Doklady Earth Sciences最新文献

{"title":"Composition of Secondary Melt Inclusions in Magnesiochromite of a Mantle Lherzolite Xenolith from the V. Grib Kimberlite Pipe (East European Craton) as an Indicator of Low H2O Content of the Kimberlite Melt","authors":"A. A. Tarasov, A. V. Golovin, E. V. Agasheva, N. P. Pokhilenko","doi":"10.1134/s1028334x24602505","DOIUrl":"https://doi.org/10.1134/s1028334x24602505","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This paper describes secondary crystallized melt inclusions trapped in magnesiochromite of lherzolite xenolith from the V. Grib kimberlite pipe (Arkhangelsk diamondiferous province). It is shown that the inclusions are microportions of melt related to magmatism, which was further formed this pipe. Daughter minerals assemblage of inclusions in magnesiochromite contain Na‒K‒Ca-, Na‒Mg-, Ca‒Mg-, Mg-, and Ca-bearing carbonates; Na–Mg carbonates with additional PO<span>(_{4}^{{3 - }})</span>, Cl^–, and SO<span>(_{4}^{{2 - }})</span> anions; chlorides; sulfate; phosphate; and silicate. The mineral assemblage of daughter phases, the amount of carbonates (77 vol %) and silicates (tetraferriphlogopite) (15 vol %) and Ca : Na : K ratios within the inclusions indicate that this melt was an alkali-enriched carbonate liquid with a low content of SiO₂ (≤6 wt %) and H₂O (≤0.6 wt %). As is known, serpentine in kimberlites is a major H₂O-bearing mineral, but the problem of water sources during serpentinization of kimberlites and an actual H₂O content in kimberlite melts is a controversial issue. The absence of serpentine and the low H₂O content (≤0.6 wt %) of the studied melt inclusions in comparison with those of kimberlites of the V. Grib kimberlite pipe (10‒14 wt %) indicate the key role of external fluids during serpentinization of these kimberlites.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"24 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141524938","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 Diatom Muds of the Chukchi Sea: Signs of Technogenic Enrichment","authors":"A. S. Astakhov, N. V. Astakhova, D. V. Kim, V. O. Krutikova","doi":"10.1134/s1028334x24602463","DOIUrl":"https://doi.org/10.1134/s1028334x24602463","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The content and distribution of precious metals in fine-grained bottom sediments, accumulated in the technogenic period (last decades) in the southwestern part of the Chukchi Sea, have been studied. The ubiquitous or local enrichment of the sediments with silver, gold, platinum, and palladium according to the average for the Earth’s crust, as well as their enrichment with gold and palladium relative to pre-technogenic (Late Holocene) deposits, was shown. Differences in the conditions of the accumulation of precious metals in the Late Holocene and modern sediments were shown. Sources of input were determined, and the possibility of technogenic enrichment of the sources was proved by the methods of multicomponent statistical analysis of the total chemical composition of the sediments.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"109 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141524939","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":"Precise Satellite Geodetic Measurements and Geodynamic Research in Northern Eurasia: State and Prospects","authors":"G. M. Steblov, P. N. Shebalin, G. E. Melnik","doi":"10.1134/s1028334x24602487","DOIUrl":"https://doi.org/10.1134/s1028334x24602487","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The issues in geodynamic research in Northern Eurasia over the past three decades with emphasis on the use of space technologies in geodesy and geodynamics are presented. The main focus is on the GNSS system as the most widespread and effective tool for geodynamic research due to the compactness and relative ease of installation of ground-based tracking equipment, as well as the possibility of its autonomous operation. The importance of precise GNSS positioning for monitoring small-scale geodynamic displacements of the Earth’s surface, which requires millimeter-scale measurement accuracy, is emphasized. The issues of development of a precise reference frame for geodynamics and maintaining its long-term consistency based on the International Terrestrial Reference Frame (ITRF) are considered, as well as the problems and prospects of precise satellite geodetic measurements and geodynamic research in the context of the current reduction in interaction with international geodetic data centers. To solve the problems that have arisen, ways are proposed based on arranging a subcontinental-scale system for equalization of raw GNSS measurements. The capabilities of the GNSS network used for solving problems of geodesy and geodynamics are demonstrated by the example of the analysis of the tectonic rigidity of cratons of Northern Eurasia and the impact of motion of adjacent tectonic plates and variations of these motions in the past geological eras on the contemporary geodynamic setting of these cratons.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"356 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141524937","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":"Age of the Zashikhinskoye Rare Metal Deposit (Eastern Sayan): Results of U–Pb (ID TIMS) Geochronological Studies of Metamictic Zircon","authors":"D. A. Lykhin, A. A. Ivanova, N. V. Alymova, E. B. Salnikova, A. B. Kotov, A. V. Nikiforov, A. A. Vorontsov, Yu. V. Plotkina, O. L. Galnikova, E. V. Tolmacheva","doi":"10.1134/s1028334x24602529","DOIUrl":"https://doi.org/10.1134/s1028334x24602529","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The issue of the age of rare-metal granites of the Zashikhinskoye field is discussed. To obtain U–Pb (ID TIMS) geochronological data, a modified “chemical abrasion” technique with preliminary high-temperature annealing was used for metamictic zircon. Estimates of the age of alkaline leucogranites and albitites coincide and correspond to the age of formation of rare-metal granites of the Zashikhinskoye field 267 ± 1 Ma. Within East Sayan, igneous rocks with close ages are not yet known. The closest area of magmatic activity of this time was the large zonal Khangai magmatic range, which arose under the influence of the mantle plume and is characterized by widespread development in its peripheral part of alkaline and bimodal associations, including rare-metal magmatic ones. The Zashikhinskoye field is more than 350 km from the edge of its range. Nevertheless, on the basis of geochronological and geochemical data, it was assumed that this field was associated with the activity of the Khangai plume.