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The palingenic calc-alkaline granitoid massifs of the Olekminsky complex form a magmatic belt stretching within the Western-Stanovoy terrane in the northeastern direction for more than 700 km. New U-Pb LA-ICP-MS dates for zircons from the granodiorites of the Marekta-Bereinsky massif of the Olekminsky complex and the granodiorites of the Yamninsky massif of the Krestovsky complex were obtained, amounting to 371±4 Ma and 364±5 Ma, respectively. These geochronological data are well consistent with the 355–358 Ma ones, therefore suggesting the Late Carboniferous age of quartz-diorite-granodiorite-granite rocks of the Olekminsky complex. However, these dates are not correlated with the existing legends of geological maps covering the area of the Western-Stanovoy structural-formation zone or the Western-Stanovoy terrane, as the intrusive formations of the Olekminsky complex are dated as the Early Paleozoic. In addition, new geochronological data call into question distinguishing of a separate Early Paleozoic Krestovsky granitoid complex.

In this paper we present the results on apatite fission-track dating, which was first performed at the Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, using the laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS, Dobretsov Geological Institute, Siberian Branch of the Russian Academy of Sciences) for two intrusions of the Siberian Permian-Triassic large igneous province: Magan alkaline-ultramafic pluton (two samples) and Kontay intrusion (one sample). The obtained AFT ages are 217.6±18.6 and 238.8±35.8 Ma (95% confidence) for the Magan intrusion and 150.0±23.0 Ma for the Kontay intrusion and mark the time since they have been cooled below 120 °C. The distributions of track lengths in apatite grains from the studied samples indicate their rapid cooling to near-surface temperatures. We provide a detailed description of the method used, and also demonstrate that the results of fissiontrack analysis performed on the "sample-to-sample" principle by the classical external detector method (EDM) and the LA-ICP-MS method in the modification of the zeta calibration coincide within the age uncertainty.

We present the first systematic results of U-Pb LA-ICP-MS dating of detrital zircons from 12 samples representing different stratigraphic levels of 5 sections of the Permian-Triassic rocks, located within the eastern part of the Moscow basin (syneclise) – Zhukov ravine, Astashikha, Nedubrovo, Balebikha and Klykovo. It is shown that the accumulation of the Upper Permian and Lower Triassic terrigenous complexes occurred under the influence of competing sources with two contrasting provenance signals with Neoproterozoic (Vendian)-Paleozoic and Paleo-Mesoproterozoic ages. The identified provenance signal patterns were used to detail the correlation and stratigraphic subdivision of the Permian-Triassic terrigenous complex of the Moscow basin. Raman spectroscopy of detrital zircon, first applied to the Permian-Triassic rocks of the East European platform, made it possible to identify sedimentary complexes of a relatively older terrigenous basin as a separate source of zircons, which experienced superimposed thermal impact in the VendianCambrian time (~500–600 Ma).

The strontium (Sr) and barium (Ba) profiles in otoliths of juvenile sockeye salmon Oncorhynchus nerka from British Columbia are measured using a Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) system and analyzed. The highest possible measurement resolution (near-daily) was used to assess variability and repeatability of the breakpoint (marine entry) estimates inferred from Sr:Ca and Ba:Ca ratios. Such resolution for the otolith chemical composition (to an accuracy of 2 μm) was reached using the rotating slit, which width was close to the daily circulus width of the otoliths. So, daily or 2-day changes in the elemental composition were recorded during the period of transition to the marine environment. Sr profiles were generally similar among the fish, starting with low values of Sr:Ca in the fresh water and increasing sharply after the marine entry. The Ba:Ca signal was more complex, showing in most cases a dramatic increase immediately before the breakpoint. Besides, multiple peaks in the Ba profiles were recorded prior to the marine transition with a significant difference of their number between fish from different populations. A breakpoint was detectable in the Ba profiles 3–11 µm prior to its appearance in the Sr profiles. The complexity of Ba profiles may cause erroneous estimates of the marine entry date; thus, the Sr signal is a more reliable marker of marine transition for juvenile sockeye.

In order to develop express methods for the quantitative assessment of properties and the selection of reference samples close to investigated sample, to ensure similar conditions for the evaporation of substances and parameters of fractionation of trace elements in LA-ICP-MS, a comparative analysis of the U-Pb isotopic composition, Raman and cathodoluminescent spectra of zircon GJ-1, Plesovice, 91500, Temora-2, Mud Tank reference samples has been performed. Variations in the position and width of the full width at half maximum (FWHM) mode of asymmetric stretching vibrations ν3(SiO4) B1g, as well as the values of the accumulated autoradiation dose Dα and the equivalent dose Dαed have been analyzed. It has been shown that in the series Mud Tank→91500→Temora-2→GJ-1→Plesovice, an increase in the degree of autoradiation damage is recorded: the first three samples are slightly damaged; Plesovice is a moderately damaged difference. The analyzed reference samples can be correctly used for LA-ICP-MS analysis of samples of weakly damaged zircons from magmatites, as well as fragments (zones) of zircon grains from metamorphic rocks of weak and medium degree of structural damage. For the first time, using a Jeol JSM6390LV SEM equipped with a Horiba H-CLUE iHR500 attachment, cathodoluminescence spectra of zircon reference samples were obtained in the 200–800 nm range. It has been found that the integral luminescence brightness varies for samples by more than an order of magnitude; the spectra are of a complex superposition nature; their decomposition into elementary components is ambiguous; a large number of components is detected, which are combined into three main Аi–Вi–Сi groups of broad bands in the near-ultraviolet (UV), blue-green and yellow regions with Emax=4.3–5.0, 2.6–3.5, and 2.1–2.3 eV, respectively. For the first time, it wasproposed to use a triple Аi–Вi–Сi diagram to discriminate zircons by their luminescent properties. It has been found that the position of zircon standards on it significantly differs, which is proposed to be used as a basis for an express assessment of their properties and selection. A comparative analysis was performed on the U-Pb isotopic composition, discordance of age determinations, features of Raman and cathodoluminescence spectra for a large sample of accessory zircon from kimberlites and diamond-bearing placers of Yakutia, as well as metamorphic rocks of the Urals – from granite of the final phase of the Neplyuevsky pluton, high-magnesian diorite massif, from high-pressure garnetites of the Mindyaksky lherzolite massif, from leptinites of the Taldyk block Mugodzhar. The Аi–Вi–Сi diagram is compared with similar data on the cathodoluminescence of the reference samples.

