Изотопный состав стронция 87Sr/86Sr скелетных тканей (зубов и костей) позволяет получать информацию о миграциях и происхождении человека и животных. На примере образца зуба человека из погребения в кургане (ранний железный век, Омская обл.) с использованием методов масс-спектрометрии с индуктивно связанной плазмой (МС-ИСП) и лазерной абляцией и электронно-зондового микроанализа оценена пригодность его различных структурных элементов (эмали и дентина) для дальнейшего изотопного анализа стронция. Проведено микроэлементное картирование фрагмента зуба. Показано отсутствие значимых диагенетических изменений эмали зуба, для которой методом МС-ИСП с многоколлекторным приемником ионов после хроматографического выделения проведено определение изотопного состава стронция. Это первое изотопное исследование материалов из археологических раскопок курганов саргатской культуры. Кроме того, показана перспективность предлагаемого подхода для реконструкции тафономических условий среды захоронения, что может внести вклад в выявление и изучение условий, способствовавших сохранению целостности скелетных тканей и археологической информации.

The paper is devoted to the Sr-, Nd-, Pb-isotope data obtained for two cores of bottom sediments taken in the Oga and Tsivolki bays of the Severny Island of the Novaya Zemlya archipelago. The studied sequence of sediments from Oga Bay has been accumulated over the last thousand years. The 87Sr/86Sr ratio decreases from top to bottom down the section from 0.72225 to 0.71995, the value of εNd varies from –6.1 to –5.5. The Pb isotopic composition varies within narrow limits: the 206Pb/204Pb ratio from 19.107 to 19.139, the 207Pb/204Pb ratio from 15.632 to 15.635, and the 208Pb/204Pb ratio from 38.568 to 38.635. A rapid decrease in the 87Sr/86Sr ratio at a relatively stable neodymium and lead isotope composition indicates a change in the source of the clastogenic material. This can be explained by the fact that the material of the destruction of Permian clay shales, and then the Devonian-Silurian sedimentary carbonates, first entered the area of glacier abrasion and further, respectively, into the sedimentation zone. The sediment column from the Tsivolki Bay was formed over a little more than 10 thousand years. Based on the Sr, Nd, and Pb isotope ratios, these bottom sediments are divided into lower and upper parts: before and after 150 cm (or ~3500 years). In the lower part of the column, the 87Sr/86Sr ratio increases from 0.72055 to 0.72580, the value of εNd remains approximately the same and varies around –8.2. In the upper part, the 87Sr/86Sr ratio drops to 0.72049 in the near-surface layer; at the same time, the value of εNd increases to –6.4. At the boundary of these two units, the 206Pb/204Pb ratio abruptly changes from about 18.0 in the lower part to 19.3 in the upper part and 208Pb/204Pb from about 36.5 in the lower part to 38.7 in the upper part of the section. The change in the Sr, Nd, and Pb isotope characteristics is likely a reflection of changes in the composition of the rocks in the area where the basin was removed, which is now being eroded by the glacier. Comparison with modern sources supplying clastic material to the Kara Sea showed that the material inputs the Oga and Tsivolki bays only from Novaya Zemlya.

