{"title":"U–Pb Age and Mineral Inclusions in Zircon from Diamondiferous Garnet–Pyroxene Rocks of the Kumdy-Kol Microdiamond Deposit in Northern Kazakhstan","authors":"A.A. Ilyin, V. Shatsky, A. Ragozin","doi":"10.2113/rgg20234661","DOIUrl":"https://doi.org/10.2113/rgg20234661","url":null,"abstract":"\u0000 ––This paper describes the results of studying inclusions and determining the U–Pb age in zircon from the diamondiferous garnet–pyroxene rock of the Kumdy-Kol metamorphogenic diamond deposit, located in the Kokchetav subduction-collision zone. The distribution of rare earth elements in garnet and clinopyroxene is used as a basis for estimating the equilibrium pressure (5.5 ± 0.3 GPa) and temperature (993 ± 24 °C), which correspond to the diamond stability field. The composition of mineral inclusions in zircon indicates its formation at both the progressive and the regressive stage of metamorphism. The concordia diagram shows that the figurative points of zircon lie on a discordia with an upper intersection at 1953 ± 139 Ma and a lower intersection at 512 ± 4 Ma. The main peak on the graph of the probability density distribution of zircon ages corresponds to an age of 519 Ma. The presence of grossular–almandine garnet inclusions in zircon confirms the previous assumption that the basement rocks of the Kokchetav massif act as protoliths of garnet–pyroxene rocks.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140490302","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The Age, Composition, and Provenances of Terrigenous Rocks in the South of the Sangilen Block of the Central Asian Orogenic Belt","authors":"L.G. Kuznetsova, S. I. Dril, S. I. Shkol’nik","doi":"10.2113/rgg20234622","DOIUrl":"https://doi.org/10.2113/rgg20234622","url":null,"abstract":"\u0000 —We have first determined the petrogeochemical, Sm–Nd isotope, and U–Th–Pb geochronological (detrital-zircon LA-ICP-MS) characteristics of terrigenous rocks from a thick sequence in the south of the Sangilen block, which is part of the Central Asian Orogenic Belt (CAOB). The rocks are heterogeneous in facies composition: From west to east, there is a transition from graywacke sandstones with an admixture of pyroclastics to much more silicic lithoid arenites. Geochronological data on detrital zircons from the predominant graywacke sandstones mark the following intervals of concordant ages (Ma): 787–907, 1870–2236, 2613–2725, and 2900–2980. With regard to the oldest determined age (early Cambrian, 520 Ma) of the igneous rocks intruding these sandstones, the possible period of accumulation of terrigenous sequences in the south of the Sangilen block is estimated at 790–520 Ma. The obtained geochemical, Sm–Nd isotope, and U–Th–Pb geochronological data point to Neoproterozoic and early Precambrian island arc and continent-marginal complexes as probable provenances for the terrigenous deposits of the “southern band”. The relative proportions of rocks of these complexes in the deposits changed with distance from the sedimentary basin (from west to east, in modern coordinates): The portion of early Neoproterozoic juvenile rocks decreased, and the portion of early Precambrian metamorphic complexes increased. The Paleoproterozoic and Mezoarchean detrital zircons found in the terrigenous rocks of the Sangilen block could not originate from any known Precambrian complexes of the Tuva–Mongolian microcontinent. This gives grounds to regard other craton blocks of the CAOB as their sources.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140496275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Vanadian–Chromian Spinels (Sludyanka Metamorphic Complex, South Baikal Area). Magnesian Spinel","authors":"L. Reznitsky, E. Sklyarov, I. G. Barash","doi":"10.2113/rgg20234659","DOIUrl":"https://doi.org/10.2113/rgg20234659","url":null,"abstract":"\u0000 —The paper presents data on two groups of magnesian Cr–V spinel occurring as rock-forming minerals in various types of Cr–V bearing rocks of the Sludyanka metamorphic complex (South Baikal area, Siberia, Russia): (i) low-Al magnesiochromite–magnesiocoulsonite spinels and (ii) Al spinels varying from V-bearing aluminous magnesiochromite and Al–Cr coulsonite to spinel proper with minor contents of Cr and V, and with complex zoning patterns. Spinels in the Sludyanka rocks are also present as iron-magnesian accessories, among which high-Cr varieties are compositionally similar to mantle-derived spinel from igneous rocks and to inclusions in diamonds. Comparison of formation conditions for mantle spinels in igneous lithologies and spinel phases in metamorphic rocks shows that their mineral chemistry is mainly controlled by the bulk composition of the igneous and sedimentary protoliths, respectively. Detrital spinel may be a false indicator poorly applicable to paleogeodynamic reconstructions and diamond potential evaluation.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139619881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
V.A. Kontorovich, A. Kontorovich, D. V. Ayunova, S.M. Ibragimova, L. Burshtein, A. Kalinin, L. Kalinina, K. Kanakova, E. Kostyreva, M. V. Solovyev, Yu.F. Filippov