The first results of U-Pb LA-ICP-MS dating of 150 detrital zircon grains from the Upper Permian sandstone of the Boyevaya Gora section (Orenburg region, the Southern Cis-Urals) are presented. 95 conditional zircon U-Pb isotopic dates form two age peaks – 381 and 529 Ma. It is assumed that clastic material entered the sedimentation basin mainly due to erosion of the Early Hercynian Ural complexes and relics of the Protouralian-Timanian orogen.

Inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation (LA) are widely used to study the trace element composition of minerals, including silicates; nevertheless, methodological activities in this area aimed at increasing the sensitivity and locality and reducing composition error, remain relevant. The paper describes methodological approaches for studying the trace element composition of a number of silicate minerals using NexION 300S quadrupole ICP-MS with an NWR 213 LA attachment, obtained on standard synthetic glasses NIST SRM 612 and 610, as well as a number of interlaboratory zircon standards Mud Tank, GJ-1, 91500, Plesovice, Temora-2 and clinopyroxene samples 1636 and 1780 from clinopyroxenite of the Nizhniy Tagil massif (Urals). Presented here are the metrological characteristics of the analysis technique (the accuracy in the determination of elements from Li to U) and variations in sensitivity for different elements, obtained with a crater diameter of 13, 20, 25, 50 and 100 microns. The MS sensitivity drift analysis has been performed through an 8-hour analytical session; a comparison has been made between the results obtained and the literature data; a satisfactory agreement of the results has been observed. The analytical errors allow the use of methods for conducting research in solving various geochemical problems.

Research subject. Sphalerite (ZnS) is a widespread mineral that can be found in various depositional environments. During formation, this mineral can accumulate minor and trace impurities, with gold being one of the most valuable component. The issue of the chemical state of Au in sphalerite has been much discussed recently.Methods. Samples of In-, Fe- and In-Febearing sphalerite with a composition ranging from 0 to 2.5 mol.% In2S3 and 0 – 40 mol.% FeS were synthesized in an Ausaturated system using gas transport and salt flux techniques. The resulting products were subsequently investigated using EPMA and LA-ICP-MS. Results. All the elements under investigation are found to be homogeneously distributed within the sphalerite matrix. After quenching, sphalerite is shown to retain Au. Our data indicates that the observed increase in Au concentration is caused by the presence of In (up to 1.02 wt % Au) and, to a lesser extent, by that of Fe (up to ≈600 ppm Au). These elements substitute Zn in the crystal structure of sphalerite following the scheme Au+ + In3+(Fe3+) ↔ 2Zn2+, which is in good agreement with previous data obtained using the XAS method.Conclusions.A higher sulphur fugacity in the system leads to a more significant accumulation of Au in sphalerite. The concentration of Au in pure sphalerite does not exceed 10 ppm under our experimental conditions and does not depend on the activity of sulphur in the system.

The results of U-Pb LA-ICP-MS dating of 150 detrital zircon grains from the Precambrian (Riphean?) sandstones of the Kildin group on the coast of the Ivanovka Bay (northeastern Kola Peninsula) are presented. A group of three youngest grains yielded constraint on the sandstone maximum depositional age of 1179±45 Ma. Detrital zircon age distribution is dominated by three maximums of 1.9, 2.4 and 2.7 Ga. The authors consider two complementary scenarios of interpretation of the data obtained. The first scenario involves the contribution of distant provenance out of granitoids in the Lapland-Kola orogen (~1.9 Ga) and adjacent areas of the Kola-Karelia region (~2.7 Ga), Imandra-Varzuga structure (~2.4 Ga), and Sveconorwegian belt (~1.2 Ga); the off-Baltic (Greenland?) sources of the detrital zircon also cannot be excluded. According to the second scenario, the Ivanovsky graben received zircons also from the proximal sources – sialic complexes formed upon melting of granite-gneiss substratum of the upper crust of the Murmansk craton during largescale episodic mafic magmatism 1.86, 2.50 and 2.68 Ga. The Raman spectroscopy showed that about 25 % of the analyzed detrital zircon grains experienced a 1.4-Ga-old thermal effect which did not lead to Pb losses but partially restored the crystalline structure of zircon. This result can be used as an additional constraint in the detailed provenance analysis of the northeastern East European Platform sedimentary basins and is indicative of 1.4-Ga-old large-scale magmatic events related to the breakup of the supercontinent Nuna.

For the first time there were obtained LA-ICP-MS U-Pb age data on detrital zircons from sediments of the Bystraya and Ernichnaya formations of the Argun series of the northwestern Argun continental massif. The results obtained lead to the following conclusions: (1) the Bystraya series combines heterochronous Low Cambrian carbonate rocks and Upper Proterozoic terrigenous deposits; (2) the age of the youngest group of detrital zircons extracted from sediments of the Ernichnaya formation allows us to restrict the lower age limit to the Ediacaran (556±11 Ma), which does not contradict a standard stratigraphic age; (3) terrigenous materials entering the basin may come from the Argun continental massif. The inferred source areas of clastic materials are the Neo- and Paleoproterozoic magmatic and metamorphic formations, widespread across the Argun massif. Besides, the deposits we studied contain a smaller amount of the Mesoproterozoic zircons. Their provenance still remains unknown since the Argun massif does not include any Mesoproterozoic magmatic rocks with sufficiently accurate geochronological age estimates.

Our study investigates a possibility of using isotope ratios of U‐Th‐Pb system in zircon analysis by the LA‐ICP‐MS technique and monitoring of precision, convergence and accuracy. New U‐Pb isotope‐geochronological data has been obtained for the salic and mafic members of the bimodal Late Paleozoic series of subparallel dykes in the central part of the Western Transbaikalia. It is shown that a series of subparallel dykes (290–280 Ma) gives evi‐ dence of extension of the continental crust at the final stage of the Late Paleozoic granitoid magmatism. Similar ages of zircons in the salic and mafic subvolcanic rocks confirm the geological indicators of the coexistence and interactions between the magmas of contrasting compositions.

