bluuebunny/crossref_metadata_2025 huggingface dataset:
Archean Phlogopite Peridotite from Gneissic Enderbites of the Bug Granulite–Gneiss Terrane (Ukrainian Shield): Compositional Features and Possible Mechanisms of its Formationn
Authors: Lobach- Zhuchenko S. B. , Baltybaev Sh. K. , Egorova Yu. S. , Yurchenko A. V.
Published: April 2024

The paper reports mineral chemistry, whole-rock major and trace element composition, structure, and geological setting of the phlogopite peridotite lens within the Bug granulite–gneiss terrane of the Dniester–Bug Province, Ukrainian Shield. Geochemical features of the studied peridotites and minerals indicate a complex evolution of the lens. The early stage is marked by the crystallization of olivine + spinel (Al-chromite) cumulus from melt of supposably picritic composition, and further crystallization of clinopyroxene. The melt shows signs of hybridization by host gneissic enderbite. Orthopyroxene crystallized later and frequently replaces clinopyroxene. The phlogopite cystallization is likely related to the fluid activity and the growth of potassium potential in the fluid. Granulite-facies metamorphism accompanied by ductile deformations affected the mineral asseblage and chemical compositions of peridotites and orthopyroxenites. At the final stage, the rocks and minerals experienced retrograde metamorphism and local foliation of the rocks.
Modeling and Predicting the Environment State in the Impact Area of a Copper–Nickel Plant: A Balanced Model of the Transformations of Atmospheric Deposition at the Catchment and in Lake
Authors: Sokolov A. V. , Moiseenko T. I. , Gashkina N. A. , Tatsiy Yu. G.
Published: April 2024

The paper discusses modeling the dynamics of nickel concentration in soils, water, and the bottom sediments of lakes caused by atmospheric emissions from the Pechenganickel plant, Kola Peninsula, throughout its whole operation period. The applied technology of balanced identification makes it possible to use a mathematical description of heterogeneous geochemical processes in ecosystems to combine heterogeneous experimental data and build up a computer model with an optimal balance of its complexity and fitting quality of the data. The model is used to analyze the spatial and temporal variability of natural objects in the zone of distribution of atmospheric pollution (nickel) from the Pechenganickel plant. The paper presents and discusses results of this study, including estimates of the retrospective state of the simulated objects (before the start of the intense studies) and a forecast of their dynamics until 2030. According to the model calculations, the intensity of Ni accumulation in the soil and bottom sediments was 2.35 and 4.48 mg/(m2 year) during the maximum deposition periods (1980–2005), whereas the model predicts a decrease in the intensity of Ni accumulation in the bottom sediments (0.23 mg/(m2 year)) and slow Ni leaching from the soil (0.19 mg/(m2 year)) after the shutdown of the plant.
Feldspar Megacrysts as a Source of Information on Crustal Contamination of Basaltic Melt
Authors: Demonterova E. I. , Ivanov A. V. , Palessky S. V. , Posokhov V. F. , Karmanov N. S. , Pel’gunova L. A.
Published: April 2024

The paper discusses data on the elemental composition and 87Sr/86Sr, and δ18O isotopic ratios of feldspar megacrysts collected from lava flows, tuffs, and cinders of three volcanic fields in the Baikal rift system: Iya–Uda, Vitim, and Khamar-Daban, which are located within the early Precambrian, Riphean, and Paleozoic crustal blocks, respectively. Megacrysts are hosted in trachybasalts in the Iya–Uda and Khamar-Daban fields and in basanites in the Vitim field. Megacrysts belong to the following three compositional groups of minerals: (i) plagioclase in lavas of the Iya–Uda field, (ii) anorthoclase in lava flows, tuffs, and cinders of the Khamar-Daban and Vitim fields, and (iii) sanidine in the Vitim field. Elemental and isotope data suggest that megacrysts crystallized in volcanic chambers at different depth levels: anorthoclase crystallized from the most primitive magma with mantle-derived isotopic signatures at subcrustal depth levels, plagioclases were produced in deep crustal chambers during the interaction between mantle-derived magma and crustal rocks, and sanidine was captured from the upper crustal rocks.
A Stepwise Dissolution Method Applied to Isotopic Chemostratigraphic and Geochronological Studies of Riphean Carbonate Rocks of the Baykit Uplift
Authors: Gorokhov I. M. , Vasil'eva I. M. , Kuznetsov A. B. , Rizvanova N. G. , Konstantinova G. V.
Published: April 2024