Research subject. Mineral assemblages of sulfides from massive and disseminated sulfide nickel-copper-platinum-group element (Ni-Cu-PGE) and low-sulfide PGE ores of the Noril’sk Province, which hosts the richest complex deposits of platinum-group metals, nickel, and copper. Aim. In order to identify sources of ore material and explore new forecasting approaches for Ni-Cu-PGE deposits, we study the Cu- and Zn isotopic compositions of sulfides from economic Kharaelakh and Noril’sk-1 intrusions containing unique and large sulphide Ni-Cu-PGE deposits (Oktyabr’sk and Noril’sk-1, respectively), subeconmic Zub-Marksheider and Vologochan intrusions containing small- to medium-size Ni-Cu-PGE deposits, and non-economic Nizhny Talnakh and Nizhny Noril’sk intrusions containing low grade disseminated Ni-Cu mineralization. Results. The analyzed samples are characterized by sulfide mineral assemblages, which contain mainly chalcopyrite, pyrrhotite, pentlandite, troilite, cubanite, and galena. Sulfide Ni-Cu-PGE ores of the Oktyabr’sk and Noril’sk-1 deposits, associated with economic intrusions (i.e., Kharaelakh and Noril’sk-1), demonstrate distinct δ65Cu values from –2.42 to –1.40‰ and from –0.33 to 0.60‰, respectively, which differ from the δ65Cu values for sulfides from other Ni-Cu-PGE deposits and ore occurrences of the Noril’sk Province (data comprise 36 analyses). We note that the Cu-isotopic composition for sulfide minerals of massive and disseminated ores from the Kharaelakh intrusion has similar “isotope-light” characteristics. The most pronounced shift towards “isotope-heavy” copper was found in the horizon of low-sulfide PGE ores of the Noril’sk-1 intrusion (δ65Cu = 0.51–0.60‰). The isotopic composition of Zn (δ66Zn) for the studied sulfide samples from economic, subeconomic, and non-economic intrusions, with the exception of one sample (0.73 ± 0.14‰), is characterized by similar “isotope-light” values (from –0.65 to –0.03‰). Conclusions. The revealed variations in the Cu- and Zn-isotopic composition in the studied sulfide assemblages from all types of ores reflect their primary characteristics; however, for the unique Oktyabr’sk Ni-Cu-PGE deposit, characterized by the most “isotopically light” composition of copper (δ65Cu = –1.9 ± 0.34‰), the possibility of assimilation of an external source of Cu during the formation of sulfide Ni-Cu-PGE ores cannot be excluded. The combined use of Cu and Zn isotopic parameters proved to be a weakly informative predictive indicator for the detection of high-grade sulfide ores, primarily due to the similarity of the Zn isotopic composition of the ore material in all investigated intrusions of the Noril’sk Province.

The 87Sr/86Sr strontium isotope ratio in skeletal tissues (teeth and bones) gives valuable information about the migrations and origin of humans and animals. In this study, we assess the suitability of various structural elements (enamel and dentin) of a human tooth sample from a burial mound (Early Iron Age, Omsk oblast) for strontium isotope analysis using inductively coupled plasma mass spectrometry (ICP–MS), laser ablation, and electron probe microanalysis. The microelemental mapping of a tooth fragment was conducted. The results indicate the absence of significant diagenetic changes in the tooth enamel, for which the 87Sr/86Sr isotope composition was determined by multicollector ICP–MS after chromatographic separation. This research represents the first isotopic study of materials from archaeological excavations of Sargat culture burial mounds. Furthermore, this approach offers promise in reconstructing taphonomic conditions of burial environments, contributing to the understanding of conditions facilitating the preservation of skeletal tissues and archaeological information.

Understanding the main events of platinum -group element (PGE) ore formation is impossible without analysis of the sources and behavior of major ore -forming components, namely, platinum, osmium, sulfur, and copper, which are important indicators of magmatic and hydrothermal processes. In contrast to the Re-Os isotope system, the radiogenic Pt-Os isotope system, as well as stable isotopes of Cu and S in PGE deposits, are still relatively understudied. Our comprehensive research is aimed at filling this gap. The paper presents data for the Guli massif of ultramafic and alkaline rocks and carbonatites in Polar Siberia and on the zonal Nizhny Tagil and Svetly Bor clinopyroxenite-dunite massifs in the Middle Urals, which include: (1) the contents of the highly siderophile elements (HSE) in whole rocks and platinum -group minerals (PGM), (2) the Re-Os and Pt-Os isotope systematics of chromitite, Os-Ir alloys, and Ru-Os sulfides, (3) the sulfur isotope composition in Ru-Os and Ir-Rh sulfides in primary and secondary PGM assemblages, and (4) the copper isotope composition in Pt-Fe minerals from chromitites and placers. The research was performed using scanning electron microscopy, electron probe microanalysis, and high -precision isotope-geochemical analysis. The high -precision Re-Os and Pt-Os isotope data show that the HSE contents in chromitites and PGM of the Guli massif were controlled by the composition of the mantle source that evolved with nearchondritic time -integrated Re/Os and Pt/Os ratios, which are also typical of the sources of most komatiites and abyssal peridotites. The delta 65Cu values of the studied samples of ferroan platinum and isoferroplatinum are identical within the analytical uncertainty and are close to 0 parts per thousand, which is typical of high -temperature Cu -containing minerals. The sulfur isotope compositions of the Ir-Rh sulfides of the kashinite-bowieite series and of the Ru-Os sulfides of the laurite-erlichmanite series in the primary PGM assemblages indicate that the source of sulfur has a chondritic isotope composition, which is in agreement with the osmium isotope composition of the Ru-Os sulfides and Os-Ir alloys. The heavy sulfur isotope composition (delta 34S = 5.6 +/- 1.5 parts per thousand) of As -containing erlichmanite is consistent with its secondary origin. The new data on the isotope compositions of osmium, copper, and sulfur can be used as new important parameters that characterize the sources of PGE mineralization.