The relevance of the study is caused by the need to develop new efficient sample preparation technique suitable for routine multielement ICP-MS analysis of geological samples which decreases time consumption and allows determining a wide number of elements in the range of single measurement using laser ablation (LA-ICP-MS). The main aim of the study is to compare metrological characteristics of two ICP-MS techniques, based on different sample preparation of silicate rocks – sample dissolution after melting with lithium metaborate and using prepared fused glasses for laser ablation. Objects: the international and Russian reference materials of natural rocks: basalts – BHVO-1, BHVO-2, BCR-2, granites – SG-1а, SG-3, gabbro SGD-1а, trap ST-1а. Methods: inductively coupled plasma mass spectrometry (ICP-MS) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). Results of the study showed that the developed multielement ICP-MS and LA-ICP-MS techniques allow determining a wide number of elements in geological samples in the range of single measurement using low, medium and high resolution. Internal and matrix-matched external standards for decreasing/correction of matrix effects and instrumental drift are used. Comparison of the obtained results with values of six reference geological materials verified the accuracy of the techniques. The LA-ICP-MS technique is faster due to the lack of sample preparation, but has higher uncertainty and detection limits in comparison to the ICP-MS technique.

The petrographic, lithogeochemical and U-Pb (LA-ICP-MS) geochronological studies were carried out to investigate the terrigenous rocks sampled from the lower part of the Ipsit suite of the Karagass series (Sayan segment of the Sayan-Baikal-Patom belt). These rocks include sandstones, aleurite sandstones and aleurolites, and their mineral compositions are close to that of arkose. Most of the studied rock samples show petrographic features typical of the epigenetic changes at the stage of catagenesis: regeneration of quartz clastic grains, pelitization of potassium-feldspar clastic grains, occurrence of clay-hydromica aggregate, sericitization of plagioclase, chloritization of biotite, and silicification of dolomite pieces, and occurrence of authigenous tourmaline. The above was confirmed by the analysis of the concentrations of petrogenic elements in the studied rocks from the lower part of the Ipsit suite. The analysis results show that the concentrations of K2O are elevated, while the concentrations of Na2O are relatively very low, which may be due to the redistribution of these elements during epigenetic transformations. According to the classification by genetic types on the basis of the system of petrochemical modules, the rocks of the lower part of the Ipsa suite are of the petrogenic nature. The acidic igneous rocks are dominant in the source area, as evidenced by the presence of granitoid and quartzite fragments in the clastogenic component, as well as the set of accessory minerals typical of the igneous rocks of the acidic composition, and the distribution pattern of rare and trace elements. According to the U-Pb (LA-ICP-MS) dating of detrital zircons from the aleurite sandstone sampled from the lower part of the Ipsit suite, the zircons are exclusively of the Archean-Early Proterozoic ages. Such ages correlate with the age of the granitoids of the Sayan complex and the felsic volcanites from the Maltsev layer of the Elash series (Biryusa block). Furthermore, the detrital-zircon age spectra of the aleurite sandstone of the lower part of the Ipsit suite are identical to the detrital-zircon age spectra of the terrigenous rocks from the underlying strata of the Shangulezh and Tagul suites of the Karagass series. This study suggests that sedimentation of the Ipsit suite of the Karagass series took place due to the influx of detrital material from the southern part of the Siberian craton into the sedimentation basin, and the acidic igneous rocks of the Biryusa block were one of the main sources of detrital material.

A unique Mn-, Cd-bearing sphalerite from quartz-calcite veins in the coal-bearing series (Visean C1v) marine sediments in a 50 km segment of the middle course of the Silova-Yakha River in the Arctic zone of the European part of Russia (Pai-Khoi Ridge) has been studied. The veins have a conformable and cross-cutting occurrence in two types of rocks: gray limestones and black siliceous-carbonaceous shales, the area is known as the Goniatite occurrence. The sulfide content in vein samples ranges from 0.1 to 2 vol.%. The chemical composition of 27 monomineral samples of Mn-, Cd-bearing sphalerites was studied, 82 points were analyzed. Correlations between typomorphic elements-impurities were revealed and correlation matrix was constructed. Cu, V, Ga, In, Sn, As, Sb, Bi, Pb, Tl, Se, Ag, Au, Ni are positively correlated with each other; Cd, Mn and Ge are negatively correlated with each other. The hydrothermal fluid involved in crystallization of sphalerite is characterized by low temperature (164-211 °С) and average salinity of 5-6 wt.% eq. NaCl. An updated “portrait” of typomorphic features (composition and properties) of sphalerite of the Pai-Khoi province was obtained. The features allowing to determine the type of impurity entering the sphalerite structure – in the form of isomorphic impurity or in the form of microinclusions of paragenetic association minerals – have been established. Submicron inclusions of sulvanite and colusite, invisible by other methods, were detected in sphalerite (by LA-ICP-MS method).The cathodoluminescence data of sphalerite from the Pai-Khoi province were typified. In contrast to other provinces, ZnS crystals here are characterized by almost complete absence of isomorphic iron. This allowed us to study pure isomorphism schemes of ZnS↔MnS, ZnS↔CdS, namely cathodoluminescence and other types of luminescence. The presence of a rare wurtzite-4H polytype in assemblage with sphalerite was revealed. High contents of strategic metals Cd, Ga, In, Ge in the ZnS matrix, as well as sulvanite (V, Cu) in a single paragenesis were found. A serious reassessment of the potential for industrial use of this mineralization will be required.

The application of inductively coupled plasma mass spectrometry (ICP-MS) is discussed in the case study of Precambrian mafic and ultramafic rocks of easternFennoscandian shield and their mineral components. Determination of bulk probe sample composition is reported to be possible using both the chemical digestion ofsamples and in situ laser ablation (LA-ICP-MS). The accuracy of the analyses was monitored by analyzing the USGS standard BHVO-2, Russian standard SGD-1A, and in-house reference materials. The composition and measurement results of in-house reference materials С-1412, KN1 and KK1 are presented. The effect of ablation modes on the accuracy and reproducibility of LA-ICP-MS elemental concentration analysis was explored for standards, minerals and rocks. The sensitivity of the method is indicated to depend not only on the physicochemical properties of the samples(melting temperature, volatility), but also on the ablation mode and analysis procedure.