The potential of the stepwise dissolution analytical procedure to obtain chemostratigraphic and geochronological information is demonstrated by a case study of Riphean carbonate rocks of the Kamovskaya Group of the Baykit Uplift (Eastern Siberia). The procedures suggested for studying Rb–Sr and U–Pb systems in carbonate rocks included (1) selection of samples with the lowest 87Sr/86Sr ratio on the basis of preliminary Rb–Sr analysis of the collection using the routine procedure of bulk leaching in 0.1N CH3COOH; (2) detailed study of the Rb–Sr system in selected samples using two-step dissolution in 0.2N CH3COOH and derivation of L(Rb–Sr)1 and L(Rb–Sr)2 fractions; (3) analysis of Pb isotope composition of the selected samples to derive the preliminary value of their age; (4) detailed study of U–Pb system of carbonate rocks using the stepwise dissolution in 0.5N HBr, resulting in six dissolved fractions L(U–Pb)1–L(U–Pb)6 for each of the selected samples; and (5) a final calculation of the Pb–Pb age of the studied rocks, based on the results from the obtained fractions, with the exclusion from the calculation of the initial fractions of this dissolution containing epigenetically altered carbonate material. The values of the primary 87Sr/86Sr ratio in L(Rb–Sr)2 fractions of carbonate rocks of the Kamovskaya Group are as follows: limestone of the Madrinskaya Formation, 0.70490; dolomites of the Yurubchenskaya Formation, 0.70495–0.70503; and dolomites of the Kuyumbinskaya and Vingoldinskaya formations, 0.70580 and 0.70521, respectively. These values characterizing the least altered carbonate material correspond to 87Sr/86Sr ratios in the Early Archean and can be used for chemostratigraphic calculations. Taking into account the Rb–Sr data, the U–Pb age of the Yurubchenskaya Formation carbonate rocks dissolved in six steps was calculated, starting from L(U–Pb)3. The slope of the resulting isochron in the coordinates 206Pb/204Pb–207Pb/204Pb corresponds to 1501 ± 23 Ma, which supports the conclusion that the carbonate rocks of the lower part of the Kamovskaya Group of the Baykit Uplift were formed in the Early Riphean.
Microwave Preparation of Geological Samples in UltraWAVE System for the Determination of Platinum Group Elements and Rhenium by Mass-Spectrometric Isotope Dilution
Authors: Palesskiy S. V. , Nikolaeva I. V. , Kozmenko O. A.
Published: April 2024

We report the first results of the application of UltraWAVE reactor-type microwave system for geological sample preparation (T = 250°C and P up to 80 bar) with a mixture of concentrated nitric and hydrochloric acids (3 : 1). Determination of the platinum group elements – Ru, Pd, Ir, Pt (PGE) and Re after acid digestion was carried out by isotope dilution using the high-resolution mass-spectrometer ELEMENT after chromatographic separation of analytes on an AG50Wx8 cation exchange resin. The monoisotopic rhodium was determined with 195Pt as an internal standard. The achieved detection limits were from 0.003 ng/g (Ir) to 0.09 ng/g (Pt). The correctness of the new procedure was confirmed by the analysis of geological reference samples—GP-13, UB-N, BHVO-2. The proposed procedure significantly accelerates and simplifies the preparation of geological samples for PGE and Re determination compared to the Carius tube technique.
Principal Studies of the First Solid Material Formed in the Early Solar System: A Review
Authors: Ivanova M. A.
Published: April 2024

This publication reviews principal recent studies of the earliest solid material in the Solar System: refractory objects, which include Ca,Al inclusions (CAIs), some chondrules, and amoeboid olivine aggregates (AOAs), with more attention paid to Ca,Al inclusions. We do not consider the ices because they do not belong to stony material, and do not consider the presolar grains that were already present in the Solar System when it was formed and were preserved in the primitive chondrites material. The review consists of an introduction, several chapters, a conclusion, a list of references, and a list of special abbreviations. Additional material is published in the Supplementary. The reference list presents the results of previous studies conducted over the past 50 years and highlights the new challenges facing researchers in the study of CAIs, then describes the most modern methods of study and approaches, the results on the chronology of the processes of the early Solar System, morphology, mineralogy, and petrography of new, little-studied representatives of CAIs from various types of chondrite material (CV3 and CH–CB), isotopic and geochemical characteristics of these objects, including REE distribution in ultrarefractory CAIs. One chapter is devoted to the search for genetic relationships between the types of CAIs and the study of the main processes that formed CAIs; this chapter also reviews results of theoretical modeling and experimental studies of the evaporation process. The conclusion summarizes principal conclusions drawn from the data and summarizes the principal results of the long-term study of refractory objects in chondrites.
Source and Generation Parameters of the Granitoid Melts of the Archean Charnockite–Enderbite Complex in Karelia, with Reference to the Pon’goma-Navolok Massif
Authors: Kozlovskii V. M. , Kurdyukov E. B. , Yakushik M. A. , Travin V. V. , Zinger T. F. , Yakushev A. I. , Fugzan M. M. , Kirnozova T. I. , Ushakova S. A.
Published: April 2024

The paper presents authors’ original detailed data on rocks of the Archean Pon’goma-Navolok charnockite−enderbite complex in northern Karelia. The rocks practically have not been modified and are preserved within a rigid block among Paleoproterozoic zones of ductile deformations and metamorphism. The geochemistry of the rocks and their isotope−geochemical features indicate that the protolith from which the enderbite melts of the main phase of the massif were derived may have been amphibolites. The enderbite melts were derived from these amphibolites under the effect of K2O-, Na2O-, and SiO2-bearing fluids; and the enderbites were subsequently charnockitized with the involvement of fluids enriched in K2O and SiO2. Physicochemical modeling indicates that the enderbite melt was derived from the amphibolite protolith at a depth of about 45 km (P = 14.8 kbar, T = 1030−1080°C) under the effect of saline H2O−CO2 fluid. Comparison of the P−T parameters of the granulite-facies metamorphism of the metabasites and the parameters under which the enderbite melts were derived indicates that Archean granulite-facies metamorphism in the Belomorian belt in northern Karelia was of contact but not regional nature and was induced by the high-temperature field of an emplaced enderbite massif. The orthogneisses hosting the Pan’goma-Navolok massif inherit geochemical features of the unsheared, ungneissose, and unmetamorphosed enderbites. This means that enderbites analogous to those of the Pan’goma-Navolok massif may have served as the protolith of some of the orthogneisses, and that enderbites may have been spread more widely in the Archean than the currently preserved single enderbite massifs.
HYDROCARBONS IN LITTORAL SEDIMENTS AND MARCH SOILS OF THE SOUTHWESTERN COAST OF THE BARENTS SEA
Authors: Kursheva A. V. , Morgunova I. P. , Petrova V. I. , Litvinenko I. V.
Published: April 2024

