Pub Date : 2024-07-09DOI: 10.24930/2500-302x-2024-24-3-566-581
D. Demezhko, A. A. Gornostaeva, B. D. Khatskevich, A. G. Vdovin, N. R. Fakaeva
Research subject. The subsurface thermal field in the city of Ekaterinburg (subsurface urban heat island). Aim. To determine criteria for the anomaly of mean annual subsurface temperatures in Ekaterinburg; to identify patterns of spatial distribution of underground temperatures; to quantify the main factors forming an urban heat island and changes in the heat content of rocks using mathematical modeling. Materials and methods. The main experimental data were obtained during the annual cycle of geothermal studies in observational boreholes of Ekaterinburg (22 boreholes) and surrounding areas (10 boreholes in Degtyarskiy, Verkh-Sysertskiy, Gagarskiy districts). Statistical analysis and mathematical modeling describing the impact of climate, local temperature anomalies of ground surface, and groundwater filtration to the underground thermal field were used when interpreting the obtained data. Results. At a depth of 20 m, the mean annual temperatures being less than 5°C and more than 6°C should be considered as anomalous. The maximum intensity of the urban heat island in Ekaterinburg is confined to densely built-up central areas of the city. The highest temperatures (>10°C) at a depth of 20 m are observed in boreholes located near buildings or directly therein. Here, a rapid decrease in temperature with depth is typical. Moderate anomalies from 6°C to 10°C are observed far from buildings. Remoteness from the central regions apparently plays a more important role in the formation of temperature anomalies than the type of urban surfaces (asphalt, concrete, lawns). Background temperatures (less than 6°C) were recorded in boreholes located outside the Ring Road. An analysis of patterns in the attenuation of annual temperature variations with depth allowed an area with intense vertical filtration (up to 24 m/year) to be identified near the City Pond. The most significant changes in heat content in the range of 10–50 m are associated with heat leakage from the basements of buildings, equaling to (23–46) × 107 J/m2. However, this heat is only hundredths of a percent of the total energy consumption spent on heating. Conclusions. The subsurface urban heat island of a large Russian city has been characterized for the first time. The results obtained can be used when developing a strategy for megacities in changing climate conditions.
{"title":"Subsurface urban heat island in the city of Ekaterinburg","authors":"D. Demezhko, A. A. Gornostaeva, B. D. Khatskevich, A. G. Vdovin, N. R. Fakaeva","doi":"10.24930/2500-302x-2024-24-3-566-581","DOIUrl":"https://doi.org/10.24930/2500-302x-2024-24-3-566-581","url":null,"abstract":"Research subject. The subsurface thermal field in the city of Ekaterinburg (subsurface urban heat island). Aim. To determine criteria for the anomaly of mean annual subsurface temperatures in Ekaterinburg; to identify patterns of spatial distribution of underground temperatures; to quantify the main factors forming an urban heat island and changes in the heat content of rocks using mathematical modeling. Materials and methods. The main experimental data were obtained during the annual cycle of geothermal studies in observational boreholes of Ekaterinburg (22 boreholes) and surrounding areas (10 boreholes in Degtyarskiy, Verkh-Sysertskiy, Gagarskiy districts). Statistical analysis and mathematical modeling describing the impact of climate, local temperature anomalies of ground surface, and groundwater filtration to the underground thermal field were used when interpreting the obtained data. Results. At a depth of 20 m, the mean annual temperatures being less than 5°C and more than 6°C should be considered as anomalous. The maximum intensity of the urban heat island in Ekaterinburg is confined to densely built-up central areas of the city. The highest temperatures (>10°C) at a depth of 20 m are observed in boreholes located near buildings or directly therein. Here, a rapid decrease in temperature with depth is typical. Moderate anomalies from 6°C to 10°C are observed far from buildings. Remoteness from the central regions apparently plays a more important role in the formation of temperature anomalies than the type of urban surfaces (asphalt, concrete, lawns). Background temperatures (less than 6°C) were recorded in boreholes located outside the Ring Road. An analysis of patterns in the attenuation of annual temperature variations with depth allowed an area with intense vertical filtration (up to 24 m/year) to be identified near the City Pond. The most significant changes in heat content in the range of 10–50 m are associated with heat leakage from the basements of buildings, equaling to (23–46) × 107 J/m2. However, this heat is only hundredths of a percent of the total energy consumption spent on heating. Conclusions. The subsurface urban heat island of a large Russian city has been characterized for the first time. The results obtained can be used when developing a strategy for megacities in changing climate conditions.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"96 12","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141663971","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 : 2024-07-08DOI: 10.24930/2500-302x-2024-24-3-507-525
K. S. Popvasev, A. Pystin, O. Grakova, Y. Pystina, E. V. Kushmanova, V. Khubanov
Research subject. Quartzites that make up the ridge part of the ridge Rosomaha in the northern part of the Lyapinsky meganticlinorium in the Subpolar Urals. Material and methods. Detrital zircons were isolated from quartzites and their optical and isotope-geochronological U-Pb (LA-SF-ICP-MS) studies were performed. On the basis of chemical analyzes of rocks using indicator ratios and coefficients, the conditions for the formation of deposits were established. Results. The stratigraphic position of the quartzite ridge Rosomaha was determined. The time and conditions for the formation of the Khobeinskaya formation were specified. The role of polymetamorphic complexes of the Subpolar Urals as possible sources of terrigenous material removal during the formation of the Upper Precambrian section of the Subpolar Urals was estimated. Conclusions. It was established that the quartzites belong to the ridge Rosomaha to the Khobeinskaya formation, whose age is limited to the interval of 850–800 Ma (Inzersky level). It is shown that the crystalline complexes of Fennoscandia and the Central Russian orogen, as well as polymetamorphic complexes of the crystalline basement of the Timan-Severoural margin of the East European Platform, could be sources of terrigenous material.