Lower Triassic sandstones in the southern part of Belsky depression (Pre-Uralian foredeep) contain detrital zircons with concordant U-Pb isotopic ages ranging from Neoarchean to the boundary of the Carboniferous and Permian. The distribution of rare and trace elements in zircons suggests that the majority of them fall into the Triassic sandstones due to erosion of basic rocks (or, taking into account the possibility of multiple recycling, most of them are crystallized in the rocks of basic composition). These data indicate a much wider age range of rocks in provenances in the Early Triassic, than it follows from petrographic observations. The micropetrografic data testify that the magmatic complexes which are distributed at present in Sakmara area were the sources of zircons with the Early and Middle Paleozoic datings. Detrital zircons with the Proterozoic and Neoarchean ages are likely redeposited from Riphean-Vendian Ural-Tau zone, where they were brought due to erosion of East European platform base. A small proportion of crystals with Late Paleozoic ages taking into account the geochemical and petrographic data, permits suggest that granite massifs of the Main Granitic axis of the Urals, during the formation of Pre-Uralian molasses has not been involved into erosion. Perhaps they have not yet been withdrawn to the surface, or were placed to the East line of the watershed. At the same time, a significant number of zircons with Precambrian age indicates that the Ural-Tau metamorphic formations were in the erosion zone. Consequently, the orogen watershed at that time was to the east of the zone. This is also evidenced by the presence in the Lower Triassic sandstones few crystals of zircon with Carboniferous age, the source of which could be to the west of modern Magnitogorsk megazone. On the basis of these data we suggest that the forming of coarse clastic formations of the final stage of orogeny in the southern Urals occurred mainly due to erosion of sedimentary, igneous and metamorphic complexes from modern western slope of the axial zone of the Urals.

The first U-Pb isotope-geochronological data were obtained on the age of early collisional granitoids of the Matut massif (Western Sangilen, SE Tuva). The rocks that have been studied are assigned to magnesian, calc-alkaline, high-potassium, and low-peraluminious varieties. LA-ICP-MS analysis on two zircon samples showed that the Matut granite massif formation age corresponds to 522 Ma (U/Pb, LA-ICP-MS, zircons, 520±3 Ma (sample KT-1070) and 524±3 Ma (sample KT-1324)). Thus, the Matut massif granitoids are among the most ancient in Western Sangilen and were formed at the early collisional stage of the structural evolution of the region. Based on the data obtained, an assessment was made of the duration of collisional orogeny on the northwestern margin of the Tuva-Mongolian massif. The initiation to collapse period of the orogen is at least 80 million years.

A study on the U-Pb age of rutile from the Ichetju polymineral occurrence has been done for the first time by LA-ICP-MS and TIMS methods. It was established that rutile originates from various sources with different ages (presumably, ca. 1000, 1660, 1860 and 1980 Ma), but all the rutile types have undergone a common thermal event at ca. 580 Ma. Obtained results are consistent with U-Pb zircon data for the Ichetju occurrence and the Pizhemskoe deposit. According to modern concepts, the closure temperature for the U-Pb system in rutile is higher than 500 °С, which suggests fairly high-temperature conditions of the rutile hydrothermal transformation during the formation of the deposits in Riphean. Obviously, a placer hypothesis of formation of titanium deposits of the Middle Timan which is supported by a number of researchers does not explain such temperature of rutile alteration.

Tonsteins, predominantly solid kaolinite clay interbeds, are widespread in the coals of the Kuznetsk Basin and usually contain idiomorphic zircon grains of magmatic origin in quantities suitable for uranium-lead (U-Pb) radiometric dating. For the first time, tonstein zircons from coal seam 78 of the Tailugan Formation (Fm) are dated by two methods: Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Chemical Abrasion Isotope-Dilution Thermal Ionization Mass Spectrometry (CA-ID-TIMS).The CA-ID-TIMS datings of 257.0 ± 1.3 Ma and 256.6 ± 0.4 Ma determine the age of the lower boundary of the Tailugan Fm and the Tailuganian Regional Stage at 257.0 Ma. We estimate the duration of the Tailuganian to be around 4.22 million years. The dating results make it possible to directly correlate the Tailuganian of the Kuzbass with the upper half of the Wuchiapingian and with most of the Changhsingian of the International Chronostratigraphic Scale.The accumulation rate of total sediments of the Tailugan Fm, calculated without considering the compaction index, is approximately 0.13–0.18 mm/year, and the rate of coal accumulation is 0.024 mm/year. Such values are comparable to the accumulation rates of the Late Paleozoic coal-bearing strata of the Donetsk Basin and Western Australia. The rate of peat accumulation during the Tailuganian, calculated at a compaction index of 10:1, has been estimated at 0.24 mm/year. This value is comparable to the rates of peat accumulation in the Holocene bogs of the Kuznetsk Alatau in Siberia and the European part of Russia.The presence of tonsteins in the coal seams of the Tailugan Fm suggests that the upper surface of the peat at the time of its accumulation was below the water level, serving as a protective screen for the thin volcanic deposits and preventing its erosion.The assemblages of macroflora, ostracods, conchostracans and bivalves considerably vary through the section of the Tailugan Fm. This variation makes it possible to identify in Kuzbass the stratigraphic level that corresponds to the boundary between the Wuchiapingian and Changhsingian stages in the future.

The relevance of the study is caused by the study and involvement of quartz-vein formations of various genetic types in the technological redistribution. Purpose: to determine the content of impurity elements in quartz of different genetic types and the degree of its suitability for obtaining high-purity quartz concentrates. Objects: quartz-vein objects of hydrothermal-metamorphogenic-metasomatic type (Berkutinskaya vein, Bolotnaya vein) and hydrothermal-metamorphogenic type (Peschanoe occurrence, Tolstikha vein, Novotroitskoe deposit). Methods: LA-ICP-MS spectroscopy of impurity elements, microscopic studies of quartz, estimation of P-T parameters of mineral formation. Results. It was found that veins of hydrothermal-metamorphogenic-metasomatic type are composed of multi-grained granular transparent, translucent, icy, sugar-like quartz, while quartz-vein objects of hydrothermal-metamorphogenic type are veins of execution and consist mainly of milky-white quartz. Quartz-vein formations of two genetic types differ in geological localization conditions, mineral formation temperatures, granulometric characteristics, the presence and location of mineral and fluid inclusions, as well as the content of the main petrogenetically informative elements-impurities (Li, Na, Mg, Al, K, Ti, Cr, Mn, Fe, Ni, Cu, Zn). It is shown that hydrothermal-metamorphogenic quartz is characterized by lower (288–410 °C) formation temperatures compared to hydrothermal-metamorphogenic-metasomatic quartz (415–519 °C), at close pressure values (2–4 kbar) and higher content of impurity elements (up to 535 g/t). The purity of quartz grains of hydrothermal-metamorphogenic-metasomatic genesis is associated with repeated exposure to the processes of metamorphism and metasomatosis, in which mineral and fluid inclusions were displaced from quartz grains into the intergranular space. The minimum values of the element content according to LA-ICP-MS spectroscopy are close to the values for the content of elements in the structural form and do not exceed 5–12 g/t for all types of quartz, with the exception of milky-white quartz of Peschanoe occurrence (up to 25 g/t). The minimum values for the content of elements-impurities in quartz show the limit of its enrichment and allow using a multi-stage enrichment system to obtain quartz concentrates of high purity.

