasite massif, Middle Urals, as a function of their composition and metamorphism","authors":"V. Bakhterev","doi":"10.24930/1681-9004-2022-22-4-526-535","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-4-526-535","url":null,"abstract":" Research subject. Chromite ores and massive chromitites with alumina (low chromium) chrome spinelide (the Podennoye deposit deposit) and chromite ores with high-chromium chrome spinelide (Kurmanovskoye deposit) of the Alapaevsky hyperbasite massif. Materials and methods. Samples of chromite ores and massive chromitites collected during field research were studied in transparent sections using chemical analysis and electrical methods (electrical conductivity, dielectric losses). Results. The temperature dependences of electrical resistance and dielectric losses in the temperature range of 20‒800°C were obtained. The electrical parameters lgRₒ and Eₒ were determined, and the inverse linear relationship bet-ween them was revealed. The electrical parameters for the three groups of samples were found to differ depending on the degree of metamorphic changes. It was established that an increase in metamorphism leads to an increase in lgRₒ and a decrease in Eₒ. For the studied samples of chromite ore from the Podennoye deposit, Eₒ and lgRₒ vary from 0.61 to 0.96 and from 2.5 to –0.41, respectively. In the Kurmanovskoye field, these parameters vary from 0.81 to 1.35 and from 0.95 to –2.8, respectively. For the studied samples of chromitites from the Podennoye deposit, Eₒ varies from 0.21 to 0.41, while lgRₒ varies from –0.08 to 1.67. In this case, the coefficients a and b are different for each group of samples. For some samples, the chemical composition was determined, and for six samples (two samples from each group), the content of ferrous and trivalent iron oxides in the original sample and a duplicate sample after calcination at temperature of up to 800 °C was determined. Relative change in the ratio of ferrous and trivalent iron oxides in the initial sample (FeO/Fe2O3)* and a duplicate sample (FeO/Fe2O3)** H = [(FeO/Fe2O3)*/(FeO/Fe2O3)**] was compared with the position of the maximum of dielectric losses on the temperature scale. In the coordinates H–T, °C, the studied samples, depending on the metamorphic changes, occupy a certain place. Conclusions. The study indicates the potential of the obtained information to be used as petrogenetic indicators of chromite deposits with a simultaneous assessment of the degree of metamorphic changes.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"112 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85863338","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 : 2022-09-03DOI: 10.24930/1681-9004-2022-22-4-512-525
V. Grishkevich
Research subject. The estimations of oil resources in Western Siberia obtained using a basin modeling of the Bazhenov formation as an oil source stratum indicated a significant deficit of its potential, calculated based on the pyrolytic kinetic parameters of catagenesis. Aim. To search for possible additional oil generating mechanisms parallel to catagenesis, thus clarifying the conceptual foundations of the modern theory of the organic origin of oil. Key points. Based on a review of literature publications, a hypothesis was formulated about the evolution of organic matter from sedimentary flow floccules to the injection of proto-oil into the microcracks of the autofluid fracturing of source rocks. In the upper unconsolidated bottom sediment layers, biofilms appear whose microbial matrix forms a basis for future kerogen. Proto-oil bitumoids appear as a by-product of biofilm microbial metabolism under the anaerobic conditions at diagenesis stage. Рroto-oil bitumoids are encapsulated and absorbed on the surfaces and inside the chambers and conducting channels of the biofilm polymer matrix (future kerogen). Local ultra-high pressure (LUHP) inside kerogen grains appears at the final “smectite – illite” transition stage of host clays, acting as a driving force for encapsulated bitumoid expulsion from kerogen grains. On the walls of microcracks, proto-oil bitumoids undergo hydropyrolysis, consuming cohesive film water and changing the surface philicity. Microphotographs and SEM images of thin sections are provided in order to illustrate LUHP-expulsion traces. Two types of oil source rocks are differentiated based on the possibility of proto-oil LUHP expulsion: those with a plastic mineral framework and a rigid mineral framework. Conclusion. The presence of porous spaces filled with bitumoids was established in the kerogen of immature potentially oil source rocks. This mass of encapsulated bitumoids is an additional resource of oil generation within the “oil window”. Their expulsion volume can be estimated and attributed to a certain temperature range. Directions for further research are outlined.