{"title":"Quartzites of the Khobeinskaya suite of the Subpolar Urals: Material composition, age limitations and possible sources of terrigenous material","authors":"K. S. Popvasev, A. Pystin, O. Grakova, Y. Pystina, E. V. Kushmanova, V. Khubanov","doi":"10.24930/2500-302x-2024-24-3-507-525","DOIUrl":"https://doi.org/10.24930/2500-302x-2024-24-3-507-525","url":null,"abstract":"Research subject. Quartzites that make up the ridge part of the ridge Rosomaha in the northern part of the Lyapinsky meganticlinorium in the Subpolar Urals. Material and methods. Detrital zircons were isolated from quartzites and their optical and isotope-geochronological U-Pb (LA-SF-ICP-MS) studies were performed. On the basis of chemical analyzes of rocks using indicator ratios and coefficients, the conditions for the formation of deposits were established. Results. The stratigraphic position of the quartzite ridge Rosomaha was determined. The time and conditions for the formation of the Khobeinskaya formation were specified. The role of polymetamorphic complexes of the Subpolar Urals as possible sources of terrigenous material removal during the formation of the Upper Precambrian section of the Subpolar Urals was estimated. Conclusions. It was established that the quartzites belong to the ridge Rosomaha to the Khobeinskaya formation, whose age is limited to the interval of 850–800 Ma (Inzersky level). It is shown that the crystalline complexes of Fennoscandia and the Central Russian orogen, as well as polymetamorphic complexes of the crystalline basement of the Timan-Severoural margin of the East European Platform, could be sources of terrigenous material.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"115 47","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141666809","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 : 2024-07-08DOI: 10.24930/2500-302x-2024-24-3-526-546
S. A. Onishchenko, S. K. Kuznetsov
Research subject. Minerals of palladium, platinum, and native gold, localized mainly in the veins of chromium-containing mica (fuchsite) in rhyolites. Aim. Clarification of the localization features of platinum group minerals, their species diversity, determination of the composition of minerals, relationships between precious metal minerals, establishment of the sequence of formation. Methods. Polished sections from ore samples and concentrates of heavy minerals mounted in epoxy resin were studied using optical and electron microscopes. The composition of minerals was determined using a scanning electron microscope with an energy dispersive spectrometer. Results. The main Pd minerals of the deposit are isomertieite/pseudomertieite and mertieite, the minor ones are ateneite and the unnamed Pd6BiSe mineral, and the platinum mineral is sperrylite. Isomertieite/pseudomertieite forms intergrowths with gold of any composition and structure, while mertieite occurs only with relatively low-copper gold of a homogeneous structure; therefore, significant areas of ore zones are characterized by the presence of one of the palladium arsenoantimonides. In some areas of ores, the replacement of isomertieite/pseudomertieite by mertieite wass established. Conclusions. The formation of fuchsite veinlets and the native gold, palladium minerals, and sperrylite contained therein is associated with one stage of mineral formation. Cr, Au, Pd, and Pt in ores form a single geochemical association, which indicates a common source of these elements. This source is most likely to be derivatives of basite-hyperbasite magmatism.
{"title":"Palladium and platinum minerals in Au-Pd ores of the Chudnoe deposit (Subpolar Urals, Russia)","authors":"S. A. Onishchenko, S. K. Kuznetsov","doi":"10.24930/2500-302x-2024-24-3-526-546","DOIUrl":"https://doi.org/10.24930/2500-302x-2024-24-3-526-546","url":null,"abstract":"Research subject. Minerals of palladium, platinum, and native gold, localized mainly in the veins of chromium-containing mica (fuchsite) in rhyolites. Aim. Clarification of the localization features of platinum group minerals, their species diversity, determination of the composition of minerals, relationships between precious metal minerals, establishment of the sequence of formation. Methods. Polished sections from ore samples and concentrates of heavy minerals mounted in epoxy resin were studied using optical and electron microscopes. The composition of minerals was determined using a scanning electron microscope with an energy dispersive spectrometer. Results. The main Pd minerals of the deposit are isomertieite/pseudomertieite and mertieite, the minor ones are ateneite and the unnamed Pd6BiSe mineral, and the platinum mineral is sperrylite. Isomertieite/pseudomertieite forms intergrowths with gold of any composition and structure, while mertieite occurs only with relatively low-copper gold of a homogeneous structure; therefore, significant areas of ore zones are characterized by the presence of one of the palladium arsenoantimonides. In some areas of ores, the replacement of isomertieite/pseudomertieite by mertieite wass established. Conclusions. The formation of fuchsite veinlets and the native gold, palladium minerals, and sperrylite contained therein is associated with one stage of mineral formation. Cr, Au, Pd, and Pt in ores form a single geochemical association, which indicates a common source of these elements. This source is most likely to be derivatives of basite-hyperbasite magmatism.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"101 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141667084","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 : 2024-07-08DOI: 10.24930/2500-302x-2024-24-3-547-565
S. V. Berzin, S. V. Petrov, D. L. Konopelko, M. Y. Kurapov, T. A. Golovina, N. Y. Chernenko, V. Chervyakovskiy