According to the results of GC-MS study of the composition and distribution of hydrocarbons (n-alkanes, isoprenoids, steranes, hopanes, polycyclic aromatic hydrocarbons (PAHs) and their alkyl homologues), the genesis, facies conditions of sedimentation, the degree of transformation of organic matter of bottom sediments and marching soils of the southwestern coast of the Barents Sea are characterized. The assessment of the toxicity levels of polyarenes on the biota inhabiting the tidal zones of the coast was carried out. Areas with increased anthropogenic load have been identified (littoral of the eastern Tana Fjord, the village of Kiberg, Abram Cape, the village of Mishukovo, the mouth of the Kulonga River, the apex part of the Yarnyshnaya Bay, Oscar Bay), indicating the unfavorable ecological state of the tidal zones of the Barents Sea coast.
COMPOSITION OF PHENOCRYSTS OF LAMPROITE LAVA, GAUSSBERG VOLCANO, EAST ANTARCTICA
Authors: Migdisova N. A. , Sushchevskaya N. M. , Portnyagin M. V. , Shishkina T. A. , Kuzmin D. V. , Batanova V. G.
Published: April 2024

This paper presents numerous new data on the geochemical composition of olivine, clinopyroxene, and leucite phenocrysts, as well as spinel inclusions in olivine and quench glass from lamproites of the Gaussberg Volcano (East Antarctica). Most of the olivine phenocrysts in the Gaussberg lamproites are high Mg varieties (Fo 89–91) with elevated Ni contents (up to 4900 ppm) and high Ni/Co ratios. According to the data of about 320 analyzes of clinopyroxenes, two groups of phenocrysts belonging to the diopside group have been established. Group I consists mainly of high-Mg varieties (Mg#80), while group II clinopyroxenes are less magnesian (Mg# 52–80). The main difference between the clinopyroxenes of the two groups is manifested in the increased contents of Al2O3, FeO and reduced TiO2, Cr2O3, and NiO in the compositions of group II compared to group I, as well as different contents of trace elements, which may reflect their crystallization from different types of primary melts. According to the study of about 550 grains of leucite phenocrysts in Gaussberg lamproites, it was shown that they correspond to the ideal stoichiometry of leucite K[AlSi2O6] and are enriched in Na2O (0.05–0.35 wt %), but depleted in K2O (19.9–20.9 wt %) compared to with leucites from lamproites of other provinces. The BaO content reaches 0.3 wt %. %, SrO –0.04 wt. %. The iron content in most leucite phenocrysts varies within 0.7–1.2 wt % Fe2O3, with individual grains with low Fe2O3 contents (0.5 wt %). In microlites of leucite in the groundmass and rims of phenocrysts, the iron content can reach 2.4 wt % Fe2O3, which may indicate more oxidized conditions at the time of lava eruption.Based on the study of natural samples, existing experimental data and computational models, the order and conditions of crystallization of Gaussberg lamproites were restored. Crystallization proceeded in the following order: chrome spinel - chrome spinel + olivine - olivine + leucite (± chrome spinel) - olivine + leucite + clinopyroxene (± chrome spinel). The near-liquidus association, represented by high-Mg olivine phenocrysts with inclusions of Cr-spinel, was formed in the temperature range from 1180 to 1250°C. Further crystallization of the melt with the formation of an association of olivine+leucite+clinopyroxene phenocrysts could occur at pressures below 2 GPa and temperatures of 1070–1180°C, corresponding to the presence of water in the magmatic system. Estimates of the redox conditions of crystallization of lamproites, obtained using different oxybarometers, vary in a wide range from QFM-0.5 to QFM+2.3.Elevated Ni contents in liquidus olivines of Gaussberg indicate high nickel contents in the source. It is shown that the possible formation of ultraalkaline magmas in the region of Gaussberg Volcano occurred during the melting of the continental lithosphere, which was heterogeneous and included both the peridotite mantle and hydrous pyroxenite fragments.
Partitioning and speciation of lanthanides in the system magnetite (hematite) – hydrothermal solution at 450 oC and 100 MPa pressure
Authors: Smagunov N. V. , Lipko S. V. , Tauson V. L. , Belozerova O. Yu. , Babkin D. N.
Published: April 2024

The initial results of the experimental study of a hydrothermal system including lanthanides (Ln) and Fe oxides (magnetite and hematite) are presented. Ln concentrations in solutions and crystals were determined by ICP-MS and LM-ICP-MS, accordingly. The Ln distribution and cocrystallization coefficients obtained are interpreted as the maximal estimates of “true” values corresponding to structurally bound admixture. It is shown that Ln (except for Eu) are the compatible elements in hydrothermal magnetite; heavy Ln (beginning with Tb) are compatible in hematite. The pronounced tendency of the elevation of both coefficients with the Ln atomic number beginning from Gd-Tb was established. This is significant for using the ratio of light and heavy Ln as a typochemical guide for localization of the source of ore elements. The high-Ln-containing phases in associations with magnetite and hematite were obtained. These phases have oxychloride (without Fe) and oxyhydroxide (with Fe) composition and demonstrate the example of co-locating light and heavy Ln in the common space of hydrothermal system due to mutual crystallization of the phases selectively accumulating light and heavy lanthanides.
DETERMINATION OF THE TRACE ELEMENT COMPOSITION OF BLACK SHALE ROCKS AND ORES. CERTIFIED REFERENCE MATERIALS OF SLg-1 AND SChS-1
Authors: Tyutyunnik O. A. , Nabiullina S. N. , Kubrakova I. V.
Published: April 2024