{"title":"On the fundamental possibility of using the bacterial and catagenetic hypotheses of the origin of oil in assessing its resources","authors":"V. Grishkevich","doi":"10.24930/1681-9004-2022-22-4-512-525","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-4-512-525","url":null,"abstract":" Research subject. The estimations of oil resources in Western Siberia obtained using a basin modeling of the Bazhenov formation as an oil source stratum indicated a significant deficit of its potential, calculated based on the pyrolytic kinetic parameters of catagenesis. Aim. To search for possible additional oil generating mechanisms parallel to catagenesis, thus clarifying the conceptual foundations of the modern theory of the organic origin of oil. Key points. Based on a review of literature publications, a hypothesis was formulated about the evolution of organic matter from sedimentary flow floccules to the injection of proto-oil into the microcracks of the autofluid fracturing of source rocks. In the upper unconsolidated bottom sediment layers, biofilms appear whose microbial matrix forms a basis for future kerogen. Proto-oil bitumoids appear as a by-product of biofilm microbial metabolism under the anaerobic conditions at diagenesis stage. Рroto-oil bitumoids are encapsulated and absorbed on the surfaces and inside the chambers and conducting channels of the biofilm polymer matrix (future kerogen). Local ultra-high pressure (LUHP) inside kerogen grains appears at the final “smectite – illite” transition stage of host clays, acting as a driving force for encapsulated bitumoid expulsion from kerogen grains. On the walls of microcracks, proto-oil bitumoids undergo hydropyrolysis, consuming cohesive film water and changing the surface philicity. Microphotographs and SEM images of thin sections are provided in order to illustrate LUHP-expulsion traces. Two types of oil source rocks are differentiated based on the possibility of proto-oil LUHP expulsion: those with a plastic mineral framework and a rigid mineral framework. Conclusion. The presence of porous spaces filled with bitumoids was established in the kerogen of immature potentially oil source rocks. This mass of encapsulated bitumoids is an additional resource of oil generation within the “oil window”. Their expulsion volume can be estimated and attributed to a certain temperature range. Directions for further research are outlined.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"37 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89010822","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 : 2022-09-02DOI: 10.24930/1681-9004-2022-22-4-448-471
I. Likhanov, P. Kozlov, N. V. Popov
Research subject. Fe- and Al-rich metapelites of the Teya, Garevka and Angara complexes of the North Yenisei Ridge (western margin of the Siberian craton) were studied. Research methods. Recently-obtained geochronologic (SHRIMP II U-Pb zircon dating) and geochemical data on the distribution of major and trace elements were used to reproduce the composition and age of the protolith, along with the paleofacies formation conditions. Results. The ferruginous-aluminous metapelites of the North Yenisei Ridge consitute redeposited and metamorphosed products of Precambrian weathering crusts predominantly of the kaolinite rather than lateritic type, as was previously thought. The chemical weathering of rocks in the Early Proterozoic on the Yenisei Ridge did not reach the deep stage of lateritization with the formation of zones of final decomposition of aluminosilicates; however, this process was limited to the formation of weathering products of predominantly kaolinite-illite-montmorillonite-quartz composition. Conclusions. The petro- and geochemical characteristics of the studied metapelites are mainly due to the features of sedimentation during the formation of the protolith, which could have been formed due to the erosion of the Lower Proterozoic microgneisses of the Siberian craton with ages in the range of 1962-2043 Ma with the involvement of granitoid and volcanic admixture of mafic rocks into the erosion area and subsequent accumulation in marginal continental shallow basins under the conditions of a humid climate and a calm tectonic regime. These results are consistent with the data of lithofacies analysis and geodynamic reconstructions of the Precambrian evolution of geological complexes in the North Yenisei Ridge.
研究课题。研究了叶尼塞北脊(西伯利亚克拉通西缘)的Teya、Garevka和Angara杂岩的富铁、富铝变质岩。研究方法。利用最近获得的地质年代学(SHRIMP II U-Pb锆石定年)和地球化学主要元素和微量元素分布数据，再现了原岩的组成和年龄，以及古相形成条件。结果。北叶尼塞岭的铁铝变质岩是前寒武纪风化壳的再沉积和变质产物，主要是高岭石，而不是以前认为的红土型。叶尼塞岭早元古代岩石化学风化未达到深部红土化阶段，形成铝硅酸盐终分解带;然而，这一过程仅限于形成以高岭石-伊利石-蒙脱石-石英成分为主的风化产物。结论。变质岩的石油地球化学特征主要是由原岩形成过程中的沉积特征决定的。它可能是在气候湿润、构造平静的条件下，下元古代西伯利亚克拉通的微片麻岩在1962-2043 Ma的侵蚀作用下，由花岗岩类和基性岩的火山混合物进入侵蚀区，并在边缘大陆浅层盆地中堆积而成。这些结果与北叶尼塞岭前寒武纪地质复合体演化的岩相分析和地球动力学重建资料一致。
{"title":"Ferruginious-aluminous metapelites of the North Yenisei Ridge: Formation paleosettings, nature and age of protolith","authors":"I. Likhanov, P. Kozlov, N. V. Popov","doi":"10.24930/1681-9004-2022-22-4-448-471","DOIUrl":"https://doi.org/10.24930/1681-9004-2022-22-4-448-471","url":null,"abstract":" Research subject. Fe- and Al-rich metapelites of the Teya, Garevka and Angara complexes of the North Yenisei Ridge (western margin of the Siberian craton) were studied. Research methods. Recently-obtained geochronologic (SHRIMP II U-Pb zircon dating) and geochemical data on the distribution of major and trace elements were used to reproduce the composition and age of the protolith, along with the paleofacies formation conditions. Results. The ferruginous-aluminous metapelites of the North Yenisei Ridge consitute redeposited and metamorphosed products of Precambrian weathering crusts predominantly of the kaolinite rather than lateritic type, as was previously thought. The chemical weathering of rocks in the Early Proterozoic on the Yenisei Ridge did not reach the deep stage of lateritization with the formation of zones of final decomposition of aluminosilicates; however, this process was limited to the formation of weathering products of predominantly kaolinite-illite-montmorillonite-quartz composition. Conclusions. The petro- and geochemical characteristics of the studied metapelites are mainly due to the features of sedimentation during the formation of the protolith, which could have been formed due to the erosion of the Lower Proterozoic microgneisses of the Siberian craton with ages in the range of 1962-2043 Ma with the involvement of granitoid and volcanic admixture of mafic rocks into the erosion area and subsequent accumulation in marginal continental shallow basins under the conditions of a humid climate and a calm tectonic regime. These results are consistent with the data of lithofacies analysis and geodynamic reconstructions of the Precambrian evolution of geological complexes in the North Yenisei Ridge.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"89 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84423360","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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