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X23060144

Понимание главных событий платинометалльного рудообразования невозможно без анализа источников и поведения главных рудообразующих компонентов, а именно платины, осмия, серы и меди, являющихся важными индикаторами магматических и гидротермальных процессов. В отличие от Re-Os изотопной системы, изотопные системы Pt-Os, меди и серы платинометалльных месторождений до сих пор остаются слабоизученными. Выполненное нами комплексное исследование направлено на частичное восполнение данного пробела. В статье представлен обширный набор данных, включая: 1) содержания сильносидерофильных элементов (ССЭ) в породах и минералах платиновой группы (МПГ), 2) Re-Os и Pt-Os изотопные вариации в хромитите, Os-Ir сплавах и Ru-Os сульфидах, 3) изотопный состав серы Ru-Os и Ir-Rh сульфидов в составе первичных и вторичных минеральных ассоциаций МПГ, 4) изотопный состав меди Pt-Fe минералов из хромититов и россыпных месторождений Гулинского массива ультраосновных и щелочных пород с карбонатитами в Полярной Сибири и зональных Нижнетагильского и Светлоборского клинопироксенит-дунитовых массивов на Среднем Урале. При проведении исследований были использованы сканирующая электронная микроскопия, рентгеноспектральный микроанализ и прецизионные изотопно-геохимические методы анализа. Высокоточные Re-Os и Pt-Os изотопные данные свидетельствуют, что содержания ССЭ в хромититах и МПГ Гулинского массива в значительной степени контролировались составом мантийного источника, который эволюционировал с околохондритовыми интегрированными по времени Re/Os и Pt/Os отношениями, характерными также для источников большинства коматиитов и абиссальных перидотитов. Значения δ65Cu для изученных образцов железистой платины и изоферроплатины в пределах погрешности неотличимы друг от друга и характеризуются изотопными составами меди, близкими к 0 ‰, что типично для высокотемпературных Cu-содержащих минералов. Особенности изотопного состава серы Ir-Rh сульфидов ряда кашинит—боуит и Ru-Os сульфидов ряда лаурит—эрликманит в составе первичных ассоциаций МПГ свидетельствуют в пользу ее источника с хондритовым изотопным составом, что находится в согласии с данными по изотопному составу осмия для Ru-Os сульфидов и Os-Ir сплавов. Изотопно-тяжелый состав серы (δ34S = 5.6 ± 1.5 ‰) As-содержащего эрликманита согласуется с его вторичным происхождением. Выявленные особенности изотопного состава осмия, платины, меди и серы могут быть использованы в качестве новых дополнительных параметров, характеризующих условия образования платиноидной минерализации. Understanding the main events of platinum-group element (PGE) ore formation is impossible without analysis of the sources and behavior of major ore-forming components, namely, platinum, osmium, sulfur, and copper, which are important indicators of magmatic and hydrothermal processes. In contrast to the Re–Os isotope system, the radiogenic Pt–Os isotope system, as well as stable isotopes of Cu and S in PGE deposits, are still relatively understudied. Our comprehensive research is aimed at filling this gap. The paper presents data for the Guli massif of ultramafic and alkaline rocks and carbonatites in Polar Siberia and on the zonal Nizhny Tagil and Svetly Bor clinopyroxenite–dunite massifs in the Middle Urals, which include: (1) the contents of the highly siderophile elements (HSE) in whole rocks and platinum-group minerals (PGM), (2) the Re–Os and Pt–Os isotope systematics of chromitite, Os–Ir alloys, and Ru–Os sulfides, (3) the sulfur isotope composition in Ru–Os and Ir–Rh sulfides in primary and secondary PGM assemblages, and (4) the copper isotope composition in Pt–Fe minerals from chromitites and placers. The research was performed using scanning electron microscopy, electron probe microanalysis, and high-precision isotope-geochemical analysis. The high-precision Re–Os and Pt–Os isotope data show that the HSE contents in chromitites and PGM of the Guli massif were controlled by the composition of the mantle source that evolved with near-chondritic time-integrated Re/Os and Pt/Os ratios, which are also typical of the sources of most komatiites and abyssal peridotites. The δ65Cu values of the studied samples of ferroan platinum and isoferroplatinum are identical within the analytical uncertainty and are close to 0‰, which is typical of high-temperature Cu-containing minerals. The sulfur isotope compositions of the Ir–Rh sulfides of the kashinite–bowieite series and of the Ru–Os sulfides of the laurite–erlichmanite series in the primary PGM assemblages indicate that the source of sulfur has a chondritic isotope composition, which is in agreement with the osmium isotope composition of the Ru–Os sulfides and Os–Ir alloys. The heavy sulfur isotope composition (δ34S = 5.6 ± 1.5‰) of As-containing erlichmanite is consistent with its secondary origin. The new data on the isotope compositions of osmium, copper, and sulfur can be used as new important parameters that characterize the sources of PGE mineralization.