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"49 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-06-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141529620","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":"Late Tectonic Vertical Movements of the Russian Far East","authors":"D. A. Simonov, A. N. Didenko, V. S. Zakharov, G. Z. Gilmanova","doi":"10.1134/s1028334x24601615","DOIUrl":"https://doi.org/10.1134/s1028334x24601615","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Morphostructural analysis of the stream network in the southern part of the Far East has been carried out. It has been established that the latest vertical movements in the region were manifested against the background of an older, partially eroded relief. Three stages of relief development are identified, reflecting neotectonic activity in the region: (a) pre–Oligocene, characterized by a more intense uplift of the Bureya Ridge, and less intense, the Sikhote-Alin Ridge; (b) Oligocene–Pliocene, characterized by the most intense vertical movements in the region during the period from the Late Eocene to the Holocene; and (c) the Pleistocene and the Holocene, during which a modern erosion-denudation relief was formed and no vertical movements of significant amplitude occurred. A map of the total amplitude of vertical neotectonic movements is constructed.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"76 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189704","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":"3D Modeling and the Age of the Collision Metamorphism of the Khan-Khukhei Block, Northern Mongolia","authors":"A. N. Semenov, O. P. Polyansky, V. V. Reverdatto","doi":"10.1134/s1028334x2460155x","DOIUrl":"https://doi.org/10.1134/s1028334x2460155x","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The reconstruction of the Early Paleozoic collision metamorphism of the Khan-Khukhei Block (Northern Mongolia) based on 3D modeling of thermal state of the crust and isotope dating is presented. The age of garnet–biotite schist from a metamorphic complex of the Khan-Khukhei Block of 517.4 ± 7.4 Ma is determined for the first time. 3D modeling was conducted to compare this age of metamorphism with the available age determinations of (post-) collision granite formation in the range of 513‒505 Ma. The model considers radiogenic heating at an elevated heat production of rocks of the thickened crust of the Khan-Khukhei block as the cause of the migmatization and granitoid melts formation. 3D modeling was conducted for the first time for thermal-dome type of metamorphism. The results provide a realistic conception of magma generation in typical collision settings in the absence of mantle magmatic heat sources. The time interval between metamorphism and the stage of anatectic magma formation is 5–12 Ma.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141198128","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":"Late Paleozoic Potassic Intrusions of the Eastern Part of the Nikolaev Line and Associated W–Mo–Cu–Au Mineralization: First Isotopic U–Pb Zircon Data (LA-ICP-MS Method) for Rocks from the Adyrtor Intrusions (Middle Tien Shan, Eastern Kyrgyzstan)","authors":"S. G. Soloviev, S. G. Kryazhev, D. V. Semenova, Y. A. Kalinin, N. S. Bortnikov","doi":"10.1134/s1028334x24602013","DOIUrl":"https://doi.org/10.1134/s1028334x24602013","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The paper presents first data on isotopic U–Pb study (LA-ICP-MS method) of zircon from intrusive rocks of the Adyrtor intrusions – a group of small intrusives situated in the easternmost part of the deep-seated fault system of the “Nikolaev Line.” Here, these intrusions cut through one of the oldest (1.8–2.6 Ga) complexes of the basement rocks of Tien Shan (metamorphic rocks of the “Kuilyu suite”). These intrusive rocks belong to the high-potassic calc-alkaline to shoshonitic series, with some geochemical signatures also of anorogenic (A-type) magmatism. These intrusions are accompanied by skarn and porphyry W–Mo–Cu–Au mineralization. Together with the other Au, W, and Cu deposits and occurrences, they are parts of the extended metallogenic belt of Tien Shan. The concordant isotopic U–Pb age data for zircon autocrysts indicate the crystallization of quartz syenite (330.7 ± 4.3 Ma) and quartz monzonite (329.5 ± 5.8 Ma) in the latest Early Carboniferous. The distinct W–Mo specialization of ore mineralization related to the intrusions studied is in agreement with the post-collisional tectonic setting during their emplacement, despite their older or similar age compared to the ore-bearing plutons in more western segments of the Middle Tien Shan, which corresponded to a subduction-related setting. This supports the possibility of the “scissor-like” (from east to west) closure of the Turkestan paleoocean that resulted in the earlier cessation of subduction in the eastern Tien Shan compared to the western Tien Shan. The rocks also contain zircon xenocrysts with older (on the order of 1.7–2.6 Ga) age, which is in agreement with the age of the host metamorphic rocks of the Tarim craton basement. This highlights the possibility of magma chamber development in the continental crust, together with the magma chambers in the metasomatically-enriched subcontinental upper mantle, the latter being common for high-potassic magmatism.