Research subject. The Tessemsky granite massif is located in the North Taimyr tectonic zone, surrounded by Cambrian rocks. The Pekinsky granite massif is located within the Central Taimyr zone, surrounded by metamorphosed Proterozoic rocks. Aim. To develop a methodology for using the composition of accessory granitoid minerals when prospecting Cu-Mo-Au-porphyry mineralization on the example of the Pekinsky and Tessemsky granitoid massifs of the Taimyr Peninsula. Materials and methods. Accessory zircon and apatite contained in two granitoid samples from the Pekinsky massif (P1, P2) and two granitoid samples from the Tessemsky massif (T2, T3) were studied. Their mineral composition was examined using an EPMA Cameca SX100 instrument. The element content in minerals was determined by LA-ICPMS using an NexION 300S instrument equipped with an NWR 213 attachment. Results. Most of the zircons from the Pekinsky and Tessemsky massifs were formed at T < 738°C in oxidized magma with ΔFMQ of 0.6–2.6, which is a favorable sign for the identification of Cu-Mo-Au-porphyry mineralization. Zircons are characterized by elevated (Eu/Eu*)Y and (Ce/Nd)n/Y ratios, which is also a favorable, though not a strongly reliable, sign for identifying porphyry mineralization. The Eu/Eu* and Sr/Y ratios in the apatites from the Tessemsky massif are higher than those in the apatites from the Pekinsky massif. The rock compositions of both massifs fall within the fields of adakites on the classification diagrams. The estimates of oxygen fugacity (logfO2) calculated from Mn in apatites for four samples agree well within the error limits. Conclusion. Specific features of using the composition of accessory minerals (zircon and apatite) for prospecting the Cu-Mo-Au-porphyry mineralization associated with granitoids were considered. Accessory indicator minerals can be used to rank granitoid massifs in order to assess their ore content. The example of two granite intrusions of the Taimyr Peninsula made it was possible to show that the Tessemsky massif is more promising for the discovery of associated Cu-Mo-Auporphyry mineralization than the Pekinsky massif.
{"title":"Utilizing compositions of zircon and apatite for prospecting of Cu-Mo-Auporphyry mineralization in the Pekinsky and Tessemsky granitoid massifs of the Taimyr-Severozemelskaya folded area","authors":"S. V. Berzin, S. V. Petrov, D. L. Konopelko, M. Y. Kurapov, T. A. Golovina, N. Y. Chernenko, V. Chervyakovskiy","doi":"10.24930/2500-302x-2024-24-3-547-565","DOIUrl":"https://doi.org/10.24930/2500-302x-2024-24-3-547-565","url":null,"abstract":"Research subject. The Tessemsky granite massif is located in the North Taimyr tectonic zone, surrounded by Cambrian rocks. The Pekinsky granite massif is located within the Central Taimyr zone, surrounded by metamorphosed Proterozoic rocks. Aim. To develop a methodology for using the composition of accessory granitoid minerals when prospecting Cu-Mo-Au-porphyry mineralization on the example of the Pekinsky and Tessemsky granitoid massifs of the Taimyr Peninsula. Materials and methods. Accessory zircon and apatite contained in two granitoid samples from the Pekinsky massif (P1, P2) and two granitoid samples from the Tessemsky massif (T2, T3) were studied. Their mineral composition was examined using an EPMA Cameca SX100 instrument. The element content in minerals was determined by LA-ICPMS using an NexION 300S instrument equipped with an NWR 213 attachment. Results. Most of the zircons from the Pekinsky and Tessemsky massifs were formed at T < 738°C in oxidized magma with ΔFMQ of 0.6–2.6, which is a favorable sign for the identification of Cu-Mo-Au-porphyry mineralization. Zircons are characterized by elevated (Eu/Eu*)Y and (Ce/Nd)n/Y ratios, which is also a favorable, though not a strongly reliable, sign for identifying porphyry mineralization. The Eu/Eu* and Sr/Y ratios in the apatites from the Tessemsky massif are higher than those in the apatites from the Pekinsky massif. The rock compositions of both massifs fall within the fields of adakites on the classification diagrams. The estimates of oxygen fugacity (logfO2) calculated from Mn in apatites for four samples agree well within the error limits. Conclusion. Specific features of using the composition of accessory minerals (zircon and apatite) for prospecting the Cu-Mo-Au-porphyry mineralization associated with granitoids were considered. Accessory indicator minerals can be used to rank granitoid massifs in order to assess their ore content. The example of two granite intrusions of the Taimyr Peninsula made it was possible to show that the Tessemsky massif is more promising for the discovery of associated Cu-Mo-Auporphyry mineralization than the Pekinsky massif.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":" 7","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141668648","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 : 2024-07-07DOI: 10.24930/2500-302x-2024-24-3-429-450
A. V. Maslov
Research subject. Sandstones and clay rocks of the Lower, Middle, and Upper Riphean (the Kyrpino, Serafimovo, and Abdulino groups, respectively) of the Kamsko-Belsk aulacogen. Changes in the characteristic values of the ratios of a number of oxides and some trace elements that are the indicators of rock composition in paleowatersheds are considered, taking the hiatuses of different nature and duration into account. Methods. An analysis of the average values of K2O/Al2O3 etc., Th/Sc, La/Co and (La/Yb)N, characteristic of sandstones and fine-grained clastic rocks (shales, fine-grained clayey siltstones and mudstones) of the main lithostratigraphic units of the Riphean section, as well as an analysis of their changes given the position below and above the break surface. Results. Throughout the entire Riphean, regardless of breaks in sedimentation associated with certain rearrangements in the recharge and sedimentation areas, the lithogeochemical characteristics of both sandstones and fine-grained clastic rocks (K2O/Al2O3, TiO2/Al2O3, Th/Sc, La/Co, etc.) were found to experience no signi ficant changes. Conclusions. The hiatuses presented in the Riphean section of the Kamsko-Belsk aulacogene were unlikely to have any significant effect on the average values of a number of ratios–indicators of rock composition in paleowatersheds (K2O/Al2O3, SiO2/Al2O3, TiO2/Al2O3, Th/Sc, La/Co, and (La/Yb)N) in sandstones and clay rocks occurring below and above the hiatus surfaces. This suggests that there were no cardinal changes in the composition of rocks in the paleowatersheds surrounding such a large negative structure as the Kamsko-Belsk aulacogene during the Riphean. Similarly, no fundamental changes occurred in the pathways of clastics entering the sedimentation area associated with the named structure.