Изотопный состав стронция 87Sr/86Sr скелетных тканей (зубов и костей) позволяет получать информацию о миграциях и происхождении человека и животных. На примере образца зуба человека из погребения в кургане (ранний железный век, Омская обл.) с использованием методов масс-спектрометрии с индуктивно связанной плазмой (МС-ИСП) и лазерной абляцией и электронно-зондового микроанализа оценена пригодность его различных структурных элементов (эмали и дентина) для дальнейшего изотопного анализа стронция. Проведено микроэлементное картирование фрагмента зуба. Показано отсутствие значимых диагенетических изменений эмали зуба, для которой методом МС-ИСП с многоколлекторным приемником ионов после хроматографического выделения проведено определение изотопного состава стронция. Это первое изотопное исследование материалов из археологических раскопок курганов саргатской культуры. Кроме того, показана перспективность предлагаемого подхода для реконструкции тафономических условий среды захоронения, что может внести вклад в выявление и изучение условий, способствовавших сохранению целостности скелетных тканей и археологической информации.

Research subject. AGV-2 and BHVO-2 geochemical reference materials for studying the Sm, Nd and Rb, Sr isotope systems along with various rocks and mineral samples. Materials and Methods. An analysis of the isotopic composition of Sm, Nd and Rb, Sr was carried out using Neptune Plus and Triton Plus mass spectrometers. Aim. To implement analytical techniques for the isotopic composition of Sm and Nd, Rb, and Sr in various rock and mineral samples using two types of multicollector mass spectrometers – inductively coupled plasma NeptunePlus and thermal ionization TritonPlus (Thermo-Fisher), as well as a description of the procedure of processing experimental data and the experience in using techniques at the “Geoanalitik” shared research facilities of the IGG UB RAS for the period 2015-2023. Results. The analytical techniques implemented included (1) column chromatography using various ion-exchange resins, optimised for the ratio of labour costs/quality of analytical results; (2) the measurement of isotope ratios using two types of mass spectrometers; (3) the correction of mass bias of isotope ratios and the determination of Sm and Nd, Rb, and Sr concentrations by the isotope dilution method using 149Sm+150Nd and 85Rb+84Sr spikes. Testing of the techniques was carried out using the AGV-2 and BHVO-2 geochemical reference materials; their metrological characteristics were presented. When using TritonPlus, the reproducibility (BHVO-2, n=60) of measurements of 143Nd/144Nd, 147Sm/144Nd isotope ratios and Sm and Nd concentrations are ±0.000020, ±0.0004, ±1.3 and ±0.4, respectively; indicators of correctness of determining the ratios 143Nd/144Nd and 147Sm/144Nd – 0.001 and 0.25% and concentrations of Sm and Nd – 2%; the reproducibility (BHVO-2, n=63) of measurements of 87Sr/86Sr, 87Rb/86Sr isotope ratios and concentrations (Rb and Sr) are ±0.0025%, ±1.5%, ±2%, respectively. The uncertainty of a single measurement of the 143Nd/144Nd and 87Sr/86Sr isotope ratio, represented by the standard error of the average single measurement in the sample, does not exceed 0.0025%. Conclusions: the results obtained for the geochemical reference materials are in satisfactory agreement with those provided in the GeoReM database, as well as with the certified values provided by the United States Geological Survey (USGS). The described analytical techniques are used at the “Geoanalitik” shared research facilities of the IGG UB RAS to analyse various rock and mineral samples. The work presents a number of experimental results obtained, which are subsequently used in geochronological applications.

