Vestnik of Saint Petersburg University Earth Sciences最新文献

{"title":"The method of economic-geographic profiling of agriculture for territories with contrasting indicators of development","authors":"A. Danshin, Andrey V. Radikevich","doi":"10.21638/spbu07.2022.106","DOIUrl":"https://doi.org/10.21638/spbu07.2022.106","url":null,"abstract":"This work explores spatial differentiation of agriculture and the identification of the existing differentiation in a territory where there are contrasts in economic development as a whole and of the agricultural sector in a particular industry. The method of economic-geographic profiling for the Inter-capital region (along the line of the Minsk-Moscow profile) was used, and dynamics for the last 10 years were investigated. Approaches are proposed for the use of profiling to identify possible growth centers that can become drivers of agricultural development, as well as depressed areas that need to be developed primarily with the help of various instruments of interethnic and regional policy. The most important role in the development of depressed areas can be played by agriculture, which is characterized by short production cycles and the ability to quickly introduce innovations that inevitably arise in cross-border cooperation due to the flow of knowledge and technology, and exchange of experience and cooperation. Because of the profile, two emerging territorial agrarian clusters in Belarus were identified. Also, quantitatively and qualitatively, the gap at the level of agricultural development between the two states was highlighted, which turned out to be more significant than expected (for some product categories by more than an order of magnitude). Profiling for different time periods includes main trends in agricultural development of the Intercapital Region: gravitation of agriculture towards the centers of districts (agropolisation), polarization and the outrunning development of the Russian sector in recent years of the import substitution policy. With this influence of the capitals of the two countries and capacious consumer markets, the formation of high-intensity suburban agriculture is not shown at this stage. The absence of the influence of the inter-capital situation for the peripheral territories of Belarus and Russia is shown.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"49 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80716265","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}

{"title":"Winter thermal and ice regimes of small Karelian lakes against the background of regional climatic variability","authors":"G. Zdorovennova, Sergei Golosov, N. Palshin, I. Zverev, T. Efremova, A. Terzhevik, R. Zdorovennov, S. Bogdanov, I. Fedorova","doi":"10.21638/spbu07.2022.108","DOIUrl":"https://doi.org/10.21638/spbu07.2022.108","url":null,"abstract":"This article investigates regularities of thermal and ice regimes of three small lakes of Karelia under current climatic conditions. Data of measurements of water temperature at autonomous stations and results of numerical calculations of the dates of ice-on and ice-off and the thickness of ice in these lakes using the one-dimensional parameterized model FLake in the anomalously warm winter season of 2019-2020 are analyzed. Data obtained are compared with long-term values over 1994-2019. The dates of the ice-on and ice-off on the lakes were quite close; however, on two larger lakes, intermediate ice destruction was observed at the beginning of winter, due to which the duration of the ice season differed between lakes by two weeks. The winter months of 2019-2020 were 6.4-9.4 ° C warmer than the baseline, which was reflected in a noticeably smaller ice thickness on the lakes compared to previous years of measurements (40-48 cm at the end of March 2020 compared to the values ​​in mid-April in 1994-2004 - 65-85 cm and in 2005-2018 - 50-65 cm). The decrease in ice thickness contributed to an early onset (mid-March) and long duration (more than five weeks) of spring subglacial convection. The model calculation, taking into account the atmospheric impact based on the ERA-5 re-analysis, reproduced the main features of the ice regime of the lakes, including the intermediate destruction of ice at the beginning of winter on two larger lakes. Significant regression relationships have been obtained between the dates of ice-on and ice-off on Lake Vendyurskoe, the dates of the onset and duration of spring under-ice convection, and the characteristics of the regional climate of southern Karelia (air temperature and the number of days with thaw in winter and spring months) for 1994-2020. The relationship between the dates of ice-on and the water temperature in the lake in winter is shown.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"97 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74374875","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}