A set of methods for studying the trace element composition of black shales has been developed, including various options for preparing samples for analysis to determine individual groups of elements, including PGE and gold, by atomic spectroscopy methods (ICP-AES, ICP-MS, ETAAS). Data on the content of 54 elements in certified reference materials (CRMs) of black shale rocks SLg-1 and SChS-1 were obtained. The metrologically characterized data will make it possible to use these CRMs for a detailed study of the composition of rocks and ores containing carbonaceous matter. The relevance of the problem is due to the absence of natural multi-element CRMs, in which elevated and clarke contents of gold, silver, as well as all PGEs, are simultaneously certified.
Biogeochemical engineering
Authors: Bashkin V. N.
Published: April 2024

At present, it is possible to identify a number of new directions for the development of biogeochemical research, at the junction of fundamental and applied research. A new field of research is being formed – engineering biogeochemistry, within the framework of which innovative biogeochemical technologies are being developed – technologies and technological processes based on modeling and management of ecosystem biogeochemical cycles. The article shows the transition from the fundamental ideas of V.I. Vernadsky to biogeochemical technologies. The application of these innovative technologies for the restoration of disturbed and polluted impact ecosystems, in particular, polar ecosystems in the zones of operation of gas-producing enterprises, is considered.
BIOGEOCHEMICAL ASPECTS OF LOCAL INTERACTION IN THE "SOCIETY-NATURE" SYSTEM UNDER CONDITIONS OF BIOSPHERE TECHNOGENESIS
Authors: Evstafeva E. V. , Yaseneva E. V. , Bogdanovа A. M. , Makarova A. S. , Zalatа O. A. , Tymchenko S. L. , Моskovchuk O. B. , Slusarenko A. E. , Еvstafevа I. A. , Boyarincevа Yu. A. , Zinchenko S. A.
Published: April 2024

The article offers a justification for the biogeochemical approach used to analyze the interaction in the system "society-nature" under conditions of anthropogenic transformation of the biosphere, with public health as one of its key indicators. It describes the basic principles and tasks of multilevel medico-ecological monitoring, which allows moving forward from a qualitative population health assessment and investigation of the ecological situation towards the quantitative determination of the ecological health risks and regional standards for technogenic factors, assuming the modifications due to the biogeochemical conditions of the environment. The results of verification of the monitoring methods are presented at the regional (Republic of Crimea), subregional (Sevastopol, Simferopol), and local (individual cohorts of the urban population) levels.The official statistics provided by the departments though being less efficient for the research at the regional level still allow identifying the territories with some significant inequalities in the environmental health risk. Sub-regional (within settlements) biomonitoring studies in Sevastopol and Simferopol revealed spatial heterogeneity and loci with higher content of some heavy metals and other chemical elements in the environment and biosubstrates (soil, plants). Cohort studies of residents where 29 chemical elements’ content was determined in human organism followed by the examination of the functional state of target systems in people from risk groups. Results of the correlation and regression analysis allowed us to estimate the physiological significance of given elements, as well as the effects of their complex influence at background exposure.6. Keywords: biogeochemical basis of rationing, medical and ecological monitoring, trace elements, xenobiotics, public health, modeling
THE ROLE OF INTERACTIONS BETWEEN BACTERIA AND CLAY MINERALS
IN PEDOCHEMICAL PROCESSES
Authors: Perelomov L. V.
Published: April 2024

The review considers bilateral interactions between bacteria and clay minerals and their influence on the chemical composition and chemical processes in soils. The participation of bacteria in the weathering, transformation and synthesis of new clay minerals is shown. These interactions contribute to changing the water-retaining properties of soils, ensuring their fertility, and contributes to the cycles of nutrients, inorganic and organic pollutants. Various processes of direct and indirect influence of phyllosilicates on microbiological activity and microbial diversity in soils and the possible biogeochemical role of these processes are described. Obviously, the prevalence of interaction types between bacteria and clay minerals is determined by the First Biogeochemical Principle formulated by V.I. Vernadsky
MORPHOGENETIC ABNORMALITIES OF BRYOBIONTS IN GEOCHEMICALLY CONTRASTING CONDITIONS IN DONBASS
Authors: Safonov A. I. , Alemasova A. S. , Zinicovscaia I. I. , Vergel K. N. , Yushin N. S. , Kravtsova A. V. , Chaligava O.
Published: April 2024

The territory of modern central Donbass is considered as an experimental site for the implementation of an ingredient biomonitoring program. Bryophytes were transplanted and exposed in the geolocalities of the direct impact of enterprises of coal mining and processing complexes, metallurgical and chemical industries, ruderal and residential ecotopes. For bryobionts with a wide amplitude of resistance to technogenic pollution (Amblystegium subtile (Hedw.) Schimp., Brachythecium campestre (Müll.Hal.) Bruch et al., Bryum argenteum Hedw., Bryum caespiticium Hedw., Bryum capillare Hedw., Ceratodon purpureus (Hedw.) Brid and Pylaisia polyantha (Hedw.) Schimp.) the following criteria of anthropotolerance were selected: 1) elements accumulation function, 2) the ability to accumulate specific pollutants, 3) structural and functional reactions and manifestation of atypical morphogenesis (teratogenesis) of plant organisms and 4) shifts in the characteristics of the survival strategy of species in the conditions of deep transformation of the landscape systems of Donbass. Specificity of accumulation of Na, Mg, Al, Si, P, S, Cl, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Zr, Mo, Cd, Sb, I, Cs, Ba, La, Ce, Nd, Sm, Eu, Tb, Dy, Yb, Hf, Ta, W, Hg, Pb, Th, U in samples of indicator plants used as seasonal phytotest monitors to assess pollution of natural environments have been defined. With a radical violation of geochemical cycles in plant life support systems, cases of specific chlorosis and necrosis of point localization, hypo- and hypergenesis and deformation, as well as fasciation, prolification, dystopia, oligomerization of vegetative organs, features of the development of individual groups of cells in the integumentary and conformational tissues of the leaf apparatus of bryobionts have been recorded. The revealed abnormalities are used as a phyto-indication characteristic when conducting an express analysis of the level of technogenic stress in field diagnostics. The coefficients of biological absorption and technogenic concentration of elements in biosubstrates were calculated when assessing the geochemical contrast of the environment. The difference in the accumulative capacity of bryobionts for individual elements or their associative groups in various ectopes is defined. The related morphogenetic heterogeneity of the structure and elemental composition of plants is an individual case of compliance with V.I. Vernadsky's ideas of the concentration, information and environment-forming functions of living matter.
Thermal and Thermochemical Study of Thaumasite
Authors: Gritsenko Yu. D. , Vigasina M. F. , Mel’chakova L. V. , Ogorodova L. P. , Ksenofontov D. A. , Dedushenko S. K.
Published: April 2024

