Abstract The paper presents the results of thermodynamic modeling of a transformation of a kerogen-bearing sedimentary rock within the temperature range of 50–400°С at a gradually increasing pressure from 300 to 2200 bar. A gradual increase in temperature and pressure, starting from 50°С, leads to the formation of the lighter and more oxidized type of kerogen. The methane–carbon dioxide gas phase is

Abstract The paper presents certain aspects of applying equilibrium-kinetic modeling to preliminarily assess the formation of the chemical composition of sewage subdump waters during upcoming mining at the Udokan deposit. The mineral dissolution rates, including oxidative dissolution of sulfides, and sorption of strontium, cobalt, zinc, and nickel on calcite are taken into account. It is shown that

Thermodynamic modeling with the HCh software complex was applied to analyze the probability of acid drainage formation during the evolution of a copper–ore deposit in low-temperature conditions (5°C) with various water levels. During the modeling, three main factors were taken into account: the percentage of pyrite in rocks, the availability of oxygen in the air, and the water content of the rocks

Abstract— A thermodynamic model of the gold–polymetallic volcanogenic massive sulfide ore-forming system, related to the evolution of a shallow acid volcanic chamber of an island arc (Galkinskoe deposit, Northern Urals) was created. The low W/R ratio (<0.25) obtained via modeling indicates slow filtration of fluid upsection in the sequence. In general, the Cu, Zn, Pb, Ag, and Au concentrations in the

Abstract Chemical interactions in carbonate rock–seawater, silty sand–seawater, clay rock–seawater, basalt–seawater, and granite–seawater systems, where the term “seawater” denotes the compositions of halite, epsomite, and sylvinite stages of seawater densification, were simulated at 25, 100, 200, and 300°С and various pressures in order to assess the ability of rocks to generate hydrocarbons. Based

Abstract The paper briefly describes some of the problems solved at the Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, to illustrate the possibilities and limitations of the promoted physicochemical computer simulation method. The computer simulation results on the formation of hydrocarbons in the Earth’s crust, acid drainage estimates, and other results of the method

Abstract The report presents extensive factual data on the chemical composition of natural waters in different regions of Central Eurasia. The features of the chemical composition of natural waters are revealed for several regions with a humid and arid climate, as well as for tectonomagmatic activation conditions. The abundance of over 50 chemical elements in natural waters is characterized. The geochemical

Abstract— The research data are presented on the chemical and isotope composition of sodium bicarbonate groundwaters in the southeast of West Siberia. It is shown that the studied waters occur ubiquitously within Mesozoic–Cenozoic sedimentary deposits at a depth roughly from 50–300 m to 1.0–2.3 km. Various geochemical characteristics and conditions of occurrence made it possible to distinguish five

Abstract— The paper presents experimental data on fluorine leaching from igneous rocks (dacite, rhyodacite, and trachyrhyolite) and greisen with distilled water and 0.01 M HCl, CH3COONa, NaHCO3, and Na2CO3 solutions. Fluorine leaching is proved to be proportional to its content in the rocks and depends on pH of the aqueous solution: the equilibrium concentrations of fluoride are minimal in the near-neutral

Abstract—Studies have shown that the concentration of heavy carbon isotope in the organic matter (OM) in the surface layer of the marine sediment increases and the amount of terrigenous OM decreases by about 1.4 times with increasing distance from the Indigirka River delta from 50 km to 600 km. This is accompanied by 1.3–2.1 times decrease of heavy metals and 1.3–1.4 times decrease of rare-earth elements

Abstract— The paper presents results of SIMS and SEM-EDS studies of the silicate minerals from one radial and one granular chondrule of the Buschhof ordinary equilibrated L6 chondrite and discusses geochemical features of the olivine, pyroxene, and plagioclase from the chondrules and matrix of this meteorite. Results show that pyroxene and plagioclase from the radial chondrule did not preserve the

Abstract Structure, defects and inclusions in natural polycrystalline ballas-type diamonds are studied by complementary techniques: Scanning Electron microscopy, cathodo- and photoluminescence, X-ray diffraction, radiography and fluorescence, infra-red spectroscopy and carbon isotope analyses. Peculiarities of internal structure of some of the samples are explained by growth of the diamonds as volume-filling

Abstract— The paper presents data on the vertical distribution of 137Cs of Chernobyl origin in arable and meadow soils to a depth of 40 cm in typical catenary junctions of predpolessie, predopolje, and opolje landscapes with a different density of 137Cs contamination 30 years after the accident at the Chernobyl nuclear power plant. Newly obtained data on the removal of 137Cs beyond the arable horizon

This paper considers the element distribution between species in the lysimetric waters and lakes of the Valdai National Park in different seasons. Seasonal studies of natural waters and element speciation in them in 2019 using membrane filtration and ion-exchange separation showed the differences in the seasonal distribution of species depending on geochemical factors. The seasonal temperature factor

Abstract— Authors’ original continuously updated database, which currently comprises data from 22 300 publications on mineral-hosted fluid and melt inclusions, is used to generalize data on the physicochemical parameters of processes that produced fluorite and barite deposits. The paper presents data on the following parameters of the fluids: temperature, pressure, density, salinity, and gas composition

Abstract Extensive field hydrogeochemical data and thermodynamic simulations demonstrate that the composition of lacustrine waters is controlled not only by evaporation but also by interaction between the waters and rocks. This interaction begins in the catchment areas of the lakes and continues in these lakes themselves, because the waters (regardless of their salinity) do not occur in equilibrium

Extremely high uranium concentrations (>100 times average crustal content) are established in the recent sediments of small lakes of the northern Murmansk region. It is substantiated that the high uranium concentrations in the sediments of the lakes of the northern Murmansk region were mainly controlled by natural uranium migration from magmatic and metamorphic rocks bearing uranium mineralization