{"title":"Dynamics of intraregional features of migration of the population of the Stavropol Territory","authors":"Ivan Soloviev","doi":"10.21638/spbu07.2022.109","DOIUrl":"https://doi.org/10.21638/spbu07.2022.109","url":null,"abstract":"Using official statistics, this article carries out an historical and geographical analysis of factors and trends of migration processes of the population of the Stavropol Territory over the past 60 years in order to identify intra-regional features of population migration (at the level of cities and districts). The main research tools are analytical, cartographic, historical reconstruction, statistical, comparative geographical, and comparative historical methods. The study also used scientific literature, archival statistical data from the North Caucasus Statistical Service, and materials from a sociological survey. The time period according to characteristics of factors, trends, and forms of population migration in Russia was divided into three parts: the last three Soviet decades (1963–1991); forced migration (1992–2000); and contemporary (2001–2019). The study revealed the transformation of population migration at each of the considered periods. The article focuses on identifying dynamics of coefficients of migration growth in cities and districts of the Stavropol Territory at different periods. The main regularity of the intraregional features of population migration in the Stavropol Territory is a gradual increase in the area of territories with negative migration performance, which was natural for agro-industrial Stavropol in the conditions of the classical stage of urbanization, and which was characterized by significant migrations of the rural population to cities. This pattern was interrupted in the 1990s, when stress factors were at work, and the opposite trend was noted. However, in the contemporary period, the growth of cities and regions with a migration decline has become a defining trend. Today, only territories included in the Stavropol and Caucasian Mineral Waters urban agglomerations have migration attractiveness in the Stavropol Territory. Thus, in the contemporary period there has been an increase in the importance of the position of territories in the “core-semi-periphery-periphery” system, as well as an increase in the socio-economic spatial polarization of Russia and its regions. The revealed patterns and tendencies of migration processes in the Stavropol Territory \"fit\" into the broad context of V. Zelinsky's theory of mobile transition, which is natural in the context of the change of the industrial era with a post-industrial society.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"1 21","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72377562","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}

{"title":"Elk Island (Losinyi Ostrov) national park: transformation of regulations in urban environment","authors":"V. Kryukov, E. Golubeva","doi":"10.21638/spbu07.2022.110","DOIUrl":"https://doi.org/10.21638/spbu07.2022.110","url":null,"abstract":"To take into account both ecosystem and socio-economic functions, it is necessary to carry out functional zoning of specially protected natural areas (SPNA). The dynamics of zoning of the Losiny Ostrov National Park from 1988 to 2012 was assessed from the position of environmental regimes using open-access data. Using GIS technologies, the estimated dynamic schemes of environmental restrictions were obtained. The tendency to easing regulations clearly exists: the weighted average dynamic parameter of environmental value is -3.27 (possible values vary from -20 to 20). The 2012 version established stronger transformations of environmental restrictions than in 2010 (dynamic indicators are -0.62 and -2.65, respectively). The greatest negative changes for natural complexes are associated with the allocation of a historical and cultural zone, the transformation of third-party user sites into economic zones, the expansion of the recreational zone, and the disappearance of the educational and excursion zone. Differences between Moscow city and the adjacent Moscow region are negligible. However, there is considerable disparity between current zoning of urban and regional parts of the park (restriction indicators are 7.41 and 12.17, respectively). Urban space is more oriented towards recreation, indicating an incompatibility with the status of a national park. In contrast to the outer 1000-meter belt, the central part of the park has had greater deterioration of nature restrictions. The weighted average indicator of ecosystem compliance (environmental restrictions and vulnerability of natural complexes) is 3.3 (possible values range from -20 to 20), which points to a sufficient level of compliance with the functional zoning of landscape vulnerability. This accordance is more typical of inner part of the park inner and territories within the boundary of Moscow.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"243 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87968703","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}