{"title":"Geological Structure and Prospects of Hydrocarbon Potential of Paleozoic Deposits in Southeastern Regions of West Siberia","authors":"V.A. Kontorovich, A. Kontorovich, D. V. Ayunova, S.M. Ibragimova, L. Burshtein, A. Kalinin, L. Kalinina, K. Kanakova, E. Kostyreva, M. V. Solovyev, Yu.F. Filippov","doi":"10.2113/rgg20234657","DOIUrl":"https://doi.org/10.2113/rgg20234657","url":null,"abstract":"\u0000 —In this paper we analyze the geological structure and prospects of hydrocarbon potential of the Paleozoic deposits in southeastern regions of West Siberia, including the Tomsk, Novosibirsk, Omsk regions and the southwest of the Krasnoyarsk Territory in the left-bank part of the Yenisei River. In the process of our studies, we analyzed the tectonic structure of the basement and made a conclusion that most of the studied area is occupied by the Central West Siberian zone of Late Hercynides. In the northeast of the Tomsk region and the adjacent area of the Krasnoyarsk Territory, the cis-Yenisei Upper Protezoic–Paleozoic sedimentary subbasin, lying on the pre-Baikal basement, developed. We constructed regional-zonal models of the Riphean–Cambrian deposits of the cis-Yenisei subprovince and Paleozoic deposits in the area of distribution of Hercynides and analyzed the material composition and age of the rocks of the pre-Jurassic basement. We assessed hydrocarbon potential of the Upper Proterozoic–Paleozoic deposits, identified prospective blocks and objects, developed seismogeological criteria to identify and map in detail the Paleozoic oil and gas prospective reservoirs and constructed seismogeological models of reference fields.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139631879","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Topical Issues of Petroleum Geology (90th birthday of Academician A.E. Kontorovich)","authors":"L. Burshtein, V.A. Kontorovich","doi":"10.2113/rgg20234696","DOIUrl":"https://doi.org/10.2113/rgg20234696","url":null,"abstract":"\u0000 —This issue of the journal is dedicated to the 90th birthday of Academician of the Russian Academy of Sciences A.E. Kontorovich. This introductory article reviews the included materials. The topics of the articles are closely connected to the scientific interests of Aleksei Emilievich, even though they are not fully represented. This anniversary issue includes articles concerning topical questions of geology, tectonics, stratigraphy, petroleum potential, as well as various aspects and characteristics of oil and organic matter geochemistry in oil-and-gas source formations of sedimentary basins of Siberia and the Arctic. Among the many lines of research A.E. Kontorovich pursued was the geology and geochemistry of concentrated forms of subsoil organic matter – coal. Therefore, this issue logically ends with an article on the study of the most ancient Devonian coals.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139636751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
P.N. Mel’nikov, A.I. Varlamov, N. K. Fortunatova, V. Poroskun, A.V. Solov’ev, M.B. Skvortsov, M.N. Kravchenko, A. Kanev, A.G. Sotnikova
{"title":"Results of Quantitative Estimation of Unconventional Oil Resources of the Russian Federation","authors":"P.N. Mel’nikov, A.I. Varlamov, N. K. Fortunatova, V. Poroskun, A.V. Solov’ev, M.B. Skvortsov, M.N. Kravchenko, A. Kanev, A.G. Sotnikova","doi":"10.2113/rgg20234679","DOIUrl":"https://doi.org/10.2113/rgg20234679","url":null,"abstract":"\u0000 —The estimation results of the initial total unconventional resources of hydrocarbon in Domanik type sediments, the Khadum and Bazhenov formations are provided. The reasonability of estimating hydrocarbon resources in these deposits by the volumetric method is substantiated. The stratigraphic interval of their distribution is given. The technique of oil and gas geological zoning based on the mapping of structural and facies zones, the degree of catagenetic transformation of organic matter, and the boundary values of the thickness of carbonaceous rocks in the section is described. The criteria for the allocation of pay intervals that make up the effective part of the section are determined. The choice of parameters such as porosity coefficient, oil recovery coefficient, oil saturation coefficient, correction factor and oil density is justified. For each complex of deposits, adjustments related to the features of the geological structure of the estimation targets, the conditions of their occurrence and the degree of geological and geophysical study have been introduced into the estimation of total geological resources. The volumes of total geological and recoverable resources of unconventional hydrocarbon sources for the Volga– Ural, Timan–Pechora, Black Sea–North Caucasus, West Siberian and Lena–Tunguska oil and gas provinces are given. The conducted research has rationalized extensive resources, the recovery of which can compensate for the decrease in oil volumes from traditional deposits.