Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.403
N. Vetrova, E. Vetrov, E. Letnikova
The geochemical and isotopic (Nd, Sr) characteristics of felsic volcanic rocks of the Pecherkinskaya Formation in the northwestern part of the Salair Ridge were studied. These rocks are closely associated with industrially significant deposits and manifestations of gold- and silver-bearing pyrite-polymetallic formations with potentially gold-bearing weathering crusts on them. The study of the material composition of unaltered volcanic rocks of the Pecherkinskaya Formation is necessary for the reconstruction of the conditions of their formation, which contributes to estimation of the mineragenic potential of this formation and the conditions during the accumulation of ore matter. Felsic volcanic rocks of the Pecherkinskaya Formation are an extreme member of the basalt-plagioryolite series, have an extremely high-sodium type of alkalinity with a low potassium content, are calcareous and characterized by high silica contents, low iron content, have low REE concentrations, are enriched in Pb and U and depleted in Ta and Nb, are characterized by high values of εNd (t) (+6.36) and primary ratio 87Sr / 86Sr (0.706977). The REE distribution spectra show a low degree of fractionation with a pronounced negative "europium anomaly". The geochemical composition of the Pecherkinskaya Formation volcanic rocks indicates that primary magmas were formed by partial melting of rocks of the lower continental crust at a pressure of ~ 8 kbar in equilibrium with Hbl + Cpx + Pl ± Opx restite and a temperature of ~ 750-790 ° C. The isotope-geochemical characteristics indicating the participation of depleted mantle in the source are probably inherited from the juvenile crust, the rocks of which could have been formed as a result of differentiation of mantle magmas. Geological and geochemical features of felsic volcanic rocks of the Pecherkinskaya Formation are characteristic of igneous rocks formed under conditions of oceanic arcs.
{"title":"Petrological model for formation of felsic volcanic rocks of the Pecherkinskaya Formation (northwestern part of the Salair Ridge)","authors":"N. Vetrova, E. Vetrov, E. Letnikova","doi":"10.21638/spbu07.2022.403","DOIUrl":"https://doi.org/10.21638/spbu07.2022.403","url":null,"abstract":"The geochemical and isotopic (Nd, Sr) characteristics of felsic volcanic rocks of the Pecherkinskaya Formation in the northwestern part of the Salair Ridge were studied. These rocks are closely associated with industrially significant deposits and manifestations of gold- and silver-bearing pyrite-polymetallic formations with potentially gold-bearing weathering crusts on them. The study of the material composition of unaltered volcanic rocks of the Pecherkinskaya Formation is necessary for the reconstruction of the conditions of their formation, which contributes to estimation of the mineragenic potential of this formation and the conditions during the accumulation of ore matter. Felsic volcanic rocks of the Pecherkinskaya Formation are an extreme member of the basalt-plagioryolite series, have an extremely high-sodium type of alkalinity with a low potassium content, are calcareous and characterized by high silica contents, low iron content, have low REE concentrations, are enriched in Pb and U and depleted in Ta and Nb, are characterized by high values of εNd (t) (+6.36) and primary ratio 87Sr / 86Sr (0.706977). The REE distribution spectra show a low degree of fractionation with a pronounced negative \"europium anomaly\". The geochemical composition of the Pecherkinskaya Formation volcanic rocks indicates that primary magmas were formed by partial melting of rocks of the lower continental crust at a pressure of ~ 8 kbar in equilibrium with Hbl + Cpx + Pl ± Opx restite and a temperature of ~ 750-790 ° C. The isotope-geochemical characteristics indicating the participation of depleted mantle in the source are probably inherited from the juvenile crust, the rocks of which could have been formed as a result of differentiation of mantle magmas. Geological and geochemical features of felsic volcanic rocks of the Pecherkinskaya Formation are characteristic of igneous rocks formed under conditions of oceanic arcs.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"15 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79722100","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.306
A. Glebova, I. Sergeev, Nikolay Bykov
The article is devoted to the identification of landscape patterns of the location of archaeological sites in the South-East Altai using GIS and machine learning. The information database of archaeological sites of South-Eastern Altai was created based on literary sources, the authors' own field research. Schemes of distribution of archaeological sites according to some landscape features: absolute height; position in relation to watercourses; slopes; exposition; solar radiation intensity in June; Intensities of solar radiation for December was created on the basis of geoinformation analysis of the relief of the territory and the available archaeological data. The obtained statistical regularities of the distribution of archaeological sites in the landscapes of South-Eastern Altai were the basis for the creation and verification of the algorithm of a machine-learning model - a neural network. Based on the results, a forecast map of the location of archaeological sites was created. The greatest probability of discovering new archaeological objects could be provided by the following landscape parameters, no further than 500-600 m from the river with a slope steepness of up to 4 degrees, with high intensity and summer (June) solar radiation and with an exposure of slopes: southern, south-eastern and western. Unexplored archaeological sites in South-East Altai are most likely located along river valleys in the middle and lower reaches, at the confluence of rivers, along the periphery of intermountain basins, or on wide flat areas of above-floodplain terraces of river valleys. The data obtained make it possible to assess the contribution of landscape features to the spatial distribution of religious buildings of ancient peoples and provide opportunities for the search for new archaeological sites.