{"title":"Monitoring of soil pollution in the area affected by the production of phosphorus fertilizers","authors":"E. Elsukova, I. S. Nedbaev, D. S. Kuzmina","doi":"10.21638/spbu07.2022.406","DOIUrl":"https://doi.org/10.21638/spbu07.2022.406","url":null,"abstract":"The soils of the Kingiseppsky district of the Leningrad region were studied in the zone of influence of the production of phosphorus fertilizers at a distance of up to 5 km from the pollution source. In 43 soil samples, the total content and mobile forms of heavy metals, sulfur, fluorine, phosphorus, calcium, magnesium, carbon, actual and potential acidity were determined. Three types of territories have been identified – conditionally background, reclaimed quarries, large man-made objects - phosphogypsum dumps and tailings. Exceedances of the MPC of mobile forms of elements in the conditionally background territory were revealed for copper, and for man-made objects - for manganese, copper, lead, nickel and zinc. The maximum gross content (in mg/kg) of barium (877), cadmium (1.5), copper (63), nickel (105), strontium (17,000), vanadium (218), zinc (107), antimony (1 ,86), chromium (103), phosphorus (13904), sulfur (1100) are typical for soils of technogenic objects. Barium, cobalt, manganese, lead, scandium, iron are evenly distributed over the study area. The average gross content of barium is 530, cadmium - 0.19, cobalt - 6, chromium - 32, copper - 14, iron - 22834, nickel - 16, manganese - 510, lead - 21, antimony - 0.36, scandium - 7 , vanadium - 48, zinc - 49, strontium - 627 mg/kg. At the same time, barium and lead are characterized by low variation; medium - cobalt, chromium, iron, manganese, scandium, zinc; high - copper, nickel, antimony, vanadium; abnormally high - cadmium and strontium. Medium mobility is characteristic of barium, increased mobility is characteristic of lead and nickel, manganese, copper and zinc are characterized by high mobility. Concentration coefficients of chemical elements in the soils of large technogenic objects calculated from the zonal background for podzolic soils: V(1.03); Zn(1,2); Ni(1,2); Cu(1.4); Sb(1.5); Pb(1.7); F(7,3); Ba(8); P(11.6); Sr(12.9); Ca(38.6). On the conditionally background territory: Zn (1,2); P(1,3); pb(2,2); F(1.5); Ba(12). Significant soil pollution and a decrease in the amount of organic matter are observed at man-made objects. In the conditionally background area, the amount and concentration of pollutants are decreasing. It is necessary to constantly monitor the ecological state of soils, especially their chemical pollution.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"1 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86696769","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}

{"title":"Geoecological assessment and monitoring of the territory: the technology based on landscape mapping of anthropogenic geocomplexes","authors":"S. V. Osipov, A. Gurov","doi":"10.21638/spbu07.2022.405","DOIUrl":"https://doi.org/10.21638/spbu07.2022.405","url":null,"abstract":"The purpose of the study is to form the methodology for assessing the state and monitoring of the territory on the basis of landscape mapping of anthropogenic geocomplexes/geosystems. The algorithm and technological scheme for assessing the state and monitoring of the area has the following components: 1) determination of the territorial level and approximate scale of mapping of anthropogenic geocomplexes; 2) selection of the classification of anthropogenic geocomplexes and it revision; 3) development of a geoinformation system and preparation of the layer (mapping) of anthropogenic geocomplexes of the selected level; 4) characteristics and assessment of the state of the area based on the analysis of the map and the spectra of anthropogenic geocomplexes; 5) comparative analysis of the state of the area at different periods – monitoring, it repeats blocks 3 and 4 for another period. The structural-functional classification of anthropogenic geocomplexes is developed. The ‘Anthropogenic geocomplexes of Primorsky Krai’ geoinformation system has been developed. Its main content consists of a set of layers, such as anthropogenic meso-landscapes, made for the entire area of the Primorsky Krai, as well as anthropogenic micro-landscapes, anthropogenic localities and anthropogenic landscapes, which are prepared for key areas. The map of anthropogenic geocomplexes/geosystems is the most important component of the technology under consideration. The indispensability of the map of techno-natural, natural-technical and technical micro-landscapes, meso-landscapes, localities or landscapes is that it gives a diverse, complex vision of the most transformed by human activity geocomplexes, their diversity, dynamics, ratio, distribution. This map allows assessing the state and tracking changes in the most important complex characteristics of the territory, first of all, the nature and degree of the transformation. Such a map is a good complement to any technology for assessing the state and monitoring the territory. When mapping anthropogenic (technical, natural-technical and techno-natural) geocomplexes, when natural geocomplexes are not involved, significantly less labor and time costs are required for creating a geoinformation system and preparing a map. In this case, mapping only anthropogenic geocomplexes is a very informative express method of assessment, analysis, and monitoring.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"31 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87828633","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}