A sample of natural thaumasite Ca3.0Si(OH)6(CO3)0.9(SO4)1.1·12.3H2O (N’Chwaning mine, Kalahari manganese ore field, South Africa) was studied by powder X-ray diffraction, infrared absorption and Raman spectroscopy, thermal analysis, and microcalorimetry. The process of thermal transformation of thaumasite was studied using the results of FTIR and Raman spectroscopy. The enthalpy of formation from elements ΔfH0(298.15 K) = −8816 ± 30 kJ/mol was determined by high-temperature melt solution calorimetry. The value of the absolute entropy was estimated, and the enthalpy and Gibbs energy of formation of thaumasite of theoretical composition were calculated: 945.4 ± 1.8 J/(mol K), −8699 ± 30 kJ/mol, −7577 ± 30 kJ/mol, respectively.
Upper Riphean and Lower Paleozoic Quartzite Sandstones of the Circumpolar Urals: Geochemical Characteristics, Source Areas, and Conditions of Formation
Authors: Nikulova N. Yu.
Published: April 2024

The results of study and comparison of geochemical characteristics of quartzite sandstones of the Upper Riphean Khobeyu and Lower Paleozoic Obeiz formations of the Circumpolar Urals are presented. It has been established that the composition of quartzite sandstone of both formations was formed mainly from recycled material of ancient metaterrigenous rocks, with the participation of destruction products of igneous rocks of felsic (Obeiz Formation) and basic (Khobeyu Formation) composition and weathering crust material. The accumulation of the Lower Paleozoic psammites was accompanied by a gradual change of clastic sources, with increasing contribution of granitoid clastics.
Atmospheric Pollution from a Storage of Tungsten–Molybdenum Ore Mining and Processing Wastes
Authors: Plyusnin A. M. , Voronina Yu. S. , Ukraintsev A. V. , Chernyavskii M. K. , Peryazeva E. G. , Chebykin E. P.
Published: April 2024

Experimental studies of the surface atmosphere pollution with mining and processing wastes of tungsten–molybdenum ore were carried out using an equipment devised for collecting aerosols above the surface of sands. It has been established that toxic components formed during the decomposition of residual sulfide mineralization and products of interaction between acidic waters and rocks are transported with water vapor from the sands to the surface. The moisture condensed over the sands contains high concentrations of aluminum, fluorine, iron, silicon, manganese, zinc, and phosphorus. These elements form an atmospheric pollution halo over the technogenic sands and are further dispersed by air currents over neighboring areas. In winter, the snow cover is polluted over a vast territory due to wind dispersion of the aerosols. The halo of pollution extends over tens of square kilometers. A dependence was identified of qualitative and quantitative composition of the components polluting the snow cover on the storage time of the ore processing products. It is shown that some of the toxic elements pass into solution during snow melting from suspended solids, which are brought by wind from the territory where the soil cover is disturbed by mining.
Geochemistry of Rocks at the Neskevara Rare-Metal Deposit of the Vuoriyarvi Alkaline–Ultramafic Complex, Kola Peninsula
Authors: Sorokhtina N. V. , Lipnitsky T. A. , Zhilkina A. V. , Yakushev A. I. , Kononkova N. N.
Published: April 2024

The Vuoriyarvi Paleozoic alkaline–ultramafic complex with carbonatites is made up of a great diversity of rocks with various ore mineralization. The paper presents data on the geochemistry of pyroxenites, phoscorites, and carbonatites from the Neskevara deposit of rare metals. The pyroxenites of the rare-metal deposit are significantly enriched in Nb, Ta, and Th relative to the primitive mantle and the primary alkaline–ultramafic melt composition calculated for the Kola alkaline province and are characterized by high Nb/Ta, Zr/Hf, and Th/U ratios of 29, 35, and 14, respectively. HFSE are maximally enriched in the phoscorites and carbonatites of stages II and III, with the highest concentrations of Nb (16 000 ppm), Th (2800 ppm), and Zr (4000 ppm) found in the calcite–tetraferriphlogopite phoscorites, in which pyrochlore crystallization on the liquidus was identified. The rocks of the carbonatite series are strongly enriched in LREE relative to carbonaceous chondrite. The calcite–dolomite carbonatites of the late magmatic–carbothermal stage show REE enrichment up to 25 800 ppm. The chondrite-normalized REE patterns and (La/Yb)N ratio indicate that REE were systematically more strongly fractionated in the sequence pyroxenite (70)—phoscorite (90)—calcite (540) and dolomite (3790) carbonatites The crystallization sequence of minerals in the rare-metal phoscorites and carbonatites of intermediate stages indicates that magnetite and pyrochlore crystallized nearly simultaneously. The crystallization temperatures of such associations are, according to data of the magnetite–ilmenite thermometer, lower than 500–600°C, at ∆NNO = –0.3 and + 1.5 and corresponded to the temperature at which the rare-metal ore mineralization of the main stage was formed.
Sr–Nd Isotopic Evidence of a Heterogeneous Magmatic Source of Alkaline–Carbonatite Rocks of the Odikhincha Alkaline–Carbonatite Massif (Maimecha-Kotui Province, Siberia)
Authors: Kostitsyn Yu. A. , Tskhovrebova A. R. , Rass I. T. , Anosova M. O.
Published: April 2024