{"title":"Geoinformation analysis with the construction of a neural network model for predicting location of archaeological monuments in the landscapes of South-Eastern Altai","authors":"A. Glebova, I. Sergeev, Nikolay Bykov","doi":"10.21638/spbu07.2022.306","DOIUrl":"https://doi.org/10.21638/spbu07.2022.306","url":null,"abstract":"The article is devoted to the identification of landscape patterns of the location of archaeological sites in the South-East Altai using GIS and machine learning. The information database of archaeological sites of South-Eastern Altai was created based on literary sources, the authors' own field research. Schemes of distribution of archaeological sites according to some landscape features: absolute height; position in relation to watercourses; slopes; exposition; solar radiation intensity in June; Intensities of solar radiation for December was created on the basis of geoinformation analysis of the relief of the territory and the available archaeological data. The obtained statistical regularities of the distribution of archaeological sites in the landscapes of South-Eastern Altai were the basis for the creation and verification of the algorithm of a machine-learning model - a neural network. Based on the results, a forecast map of the location of archaeological sites was created. The greatest probability of discovering new archaeological objects could be provided by the following landscape parameters, no further than 500-600 m from the river with a slope steepness of up to 4 degrees, with high intensity and summer (June) solar radiation and with an exposure of slopes: southern, south-eastern and western. Unexplored archaeological sites in South-East Altai are most likely located along river valleys in the middle and lower reaches, at the confluence of rivers, along the periphery of intermountain basins, or on wide flat areas of above-floodplain terraces of river valleys. The data obtained make it possible to assess the contribution of landscape features to the spatial distribution of religious buildings of ancient peoples and provide opportunities for the search for new archaeological sites.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"35 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81634197","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.301
V. Akimova, M. Kuptsova
The global textile and apparel sector historically played a key role in the developing economies of Asia, which now account for three quarters of global apparel exports. Today as new countries embark on the path of export-oriented industrialization, the geography of the industry is expanding due to the emergence of new clothing manufacturing centers in Asia. The article is dedicated to a comprehensive analysis of the spatial organization of the garment industry in the Asian region. The modern dynamics of the economic indicators of the industry at the national level is considered, key trends are indicated. The parameters of the suppliers search in combination with the location factors of the textile and apparel industry are revealed, and their influence on the spatial pattern of the industry is explained. At the regional level, the identification, qualitative and quantitative analysis of the concentration areas of the textile and apparel industry is carried out based on location of production sites of the leading companies in the industry. In total, 14 areas of the export-oriented textile and apparel industry in Asia have been highlighted and divided into three types based on their product and technological specialization, the size and ownership structure of enterprises, and backward linkages to the textile sector. It was revealed that the trend of shift of garment production continues both at the level of national economies (to other countries) as well as at the regional level (from large centers to the inner regions of countries), however, the return on the model of constant search for new production facilities for cost reduction is decreasing.