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2024-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139636305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Seismic Waves Penetrating the Earth’s Core: Analysis of Parameter Variations","authors":"V. Ovtchinnikov, O. Usoltseva","doi":"10.2113/rgg20234635","DOIUrl":"https://doi.org/10.2113/rgg20234635","url":null,"abstract":"\u0000 ––The wavefield structure is studied from explosions within the Mururoa atoll based on seismic records from four stations (BCAO, KAAO, GRFO, BRVK) located at distances 152.1º, 152.4º, 143.6º, 141.7º, respectively. The cross-correlation analysis was used as the main tool of the similarity of explosion seismograms conducted at different times. It has been concluded that changes in correlation similarity in time are reconcilable with the hypothesis of differential rotation of the Earth’s inner core in the period from 1977 to 1991. The evidence of structural anomalies not only in the inner core but also in the outer core has been demonstrated.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138960253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Spatial Correlations between the Terrain Features, Gravitational Field and Seismic Velocity Anomalies in the Central Kamchatka Region","authors":"E.I. Esin, A. Vasilevskiy, N. Bushenkova","doi":"10.2113/rgg20234579","DOIUrl":"https://doi.org/10.2113/rgg20234579","url":null,"abstract":"\u0000 ––Different approaches to tectonic zoning and different types (complexes) of used data, on the basis of which the zoning is performed, are the plurality of tectonic schemes of Kamchatka and the Kamchatka region previously obtained by different authors. In this work, a joint analysis of gravity field anomalies, gravity field and relief transforms, magnetic field and modern seismotomographic models of velocity anomalies was used to study spatial relationships of tectonic manifestations of geological processes. As a result of this study, a linear-block type tectonic scheme was constructed. The obtained linear structural elements are in good agreement with the data of potential fields, seismic constructions and previously published materials. The productivity of the presented method of complex analysis of geophysical fields for revealing their spatial relations and block structures of the environment is shown. The analysis outcomes can be used to establish spatial constraints for gravity field sources when solving inverse problems, potential field separation problems and their detailed geological interpretation.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-12-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138960086","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
N. Astakhova, O. Kolesnik, A. S. Astakhov, X. Shi, L. Hu, A. Alatortsev
{"title":"Precious Metals in the Holocene Sediments of the Chukchi Sea","authors":"N. Astakhova, O. Kolesnik, A. S. Astakhov, X. Shi, L. Hu, A. Alatortsev","doi":"10.2113/rgg20234598","DOIUrl":"https://doi.org/10.2113/rgg20234598","url":null,"abstract":"\u0000 ––We studied the distribution of gold, silver, and platinum group elements (Pd, Pt, Rh, Ir, and Ru) in two bottom sediment cores of the southern Chukchi Sea. It is shown that the Holocene pelite–silty sediments with an age of up to 4.0 ka BP are significantly enriched in these elements, except for Ru and Rh, relative to their clarkes. Native silver minerals were found in all samples by probe microanalysis, whereas gold minerals were revealed only in the surface layer of the sediment core closest to the Chukchi Sea coast. Multicomponent statistical analysis of the chemical composition and grain size of the sediments and the content of organic matter in them has led to the conclusion about the accumulation of clastogenic and chemogenic forms of precious metals. The abnormally high content of gold (0.3 ppm) in the recent sediments near the Chukchi Peninsula coast might be due to its additional removal from the continent as a result of the placer mining there.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139007951","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Novoselov, E. Belogub, I. Blinov, D. A. Artem’ev
{"title":"Detrital Chrome Spinels of the Udokan Sedimentary Basin in Transbaikalia","authors":"K. Novoselov, E. Belogub, I. Blinov, D. A. Artem’ev","doi":"10.2113/rgg20234632","DOIUrl":"https://doi.org/10.2113/rgg20234632","url":null,"abstract":"\u0000 ––The Udokan sedimentary basin is a unique geological structure containing many copperstone deposits and occurrences. A detrital chrome spinel is identified in the metasandstones of the Sakukan Formation at the Udokan and Unkur deposits, which tend to interlayers of natural heavy mineral concentrates. The mineral forms relict inclusions in magnetite crystals. Its composition is distinguished by high concentrations of zinc (up to 11.62 wt.% ZnO) and manganese (up to 6.32 wt.% MnO) with an almost complete absence of magnesium. In comparison with the associated magnetite, chromite is significantly enriched in germanium (up to 666 ppm) and gallium (up to 59.1 ppm). The formation of Zn-chrome spinel occurred during the transformation of detrital chromite against the background of specific chemical processes accompanying the deposition and crystallization of iron gel enriched with adsorbed impurities.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":null,"pages":null},"PeriodicalIF":1.1,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139009347","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}