This study focuses on the igneous rocks composing the Odikhincha massif. The massif is typical ring alkaline–ultrabasic massif with carbonatites, second largest in the Maimecha-Kotui province. The Sr-Nd isotopic values of the traps of the Arydzhang Formation and the host dolomites were also determined for comparison. The Rb–Sr isotope system of phlogopite and calcite from the Od-16-19 carbonatite of the Odikhincha massif is disturbed; the obtained age on the mineral isochrone (245 ± 3 Ma) is close to the time of formation of the Siberian traps and rocks of the ultrabasic–alkaline Maimecha-Kotui complex, but the large scatter of analytical points (MSWD = 22) does not allow this date to be considered as reliable. The disturbance of the isotope system is probably related to the fact that the strontium isotope ratio in the fluid was not constant during autometasomatic phlogopitization of carbonatite. The U–Pb isotopic system of titanite and perovskite from the same carbonatite sample Od-16-19 also appeared to be disturbed, since data points formed discordia. The U–Pb age obtained for titanite and perovskite are 244 ± 5 Ma (MSWD = 1.8) and 247 ± 18 Ma (MSWD = 4), respectively. Apparently, the age values provided by the two isotopic systems (245 ± 3 Ma by Rb–Sr and 247 ± 18 and 244 ± 5 Ma by U–Pb) are consistent with each other and reflect the time of metasomatic processes, i.e., phlogopitization and iolitization. Rb–Sr and Sm–Nd isotope data for ultrabasic–alkaline intrusive rocks with carbonatites of the Odikhincha massif and volcanics of the Arydzhang Formation indicate an enriched, relative to the composition of the convecting mantle, isotopically heterogeneous source of their parent melts. This source could be a combination of ultrabasic mantle rocks and rocks of basic composition (basites). The latter played the role of an enriched component. No signs of contamination of the melts with the host sedimentary rocks in situ were found, however, variations of Sr and Nd isotopic ratios in the rocks of the Odikhincha massif may indicate that during the introduction of deep magmas their interaction and substance exchange with the surrounding rocks of the lithosphere continued up to complete solidification of the melts, as indicated by the nature of local isotopic heterogeneity within the Odikhincha intrusion.
Major, Volatile, Ore, and Trace Elements in Magmatic Melts in the Earth’s Dominant Geodynamic Environments. I. Mean Concentrations
Authors: Naumov V. B. , Dorofeeva V. A. , Girnis A. V.
Published: April 2024

Data from our original database, which includes more than 2 600 000 analyses for 75 elements of mineral-hosted melt inclusions and quench glasses in volcanic rocks, are generalized to calculate the mean concentrations of major, volatile, ore, and trace elements in magmatic melts from the following dominant geodynamic environments: (I) spreading zones of oceanic plates (mid-oceanic ridges), (II) environments affected by mantle plumes in oceanic plates (oceanic islands and lava plateaus), (III, IV) environments related to subduction processes (III is zones of arc magmatism on the oceanic crust, and IV is zones of magmatism in active continental margins in which magma-generating processes involve the continental crust), (V) environments of continental rifts and areas with continental hotspots, and (VI) environments of backarc spreading. A histogram of SiO2 distribution in natural magmatic melts shows a bimodal distribution: one of the maxima falls onto SiO2 concentrations of 50–52 wt % and the other onto 72–76 wt %. The most widely spread melts contain 62–66 wt % SiO2. Mean temperatures and pressures are calculated for each of the environments. The normalized multielemental patterns presented for environments I through VI show the ratios of the mean concentrations of elements in magmatic melts of mafic, intermediate, and felsic composition to the concentrations in the primitive mantle. Mean ratios of incompatible, trace, and volatile components (H2O/Ce, K2O/Cl, Nb/U, Ba/Rb, Ce/Pb, etc.) are evaluated for the melts of each of the environments. The variations in these ratios are calculated, and it is demonstrated that the ratios of incompatible elements are mostly statistically significantly different in the different environments. The differences are particularly significant between the ratios of the most differently incompatible elements (e.g., Nb/Yb) and some ratios involving volatile components (e.g., K2O/H2O).
Strontium and Neodymium Isotopic Signatures in Basalt Glasses of the Mid-Atlantic Ridge, 12°–31° N
Authors: Tskhovrebova A. R. , Shabykova V. V. , Silantyev S. A. , Buikin A. I.
Published: April 2024