{"title":"Asian apparel industry: geographic specifics and key development areas","authors":"V. Akimova, M. Kuptsova","doi":"10.21638/spbu07.2022.301","DOIUrl":"https://doi.org/10.21638/spbu07.2022.301","url":null,"abstract":"The global textile and apparel sector historically played a key role in the developing economies of Asia, which now account for three quarters of global apparel exports. Today as new countries embark on the path of export-oriented industrialization, the geography of the industry is expanding due to the emergence of new clothing manufacturing centers in Asia. The article is dedicated to a comprehensive analysis of the spatial organization of the garment industry in the Asian region. The modern dynamics of the economic indicators of the industry at the national level is considered, key trends are indicated. The parameters of the suppliers search in combination with the location factors of the textile and apparel industry are revealed, and their influence on the spatial pattern of the industry is explained. At the regional level, the identification, qualitative and quantitative analysis of the concentration areas of the textile and apparel industry is carried out based on location of production sites of the leading companies in the industry. In total, 14 areas of the export-oriented textile and apparel industry in Asia have been highlighted and divided into three types based on their product and technological specialization, the size and ownership structure of enterprises, and backward linkages to the textile sector. It was revealed that the trend of shift of garment production continues both at the level of national economies (to other countries) as well as at the regional level (from large centers to the inner regions of countries), however, the return on the model of constant search for new production facilities for cost reduction is decreasing.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"46 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85934049","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.401
Sergey V. Malyshev, A. Pasenko, A. Khudoley, A. Ivanov, N. Priyatkina, Anna A. Pazukhina, A. Marfin, A. Dufrane, I. Sharygin, Egor A. Gladkochub
The Udzha paleorift is located between the Anabar and Olenek rivers and is a key structure indicative of the breakup of the Nuna supercontinent. However, the age of initiation and duration of paleorift activity is not defined nowadays. Here we present new U-Pb data for detrital zircons from two terrigenous and volcanic-sedimentary successions of the Udzha sedimentary basin (Unguokhtakh and Udzha Fm), from terrigenous rocks overlying the Udzha basin (Tomtor Fm), and from the sandstone of the lower Mesoproterozoic Mukun Group in the northwest part of Anabar region. The dating results show that sedimentation in the Udzha rift basin began later than ca 1459 Ma, and the duration of the rift activity is estimated as not longer than 73 My. The Udzha rift basin was an isolated basin in the northern part of Siberia, and detrital material came from local sources. A previously unknown source for tuff-sandstone of Unguokhtah Formation with an age of 1850 Ma has been identified, which corresponds by age to the Paleoproterozoic post-orogenic magmatism of the Siberian Craton. In the Neoproterozoic, detrital material of the Tomtor Fm was supplied from the northeast, and the sources were igneous suites of active margin or collision settings. The maximum depositional age of Tomtor Fm is estimated as 565 Ma on the youngest zircon population, which suggests an over 800 Ma gap in sedimentation in northern Siberia in Meso- Neoproterozoic.
{"title":"What is the age of the Udzha paleorift?: U-Pb age of detrital zircons from Udzha basin terrigenous succession, northern Siberia","authors":"Sergey V. Malyshev, A. Pasenko, A. Khudoley, A. Ivanov, N. Priyatkina, Anna A. Pazukhina, A. Marfin, A. Dufrane, I. Sharygin, Egor A. Gladkochub","doi":"10.21638/spbu07.2022.401","DOIUrl":"https://doi.org/10.21638/spbu07.2022.401","url":null,"abstract":"The Udzha paleorift is located between the Anabar and Olenek rivers and is a key structure indicative of the breakup of the Nuna supercontinent. However, the age of initiation and duration of paleorift activity is not defined nowadays. Here we present new U-Pb data for detrital zircons from two terrigenous and volcanic-sedimentary successions of the Udzha sedimentary basin (Unguokhtakh and Udzha Fm), from terrigenous rocks overlying the Udzha basin (Tomtor Fm), and from the sandstone of the lower Mesoproterozoic Mukun Group in the northwest part of Anabar region. The dating results show that sedimentation in the Udzha rift basin began later than ca 1459 Ma, and the duration of the rift activity is estimated as not longer than 73 My. The Udzha rift basin was an isolated basin in the northern part of Siberia, and detrital material came from local sources. A previously unknown source for tuff-sandstone of Unguokhtah Formation with an age of 1850 Ma has been identified, which corresponds by age to the Paleoproterozoic post-orogenic magmatism of the Siberian Craton. In the Neoproterozoic, detrital material of the Tomtor Fm was supplied from the northeast, and the sources were igneous suites of active margin or collision settings. The maximum depositional age of Tomtor Fm is estimated as 565 Ma on the youngest zircon population, which suggests an over 800 Ma gap in sedimentation in northern Siberia in Meso- Neoproterozoic.","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":"90035615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.404
I. Serykh, D. Sonechkin
Based on the monthly average data of NCEP/NCAR Reanalysis, using a specially developed technique, the interannual variability of the sea level pressure (SLP) anomalies associated with the Global Atmospheric Oscillation (GAO) for the period 1950-2021 was studied. The field of mean deviations of the SLP anomalies during the El Niño – Southern Oscillation (ENSO) from the interannual GAO variability has been calculated. It is shown that the variability of the SLP anomalies during the GAO contains, in addition to the mode associated with the ENSO, also the mode of interannual climatic variability associated with the Antarctic Oscillation (AAO) – the Southern Annular Mode (SAM). It was found that the GAO does not include a part of the SLP anomaly variability associated with El Niño and La Niña events of the Central Pacific type. At all other grid nodes, the field of mean deviations of the SLP anomalies in the ENSO from the GAO has SLP differences slightly different from zero and formally statistically insignificant. This means that in the interannual climatic variability of the SLP associated with the GAO, there are only two modes: ENSO and SAM. With the help of cross-wavelet analysis, the relationships between the ENSO and SAM indices were studied. Negative relationships were found between these indices on fluctuation periods of about 11 years. An analysis of the time series of these indices and the time series of total solar irradiance (TSI) made it possible to put forward a hypothesis about the influence of synchronization and desynchronization of quasi-11-year changes in solar activity and ENSO on the weakening and strengthening of negative relationships between ENSO and SAM at periods of oscillations of about 11 years.