The Srednyaya Zima alkaline-ultramafic carbonatite complex is located in the Eastern Sayan and is a part of the area of manifestation of Neoproterozoic rare-metal alkaline-carbonatite magmatism along the southern and southeastern margins of the Siberian craton. Mineralogical studies of calciocarbonatites of the Srednyaya Zima complex have shown the presence of primary magmatic mineral phases of calcite, biotite (annite-phlogopite), ilmenite, and fluorapatite. Pyrochlore, zircon, burbankite, magnetite, rutile, titanite, strontianite, and barite were identified of the accessory minerals. The chemical composition of the magmatic minerals of the Srednyaya Zima carbonatites is similar to the mineral composition of the closely aged carbonatite complexes Belaya Zima and Arbarastakh. The rare-element and structural analysis of zircon from carbonatites showed the presence of two zones – a magmatic core and areas of recrystallization. U-Pb dating of igneous zircon showed the age interval of its crystallization – 637±4 Ma, which coincides with the geochronology of the formation of alkali-ultramafic rare-metal complexes along the southern margin of the Siberian craton. The formation of Neoproterozoic alkaline-carbonatite complexes is associated with tectonic events of the breakup of the Rodinia supercontinent.

The shift in strontium (Sr) concentrations in fish otoliths is a commonly used proxy for identification of marine environment entry during diadromous migrations. However, there is still controversy about the appearance of the Sr-based sea entry mark relative to the true point of entry. In this study, the Sr signal lag was assessed in otoliths of juvenile sockeye salmon (Oncorhynchus nerka) under experimental conditions replicating the transition to seawater during juveniles’ seaward migration. A Sr signal delay was observed to average at 8.2 (SD = 5.1) days for fish with a body length of 140–170 mm (and a weight of 30–70 g). This lag may be species-specific and should be taken into consideration when estimating marine entry timing and marine residence duration of juvenile salmon.

Relevance. The LA-ICP-MS analysis of sulfides is one of the promising directions in study of ore deposits. The understanding of mineralogical-geochemical evolution of sulfides allows interpretation of differentiation of components at stages of hydrothermal sedimentogenesis and further lithogenesis of massive sulfide deposits. This work is important for development of models of sulfide authigenesis. The main aim of the research is to compare mineralogical-geochemical features of chalcopyrite types to identify the evolution of sulfide ores from the Yubileynoe massive sulfide deposit (South Urals). Methods. The morphogenetic types of chalcopyrite were identified using ore-facial mapping in the open pit of the deposit. The mineralogical features of ores were studied under an Olympus BX51 optical microscope. The chemical composition of minerals was analyzed on a Tescan Vega 3 SBU scanning electron microscope equipped with an Oxford Instruments X-act energy dispersive analyzer. The trace element contents of chalcopyrite were determined using LA-ICP-MS on an Agilent 7700x mass spectrometer equipped with a New Wave Research UP-213 laser ablation device at the SU FRC MG UB RAS and University of Tasmania (Hobart, Australia). Results. Chalcopyrite was subdivided into two genetic types: hydrothermal and post-sedimentary. The hydrothermal type includes subhedral chalcopyrite from chalcopyrite-pyrite, chalcopyrite-pyrite-sphalerite, and sphalerite-pyrite-chalcopyrite smoker chimneys. The post-sedimentary type of pseudomorphic, interstitial, nodular, and veinlet (dynamometamorphic) chalcopyrite is typical of clastic ore. Each chalcopyrite type is characterized by various mineral assemblages and trace element contents, reflecting different formation conditions. Themorphology of chalcopyrite changes from spear-like and dendritic crystals to graphic and epitaxial intergrowths of chalcopyrite and sphalerite in a range from chalcopyrite-pyrite to mostly sphalerite smoker chimneys. The median contents of high-temperature (Se, Bi), medium-temperature (Te, Sb) and low-temperature (Tl) trace elements of hydrothermal chalcopyrite decrease in this range. The post-sedimentary chalcopyrite has the lower Sn contents and exhibits minor variations in Se contents. The median Mn, Co, Ni, Mo, As, Tl, Au, Ag, Bi, and Te contents decrease in a consecutive range of post-sedimentary chalcopyrite: pseudomorphic→interstitial→nodular→veinlet.

The Shared Research Facilities "Geospectrum" of the Geological Institute SB RAS (Ulan-Ude) was created based on the analytical base of the Geological Institute SB RAS (GIN SB RAS, Ulan-Ude). Its equipment is used for isotopy of light elements, U-Th-Pb geochronology of igneous, metamorphic and sedimentary rocks. In addition, a large volume of mineralogical and geochemical research is carried out to solve petrological, geochemical, lithological-geochemical and environmental basic and applied problems.

В статье представлены результаты изотопного U-Pb датирования методом лазерной абляции (LA-ICP MS) цирконов из различных типов пород (карбонатитов, миаскитов, щелочных метасоматитов, гипербазитов) Ильмено-Вишневогорского щелочно-карбонатитового комплекса (ИВК) Южного Урала. Датирование циркона миаскитов показывает возраст ранних стадий кристаллизации щелочно-карбонатитовой магматической системы (T = 428 ± 8 млн лет). Возраст цирконов карбонатитов (T = 417.3 ± 2.8 млн лет) соответствует позднемагматической стадии кристаллизации остаточных щелочно-карбонатитовых расплавов. Кроме того, в различных породах ИВК (миаскитах, карбонатитах, гипербазитах) устанавливаются поздние генерации цирконов (T = 270-350 млн лет), формирование которых, по-видимому, связано с постколлизионными метаморфическими и метасоматическими процессами. Hf-изотопные данные, полученные для цирконов ИВК, подтверждают мантийный характер источника магм ИВК и указывают на участие в магмогенерации вещества умеренно обедненной мантии (DM) и более обогащенного в отношении нерадиогенного Hf источника (возможно, представляющего собой нижнекоровый компонент).