{"title":"Dynamics of socio-economic development of municipalities with preferential regimes in the Far East in 2013-2020","authors":"D. Zemlianskii, V. Chuzhenkova","doi":"10.21638/spbu07.2022.303","DOIUrl":"https://doi.org/10.21638/spbu07.2022.303","url":null,"abstract":"The development of the Far Eastern Federal District is a priority of the federal investment and regional policy. To create new jobs and attract private investment to the territory of the district, preferential regimes are being created in the macroregion – Special economic Zones (SEZ), Territories of advanced socio-economic development (TASED), the Free Port of Vladivostok (FPV), etc. The article analyzes the differences in the dynamics of socio-economic development of municipalities (hereinafter referred to as MO), on the territory of which preferential regimes operate with other MO of the macroregion. At the same time, not all preferential regimes are considered, but specific for the Far East - territories of advanced socio-economic development and the free port of Vladivostok. The analysis is carried out only for territories with TOCER and SPV created in 2015-2016, taking into account the possibility of the emergence of appropriate socio-economic effects. For this purpose, a monitoring index of the level of socio-economic development of municipalities was compiled and calculated. The effects of additionality for the applied support measures are also evaluated. The results showed that for 2013-2020 the level of socio-economic development of the municipalities of the Far Eastern Federal District has increased and there has been a reduction in differences within the federal district. In general, the overall \"effect of additionality\" of the functioning of TASED and FPV is positive. The maximum local effect is observed in municipalities with a low level of socio-economic development and where preferential regimes occupy most of the territory of the region. At the same time, it is established that at this stage the activity of preferential regimes does not provide a sustainable and systematic improvement of the socio-economic situation. The results of this study will be useful to the executive authorities to assess the effectiveness of the functioning of the TASED and FPV.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"19 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89859249","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}

{"title":"Late Glacial and Early Holocene lacustrine sedimentation history of the northern Mologa-Sheksna Lowland derived from Lake Beloye sediments (NW Russia)","authors":"Dmitriy Sadokov, T. Sapelko, N. Bobrov, M. Melles, G. Fedorov","doi":"10.21638/spbu07.2022.204","DOIUrl":"https://doi.org/10.21638/spbu07.2022.204","url":null,"abstract":"Few detailed case studies have been devoted so far to the Late Pleistocene palaeogeography of the northern Mologa-Sheksna Lowland (MSL), compared to adjacent regions covering the Valdai glaciation marginal zone. Lake Beloye (Russia, Vologda region, Babaevo district) bottom sediments were studied using ground penetrating radar (GPR) and subsequently were cored in order to build a palaeoclimatic reconstruction for the northern MSL, because lacustrine deposits are considered to be valuable and representative palaeoarchive of the area. Chronology of regional palaeoclimatic and palaeohydrological changes from the Bølling — Allerød warming to the Early Holocene was traced on the basis of inorganic and organic geochemistry, mineralogical proxies, grain-size, magnetic susceptibility, accelerator mass spectrometry radiocarbon dating and optical microanalysis. During the Late Glacial and the Pleistocene/Holocene transition in the northern MSL interstadial climatic conditions were determined at ~ 14.0 cal. ka BP (Bølling, stage GI-1e of the GICC05 timescale) and ~ 13.0 cal. ka BP (Allerød, stages GI-1c3 — GI-1a). A pronounced cold period associated with Younger Dryas (stage GS- 1) was registered in the multiproxy record at 12.8–11.7 cal. ka BP. High-resolution x-ray fluorescence (XRF) core scanning helped to reveal short-term “cold” events at ~ 13.7, ~ 13.1 and ~11.5 cal. ka BP, which were associated with Older Dryas (stage GI-1d), Gerzensee-Killarney oscillation (stage GI-1b) and Preboreal oscillation respectively, and “warm” episodes at ~ 13.2 and ~ 11.8 cal. ka BP, which presumably correspond to the end of the stage GI-1c1 and Greenlandian Stage/Age respectively. Ultimate interglacial (Holocene) climate onset within the MSL was attributed to ~ 11,7 cal. ka BP, which is marked by the sharp rise of total organic carbon content in the sediments and lithological changes to muddy fraction. Numerous water level oscillations occurred in the large proglacial lakeduring the last glacial termination, ending with Its final drainage in the northern MSL by ~ 10.9 cal. ka BP. The reconstructed palaeoclimatic dynamics is in overall agreements with the global reconstructions for the North Atlantic and Fennoscandia regions.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"5 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81587416","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}