{"title":"Link of ENSO and Southern Annular Mode as elements of Global Atmospheric Oscillation","authors":"I. Serykh, D. Sonechkin","doi":"10.21638/spbu07.2022.404","DOIUrl":"https://doi.org/10.21638/spbu07.2022.404","url":null,"abstract":"Based on the monthly average data of NCEP/NCAR Reanalysis, using a specially developed technique, the interannual variability of the sea level pressure (SLP) anomalies associated with the Global Atmospheric Oscillation (GAO) for the period 1950-2021 was studied. The field of mean deviations of the SLP anomalies during the El Niño – Southern Oscillation (ENSO) from the interannual GAO variability has been calculated. It is shown that the variability of the SLP anomalies during the GAO contains, in addition to the mode associated with the ENSO, also the mode of interannual climatic variability associated with the Antarctic Oscillation (AAO) – the Southern Annular Mode (SAM). It was found that the GAO does not include a part of the SLP anomaly variability associated with El Niño and La Niña events of the Central Pacific type. At all other grid nodes, the field of mean deviations of the SLP anomalies in the ENSO from the GAO has SLP differences slightly different from zero and formally statistically insignificant. This means that in the interannual climatic variability of the SLP associated with the GAO, there are only two modes: ENSO and SAM. With the help of cross-wavelet analysis, the relationships between the ENSO and SAM indices were studied. Negative relationships were found between these indices on fluctuation periods of about 11 years. An analysis of the time series of these indices and the time series of total solar irradiance (TSI) made it possible to put forward a hypothesis about the influence of synchronization and desynchronization of quasi-11-year changes in solar activity and ENSO on the weakening and strengthening of negative relationships between ENSO and SAM at periods of oscillations of about 11 years.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"16 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90174435","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.307
M. Kuznetsova, G. Priakhina
The paper studies the validity of snowmelt calculation methods, which are mostly used in hydrology, for the Larsemann Hills oasis (East Antarctica). The study bases on snow surveys data obtained on catchments of Low Lake, Reid Lake and Stepped Lake during the 65th season of the Russian Antarctic Expedition (RAE) in 2019-2020. Materials of the fond of Arctic and Antarctic Research Institute (AARI) are also used: snow surveys data collected on the catchment of Stepped Lake during the 57th RAE season in 2012 and on catchments of Low Lake, Reid Lake, Scandrett Lake and Stepped Lake during the 62th RAE season in 2017. Considered three methods of snowmelt calculation were derived by Kuz'min P.P., Popov E.G., Vinogradov Yu.B. Results of calculation are compared with snowmelt value obtained according to snow surveys. The paper shows two variants of calculations: in the first albedo of snow is determined from function of snow age as different values for each day, in the second albedo is determined from remote sensing data as average value for all period. Results of snowmelt calculation depend on the method which sets value of snow albedo: relative inaccuracies of results obtained of all discussed methods are smaller when albedo is determined as average value. The equation by Kuz'min P.P. gives the smallest inaccuracies of snowmelt calculation results in relative to real snowmelt values estimated from snow survey data. This snowmelt calculation method in the majority of cases reviewed gives satisfactory results and should be recommended for estimation of snowmelt values for this Antarctic territory.