The paper shows new fluid inclusion and isotopic-geochemical data for minerals from sulphide-carbonate-quartz veins of Vosnesensky Cu-porphyry deposit. Fluid inclusions were analyzed by means Linkam TMS-600 cryostage equipped with Olympus BX 51 optical microscope; trace element amounts were performed used Agilent 7700x and ELAN 9000 mass-spectrometers; sulphur isotopic composition was analyzed on DeltaPLUS Advantagе mass-spectrometer. We determined that fluid inclusions in quartz were homogenized between 215 and 315 ºС, and in latest calcite, they are 230–280 ºС. Fluids are К-Na water chloride with salinity of 3–12 wt % NaCl-eq. Quartz contain high amounts of Al (184–5180 ppm), K (20.1–1040 ppm), Na (30.2–1570 ppm) and Ti (38.4–193 ppm). The REE distribution spectra of pyrite are characterized by light lanthanides accumulation (LaN/YbN = 3.6–6.44), and negative of Ce anomalies (0.7–0.92) and Eu (0.78–0.99). The Y/ Ho ratio in pyrite varies from 27.6 up to 36.8. The δ34S values in pyrite were –1.01…0.8 ‰, in chalcopyrite – 0.9 ‰. The data testify the Cu-porphyry mineralization of Vosnesensky deposit was formed due to magmatic acid high-aluminous К-Na chloride fluid enriched with light REE in mesothermal environment. We identified the geochemical markers of interaction between fluid and host rocks.

Object . The zonal pyrite nodules and metacrystals from siliceous siltstones of ore-bearing horizon of the Second ore body from the Yubileynoe massive sulfide deposit are studied. Materials and methods . We used 9 samples and 15 polished sections of siliceous siltstones with pyrite mineralization. Analysis of chemical composition minerals was determined by Tescan Vega 3 with an energy dispersive microprobe Oxford Instruments X-act (Institute of Mineralogy UB RAS, Miass). Quantitave LA-ICP-MS analysis of pyrite for major and trace elements was carried out using New Wave Research UP-213 laser microprobe coupled to an Agilent 7500 quadrupole ICP-MS housed (University of Tasmania, Australia). Results. Microtopochemistry was established that the diagenetic core of the nodule is characterized by trace elements of typical poikilites of quartz (Si) and alumosilicates (Si, Al, Mg, V, Cr, K, Na, Ca), rutile and titanite (Ti), inclusions of chalcopyrite (Cu), sphalerite (Zn), galena (Pb, Sb, Bi), tetrahedrite-tennantite (As, Sb), native gold, petzite, hessite (Au, Ag, Te), tellurobismuthite, altaite, and coloradoite (Te, Bi, Pb). Cobalt and Ni substitute for Fe2+. The rim of subhedral pyrite is depleted in most trace elements except for Ni and As. Subhedral pyrite became rich in chalcophile (Au, Ag, Sb, Bi, Cu, Zn, Hg) and lithophile (Ca, K, Na, Cr) elements at the final stage of growth of the nodule. Similar mineralogical and geochemical zonation is typical of the pyrite metacrystals, where a micro-grained core concentrates Pb, Bi and Te, and a rim of subhedral pyrite is depleted in most trace elements. Similarly to the nodules, the outer rim of pyrite metacrystals is enriched in most trace elements (Pb, Au, Ag, Sb, Cu, As, Mo, Cr, etc.). The nodules and metacrystals were formed from diagenetic micronodule of poikilite pyrite. Conclusions. It is suggested that mineralogical and geochemical differences in pyrite metacrystals and nodules are caused by the greater degree of development of rims of subhedral pyrite.

We studied the contents of trace elements in troilite, iron and in iron-nickel metal from meteorite Chelyabinsk by means of LA-ICP-MS. The features of the distribution of siderophile and chalcophile elements in sulfide and metallic phase in gray and black (impact modified) meteorite fragments were identified and the correlations in the content of these elements was analyzed. The correlation of PGE and Au versus Ni was determined, which is probably related to their joint fractionation between sulfide and metallic phase during high-temperature recrystallization in gray meteorite fragments. In contrast, in black meteorite fragments the contents of these elements are flattened in metal and troilite. Distribution of siderophile elements in metal of meteorite Chelyabinsk black fragments essentially differs from the same in chondrites ALHA78109 (LL5) and Soko-Banja (LL4). For the gray fragments there are no such differences, this apparently indicates to the redistribution of some siderophile elements between metal and sulfide phase of meteorite as a result of melting under impact events.

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This paper presents the results of isotope-geochronological and petrological studies of gabbroic and combined diorite-granite dikes located in the eastern part of the Kaakhem magmatic area. Both groups of dikes cut through diorite-tonalite-plagiogranite associations of different ages (489±5 and 476±4 Ma). Zircons from granitoid of mingling dikes have an age of 477±3 Ma (LA-ICP-MS). The age of the gabbroic dikes was determined by LA-ICP-MS (zircon) and Ar-Ar (amphibole) methods and is 454±10 and 450±6.3 Ma, respectively. Similar contents of major and trace elements in basic and intermediate rocks of dikes indicate their formation from a single source with subduction characteristics. The salic rocks of the combined dikes vary in composition and are close to the heterogeneous diorite-tonalite-plagiogranite-granite associations of the host rocks. The formation of dike complexes occurred at the collisional stage of development of the Kaakhem magmatic area and is associated with the development of local extension zones.