{"title":"Riphean of the Kamsko-Belsk aulacogen: Hiatuses and lithogeochemistry of clastic rocks","authors":"A. V. Maslov","doi":"10.24930/2500-302x-2024-24-3-429-450","DOIUrl":"https://doi.org/10.24930/2500-302x-2024-24-3-429-450","url":null,"abstract":"Research subject. Sandstones and clay rocks of the Lower, Middle, and Upper Riphean (the Kyrpino, Serafimovo, and Abdulino groups, respectively) of the Kamsko-Belsk aulacogen. Changes in the characteristic values of the ratios of a number of oxides and some trace elements that are the indicators of rock composition in paleowatersheds are considered, taking the hiatuses of different nature and duration into account. Methods. An analysis of the average values of K2O/Al2O3 etc., Th/Sc, La/Co and (La/Yb)N, characteristic of sandstones and fine-grained clastic rocks (shales, fine-grained clayey siltstones and mudstones) of the main lithostratigraphic units of the Riphean section, as well as an analysis of their changes given the position below and above the break surface. Results. Throughout the entire Riphean, regardless of breaks in sedimentation associated with certain rearrangements in the recharge and sedimentation areas, the lithogeochemical characteristics of both sandstones and fine-grained clastic rocks (K2O/Al2O3, TiO2/Al2O3, Th/Sc, La/Co, etc.) were found to experience no signi ficant changes. Conclusions. The hiatuses presented in the Riphean section of the Kamsko-Belsk aulacogene were unlikely to have any significant effect on the average values of a number of ratios–indicators of rock composition in paleowatersheds (K2O/Al2O3, SiO2/Al2O3, TiO2/Al2O3, Th/Sc, La/Co, and (La/Yb)N) in sandstones and clay rocks occurring below and above the hiatus surfaces. This suggests that there were no cardinal changes in the composition of rocks in the paleowatersheds surrounding such a large negative structure as the Kamsko-Belsk aulacogene during the Riphean. Similarly, no fundamental changes occurred in the pathways of clastics entering the sedimentation area associated with the named structure.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":" 37","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141670792","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 : 2024-07-07DOI: 10.24930/2500-302x-2024-24-3-451-478
S. Dub, O. Melnichuk, M. Krupenin
Research subject. Carbonate-siliciclastic deposits of the Lower Uk Subformation were thoroughly studied in the section along the Yuryuzan river (near Ust-Katav town, Chelyabinsk region) and correlated with subformation sections along the Basu, Zilim and Bolshoy Inzer rivers. Material and methods. A detailed description of the stratotype section was carried out; sandstones, siltstones and limestones were studied in thin sections. The sections were correlated with each other. Results. Relationships between the Lower Uk Subformation and the underlying deposits are studied. The petrographic characteristics of rocks are presented. The Lower Uk Subformation sequences are traced between sections of various structural-tectonic zones of the Bashkirian Mega-anticlinorium (BMA). Conclusions. The set of features supports the idea about the presence of a sedimentary hiatus at the base of the formation, even in the most complete sequences (which contain the locally developed Shubino Member of the Minyar Formation). In the stratotype and in other reference sections, the Lower Uk Subformation has a pronounced three-membered structure; it is subdivided into the lower (siliciclastic) Yamashta, middle (substantially carbonate) Akkostyak, and upper (siliciclastic-carbonate) Avdyrdak members. The lithofacies analysis results suggest a change in environments from coastal-marine siliciclastic to shallow-marine siliciclastic-carbonate (middle and inner ramps) due to fluctuations in the relative sea level and, probably, climate change. It was established that the area of the Suleimanovo anticline at latest Riphean corresponded to the distal sedimentary environments in comparison with the southern and western zones (Alatau anticlinorium) of the BMA.