{"title":"Methods of snowmelt calculation in the Antarctic oasis Larsemann Hills","authors":"M. Kuznetsova, G. Priakhina","doi":"10.21638/spbu07.2022.307","DOIUrl":"https://doi.org/10.21638/spbu07.2022.307","url":null,"abstract":"The paper studies the validity of snowmelt calculation methods, which are mostly used in hydrology, for the Larsemann Hills oasis (East Antarctica). The study bases on snow surveys data obtained on catchments of Low Lake, Reid Lake and Stepped Lake during the 65th season of the Russian Antarctic Expedition (RAE) in 2019-2020. Materials of the fond of Arctic and Antarctic Research Institute (AARI) are also used: snow surveys data collected on the catchment of Stepped Lake during the 57th RAE season in 2012 and on catchments of Low Lake, Reid Lake, Scandrett Lake and Stepped Lake during the 62th RAE season in 2017. Considered three methods of snowmelt calculation were derived by Kuz'min P.P., Popov E.G., Vinogradov Yu.B. Results of calculation are compared with snowmelt value obtained according to snow surveys. The paper shows two variants of calculations: in the first albedo of snow is determined from function of snow age as different values for each day, in the second albedo is determined from remote sensing data as average value for all period. Results of snowmelt calculation depend on the method which sets value of snow albedo: relative inaccuracies of results obtained of all discussed methods are smaller when albedo is determined as average value. The equation by Kuz'min P.P. gives the smallest inaccuracies of snowmelt calculation results in relative to real snowmelt values estimated from snow survey data. This snowmelt calculation method in the majority of cases reviewed gives satisfactory results and should be recommended for estimation of snowmelt values for this Antarctic territory.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"14 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74903876","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.105
M. Petrakova, R. Terentiev, A. Yurchenko, K. Savko
This article presents new and summaries of previously published geochemical and geochronological data on rocks of the Potudan pluton and host granitoids of the Kholhol-Repyevka batholith in the central part of the Don Terrane (DT) of Volga-Don orogen. The host granitoids of the Khokhol-Repyevka batholith are assigned to the Pavlovsk granitoid complex, which is widespread in the southern part of the DT. The studied Potudan pluton rocks are differentiated from quartz monzogabbro to granodiorites. They are ferroan, meta-aluminous, and the K2O content displays their relationship to the shoshonite series. For the intrusive complexes of the Don terrane, it is assumed that an enriched heterogeneous source with high contents of alkalis, LILE (large-scale lithophile elements) and LREE (light rare earth elements) is involved, the mantle component is confirmed by increased of MgO, Cr, Ni, Ti, as well as high Sr/Y ratios, (La/Yb)n, (Dy/Yb)n, indicating the deep origin of magmas. The source heterogeneity could have been provided by subduction events about 2.1 Ga. The U-Pb zircon age of crystallization of the Potudan pluton rocks (using the SHRIMP II instrument) is 2061 ± 5.4 Ma and corresponds to the postcollision event in the junction zone of the Sarmatian and Volga-Ural segments of the East European Craton. Association of Potudan rocks with Pavlovsk granitoids in time and space and also morphological features of zircon from various types of rock suites prove the effect of hybridization process during crystallization of the composite batholith. The new data make it possible to expand our understanding of the evolution of crust of the Don Terrane and geodynamic regims of its formation.