This paper presents the new geochemical isotope (Sr–Nd system, H2O, Cl) data obtained for basalt glasses of the Mid-Atlantic Ridge (MAR) sampled from six areas of the MAR axial zone between 31° and 12° N. The data are consistent with the existing ideas about large-scale geochemical segmentation of the MAR. It is shown that samples from predominantly serpentinite segments have a narrower range of variations of strontium isotopic composition (87Sr/86Sr = 0.7027–0.7032) in comparison with samples collected from the areas where the crustal section is dominated by basalts (87Sr/86Sr = 0.7024–0.7041). The variation ranges of the neodymium isotopic composition in these two groups of samples are almost identical (εNd = +4.9 to +10.9 and +5.9 to +11.6 in serpentinite and basalt segments, respectively), although, in general, serpentinite segments have a slightly more enriched composition. The wide variations of the neodymium isotopic composition and increased contents of Cl, H2O, and U, as well as increased K2O/TiO2 and La/Sm ratios, in samples from serpentinites can most probably be related to the participation of different geochemically heterogeneous sources in the magmatism of the MAR axial zone. The influence of enriched plume-type matter cannot be excluded in some segments. The isotopic composition of noble gases may shed light on the subject.
SILVER SULFIDES AND SELENIDES IN ORES FROM Au-Ag EPITHERMAL DEPOSITS OF THE OKHOTSK-CHUKOTKA VOLCANIC BELT
Authors: Beliaeva T. V. , Palyanova G. A.
Published: April 2024

Mineral associations and compositions of sulfoselenides and other silver chalcogenides from epithermal deposits of the Okhotsk-Chukotka volcanic belt (North-East Russia) - Rogovik, Lunnoye, Julietta, Valunistoe, Corrida and Pepenveem have been studied. Different types of relationships between S-naumannite and Se-acanthite in the ores of the studied deposits have been established. It is shown that a general pattern in the sequence of formation of silver chalcogenides is the replacement of S-naumannite and Se-bearing minerals (Se-galena, Se-stephanite) of early parageneses by Se-acanthite or acanthite at later stages. Based on the results of thermodynamic calculations and data on the composition of the main productive mineral associations, the physicochemical parameters (T, ƒS2, ƒSe2, ƒO2, pH) of ore formation at these deposits were reconstructed.
Metal-Sulfide Liquation Of Ore-Forming Melt In The Fe–Fe(NiCu)S–C System And Its Role In The Genesis Of Magmatic Sulfide Deposits In The Norilsky Region (By Experimental And Geological Data)
Authors: Gorbachev N. S. , Kostyuk A. V. , Gorbachev P. N. , Nekrasov A. N. , Soultanov D. M.
Published: April 2024

The results of an experimental study of the melting of a graphite-saturated Fe–Fe(CuNi)S–C system at 0.5 GPa and 1150–1250°С with the addition of impurity elements Ag, Au, Re, Pt, Pd, and Rh are presented. The quenched sulfide melt forms the matrix of the sample, at 1150–1200°С it is represented by the FeNiS pyrrhotite phase (Mss) with inclusions of the FeCuS phase (Iss) anomalously enriched in Cu. At 1250°С, the sulfide melt is quenched in the form of a homogeneous pyrrhotite Ms phase of the Fe(CuNi)S composition. The change in the Ms composition of the quenched sulfide melt by the two-phase Mss + Iss association is considered as evidence of the existence of supra-liquidus Mss and Iss stratification of the sulfide Fe–Ni–Cu melt in the range of 1150–1250°С. As a result of fractionation of elements between immiscible Fe-sulfide (Ms) and Fe-metal (Mc) melts, Fe, Ni, Pt, Re, Au are predominantly concentrated in the metal melt, while Cu, Ag are concentrated in the sulfide melt. The role of the supra-liquidus Mss–Iss liquation in the genesis of sulfide mineralization of the deposits of the Talnakh ore cluster, including pyrrhotite-chalcopyrite "drops" in picritic gabbro-dolerites, as well as pyrrhotite and chalcopyrite types of ores of zonal sulfide deposits, is discussed. The role of Ms and Mc separation of the Fe-sulfide melt during carbon contamination in the Cu–Pd specialization of magmatic sulfide deposits of the Norilsk region is considered.
COUPLED SOLUBILITY OF Cu and Ag IN CHLORIDE-BEARING HYDROTHERMAL FLUIDS (350-650 °С, 1000 - 1500 BAR)
Authors: Rubtsova E. A. , Tagirov B. R. , Akinfiev N. N. , Reukov V. L. , Korolev L. A. , Nikolaeva I. Yu. , Tarnopolskaya M. E. , Volchenkova V. A.
Published: April 2024

The coupled solubility of Cu(cr) and Ag(cr) was measured in acidic chloride solutions at 350 °С/1000 bar, 450 °С/1000 bar and 653 °С/1450 bar in a wide range of chloride concentrations (0.02m HCl + (0-15m) NaCl). The experiments were performed using autoclave (350, 450 °С) and ampoule (653 °С) techniques, the dissolved metal concentrations were measured after quenching the experimental system. The equilibrium constants of the reaction combining the dominant forms of transport of the metals are determinedCu(cr) + AgCl2- = Ag(cr) + CuCl2- K°(Cu-Ag) . The calculated reaction constant is independent of chloride concentration. It is known that AgCl2- predominates in the studied chloride concentration range. Therefore, the main cupper form of occurrence is CuCl2- in all experimental fluids with chloride content up to 47 wt.%, which is close to the NaCl saturation limit. The constant of the coupled Cu and Ag solubility was determined for the experimental PT-parameters as lg K°(Cu-Ag) = 2.65±0.20 (350 °С/1000 bar), 2.28±0.10 (450 °С/1000 bar), 1.49±0.34 (653 °С/1450 bar). These data, together with values from the literature for temperatures from 200 to 900 °С and pressure up to 2000 bar were fitted to the density model equation: lg K°(Сu-Ag) = 1.066 + 1.108∙103∙T(K)-1 + 3.585lgd(w) – 1.443∙lg d(w)103T(K)-1, where d(w) is the pure water density. According to these data, copper is much more soluble in chloride solutions compared to silver, but the difference in the solubility decreases with the temperature increase. Reliable literature data on the silver solubility constant allow to calculate the copper solubility oneCu(к) + HCl° + Cl- = CuCl2-+ 0.5H2(р-р) K°(Cu) ,lg K°(Cu) = 1.39±0.20 (350 °С, 1000 bar), 1.91±0.10 (450 °С, 1000 bar), 2.06±0.34 (653 °С, 1450 bar). The new values of K°(Cu) are combined with reliable literature data to calculate the density model parameters. The obtained density model equation can be used to calculate the copper solubility constant up to 800 °C and pressures to 2000 bar: lg K°(Сu) = 6.889 – 3.298∙103∙T(K)-1 + 8.694∙lg d(w) – 4.807∙lg d(w)∙103∙T(K)-1. The solubility of chalcopyrite in the system with mineral buffer assemblages pyrite-hematite-magnetite and K-feldspar-muscovite-quartz is discussed.
SEARCH-ORIENTED TECHNIQUE OF THE NUMERICAL FORECASTING OF THE RARE-METAL PROXIMAL (NEAR DRIFT) PLACERS: EVIDENCE FROM THE LOVOZERO PLACER DISTRICT
Authors: Chefranov R. M. , Lalomov A. V. , Chefranova A. V.
Published: April 2024