{"title":"Carbonate-siliciclastic deposits of the Lower Uk Subformation (Neoproterozoic) in the stratotype section and its correlation within Bashkirian Mega-Anticlinorium of the Southern Urals","authors":"S. Dub, O. Melnichuk, M. Krupenin","doi":"10.24930/2500-302x-2024-24-3-451-478","DOIUrl":"https://doi.org/10.24930/2500-302x-2024-24-3-451-478","url":null,"abstract":"Research subject. Carbonate-siliciclastic deposits of the Lower Uk Subformation were thoroughly studied in the section along the Yuryuzan river (near Ust-Katav town, Chelyabinsk region) and correlated with subformation sections along the Basu, Zilim and Bolshoy Inzer rivers. Material and methods. A detailed description of the stratotype section was carried out; sandstones, siltstones and limestones were studied in thin sections. The sections were correlated with each other. Results. Relationships between the Lower Uk Subformation and the underlying deposits are studied. The petrographic characteristics of rocks are presented. The Lower Uk Subformation sequences are traced between sections of various structural-tectonic zones of the Bashkirian Mega-anticlinorium (BMA). Conclusions. The set of features supports the idea about the presence of a sedimentary hiatus at the base of the formation, even in the most complete sequences (which contain the locally developed Shubino Member of the Minyar Formation). In the stratotype and in other reference sections, the Lower Uk Subformation has a pronounced three-membered structure; it is subdivided into the lower (siliciclastic) Yamashta, middle (substantially carbonate) Akkostyak, and upper (siliciclastic-carbonate) Avdyrdak members. The lithofacies analysis results suggest a change in environments from coastal-marine siliciclastic to shallow-marine siliciclastic-carbonate (middle and inner ramps) due to fluctuations in the relative sea level and, probably, climate change. It was established that the area of the Suleimanovo anticline at latest Riphean corresponded to the distal sedimentary environments in comparison with the southern and western zones (Alatau anticlinorium) of the BMA.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":" 57","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141670766","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 : 2024-07-07DOI: 10.24930/2500-302x-2024-24-3-479-506
N. Inkina, V. Saldin
Research subject. The Upper Carboniferous-Lower Permian rocks of the Losinoostrov Formation of the Belsk-Eletsk structural-formational zone, exposed on the left bank of the Kozhim river, near the mouth of the stream Northnichael of the western slope of the Subpolar Urals. Methods. Optical and electron microscopic methods (including cathodoluminescence), chemical silicate, carbonate and X-ray diffraction analyses. Results and conclusions. The studied rocks are assigned to three main groups: mixtolites (rocks of mixed composition), carbonatoliths, and silicytolites with varieties. Mixtoliths consist of three and four main components: carbonate, silty, argillaceous and siliceous. The variable ratio of rock-forming components of mixtolites was clearly reflected in the discriminative modular diagram. Here, fields of predominantly siliceous and silty mixolites (cluster I), predominantly argillaceous (cluster III), as well as transitional mixolites (cluster II) are identified. Relatively pure and silty-argillaceous-siliceous limestones were distinguished among carbonatoliths. According to the formed elements, pure limestones are divided into bioclastic and peloid-micritic. Silicytolites are represented by (1) radiolarites and radiolarian spongoliths; (2) silty-argillaceous silicytolites and (3) cherts (secondary siliceous formations). The established quantitative ratios of rock-forming components showed that more than half of the studied mixtoliths are composed mainly of the material of extrabasinal origin. Relatively high contents of extrabasinal fine material in carbonatoliths indicate a periodic decrement of the hydrodynamic regime during the accumulation of the upper part of the formation. The studied deposits were probably formed in distal and proximal ramp settings.
研究课题贝尔茨克-埃列茨克构造形成带洛希诺斯特罗夫地层上石炭统-下二叠统岩石，出露于乌拉尔次极地西坡诺斯尼夏尔河口附近的科日姆河左岸。研究方法光学和电子显微镜方法（包括阴极发光）、化学硅酸盐、碳酸盐和 X 射线衍射分析。结果和结论。所研究的岩石主要分为三类：混合岩（混合成分的岩石）、碳岩和硅鲕粒。 混合岩由三种和四种主要成分组成：碳酸盐岩、硅质岩、霰石岩和硅质岩。混杂岩成岩成分的不同比例清楚地反映在判别模块图中。在这里，确定了以硅质和硅质混合岩为主的区域（群组 I）、以假火山岩为主的区域（群组 III）以及过渡混合岩（群组 II）。在碳酸盐岩中，还发现了相对纯净的硅质灰岩和硅质-镁质-硅质灰岩。根据形成的元素，纯灰岩分为生物碎屑岩和球状微晶岩。硅质灰岩的代表有：(1) 放射虫和放射虫海绵石；(2) 硅质-砾质硅质灰岩；(3) 凝灰岩（次生硅质地层）。已确定的成岩成分定量配比表明，所研究的半数以上混合岩主要由基质外物质组成。碳酸盐岩中基底外细小物质的含量相对较高，这表明在岩层上部的堆积过程中，水动力机制会周期性地减弱。所研究的沉积可能是在远端和近端斜坡环境中形成的。
{"title":"Composition features of the Upper Carboniferous-Lower Permian rocks of the Losinoostrov Fm. and the role of extrabasin sources in their formation (Subpolar Urals)","authors":"N. Inkina, V. Saldin","doi":"10.24930/2500-302x-2024-24-3-479-506","DOIUrl":"https://doi.org/10.24930/2500-302x-2024-24-3-479-506","url":null,"abstract":"Research subject. The Upper Carboniferous-Lower Permian rocks of the Losinoostrov Formation of the Belsk-Eletsk structural-formational zone, exposed on the left bank of the Kozhim river, near the mouth of the stream Northnichael of the western slope of the Subpolar Urals. Methods. Optical and electron microscopic methods (including cathodoluminescence), chemical silicate, carbonate and X-ray diffraction analyses. Results and conclusions. The studied rocks are assigned to three main groups: mixtolites (rocks of mixed composition), carbonatoliths, and silicytolites with varieties. Mixtoliths consist of three and four main components: carbonate, silty, argillaceous and siliceous. The variable ratio of rock-forming components of mixtolites was clearly reflected in the discriminative modular diagram. Here, fields of predominantly