{"title":"Geochemistry and geochronology of quartz monzogabbro – monzodiorite – granodiorites of the Potudan pluton (Volga-Don orogen)","authors":"M. Petrakova, R. Terentiev, A. Yurchenko, K. Savko","doi":"10.21638/spbu07.2022.105","DOIUrl":"https://doi.org/10.21638/spbu07.2022.105","url":null,"abstract":"This article presents new and summaries of previously published geochemical and geochronological data on rocks of the Potudan pluton and host granitoids of the Kholhol-Repyevka batholith in the central part of the Don Terrane (DT) of Volga-Don orogen. The host granitoids of the Khokhol-Repyevka batholith are assigned to the Pavlovsk granitoid complex, which is widespread in the southern part of the DT. The studied Potudan pluton rocks are differentiated from quartz monzogabbro to granodiorites. They are ferroan, meta-aluminous, and the K2O content displays their relationship to the shoshonite series. For the intrusive complexes of the Don terrane, it is assumed that an enriched heterogeneous source with high contents of alkalis, LILE (large-scale lithophile elements) and LREE (light rare earth elements) is involved, the mantle component is confirmed by increased of MgO, Cr, Ni, Ti, as well as high Sr/Y ratios, (La/Yb)n, (Dy/Yb)n, indicating the deep origin of magmas. The source heterogeneity could have been provided by subduction events about 2.1 Ga. The U-Pb zircon age of crystallization of the Potudan pluton rocks (using the SHRIMP II instrument) is 2061 ± 5.4 Ma and corresponds to the postcollision event in the junction zone of the Sarmatian and Volga-Ural segments of the East European Craton. Association of Potudan rocks with Pavlovsk granitoids in time and space and also morphological features of zircon from various types of rock suites prove the effect of hybridization process during crystallization of the composite batholith. The new data make it possible to expand our understanding of the evolution of crust of the Don Terrane and geodynamic regims of its formation.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"37 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76435445","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.202
E. Perova, A. Zaitsev, J. Spratt, N. Vlasenko, Nataliya Vladimirovna Platonova, O. Bubnova
The Laetoli area in northern Tanzania is an important palaeo-anthropological site, where the oldest footprints of Australopithecus afarensis reside. Aeolian tuffs are the major rock type at Laetoli and they are divided into Lower and Upper Laetolil Beds that were deposited at an interval of 4.36 and 3.63 million years. The Upper Laetolil Beds contain eight layers of air-fall tuffs known as marker tuffs. The Australopithecus afarensis footprints are observed on the surface of the white tuff, which is a part of the Upper Laetolil marker tuff 7, also known as the “Footprint Tuff.” The interpolated age of the marker tuff 7 is 3.66 million years. Two mineral assemblages are distinguished in the Upper Laetolil marker tuffs. The first assemblage consists of primary tuff minerals and includes clinopyroxene (diopside, augite, aegirine-augite), nepheline, melilite (åkermanite and alumoåkermanite), garnet (andradite and schorlomite), magnetite, and others. The second mineral assemblage consists of secondary minerals, montmorillonite, calcite, and phillipsite. They were formed during replacement of the primary minerals, volcanic glass, and ash cementation. Thermodynamic calculations show that the major primary tuff minerals (melilite and nepheline) are stable at variable sodium activity and pH values. Replacement of melilite and nepheline by montmorillonite is caused by a decrease of sodium activity in slightly alkaline, neutral and acidic conditions (рН < 10). Montmorillonite is not present in the altered nephelinitic tuff of the Sadiman volcano (which is considered as a source of the Laetolil Beds) where kaolinite is the major secondary mineral. This is explained by the difference in H2O fugacity with higher lgfH2O values in Sadiman and lower values in Laetoli. Relationships between primary and secondary tuffs minerals on the lgaHCO3 vs pH plot suggest mineral transformation within the Laetolil Beds in slightly acid and neutral con- ditions (рН = 5–7) compared with more alkaline conditions at Sadiman (рН > 10).
{"title":"Thermodynamic analysis of primary and secondary minerals stability in melilite-nephelinite tuff with Australopithecus Afarensis footprints, Laetoli, Tanzania","authors":"E. Perova, A. Zaitsev, J. Spratt, N. Vlasenko, Nataliya Vladimirovna Platonova, O. Bubnova","doi":"10.21638/spbu07.2022.202","DOIUrl":"https://doi.org/10.21638/spbu07.2022.202","url":null,"abstract":"The Laetoli area in northern Tanzania is an important palaeo-anthropological site, where the oldest footprints of Australopithecus afarensis reside. Aeolian tuffs are the major rock type at Laetoli and they are divided into Lower and Upper Laetolil Beds that were deposited at an interval of 4.36 and 3.63 million years. The Upper Laetolil Beds contain eight layers of air-fall tuffs known as marker tuffs. The Australopithecus afarensis footprints are observed on the surface of the white tuff, which is a part of the Upper Laetolil marker tuff 7, also known as the “Footprint Tuff.” The interpolated age of the marker tuff 7 is 3.66 million years. Two mineral assemblages are distinguished in the Upper Laetolil marker tuffs. The first assemblage consists of primary tuff minerals and includes clinopyroxene (diopside, augite, aegirine-augite), nepheline, melilite (åkermanite and alumoåkermanite), garnet (andradite and schorlomite), magnetite, and others. The