The results of U–Pb age determination, Nd–Sr–Pb isotope systematics and geochemical study of quartz diorites associated with ore-bearing (Cu–Pd–Au–Ag) gabbro of the Volkovskiy massif localized within the Ural Platinum Belt, at its eastern border with Silurian-Devonian volcanogenic complexes of the Tagil megazone are presented. The age of quartz diorites by U–Pb (TIMS) age determination is 429±9 mln years, MSWD = 0.009. Sr–Nd–Pb isotope characteristics (ƐNd(T) = +5.5 ÷ +6.7; (87Sr/86Sr)t= 0.70382−0.70392;206Pb/204Pb = 18.38−18.57;207Pb/204Pb = 15.56−15.58;208Pb/204Pb = 38.14−38.30) indicate a juvenile source with a model age of 570−760 mln years. The obtained data do not go beyond the values typical for basalts of enzymatic island arcs. The geochemical features of the granitoids of the Volkovskiy massif (low REE concentration, differentiation of their spectrum (La/Yb = 8−14) with weak positive Eu-anomaly (Eu/Eu* = 0.9−1.4)) are consistent with the characteristics of melts obtained in water melting experiments for mafic rocks in equilibrium with amphibole-pyroxene restite. The anomalous strontium concentration (more than 1000 g/t) in quartz diorites is due to the high content of this element in the source. Such source could be the earliest rocks of the Ural Platinum Belt – olivine gabbro and surrounding metamorphic rocks. The same age of quartz diorites of the Volkovskiy massif and monzonitoids of the Kushvinskiy massif allows us to consider these rocks as a result of the mantle and crust melting converged in time at the final stage of the Tagil island-arc system formation.

Recent data on the bulk and isotopic (Sr, Nd) composition of kimberlites from the low-diamondiferous TsNIGRI–Arkhangelskaya pipe, located in the Kepino field of the Arkhangelsk diamondiferous province, are presented. It is shown that the kimberlites belong to the moderate titanium type of kimberlites of the province and differ significantly from the previously studied kimberlites of the Kepino field in the lower concentrations of TiO2, Ba, high field strength, and light rare earth elements. Among all the kimberlites of the province, the kimberlites from the TsNIGRI–Arkhangelskaya pipe have the most radiogenic Sr composition (87Sr/86Sr t from 0.7068 to 0.7089), which may be related to a combination of several factors. It has been established that the kimberlites from the pipe are represented by two varieties, having differences both in the concentrations of major and trace elements and in the Sr and Nd isotopic composition. The Nd isotopic composition (εNd from 0 to –0.6) for type-I kimberlites indicates their enriched source in the lithospheric mantle. The type-II kimberlites have a less radiogenic Nd composition (εNd from –3.5 to –4.9), which is interpreted ambiguously: their formation from an even more ancient enriched source inside the lithospheric mantle compared to type-I kimberlites cannot be excluded.