siliceous and silty mixolites (cluster I), predominantly argillaceous (cluster III), as well as transitional mixolites (cluster II) are identified. Relatively pure and silty-argillaceous-siliceous limestones were distinguished among carbonatoliths. According to the formed elements, pure limestones are divided into bioclastic and peloid-micritic. Silicytolites are represented by (1) radiolarites and radiolarian spongoliths; (2) silty-argillaceous silicytolites and (3) cherts (secondary siliceous formations). The established quantitative ratios of rock-forming components showed that more than half of the studied mixtoliths are composed mainly of the material of extrabasinal origin. Relatively high contents of extrabasinal fine material in carbonatoliths indicate a periodic decrement of the hydrodynamic regime during the accumulation of the upper part of the formation. The studied deposits were probably formed in distal and proximal ramp settings.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":" 42","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141671451","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 : 2024-05-07DOI: 10.24930/1681-9004-2024-24-2-347-363
L. I. Bogdanova, Yulia Shchapova, L. Y. Sushanek, E. A. Vasiliev, S. L. Votyakov
Aim. To describe a technique for studying the internal structural heterogeneity of natural diamond crystals, based on confocal Raman spectroscopy with polarization analysis, including angular resolution, at high spectral (0.5–0.6 cm–1) and spatial (1 μm) resolution. Results. The parameters of the F2g vibrational mode in diamond (position, width, intensity, shape, including the Gaussian and Lorentzian contributions to the broadening) are determined by the superposition influence of a number of factors, including the type and content of structural stresses, deformations, various types of defects, as well as orientation of crystallographic axes of the crystal relative to the directions of incident and scattered rays and the directions of their electric polarization vectors. The proposed analytical technique includes: (1) analysis of the crystallographic orientation of the sample in the spectrometer coordinate system and possible misorientations of its fragments with an error of ≈8–15°; (2) visualization of the distribution of structural stresses, deformations, twins, impurity defects and their associates based on sample surface mapping by spectral parameters of the F2g vibration mode; (3) obtaining statistical characteristics of the internal structural heterogeneity of the samples based on diagrams of spectral parameter frequency with a statistically significant number (≈103): unimodality (uni-, bimodal distributions) and distribution dispersion (from ≈0.1 to ≈0.6 cm–1 for width and from ≈0.04 to ≈0.6 cm–1 for line position). The procedure was tested using two synthetic CVD diamond single crystals doped with nitrogen and boron. The possibility of typification of natural samples by statistical characteristics of internal heterogeneity is considered using the example of samples from kimberlite pipes of Yakutia and placers of the Western Cis-Urals. Conclusions. A method for determining the internal structural heterogeneity of natural diamond crystals based on confocal Raman spectroscopy with polarization analysis is proposed. The possibility of using statistical characteristics of heterogeneity as a typomorphic feature of the original diamond source is demonstrated. The proposed diagrams are promising for sample comparison and typification.
{"title":"Determination of the internal structural heterogeneity of natural diamond: Methodological aspects of using confocal Raman spectroscopy with polarization analysis","authors":"L. I. Bogdanova, Yulia Shchapova, L. Y. Sushanek, E. A. Vasiliev, S. L. Votyakov","doi":"10.24930/1681-9004-2024-24-2-347-363","DOIUrl":"https://doi.org/10.24930/1681-9004-2024-24-2-347-363","url":null,"abstract":"Aim. To describe a technique for studying the internal structural heterogeneity of natural diamond crystals, based on confocal Raman spectroscopy with polarization analysis, including angular resolution, at high spectral (0.5–0.6 cm–1) and spatial (1 μm) resolution. Results. The parameters of the F2g vibrational mode in diamond (position, width, intensity, shape, including the Gaussian and Lorentzian contributions to the broadening) are determined by the superposition influence of a number of factors, including the type and content of structural stresses, deformations, various types of defects, as well as orientation of crystallographic axes of the crystal relative to the directions of incident and scattered rays and the directions of their electric polarization vectors. The proposed analytical technique includes: (1) analysis of the crystallographic orientation of the sample in the spectrometer coordinate system and possible misorientations of its fragments with an error of ≈8–15°; (2) visualization of the distribution of structural stresses, deformations, twins, impurity defects and their associates based on sample surface mapping by spectral parameters of the F2g vibration mode; (3) obtaining statistical characteristics of the internal structural heterogeneity of the samples based on diagrams of spectral parameter frequency with a statistically significant number (≈103): unimodality (uni-, bimodal distributions) and distribution dispersion (from ≈0.1 to ≈0.6 cm–1 for width and from ≈0.04 to ≈0.6 cm–1 for line position). The procedure was tested using two synthetic CVD diamond single crystals doped with nitrogen and boron. The possibility of typification of natural samples by statistical characteristics of internal heterogeneity is considered using the example of samples from kimberlite pipes of Yakutia and placers of the Western Cis-Urals. Conclusions. A method for determining the internal structural heterogeneity of natural diamond crystals based on confocal Raman spectroscopy with polarization analysis is proposed. The possibility of using statistical characteristics of heterogeneity as a typomorphic feature of the original diamond source is demonstrated. The proposed diagrams are promising for sample comparison and typification.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"34 S131","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141003756","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 : 2024-05-07DOI: 10.24930/1681-9004-2024-24-2-416-423
