Russian Geology and Geophysics最新文献

{"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":" 942","pages":""},"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":" 10","pages":""},"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}

{"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":"58 166","pages":""},"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}

{"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":"21 23","pages":""},"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}

{"title":"Exploration and Development of Shale Oil in China: State, Challenges, and Prospects","authors":"Z. Jin, X. Liang","doi":"10.2113/rgg20234647","DOIUrl":"https://doi.org/10.2113/rgg20234647","url":null,"abstract":"\u0000 ––This article presents the latest state of exploration and development of shale oil of continental lacustrine formations in the main basins of China, summarizes the main theoretical considerations and key technologies for exploration and development, and suggests prospects for exploration and development of shale oil in China. It is believed that the exploration and development of oil in shale formations rich in organic matter of types I and II of medium and high maturity are key to the breakthrough of production of 10 million tons in China. This will play an important role in China’s stable oil production at the level of 200 million tons per year in the future. The efficient development of medium- and low-maturity shale oil resources can be significantly improved and lead to serious changes in oil production only after new breakthroughs in the theory and technology of shale deposits.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":"38 7","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139008442","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":"Differentiation of Lamproitic Magma: Case Study of Mesozoic High-K Dikes of the Ryabinovyi Massif (Central Aldan)","authors":"A. Izokh, I. Chayka, I.V. Gaskov, V.V. Egorova","doi":"10.2113/rgg20234610","DOIUrl":"https://doi.org/10.2113/rgg20234610","url":null,"abstract":"\u0000 ––Studies of the mineral–petrographic and geochemical compositions of high-potassic lamprophyric dikes of the Tobuk complex, manifested at the Ryabinovyi plutonic massif (Central Aldan Mesozoic magmatic province, Russia), have shown that these dikes compose a single fractionation series formed from a high-Mg lamproitic parental melt in an intermediate chamber. The composition of the rocks ranges from olivine–diopside–phlogopite and diopside–phlogopite lamproites through minettes to microsyenites and syenite–porphyry. Early crystallization of high-Mg olivine and chromite in an intermediate chamber could produce cumulative dunites similar to those of the Inagli intrusion. Crystallization of olivine and chromite was followed by cotectic crystallization of olivine and clinopyroxene, then that of clinopyroxene and phlogopite, and, finally, eutectic crystallization of Na-rich clinopyroxene, phlogopite, and K-feldspar. Crystallization and gravitational differentiation of lamproitic melt was complicated by silicate–carbonate immiscibility, which is texturally manifested in minettes as carbonate–silicate globules and interstitial calcium and magnesium carbonates. Furthermore, compositional zoning of Sr in apatite and Ba in phlogopite and K-feldspar is considered to have resulted from the immiscibility. Separation of the carbonate–fluorite melt fraction might have led to formation of the carbonatite and fluorite–carbonatite schlieren and gangues which have been described in drill cores from the Ryabinovyi massif. In most of the geochemical and mineralogic features, the Ryabinovyi massif lamproites are similar to the low-Ti lamproites of the Mediterranean postcollisional belt and northern Vietnam and differ from typical high-Ti within-plate lamproites.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":"34 5","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139008974","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":"Algama Gold Ore Cluster (Aldan–Stanovoi Shield): Mineralogy, Formation Conditions, Sources of Ore Matter, and Age of Mineralization","authors":"V. Kardashevskaia, G. Anisimova, E. Badanina, V. Savatenkov, A. Travin","doi":"10.2113/rgg20234618","DOIUrl":"https://doi.org/10.2113/rgg20234618","url":null,"abstract":"\u0000 —The paper presents results of research into the conditions of formation of ores in the poorly studied Algama ore cluster (Bodorono deposit and Dyvok ore occurrence) located at the junction of the Aldan Shield and the Stanovoi area. We have established that Bi and Se minerals (bismuthinite, lillianite, native bismuth, tellurobismuthite, tetradymite, hedleyite, pilsenite, and laitakarite) are present in the ores of the Bodorono deposit. Two successive productive stages of mineral formation have been distinguished: Au–polymetallic and Au–Bi–Te. The corresponding minerals are products of the evolution of a hydrothermal system, during which a gradual decrease in fluid temperature (from 300 to 145 °C) and salinity (from 5 to 1.9 wt.% NaCl equiv.) took place. The fineness of native gold gradually increases from early (~840‰) to late (~940‰) stages and changes in passing from simple sulfides to sulfosalts. The evolution of the ore system is accompanied by a change in the composition of the vapor phase of fluid inclusions from CH4–CO2 to CO2 with an impurity of N2 and CH4. The results of 40Ar/39Ar dating of pre-ore metasomatites point to ore-forming processes at the Bodorono deposit ca. 150 ± 1.8 Ma. Analysis of the isotopic composition of lead in galena shows the leading role of the ancient crustal source of ore matter. The calculated isotopic composition of oxygen (δ18OH2O) in ore-bearing quartz varies from 1.0 to 7.3‰, which corresponds to an aqueous fluid of a mixed source. The Dyvok ore occurrence differs from the Bodorono deposit in the mineral composition of ores and the physicochemical parameters of ore formation. Four mineral stages have been established within the ore occurrence: gold–arsenopyrite–pyrite–quartz, pyrite–chalcopyrite–sphalerite, quartz–boulangerite, and telluride. The telluride stage is represented by hessite, altaite, volynskite, merenskyite, melonite, and rucklidgeite. Gold-bearing mineralization formed from a fluid of medium salinity (0.9–9.2 wt.% NaCl equiv.) with a predominance of CO2 and an impurity of CH4 in the vapor phase at moderate temperatures (310–360 °C). The calculated values of δ34S and δ18O varied from 2.2 to 3.0‰ and from 0.6 to 12.0‰, respectively. The 40Ar/39Ar age of gold mineralization is 124.0 ± 1.5 Ma, which corresponds to the stage of tectonomagmatic activity in the Aldan Shield.