second mineral assemblage consists of secondary minerals, montmorillonite, calcite, and phillipsite. They were formed during replacement of the primary minerals, volcanic glass, and ash cementation. Thermodynamic calculations show that the major primary tuff minerals (melilite and nepheline) are stable at variable sodium activity and pH values. Replacement of melilite and nepheline by montmorillonite is caused by a decrease of sodium activity in slightly alkaline, neutral and acidic conditions (рН < 10). Montmorillonite is not present in the altered nephelinitic tuff of the Sadiman volcano (which is considered as a source of the Laetolil Beds) where kaolinite is the major secondary mineral. This is explained by the difference in H2O fugacity with higher lgfH2O values in Sadiman and lower values in Laetoli. Relationships between primary and secondary tuffs minerals on the lgaHCO3 vs pH plot suggest mineral transformation within the Laetolil Beds in slightly acid and neutral con- ditions (рН = 5–7) compared with more alkaline conditions at Sadiman (рН > 10).","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"30 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74184717","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.308
D. Petrov, A. Yakusheva
The work is devoted to the topical issue of assessing the state and changes of river ecosystems located within the boundaries of large cities and industrial agglomerations. The paper presents the results obtained during hydrobiological studies on small rivers of St. Petersburg (Russian Federation) in 2019-2021. The application of bioindication methods is substantiated in order to assess long-term changes in aquatic ecosystems under conditions of increasing anthropogenic load. Various characteristics of the community of benthic invertebrates are used as biological indicators of the state of hydroecosystems. Benthos samples were taken on eight small watercourses of the city, which are both tributaries of the Neva River of various orders (the Okhta, Slavyanka, Chernaya Rechka, Lubya, Okkervil, Volkovka rivers) and delta watercourses (the Smolenka and Karpovka rivers). The paper provides a brief description of the studied water bodies and sampling sites. A number of biotic metrics and biotic indices used for bioindication purposes both in Russia and abroad have been identified. It is noted that the unstable hydrochemical regime and low flow velocity in the small watercourses of the Neva River delta contribute to the intensification of the accumulation of sediments with high concentrations of ecotoxicants, which negatively affects both quantitative and qualitative characteristics of biocenoses. In some watercourses re is a complete absence of bottom invertebrates, which can be assessed as an ecological disaster. When assessing water quality by quantitative and qualitative characteristics of communities of benthic invertebrates (Mayer index, BMWP index, some biotic metrics), it can be concluded that Okkervil River, Chernaya Rechka River and Volkovka River should be attributed to watercourses whose ecological state is extremely unfavorable. The ecological state of the rivers Karpovka River, Slavyanka River, as well as the estuaries of Okhta River and Smolenka River should be considered unfavorable. And finally, the situation in Lubya River, the source of Smolenka River and in the middle reaches of the Okhta River can be considered close to satisfactory (low quality according to BMWP or moderately polluted water according to IM).
{"title":"Assessment of the ecological state of small rivers of St. Petersburg according to the benthic macroinvertebrates indicators in 2019-2021","authors":"D. Petrov, A. Yakusheva","doi":"10.21638/spbu07.2022.308","DOIUrl":"https://doi.org/10.21638/spbu07.2022.308","url":null,"abstract":"The work is devoted to the topical issue of assessing the state and changes of river ecosystems located within the boundaries of large cities and industrial agglomerations. The paper presents the results obtained during hydrobiological studies on small rivers of St. Petersburg (Russian Federation) in 2019-2021. The application of bioindication methods is substantiated in order to assess long-term changes in aquatic ecosystems under conditions of increasing anthropogenic load. Various characteristics of the community of benthic invertebrates are used as biological indicators of the state of hydroecosystems. Benthos samples were taken on eight small watercourses of the city, which are both tributaries of the Neva River of various orders (the Okhta, Slavyanka, Chernaya Rechka, Lubya, Okkervil, Volkovka rivers) and delta watercourses (the Smolenka and Karpovka rivers). The paper provides a brief description of the studied water bodies and sampling sites. A number of biotic metrics and biotic indices used for bioindication purposes both in Russia and abroad have been identified. It is noted that the unstable hydrochemical regime and low flow velocity in the small watercourses of the Neva River delta contribute to the intensification of the accumulation of sediments with high concentrations of ecotoxicants, which negatively affects both quantitative and qualitative characteristics of biocenoses. In some watercourses re is a complete absence of bottom invertebrates, which can be assessed as an ecological disaster. When assessing water quality by quantitative and qualitative characteristics of communities of benthic invertebrates (Mayer index, BMWP index, some biotic metrics), it can be concluded that Okkervil River, Chernaya Rechka River and Volkovka River should be attributed to watercourses whose ecological state is extremely unfavorable. The ecological state of the rivers Karpovka River, Slavyanka River, as well as the estuaries of Okhta River and Smolenka River should be considered unfavorable. And finally, the situation in Lubya River, the source of Smolenka River and in the middle reaches of the Okhta River can be considered close to satisfactory (low quality according to BMWP or moderately polluted water according to IM).","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":"82604171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-01-01DOI: 10.21638/spbu07.2022.302