S. Mamontova, O. Belozerova
Research subject. Silicate ingots containing four species-forming components Be, Mg, Al, and Si and belonging to the crystallization region of beryllium indialite (with the formula of Mg2BeAl2Si6O18 and a beryl-type structure). Aim. To investigate the fundamental problem of identifying the patterns of matter differentiation and the stable and metastable phase formation in silicate matrices. Methods. The evolution of the phase composition of silicate melts was registered using a temperature gradient method. Results. New data on the features of phase transformations in silicate melts belonging to the region of beryllium indialite were obtained by electron probe microanalysis (EPMA). Co-existing metastable and stable mineral phases were identified, and the similarity of their compositions with different structures was shown. The nature of impurity phases at each stage of crystallization was established. Conclusions. The evolutionary sequence of phase associations ensuring the crystallization of beryllium indialite and metastable phases of a similar composition, the nature of which is determined by the initial ratio of components, was experimentally recorded. The range of possible phase associations that co-crystallize or replace a stable phase with a beryl structure in melts from the region of existence of beryllium indialite in the BeO–MgO–Al2O3–SiO2 system was extended. The selectivity of the coloring element chromium entry into various phases of the studied system is shown depending on the capabilities of their structure. The addition of a chromophore is a reliable criterion for visualizing successive layers, zones, and areas of changing phase associations in the final ingot.
研究课题。含有 Be、Mg、Al 和 Si 四种成分的硅酸盐锭，属于铍铟铁矿（分子式为 Mg2BeAl2Si6O18，具有绿柱石型结构）的结晶区域。目的研究确定硅酸盐基体中物质分化和稳定与蜕变相形成规律的基本问题。方法。采用温度梯度法记录硅酸盐熔体相组成的演变过程。结果。通过电子探针显微分析（EPMA）获得了属于铍铟锡石区域的硅酸盐熔体中相变特征的新数据。确定了共存的可蜕变和稳定矿物相，并显示了不同结构矿物相组成的相似性。确定了每个结晶阶段杂质相的性质。得出结论。实验记录了确保铍铟铁矿和成分相似的可转移相结晶的相联演化顺序，其性质由初始成分比例决定。扩大了在 BeO-MgO-Al2O3-SiO2 体系中铍铟铁矿存在区域的熔体中与绿柱石结构共晶或取代稳定相的可能相联范围。研究表明，着色元素铬进入所研究体系各相的选择性取决于其结构的能力。添加发色团是观察最终铸锭中相联变化的连续层、带和区域的可靠标准。
{"title":"Studying the features of complex beryllium-containing silicate phases co-crystallization in zonal samples using the x-ray electron probe microanalysis method","authors":"S. Mamontova, O. Belozerova","doi":"10.24930/1681-9004-2024-24-2-416-423","DOIUrl":"https://doi.org/10.24930/1681-9004-2024-24-2-416-423","url":null,"abstract":"Research subject. Silicate ingots containing four species-forming components Be, Mg, Al, and Si and belonging to the crystallization region of beryllium indialite (with the formula of Mg2BeAl2Si6O18 and a beryl-type structure). Aim. To investigate the fundamental problem of identifying the patterns of matter differentiation and the stable and metastable phase formation in silicate matrices. Methods. The evolution of the phase composition of silicate melts was registered using a temperature gradient method. Results. New data on the features of phase transformations in silicate melts belonging to the region of beryllium indialite were obtained by electron probe microanalysis (EPMA). Co-existing metastable and stable mineral phases were identified, and the similarity of their compositions with different structures was shown. The nature of impurity phases at each stage of crystallization was established. Conclusions. The evolutionary sequence of phase associations ensuring the crystallization of beryllium indialite and metastable phases of a similar composition, the nature of which is determined by the initial ratio of components, was experimentally recorded. The range of possible phase associations that co-crystallize or replace a stable phase with a beryl structure in melts from the region of existence of beryllium indialite in the BeO–MgO–Al2O3–SiO2 system was extended. The selectivity of the coloring element chromium entry into various phases of the studied system is shown depending on the capabilities of their structure. The addition of a chromophore is a reliable criterion for visualizing successive layers, zones, and areas of changing phase associations in the final ingot.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"38 4","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141004149","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 : 2024-05-07DOI: 10.24930/1681-9004-2024-24-2-376-397
V. A. Bulatov, D. A. Zamyatin, S. L. Votyakov, D. D. Korovin, V. N. Smirnov, S. V. Pribavkin