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"44 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141198129","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":"Monitoring of Chrome and Nickel Contents in Agroecosystems of the Central Chernozem Region of Russia","authors":"S. V. Lukin","doi":"10.1134/s1028334x24601883","DOIUrl":"https://doi.org/10.1134/s1028334x24601883","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>This study was performed under the state agroecological monitoring program. The purpose of this work is to conduct an environmental assessment of the contents of chromium and nickel in the agroecosystems of the southwestern part of the Central Chernozem region (CChR) from the example of Belgorod oblast. All analytical studies were carried out in the accredited testing laboratory by generally accepted methods. During this study, it was established that the average total Cr and Ni contents in the arable layer in leached chernozems are 19.8 and 24.5; in typical chernozems, 20.0 and 24.9; and in ordinary chernozems, 20.9 and 26.6 mg/kg, respectively. The average contents of mobile forms of chromium and nickel in the studied soils range within 0.13–0.14 and 0.37–0.41 mg/kg, respectively. The levels of the approximate permissible concentration of nickel and the maximum permissible concentration of mobile forms of these heavy metals in soils are not exceeded. In the agroecosystems of Belgorod oblast, Cr and Ni are mainly supplied with organic fertilizers, but this does not pose a risk for soil contamination and crop products. The highest average chromium content (0.45 mg/kg) is observed in sunflower seeds, and the lowest (0.22 mg/kg) is in corn grain. Soybeans are characterized by an anomalously high nickel content (4.81 mg/kg), and the lowest concentration (0.63 mg/kg) is recorded in corn kernels.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"22 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189753","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":"Content and Composition of Rock Debris at Lomonosov Ridge (83° N): Indication of Palaeoenvironmental Changes","authors":"E. A. Popova, V. A. Bogin, S. A. Malyshev, K. V. Filchuk, A. S. Makarov, V. D. Kaminsky","doi":"10.1134/s1028334x24602074","DOIUrl":"https://doi.org/10.1134/s1028334x24602074","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>The results of studying the quantitative, material, and morphometric composition of rock debris in sediments sampled by a box-corer on Lomonosov Ridge (83° N), Arctic Ocean, during the Severnyi Polyus 41 expedition of the Arctic and Antarctic Research Institute are presented. Clasts ≥ 1 cm in size were sampled from each distinguished layer according to the lithological description. The age model was created by the lithostratigraphic correlation with previously dated cores. The content of clasts on the eastern slope and summit is significantly higher than on the western slope, which is explained by the higher sedimentation rate on the western slope after the deglaciation peak. The change in the rock composition from carbonate to igneous and the increase in roundness with time indicate a higher input of Eurasian material in MIS 1.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"75 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189741","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":"Investigating the Geomorphic Evidence and Movement Potential of Active Faults in Golpayegan Area, Iran","authors":"Nafiseh Hajnorouzi, Mohsen Pourkermani, Mehran Arian, Zahra Maleki, Ali Solgi","doi":"10.1134/s1028334x23603590","DOIUrl":"https://doi.org/10.1134/s1028334x23603590","url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Along the western part of Golpayegan city, in an area parallel to the main axis of Zagros, the calculation of morphometric indices in the Golpayegan basin means that the tectonic activity is significant from a morphometric point of view. Tectonic activity was not the same throughout the region and although no major earthquake was reported in Golpayegan region, morphometric evidence shows the general tectonic activity of the region. Geomorphic evaluation of the Golpayegan area shows that some of the northwest-southeast trending faults and the tips of some faults in the west Golpayegan city should be considered as potential earthquake areas. The Golpayegan area is located in the Sanandaj-Sirjan structural zone, one of Iran’s most active seismic zones. The present study aimed to evaluate the effect of faults on landforms through morphotectonic indices and the causes of knick points and knick zones in the Bedrock Rivers in part of the Sanandaj-Sirjan tectonic zone. To this end, six morphometric indices such as longitudinal gradient (<span>(SL)</span>), hierarchical anomaly (<span>(Delta a)</span>), the bifurcation index (<span>(R)</span>), hypsometric integral and hypsometric curve (Hi-Hc), relative relief (<span>(Bh)</span>), and basin shape (<span>(Bs)</span>) were calculated and analyzed in 22 sub-basins of the area. Based on the findings, the existence of slope-break knick points at the mountain piedmont and at the outlet of large rivers through active faults demonstrated these landforms were created by movements along the main faults such as Bid Arab and Khansar faults which have the highest mobility potential.</p>","PeriodicalId":11352,"journal":{"name":"Doklady Earth Sciences","volume":"128 1","pages":""},"PeriodicalIF":0.9,"publicationDate":"2024-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140929676","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}