Petrographic, geochemical and U-Pb geochronological research studies are done into cataclastic granitoids of the southeastern part of the Irkutsk block of the Sharyzhalgay basement uplift of the Siberian craton – the uplift which is considered southern part of the Tungus superterrane according to most of tectonic schemes. The representative sample of these granitoids corresponds to granodiorite in its geochemical properties and is characterized by high contents of Al2O3, Th, Sr, Ba, low concentrations of K2O, Nb, Y, Yb, a highly fractionated rare earth elements pattern (Lan/Ybn=284), and the absence of europium anomaly. U-Pb geochronological studies of zircon from cataclastic granodiorite were carried out independently by two methods: SIMS and LA-ICP-MS, which showed good consistency of the results. The U-Pb age of the cores of zircon grains with magmatic zoning corresponds to 2893±19 Ma (SIMS method) and 2889±16 Ma (LA-ICP-MS method). These results can be interpreted as the age of the Archean granodiorite protolith. The rims of zircon crystals with the Archean cores, as well as the individual zircon crystals with parallel zoning, yielded ages of 1855±6 Ma (SIMS method) and 1864±5 Ma (LA-ICP-MS method), which record the time of granodiorite transformations. The age of about 1.86 Ga corresponds to the main Early Proterozoic stage of metamorphism, migmatization and magmatism, which show their widespread occurrence in the Sharyzhalgay basement uplift. This age estimate together with the previously published ages for metamorphic and their synchronous magmatic events in the Sharyzhalgay uplift allowed concluding that the Tungus superterrane joined the earlier formed core of the Siberian craton in the time interval 1.85–1.88 Ga. The final stage in the Siberian craton formation is the development of the South Siberian post-collisional magmatic belt, intersecting all large Early Precambrian blocks of the southern part of the Siberian craton, already united into a single structure.

Research subject. We studied PT conditions, composition and sources of ore-forming fluids of the Bolshoy Karan goldporphyry deposit (South Urals) confined to the Main Urals Fault zone at Southern Urals. Methods. Temperatures of ore mineral formation, salt composition and fluid salinity were estimated using a Linkam TMS-600 cryostage equipped with an Olympus BX 51 optical microscope. The gas composition of fluid inclusions was determined using a Horiba LabRam HR800 Evolution Raman spectrometer and an Olympus BX-FM optical microscope. Trace elements were detected by means of LA-ICP-MS analysis. С and О isotopic composition was identified using a MAT 253 (Thermo Fisher Scientific) mass-spectrometer. S in the minerals of sulphide-carbonate-quartz ores was identified using a DeltaPLUS Advantage mass-spectrometer.Results. It is shown that the fluid inclusions in quartz are homogenized at 370–310ºC, while those of the latest calcite – at 234–200ºС. The fluids contain Mg-Na chloride solutions with a salinity of 3.0–11.9 wt % NaClэкв. According to LA-ICP-MS data, quartz contains high Al contents (916–1556 ppm) confirming its formation from a high aluminous acid fluid. The REE distribution spectra in calcite are characterized by the accumulation of light lanthanides (LaN/YbN = 3.4–9.11) pointing to the acid fluid composition, as well as by negative Ce (0.58–0.88) and positive Eu (1.51–3.61) anomalies. The negative Ce anomaly may have been caused by interactions between the fluid and host limestones. The positive Eu anomaly reflects the existence of a middle-temperature environment (>250ºC) prior to calcite crystallization. Y/Ho values in calcite (29.3–35.6) suggest the presence of magmatic components and those extracted from limestones. The values of δ18О in calcite vary from 14.7 to 19.8‰, while those of δ13С – from –4.1 to 0.7‰. The values of δ18ОH2O for the ore-forming fluid, which were calculated based on average homogenization temperatures of fluid inclusions in calcite (230ºС), vary from 6.5 to 11.5‰, while δ13ССO2 – from –3.21 to 1.6‰. δ34S values in pyrite ranged from –0.60 to – 1.50‰. Conclusions. Our data confirm the formation of the gold-porphyry mineralization of the Bolshoy Karan deposit under mesothermal conditions. Magmatic fluids played the key ore-formation role. The geochemical peculiarities of interactions between the fluid and host rocks were revealed.

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The problem of the beginning of iron production in the Late Bronze Age of the Ural-Kazakhstan region is discussed. For this, 13 iron-bearing artefacts from nine settlements that functioned in the 2nd mil. BC were studied using the SEM-EDS and LA-ICP-MS methods: metal objects, metallurgical slags, and a bimetallic droplet. Most of the studied artefacts are not related to the iron metallurgy. High ferric impurities in copper metal products of the Late Bronze Age on the territory of the Southern Trans-Urals are caused by the use of iron-rich ore concentrates. The raw materials for these products were represented by mixed oxidized-sulphide ores from the cementation subzone of the volcanogenic massive sulphide and skarn copper deposits. Iron droplets, frequently found in the Late Bronze Age copper slag in the Ural-Kazakhstan region, are not directly related to iron metallurgy. They are by-products of the copper metallurgy formed in the process of copper extraction from the iron-rich components of the furnace charge or fluxes (brown iron ore, iron sulphides). The only artefacts that indicate direct smelting of metal from iron ore are the slag fragments from the Kent settlement. Presumably, oxidized martitized ore of the Kentobe skarn deposit or its nearby analogues was used to extract iron at the Kent settlement. Rare finds of iron slags from the Late Bronze Age, known only in the territory of Central Kazakhstan, confirm an extremely small scale of iron production. Iron ore had been already deliberately used for these experiments. However, iron metallurgy in the Ural-Kazakhstan region developed into a mature industry much later. The discovery of iron metallurgy based on the smelting of copper-sulphide ores in the Ural-Kazakhstan steppes is doubtful. The use of sulphide ores here is known from the 20th c. BC, and it was widespread. In the meantime, the first iron slags and products appear much later, and their finds are sporadic. The development of iron metallurgy on the basis of experiments with iron ores seems more likely.