Research subject. Phosphate mineral geochronometers – the international reference sample of Trebilcock monazite from pegmatites with the age of 272 ± 2 Ma, as well as samples of monazite from pegmatites of the Shartash massif and monazite, cheralite and xenotime from leucogranite of the Peshcherninsky stock and diorite of the Khomutinsky massif, Middle Urals. Methods. The composition of minerals was studied using CAMECA SX100 microprobe; Raman spectra were obtained using LabRAM HR800 Evolution confocal spectrometer. Research aim. Study of the internal texture of the grains of phosphate minerals on the basis of their elemental and spectroscopic mapping; analysis of the mineral crystal chemistry and estimation of auto-irradiation doses; microprobe non-isotopic U–Th–Pbtot dating of phosphate minerals; development of the appropriate algorithm for using analytical techniques. Results. It has been shown that the studied monazites belong to the cerium variety with ThO2 content from 1.1 to 17.2; UO2 – from 0 to 0.8; PbO – from 0.01 to 0.23 wt % (detection limits 160, 230, and 110 ppm). When analyzing the PbO content, the background line was interpolated into models of linear background (Trebilcock monazite, monazite and cheralite of the Peshcherninsky stock) and exponential background (monazite of the Shartash massif). It has been shown that for monazite, both huttonite and cheralite types of isomorphism are realized; the non-stoichiometric parameter of its composition β = (Si + Ca)/(Th + U + Pb + S) lies in the range of 0.95–1.05, which indicates the preservation of the U–Th–Pb-system. The analysis of BSE-images, intensity distribution maps of the Th Mα and Pb Mα RE lines, compositional point analyses and the results of spectroscopic mapping of the parameters of the ν1(PO4) vibrational mode testify to high homogeneity of Trebilcock monazite and pronounced zoning of the Ural monazites. It has been shown that the parameters of the ν1(PO4) vibrational mode in monazites are determined by the superposition of two factors, i.e. chemical and radiation disorder. The data on U, Th, and Pb content for different zones of monazite grains were used to perform non-isotopic U–Th–Pbtot dating: weighted average age values for the zones were obtained, and isochron plotting was made on the ThO2* vs. PbO diagram. The datings obtained based on the Trebilcock sample are in satisfactory agreement with the literature. Conclusions. The dating of monazite from leucogranite of the Peshcherninsky stock and the Shartash massif are in agreement with the U-Pb isotopic dating of zircon. The physical and chemical characteristics of cheralite, xenotime, and zircon in samples from the Peshcherninsky stock were analyzed. The U–Th–Pbtot dating of cheralite, xenotime, and zircon was attempted. The described algorithm and analytical methods were used at the Geoanalitik Common Use Center for microprobe non-isotopic dating of phosphate minerals.
{"title":"Phosphate geochronometer minerals: Crystal chemistry and radiation disorder, methodological issues of their microprobe non-isotope U–Th–Pbtot dating","authors":"V. A. Bulatov, D. A. Zamyatin, S. L. Votyakov, D. D. Korovin, V. N. Smirnov, S. V. Pribavkin","doi":"10.24930/1681-9004-2024-24-2-376-397","DOIUrl":"https://doi.org/10.24930/1681-9004-2024-24-2-376-397","url":null,"abstract":"Research subject. Phosphate mineral geochronometers – the international reference sample of Trebilcock monazite from pegmatites with the age of 272 ± 2 Ma, as well as samples of monazite from pegmatites of the Shartash massif and monazite, cheralite and xenotime from leucogranite of the Peshcherninsky stock and diorite of the Khomutinsky massif, Middle Urals. Methods. The composition of minerals was studied using CAMECA SX100 microprobe; Raman spectra were obtained using LabRAM HR800 Evolution confocal spectrometer. Research aim. Study of the internal texture of the grains of phosphate minerals on the basis of their elemental and spectroscopic mapping; analysis of the mineral crystal chemistry and estimation of auto-irradiation doses; microprobe non-isotopic U–Th–Pbtot dating of phosphate minerals; development of the appropriate algorithm for using analytical techniques. Results. It has been shown that the studied monazites belong to the cerium variety with ThO2 content from 1.1 to 17.2; UO2 – from 0 to 0.8; PbO – from 0.01 to 0.23 wt % (detection limits 160, 230, and 110 ppm). When analyzing the PbO content, the background line was interpolated into models of linear background (Trebilcock monazite, monazite and cheralite of the Peshcherninsky stock) and exponential background (monazite of the Shartash massif). It has been shown that for monazite, both huttonite and cheralite types of isomorphism are realized; the non-stoichiometric parameter of its composition β = (Si + Ca)/(Th + U + Pb + S) lies in the range of 0.95–1.05, which indicates the preservation of the U–Th–Pb-system. The analysis of BSE-images, intensity distribution maps of the Th Mα and Pb Mα RE lines, compositional point analyses and the results of spectroscopic mapping of the parameters of the ν1(PO4) vibrational mode testify to high homogeneity of Trebilcock monazite and pronounced zoning of the Ural monazites. It has been shown that the parameters of the ν1(PO4) vibrational mode in monazites are determined by the superposition of two factors, i.e. chemical and radiation disorder. The data on U, Th, and Pb content for different zones of monazite grains were used to perform non-isotopic U–Th–Pbtot dating: weighted average age values for the zones were obtained, and isochron plotting was made on the ThO2* vs. PbO diagram. The datings obtained based on the Trebilcock sample are in satisfactory agreement with the literature. Conclusions. The dating of monazite from leucogranite of the Peshcherninsky stock and the Shartash massif are in agreement with the U-Pb isotopic dating of zircon. The physical and chemical characteristics of cheralite, xenotime, and zircon in samples from the Peshcherninsky stock were analyzed. The U–Th–Pbtot dating of cheralite, xenotime, and zircon was attempted. The described algorithm and analytical methods were used at the Geoanalitik Common Use Center for microprobe non-isotopic dating of phosphate minerals.","PeriodicalId":18202,"journal":{"name":"LITHOSPHERE (Russia)","volume":"76 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141004244","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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