{"title":"Authigenesis of carbonates in the deposits of the gas-hydrate-bearing structure of the CHAOS (Sea of Okhotsk)","authors":"E. Logvina, A. Krylov, T. Matveeva, F. Maksimov, V. Kuznetsov","doi":"10.21638/spbu07.2022.103","DOIUrl":"https://doi.org/10.21638/spbu07.2022.103","url":null,"abstract":"The paper presents the results of studies of authigenic carbonates sampled in the near-surface sediments of the gas-hydrate-bearing CHAOS structure located on the western slope of the Deryugin Basin in the Sea of Okhotsk. Carbonates were at different stages of formation, the most common morphological forms of which were concretions. Microscopic studies have shown that the concretions are formed by pelitomorphic carbonate cementing the terrigenous clay-clastic matrix and organic detritus. According to X-ray phase analysis, the dominant mineral composing nodules is cryptocrystalline high-Mg calcite (14.2-16.9 mol% Mg). Based on the geochemical modeling the intervals of the sediments with favorable conditions for the formation of basic carbonate minerals (aragonite, calcite, and dolomite) were identified. Almost over the entire area of the structure, the formation of carbonates occurs at more than 1m and up to 5m sub-bottom depths. In the central part of the structure (station LV31-27GC) the formation of carbonates is also possible in the upper part of the sedimentary section - from 0 to 1,5 m. On the basis of balance calculations of the δ13C isotopes content in nodules, the contribution of the main carbon sources involved in their formation was estimated. These sources turned out to be organic matter and microbial methane in a ratio of 67.5: 32.5. It was found that the conversion of carbon dioxide into bicarbonate ion occurs under conditions of early diagenesis due to the interaction of the fluid with aluminosilicates. Calculations of the isotopic composition of pore waters (the main source of oxygen in carbonates) and paleotemperatures indicate crystallization of carbonates at low (close to 0 ° C) temperatures. Based on 230Th/U-dating of carbonates, the age of the studied unloading source was determined as ~ 3.5 thousand years. It was found that the CHAOS structure is one of the “youngest” on the northeastern slope of the Sakhalin Island.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"194 1 Suppl 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"78324767","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}

{"title":"New geochemical and isotopic (Rb-Sr and Sm-Nd) data for the rocks of the alkali-ultrabasic massif Kondyor of the Aldan Shield (Khabarovsk Territory, Russia)","authors":"V. Savatenkov, A. Mochalov","doi":"10.21638/spbu07.2022.402","DOIUrl":"https://doi.org/10.21638/spbu07.2022.402","url":null,"abstract":"The chemical composition and Rb-Sr and Sm-Nd isotope characteristics of various rocks that make up the alkali-ultramafic Kondyor massif of the Aldan Shield were studied: dunites, clinopyroxenites, gabbro, kosvites, alkaline syenites. Ultrabasic rocks of the early stage (dunites, clinopyroxenites) have a significant metasomatic alteration associated with the intrusion of a dike complex of alkaline rocks. The petrochemical features of dunites and clinopyroxenites indicate that these rocks are cumulative phases that successively crystallized from picritic melt at an early stage of the formation of the massif. Gabbro and kosvites of the marginal series were formed from the residual melt after the crystallization of dunites and clinopyroxenites. The Rb-Sr and Sm-Nd isotopic characteristics in the rocks of the early intrusion stage (dunites, clinopyroxenites, gabbro) indicate that these rocks were formed with the participation of the host rock contamination processes. The isotope-geochemical characteristics of the rocks of the dike complex (kosvites and alkaline rocks of the dunite core) indicate that these rocks crystallized from a deep melt that was not significantly contaminated by the continental crust. Differences in isotopic characteristics between ultramafic rocks and rocks of the dike complex of the dunite \"core\" - kosvites and alkaline rocks, suggest at least two sources of melts that participated in the formation of the Konder massif: (1) an early, deep-seated melt that formed ultrabasic rocks at the upper level, and also kosvites, plagioclase pyroxenites and gabbro of the outer “ring” with a significant degree of contamination; (2) late, differentiated (monzonite and alkaline-syenite) deep-seated melt (far from the contaminant) that became the source of kosvite and alkaline rock dikes in the central part of the Konder massif.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"55 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84495971","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}