An Erratum to this paper has been published: https://doi.org/10.1134/S1028334X23050240

The combined petrographic, petrological, geochemical and geochronological study of the Neoproterozoic gneisses of the Sarychabyn and Baskan complexes of the Junggar Alataw of South Kazakhstan elucidate the Precambrian tectonic evolution of the Aktau-Yili terrane. It is one of the largest Precambrian crustal blocks in the western Central Asian orogenic belt. The U-Pb single-grain zircon ages indicate that granite-gneisses formed from the same source and crystallised in the early Neoproterozoic ca. 930-920 Ma. The chemical composition of gneisses corresponds to A2-type granites. The whole-rock Nd isotopic characteristics (epsilon Nd(t) = -4.9 to -1.0 and TNd(DM-2st) = 1.9 to 1.7 Ga) indicate the involvement of Paleoproterozoic crustal rocks in magma generation. Early Neoproterozoic ca. 930-920 Ma A-type granitoids in the Aktau-Yili terrane of South and Central Kazakhstan might reflect within-plate magmatism adjacent to the collisional belt or a local extension setting in back-arc areas of the continental arc. image

At the boundary of the Meso- and Neoproterozoic, Grenville collision events were widely manifested on the margins of ancient continental blocks. Most of the sedimentary sequences that had accumulated by that time had undergone significant thermal–metamorphic changes. In many ways, this is the main reason for the lack of isotopic data for carbonate deposits in the interval of 1200–900 Ma in world practice. Sr–isotopic composition in carbonate rocks with an age of 980–920 Ma was determined in the only section of the World – the Huainan Formation of the North China Platform with accumulation time determined by U–Pb dating of detrital zircon grains. In the upper part of the Nizhny Tunguska suite of the Turukhansk uplift, among carbonate deposits, we established the presence of altered volcanic rocks, as well as weathering crust products along them – poor bauxite and chamosite ores. Based on U–Pb zircon isotope dating, the age of the volcanic rocks is 964 Ma. For the least altered limestones of the upper part of the Nizhny Tungusska Formation, received 87Sr/86Sr values are 0.70532–0.70578, which are close enough to those found in the rocks of the Huainan Formation. Geochronological age of the studied limestones gives us more correct data. These data can be used to refine the previously proposed configuration of the Sr–isotopic composition variation curve in the Early Neoproterozoic. The Nizhny Tunguska Formation is the only carbonate section of the Early Neoproterozoic in the world with correctly geochronologically substantiated dating (based on zircon from subsynchronous volcanic rocks). This compares favorably with the Huainan formation.

Troctolites, olivine and picrite gabbrodolerites account for up to 75% of the Lower Talnakh type intrusions in places of their increased thickness whereas reduced thickness sections consist of olivine-free and olivine-bearing gabbrodolerites. Differentiation is not obvious within these high-Mg cumulates, although the content of TiO2 and alkalis increases towards the upper endocontacts. The transitions between the rock types are gradational, and the composition of low Ni olivine in different rocks (Fo70–83, 0.01–0.2 wt % NiO) overlap significantly. Clinopyroxene (Fs7–13, Mg# 68–89) is characterized by both the lowest contents and variation ranges of Cr2O3 (0.01–0.5 wt %) and TiO2 (0.05–1.0 wt %) among all types of the intrusions of the Norilsk complex that is consistent with the Cr-depleted (0.002–0.051 wt % Cr2O3) bulk rock compositions. Later orthopyroxene (Fs15–30) is crystallised by the reaction of the residual melt with early olivine. Plagioclase forms porphyritic phenocrysts and their intergrowths along with ophitic laths as well as dominates in schlieren and fragments of leucocratic rocks in taxitic and picritic gabbrodolerites with a poorly sorted layered texture. In olivine-rich rocks, sulfides are represented by the association of troilite ± hexagonal pyrrhotite + Fe- and Co-rich pentlandite + Fe-enriched chalcopyrite (± putoranite, talnakhite) ± cubanite. In the upper and lower parts of the intrusions, the association of hexagonal pyrrhotite + chalcopyrite + pentlandite occurs, while monoclinic pyrrhotite + chalcopyrite + Ni-enriched pentlandite are formed in the endo- and exocontacts. The concentration of base (0.077–0.21 wt % Ni, 0.05–0.38 wt % Cu) and platinum metals (0.03–0.26 to 0.40 g/t total PGE) in mineralized rocks is very low. Upon small amounts of sulfides and extremely low base and platinum metal tenors, the heterogeneous S isotopic composition of Lower Talnakh type sulfides (mainly 3.8–8.6‰, but up to 11.8%) most likely reflects the achievement of repeated sulfide saturation during the assimilation of sulfate S by magma that has previously experienced loss of chalcophile metals into a coexisting sulfide fluid at depth. The Sr-Nd isotopic compositions of the Lower Talnakh intrusions (Sri – from 0.7073 to 0.7087 and εNd(Т) from –1.8 at –5.9 recalculated to 250 Ma) show the predominant contamination with Proterozoic material, in contrast to the ore-bearing intrusions, which Sr-Nd isotope compositions indicate contamination with upper crustal sedimentary matter of the Paleozoic age.