Rare metals (including rare earth metals) are significant raw materials which determine technical and scientific level of development of the industry; first of all – innovative technologies. An important source of rare metals can be a group of unique in genesis and mineral composition of loparite placers associated with the Lovozero massif of nepheline syenites (Cola peninsula). In the present work Within the Northern periphery of the Lovozero massif, which includes the Revda placer deposit, the authors have identified the main factors controlling the formation of proximal (near drift) rare-metal loparite placers. They have performed the formalization (numerical evaluation) of this factors and developed multiplicative indicators that reflect the placer potential of territories. To assess the effectiveness of the proposed technique based on the developed multiplicative coefficients, independent forecasts of placer metal content for the western and eastern placer-bearing areas of the Revda group of placers were calculated. For additional verification of the technique, the paper compares the obtained results with similar forecasts obtained using the methods of Linear Regression and Random forest of Regression trees. The developed method allows automating the process of forecasting of placer parameters, which is especially important for assessing deep-seated placers that are difficult to search and exploration and are not shown on the surface.
Tectonophysical Forecasting Criteria of Vein Bodies Thicknesses in Deep Horizons of the Nadvigovaya Zone, Badran Ore Field, Republic of Sakha (Yakutia)
Authors: Rebetsky Yu. L. , Voitenko V. N.
Published: April 2024

A new technology of stress inversions is proposed on the basis of data of mute fracturing with measured amplitudes of dilative opening of fractures (tension shear), which are registered by mineralization (vein bodies). The involvement of a basic law of geomechanics of supercritical deformation, which determines the interrelation between amplitudes of shear deformations and deformations of transverse extension (dilatancy), allows us to link the amplitudes of opening of shear fractures with the level of Coulomb stresses. This approach can be used for a conjugated fracture system and fault zones with a system of similarly oriented fractures. Our algorithm and technology of stress calculation consist of consecutive analysis of a geometrical form and characteristic lineaments of density zone of fracture poles on the stereospheres and stress conditions of these fractures on Mohr’s diagram. The algorithm allows the calculation of the parameters of stress tensor both on the basis of graphical analysis on the stereonets and Mohr’s diagram and using a group of formulas. The algorithm is applied for the Nadvigovaya zone of the Badran deposit. The stress values are calculated for a fault area with measured fracturing, and a forecast for promising areas is given for a deeper fault part in areas with possible most intense dilatancy of fracture flow.
Ore-Bearing Faults of Transpressional–Collisional Kinematics in the Verkhoyansk–Kolyma Fold Belt (Structural Consequences of the Geodynamic Model)
Authors: Savchuk Yu. S. , Volkov A. V. , Aristov V. V. , Murashov K. Yu.
Published: April 2024

The Verkhoyansk–Kolyma fold-thrust belt is an important metallogenic structure of northeastern Russia. Based on irregularly distributed gold mineralization within this belt two large ore-placer districts are distinguished: the Upper Indigirka district (UID) in the northwest and the Central Kolyma district (CKD) in the southeast. The gold grade in these areas is largely provided by a large fault structure—the ore-controlling Adycha–Taryn deep fault. Along the entire length, this fault changes its kinematic characteristics, from an overthrust reverse fault in the north to a strike-slip reverse fault (Tenka fault) in the south. Such a change of the fault kinematics laterally, in the principal ore-controlling structure, is reflected in the structure of specific ore-bearing faults in ore areas, as we have shown on the example of the Degdekan (CKD) and Drazhnoe (UID) deposits. In the Degdekan deposit, synthetic overthrust reverse faults, which control large-volume deposits of relatively poor ores, are ore-bearing, and, in the Drazhnoe deposit, opposite strike-slip faults contain small-size, superimposed rich ore bodies. The change of ore-bearing faults in different ore areas is explained by their position in the changing stress field that formed at different stages of geodynamic development: (1) associated with the collision of the Kolyma–Omolon superterrane and the Siberian craton and collision with the Alazeya arc (early ore mineralization of the Upper Indigirka ore district) and the Uda–Murgal arc (early disseminated pyrite mineralization of the Central Kolyma ore district) and (2) collision with the Chukchi microcontinent and re-activation of earlier faults (the main gold-sulfide-quartz mineralization of the Yana–Kolyma metallogenic belt)