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":"12 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139007516","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":"Artificial Neural Network-Based Computational Algorithm of Inverse Sumudu Transform Applied to Surface Transient Electromagnetic Sounding Method","authors":"M. Epov, K. Danilovskiy, O.V. Nechaev, I. Mikhaylov","doi":"10.2113/rgg20234607","DOIUrl":"https://doi.org/10.2113/rgg20234607","url":null,"abstract":"\u0000 ––The paper discusses the results of the development of a deep learning-based algorithm of the inverse Sumudu transform applied to the problem of on-ground non-stationary electromagnetic sounding. The Sumudu transform has potential for solving forward geoelectric problems in three-dimensional earth models because, unlike using the Laplace or Fourier transform, the Sumudu image of a real function is also a real function. Thus, there is no need to use complex numbers in subsequent calculations, which reduces computational costs and memory requirements in case of successful determination of the Sumudu image of the function. The disadvantages of the approach include the absence of an explicit method for calculating the inverse transform. The inversion can be done by solving the corresponding Fredholm integral equation of the first kind, but this is a poorly conditioned task leading to high requirements for the accuracy of the Sumudu image. The use of modern machine learning techniques can provide a method that is more robust to noise in the input data. This paper describes the process of creating a training dataset and developing a neural network algorithm; we evaluate the accuracy and performance of the obtained solution. The proposed method can contribute to the development of new approaches to physical processes modeling as well as to analysis, processing and interpretation of measured geophysical data.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":"419 ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"138983104","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":"Composition and Sources of Clastic Material of Terrigenous Rocks of the Khabarovsk Accretionary Complex (Sikhote-Alin)","authors":"S.M. Mednikov, А.V. Kudymov, N. N. Kruk, E. Demonterova, А.N. Didenko, S. Oto, А.Yu. Peskov","doi":"10.2113/rgg20234642","DOIUrl":"https://doi.org/10.2113/rgg20234642","url":null,"abstract":"\u0000 ––The results of comprehensive studies of terrigenous rocks of the Khabarovsk Sikhote-Alin accretionary complex are presented. It is established that the fragments of Jurassic and Permian–Triassic sandstones are dominated by poorly rounded and poorly separated material mainly from local provenance areas. The detrital part of the rocks is mainly represented by quartz, in a smaller amount by feldspar and rock fragments. Sandstones are characterized by high silica content, moderate alumina content, low concentrations of femic elements and calcium, moderate alkali content with significant variations in the K/Na ratio. Both Jurassic and Permian–Triassic rocks are typically characterized by reduced contents of LILE, REE, to a lesser extent HFSE and negative values of the ɛNd(T) parameter – compared to PAAS. The model Nd age of Jurassic sandstones varies from 1.36 to 1.71 Ga, Permian–Triassic – from 1.14 to 1.35 Ga. Most of the detrital zircon population is of late Paleozoic–early Mesozoic age, approximately 25% are older (pre-Paleoproterozoic). The studied sandstones are mainly rocks of the first cycle of weathering (petrogenic), formed during the erosion of igneous rocks of felsic composition. The synthesis of the obtained data suggests that the main source of the cluster material for the Mesozoic sedimentary rocks was the geological formations of the northern part of the Bureya–Khanka superterrane (Bureya and Malokhingan blocks), as well as, possibly, the eastern part of the Mongol–Okhotsk belt. The Khabarovsk terrane has not drifted significantly along the Tan Lu stike-slip system and is an “autochthonous” block in the present-day structure of Sikhote-Alin.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":"243 ","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139010837","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":"Geochemical Characteristics and Geological Significance of Mud Shale of the Second Member, Permian Lucaogou Formation, Jimsar Sag, Junggar Basin, NW China","authors":"J. Jin, J. Liu, Z. Lou, J. Wang, J. Li, R. Zhu, Y. Wang","doi":"10.2113/rgg20234581","DOIUrl":"https://doi.org/10.2113/rgg20234581","url":null,"abstract":"\u0000 ––The Lucaogou Formation in Jimsar sag is an important shale oil-producing layer in the Junggar basin. In this paper, core data, organic carbon, rock pyrolysis, biomarker compounds, and organic matter group component separation were used to study the sedimentary environment, parent material type, organic maturity and oil-bearing property of mud shale of the Second member of the Lucaogou Formation. The results showed that the sedimentary environment is a semi-oxidation and semi-reduction environment. The parent material is mainly aquatic with minor input of higher plants. The average TOC is 7.43%, the average value of hydrocarbon generation potential (S1+S2) is 50.54 mg/g, and the average value of Tmax is 446 °C, showing high maturity of the mud shale. The chloroform bitumen “A” features high saturated hydrocarbon content (34.10% on average), low aromatic hydrocarbon content (15.39% on average), and high saturated/aromatic ratio (2.54). The carbon number of saturated hydrocarbons is distributed between n-C13 and n-C33. Their peak are mainly n-C17 and n-C23, which are biased toward medium-low molecular weight alkanes. The average of the ΣC21–/ΣC22+ is 1.19, indicating that the alkane has advantage of short chain. The mud shale in the Second member of the Lucaogou Formation has a large sedimentary thickness, high organic matter content, and high oil generation potential. It is an important replacement target for shale oil in Jimsar sag and has important exploration significance in the future.","PeriodicalId":49587,"journal":{"name":"Russian Geology and Geophysics","volume":"246 4","pages":""},"PeriodicalIF":1.1,"publicationDate":"2023-12-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139011561","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}