The isotopic composition of copper is of great interest for researchers in various fields of science, geochemistry and hydrology in particular, wherein the consideration is being given to the variations in the isotopic composition of the Earth’s crust, extraterrestrial matter, and water basins, as well as to the origin and transfer of matter. Zn isotopes appear to be promising for identifying the sources and pathways of the environmental pollution. The aim of this study involves the refinement and validation of the zinc and copper isotopic ratio determination methodology covering the whole process from sample digestion to MC ICP-MS measurements. For this reason, as well as to assess the suitability of the methodology for the analysis of environmental samples, Zn and Cu isotopic analysis of the BHVO-2, BCR-2 and AGV-2 USGS certified reference materials has been performed. The method for determination of Cu and Zn stable isotope ratios by multi-collector inductively coupled plasma mass spectrometry in environmental samples is developed. The application of the AG MP-1 resin with optimized layer parameters (resin bed height 3.5 cm, diameter 1 cm) provides the high-purity Cu and Zn fractions. The method is characterized by high throughput and adequate analytical figures of merit when using the standard-sample bracketing technique for mass bias correction. The procedural blanks related to chemical dissolution and ion exchange procedures are lower than 1 and 3 ng for Cu and Zn, respectively, assuring no blank effect on the isotopic composition of samples. The accuracy and precision obtained for Cu and Zn isotope measurements in the BHVO-2, BCR-2 and AGV-2 geological certified reference materials demonstrate good agreement with the reference values published.

87Sr/86Sr isotopic ratios are widely used to identify strontium sources and study strontium behaviour in(bio)geochemical cycles. 87Sr/86Sr in surface waters can reflect the average composition of bioavailable (i.e. available forfurther absorption by plants and animals) strontium in the catchment specific area. Based on those 87Sr/86Sr ratios, theregional maps of the bioavailable strontium distribution (strontium isoscapes) can be compiled. A complex block structurecharacterizes the Ural mountain system. Individual parts (blocks) are composed of rocks of various ages, genesis andgeochemical characteristics, which can radically change at a distance of several tens of kilometres. Such variability wouldbe reflected in strontium isotopic ratios, thus making it possible to determine the local isotopic signatures of bioavailablestrontium.This work aimed to study 87Sr/86Sr in the water in the rivers of the Southern Urals. We determined the contents andisotopic ratios of strontium in river water samples collected from the territories of the Orenburg and Chelyabinsk regionsand the Republic of Bashkortostan in 2019–2020.For the first time in the surface water of the rivers in the Southern Urals (Ural, Belaya, Tobol, Karagaily-Ayat, Sim, andothers), the 87Sr/86Sr isotopic ratios have been determined, and their variations have been analyzed. 87Sr/86Sr values varyin the range 0.70666–0.71063 (average 0.70908) for the rivers of the Urals basin, 0.70749–0.71058 (average 0.70924)for the Kama-Volga basin, 0.70946–0.71176 (average 0.71071) for the Tobol basin. Such features of the strontium isotopiccomposition may be due to the influence of underlying rocks of the catchment area drained by river water. The dataobtained can be used to identify the sources of strontium input into the water system during hydrological and environmentalstudies; to confirm the authenticity of food products of plant and animal origin; to carry out comparisons in thestudies of the migration of ancient people and animals, as well as to determine the raw material areas for the productionof vegetable and woollen textiles and wooden products in antiquity.