The Upper Cambrian-Lower Ordovician terrigenous strata, unconformably overlying the Upper Riphean-Vendian rocks of the Timanide orogen in the north of the Urals, and contemporaneous bimodal volcanics and intrusive rocks are considered complexes marking the beginning of rifting which led to the opening of the Paleo-Ural Ocean later on. The article presents the results of U-Pb (LA-ICP-MS) dating of detrital zircons from sandstones lying at the base of the section of the rift complex in the Malaya Usa River basin in the Polar Urals. It was found that the clastic sequence (identified as the Khoydyshor formation) began to accumulate no earlier than the Cambrian–Ordovician transition. Zircon ages fall within the continuous Vendian to Early Ordovician (575–478 Ma) interval with peak at 512 Ma. This age range overlaps with the age of rhyolites interlayered conformably with sandstones and rhyolite porphyry dikes intruding the Khoydyshor formation, thus indicating a possible admixture of products of synsedimentary volcanism. A narrow zircon age pattern allows us to conclude that the main sources of detrital zircons in sandstones were the Early-Middle Cambrian igneous rocks formed at the stage of pre-rift uplift, and, to a lesser extent, the Late Cambrian-Early Ordovician riftogenic magmatic complexes, marking the beginning of the Uralian tectonic cycle, as well as the Late Vendian igneous rocks of the underlying Timanide orogen. Judging by the Th/U ratio, most of the detrital zircons within the sandstones were derived from the Early Paleozoic silicic volcanic and hypabyssal rocks and the Vendian granitoids and diorites. The almost complete absence of older grains, which are typical of coeval sandstones of the northern part of the Urals, may indicate the accumulation of the considered sandstones in a local trough with local clastic material sources. Probability density estimation of U-Pb ages for zircon from igneous and metamorphic rocks of the Polar Urals indicates that there were no gaps in the Late Riphean to Early Ordovician endogenous activity in this region. The main peaks occur at 552, 521 and 500 Ma, and an additional peak – at 665 Ma. The results of dating of detrital zircons from sandstones of the Khoydyshor formation together with the database of U-Pb isotope ages of igneous and metamorphic rocks of the Polar Urals (119 items), compiled by the authors, indicate that the change in geodynamic regime from collisional orogenesis in the Late Vendian to the Early-Middle Cambrian pre-rift uplift and following Late Cambrian rifting was not accompanied by a longterm discontinuity in magmatic activity.

The article presents new data on the age and isotopic (Sr, Nd) characteristics of the Yuzhnoe and Ulan-Ude REE-fluorite occurrences, paragenetically related to alkaline carbonatite magmatism. Age estimates of the fluorite-containing rocks were obtained from bastnaesites using U-Th-Pb (LA-ICP-MS) method and are 130.2±1.1 and 136.6±1.9 Ma for the Yuzhnoe and Ulan-Ude occurrences, respectively. The ƐNd(T) values of the bastnaesites vary from –7.41 to –6.08 for the Yuzhnoe occurrence and from –4.28 to –2.67 for the Ulan-Ude occurrence. The Yuzhnoe carbonatites are characterized by 87Sr/86Sr(I) ratios ranging from 0.705883 to 0.706011, and 87Sr/86Sr(I) ratios obtained for the Ulan-Ude bastnaesite-fluorite rocks are ranging from 0.70683 to 0.70687. The age estimates are consistent with the published geochronological data on alkaline carbonatite magmatism of the Central Asian orogenic belt related to Late Mesozoic intraplate magmatism and rifting. Isotopic Sr-Nd signatures of bastnaesite, as well as of the Yuzhnoe carbonatites and the Ulan-Ude bastnaesite-fluorites, indicate that their source rocks came from the enriched lithospheric mantle.

The Middle – Dnieper megablock, which is a fragment of archean craton, differs from other cratons on Earth by a large variety of Archean granitoids (Tok, Mokro-Moscowka, and Demurino complexes) which were formed later than the Mesoarchean TTG of sura complex. In this regard, the Middle – Dnieper megablock is an important area for studying the genesis and geodynamic conditions of Late Archaean granitoid formation. The poorly studied Late Archean granitoids in the Middle – Dnieper block include the Hannivka granites in the East Hannivka monocline of the Kryvyi Rig – Kremenchuk structure, the age and stratigraphic position of which have been the subject of a long debate. The aim of the work is to determine geochemical peculiarities. genesis and U-Pb age of Hannivka granites and to compare them with other archean granitoid complexes of the Middle-Dnieper fragment of the Mesoarchean craton. The LA-ICP-MS method determined the U-Pb age of zircon from Hannivka granite 2827 ± 16 Ma. They are close in time to the granitoids of the Tok and Mokro-Moscowka complexes and were formed much later than the granitoids of the Demurino complex. The Hannivka granites could have been formed in a crustal magmatic source as a result of melting of an older crust. They differ from other Archaean granitoids of the Middle-Dnieper megablock by the increased content of U (56.4 ppm) and the presence of Mo (4.3 ppm). Unsolved problems that require further study include determination of the connection of Hannivka granites with granitoid intrusions of the Mokra-Moscowka and Tok complexes outside the Eastern Hannivka structure and the origin of ore mineralization for uranium and molybdenum.

The paper presents research results of the copper smelting furnace at the turn of the 3rd/2nd millennium BC discovered in the ancient mine Novotemirsky. This is the first evidence of the metals smelting from ores directly at the deposit in the Bronze Age of the Southern Trans- Urals. The technology of smelting metals from ores (the furnace structure, the type of ores and slags, the melting temperature, and the metal composition) was determined using a complex of mineralogical and geochemical research methods (optical and electron microscopy, X-ray diffraction, X-ray fluorescence analysis and LA-ICP-MS)., The results demonstrate an original metallurgical technology despite the territorial-chronological localization of the furnace within the Sintashta culture. In particular, sulfide inclusions in the Cr-rich containing olivine slags find analogies in the Abashevo culture from multilayer Bronze Age settlements of the Southern Urals.

The paper presents the first U-Pb (LA-ICP-MS) dating results for detrital zircons from the quartzsericite-chlorite schist of the Anai formation within the Baikal salient of the Siberian platform basement. During the study the detrital zircons showed a major age peak at 1.86 Ga, which indicates that the rocks of the Anai formation were accumulated after the development of magmatic rocks of the South Siberian post-collisional magmatic belt with an age of 1.88‒1.84 Ga. This fact makes it possible to reconsider a point of view on the belonging of the Anai formation to the section of the Paleoproterozoic Sarma group whose rocks were intruded by granitoids of the South Siberian magmatic belt. It is shown that the rocks of the Anai formation can be considered as age and facial equivalents of the Proterozoic sediments of the Purpol formation of the Patom zone. Taking into account the Anai formation sediments intruded by sills and dikes of the Neoproterozoic (~720 Ma) dolerites, it can be concluded that the rocks of this formation were presumably accumulated in the Early Neoproterozoic time.