K. Voloshenko, K. Morachevskaya, A. Novikova, E. Lyzhina, Leonid Kalinovskiy
Foreign trade relations of Russia in the 2010s developed in the context of various geopolitical challenges, which led to a radical transformation of the volume and geography of export-import operations, including the food sector. The 2014 embargo triggered an intensification of the import substitution policy in the Russian agriculture and food production. The value of the import component in the food market, the basic level of agriculture and food production development, and the level of diversification and localisation of raw material relations of enterprises acted as differentiating factors in the influence of new external challenges on the food security of the regions. Kaliningrad Oblast is of particular interest for studying the transformation of food security, taking into account the exclave position, the low level of agriculture development a decade ago, close export-import relations with European countries until 2014. The paper calculates food security indicators, analyses territorial and sectoral shifts in agriculture and food production, and estimates changes in the import component in the food market of Kaliningrad Oblast. The data of the federal state statistics service, the Kaliningrad regional customs, as well as the results of expert interviews and visual observations conducted by the authors in August 2020 are used. It was revealed that the transformation of food security in Kaliningrad Oblast, on the one hand, reflected national trends, and, on the other hand, had unique features. The latter were characteristic of changes in the food independence of the region. Its increase was associated with the rapid growth of agriculture with a high return of government support. In addition, there was a relatively dispersed distribution of key centers of agricultural production, atypical for many regions of “mainland” Russia. The beneficiaries of the free niches on the market, which opened after the food embargo in 2014, as in most of the territory of Russia, were large agroholdings, but many of them, in contrast to those located in the interior regions of the country, were rather acutely experiencing the ruptures of raw materials ties.
{"title":"Transformation of food security of the border region in the face of external challenges: a case study of Kaliningrad Oblast","authors":"K. Voloshenko, K. Morachevskaya, A. Novikova, E. Lyzhina, Leonid Kalinovskiy","doi":"10.21638/spbu07.2022.302","DOIUrl":"https://doi.org/10.21638/spbu07.2022.302","url":null,"abstract":"Foreign trade relations of Russia in the 2010s developed in the context of various geopolitical challenges, which led to a radical transformation of the volume and geography of export-import operations, including the food sector. The 2014 embargo triggered an intensification of the import substitution policy in the Russian agriculture and food production. The value of the import component in the food market, the basic level of agriculture and food production development, and the level of diversification and localisation of raw material relations of enterprises acted as differentiating factors in the influence of new external challenges on the food security of the regions. Kaliningrad Oblast is of particular interest for studying the transformation of food security, taking into account the exclave position, the low level of agriculture development a decade ago, close export-import relations with European countries until 2014. The paper calculates food security indicators, analyses territorial and sectoral shifts in agriculture and food production, and estimates changes in the import component in the food market of Kaliningrad Oblast. The data of the federal state statistics service, the Kaliningrad regional customs, as well as the results of expert interviews and visual observations conducted by the authors in August 2020 are used. It was revealed that the transformation of food security in Kaliningrad Oblast, on the one hand, reflected national trends, and, on the other hand, had unique features. The latter were characteristic of changes in the food independence of the region. Its increase was associated with the rapid growth of agriculture with a high return of government support. In addition, there was a relatively dispersed distribution of key centers of agricultural production, atypical for many regions of “mainland” Russia. The beneficiaries of the free niches on the market, which opened after the food embargo in 2014, as in most of the territory of Russia, were large agroholdings, but many of them, in contrast to those located in the interior regions of the country, were rather acutely experiencing the ruptures of raw materials ties.","PeriodicalId":41676,"journal":{"name":"Vestnik of Saint Petersburg University Earth Sciences","volume":"101 1","pages":""},"PeriodicalIF":0.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76853294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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