87Sr/86Sr isotopic ratios are widely used to identify strontium sources and study strontium behaviour in(bio)geochemical cycles. 87Sr/86Sr in surface waters can reflect the average composition of bioavailable (i.e. available forfurther absorption by plants and animals) strontium in the catchment specific area. Based on those 87Sr/86Sr ratios, theregional maps of the bioavailable strontium distribution (strontium isoscapes) can be compiled. A complex block structurecharacterizes the Ural mountain system. Individual parts (blocks) are composed of rocks of various ages, genesis andgeochemical characteristics, which can radically change at a distance of several tens of kilometres. Such variability wouldbe reflected in strontium isotopic ratios, thus making it possible to determine the local isotopic signatures of bioavailablestrontium.This work aimed to study 87Sr/86Sr in the water in the rivers of the Southern Urals. We determined the contents andisotopic ratios of strontium in river water samples collected from the territories of the Orenburg and Chelyabinsk regionsand the Republic of Bashkortostan in 2019–2020.For the first time in the surface water of the rivers in the Southern Urals (Ural, Belaya, Tobol, Karagaily-Ayat, Sim, andothers), the 87Sr/86Sr isotopic ratios have been determined, and their variations have been analyzed. 87Sr/86Sr values varyin the range 0.70666–0.71063 (average 0.70908) for the rivers of the Urals basin, 0.70749–0.71058 (average 0.70924)for the Kama-Volga basin, 0.70946–0.71176 (average 0.71071) for the Tobol basin. Such features of the strontium isotopiccomposition may be due to the influence of underlying rocks of the catchment area drained by river water. The dataobtained can be used to identify the sources of strontium input into the water system during hydrological and environmentalstudies; to confirm the authenticity of food products of plant and animal origin; to carry out comparisons in thestudies of the migration of ancient people and animals, as well as to determine the raw material areas for the productionof vegetable and woollen textiles and wooden products in antiquity.

Research subject. Permian-Triassic flood basalts in the basement of the Arctic zone of the West Siberian Platform locate mainly in graben-rift structures. Flood basalts in this region remain to be understudied in comparison with other areas of its distribution, mainly due to the significant depth of their occurrence (4–6 km). Materials and methods. 36 core samples from 11 superdeep and deep boreholes were studied. Isotopic ratios were measured on mass spectrometers NEPTUNE PLUS (Nd, Sm) and TRITON PLUS (Rb, Sr). Bitumen were studied using a Raman spectrometer LabRAM HR800 Evolution. The Raman spectra were deconvoluted (“Peak fitting” procedure), and the bitumen conversion temperature was estimated. Results . About half of the samples of volcanic rocks underwent metamorphism of the prehnite-pumpellite and locally greenschist facies or intense low-temperature hydrothermal alteration. The studied basalts are close to typical flood basalts and are somewhat similar to island-arc volcanic rocks in terms of their geochemical characteristics. For the first time, thin inclusions of bitumen were found in the amygdalae of Permian-Triassic basalts in the superdeep borehole Tyumenskaya SG-6 at a depth of 7310.6 m. A high similarity of the studied volcanics by geochemical characteristics and the isotopic composition of Sr and Nd with the flood basalts of the Siberian platform is shown. Conclusions . The presence of a negative Ta, Nb, Ti anomaly, as well as a negative Ce anomaly, in some of the analyzed samples indicates a possible contamination of the basalts by island arc volcanics and volcanogenic-sedimentary rocks. The temperature of transformation of bitumen in inclusions in basalts from the well Tyumenskaya SG-6 according to Raman spectroscopy is estimated at 150–300°C and generally corresponds to the temperature of metamorphism of the host basalts. The presence of bitumen in the amygdalae may indicate the migration of hydrocarbons through the basalts.

Our multidisciplinary petrologic, mineralogical, and geochemical studies of volcanic material sampled from three chronologically discrete, but successive, ash discharges during the period from November 30, 2020 to January 18, 2021 were concerned with grain-size inhomogeneity, chemical and mineral phase composition, the concentrations of trace elements, the isotopy of Sr, Nd, and carbon, and with the composition of inorganic and organic lithogenic gases. For the first time volcanic ashes were found to contain eskolaite, mantle spinellids of the magnetite–magnesioferrite composition, hybrid compounds of Ca–Zn-carbonates with titanium formate, and polycomponent metallo-organic compounds. The net result was to obtain proof of a mantle–asthenosphere origin of the ash material and to identify a previously unknown pattern consisting in a conjugate temporal orderliness in the variations of many properties in the material sampled from the explosions. This seems to reflect the evolution of the melt in the mantle magma chamber.