Abstract— The paper presents the first data on the nitrogen isotope composition of the associated gases of mineral waters in the North Caucasus and newly acquired data on the carbon isotope composition of the CO2 and CH4. Most of the samples were taken from the high-\({{p}_{{{\text{C}}{{{\text{O}}}_{{\text{2}}}}}}}\) waters of the Elbrus and Kazbek volcanic areas in the Greater Caucasus. It is shown

Abstract — The paper presents data on 48 samples of crude oil and oil shows from oil fields and surface oil seeps in the Krasnodar Territory, Crimea, and the Russian part of the Black Sea. The oil samples were analyzed for isotope and molecular composition. According to the results, all crude oil samples were classified into three genetic types (Akhtyrsky, Sladkovsky, and Nikolaevsky), which differ

Numerous orogenic gold deposits of different age, scale, and mineralization type are located within Northern Transbaikalia. Among them, there is a large group of Early Permian deposits, whose sources and relationships with Late Paleozoic magmatism remain debatable. These issues were solved by the example of the middle-scale (~24 t, Au) Irokinda deposit, localized within the Precambrian rocks of the

Abstract— The model of the formation of the Earth–Moon system during the compression and fragmentation of a gas–dust cloud (Galimov, 2011; Galimov and Krivtsov, 2012) suggests an unusual mechanism for the formation of the Earth’s core. In particular, the model predicts that iron in the Earth’s core should be enriched in the light isotope, and the Earth’s mantle should be, conversely, enriched in the

Abstract The first experimental data were obtained on the distribution of boron isotopes between gas and liquid at 100–350°С and the pressure of saturated water vapor, and the effect of pH on this distribution at 100°С was studied. The results showed that the value of δ11Bgas–δ11Bliquid was 5.9, 3.7, 1.1, 0.8, and –1.3 ‰ at 100, 200, 250, 300, and 350°С. In an alkaline solution, the boron distribution

A series of photochemical experiments with sulfur dioxide were carried out using a xenon lamp (λ > 200 nm), a low-pressure mercury lamp (λ = 184.9 and 253.7 nm), and an UP-213 laser system (λ = 213 nm) as light sources. Based on the isotope data obtained for elemental sulfur (the end product of SO2 photolysis), we revealed specifics in correlations between δ34S, ∆33S, and ∆36S values depending on the

Abstract— The isotopic composition of noble gases, nitrogen, and carbon in two samples of the Ozerki L chondrite, which differ in the degree of impact metamorphism, analyzed by the methods of stepwise oxidation and crushing, is reported. The data obtained indicate that the meteorite contains gases trapped on the asteroid during the impact events. The isotopic composition of trapped argon, studied by

Abstract— The first data on the isotopic composition and elemental ratios of nitrogen, carbon, and noble gases in samples from the early stages of the formation of the Guli Complex (Maimecha-Kotui igneous province, Polar Siberia), obtained using the method of stepwise crushing, are reported. The 40Ar/36Ar ratios in the crushing steps vary from the values close to atmospheric (~296) in the meimechite

Abstract— Distinguishing between components (stomatal conductivity, mesophyll conductivity, carbon dioxide fixation in chloroplasts, and respiration) of the complex biochemical mechanism of plant photosynthesis is a challenging problem. To solve it, we used both experimental data obtained in natural conditions (time series of recorded indicators) and a specially designed experiment: determination of

Abstract Geochemical processes controlling hydrochemical evolution of shallow groundwater (<200 m) were studied in the Chahan Lake Basin, China. A combination of chemical and isotopic tracers (δ2H, δ18O, 87Sr/86Sr, 3H and 14C), along with inverse geochemical modeling were applied. Shallow groundwater primarily originates from local precipitation, and has negligible mixture with deep groundwater. Shallow

Kola nuclear power plant, which discharges warm water into one of the bays of sub-arctic Lake Imandra, significantly changes the fish habitat, creating temperature gradient from 2 to 8°C compared to water temperature in the other part of the lake. The permeation, metabolism and bioaccumulation of elements in the stenothermal cold-water species (Coregonus lavaretus L.) in warm water impact zone are

The paper reports chemical data on the atmospheric precipitation within the studied area of the Valdai National Park during monitoring in 2015–2018. The main parameters of atmospheric precipitation as well as major and trace-element compositions of waters are analyzed. Seasonal dynamics and possible pathways of element uptake in atmospheric precipitation are considered. Multidimensional statistical

Abstract— The paper presents a concept of the sustainability of aquatic ecosystems, their disorganization when impacted by anthropogenic pollution, and evolutionary development after the effect of the toxicants decreased. The general laws of the ecosystem transformations are explained from the viewpoint of the ecological theory and the mechanism of thermodynamic ordering of matter in living systems

Abstract— The concept of toxicity is analyzed from the standpoints of theoretical biogeochemistry and geochemical ecology. The phenomenon of toxicity is demonstrated to appear and be able to significantly manifest itself only as a consequence of anthropogenic disturbances of self-regulation systems and dynamic equilibria that existed in natural biogeochemical cycles throughout the whole history of

The paper addresses the removal of chemical elements by suprasoil and subsoil phytomasses of herbaceous phytocenoses and their subsequent return to soil during decomposition of plant remnants. The obtained results allowed us to evaluate the biogeochemical cycles of essential (Zn, Cu) and toxic (Pb, Cd) elements in natural biogeocenoses of the Middle Urals. It has been shown that the intensity of such

Abstract— The paper presents data on seasonal fluctuations in hydrochemical characteristics and the supply dynamics of biogenic elements in four hypersaline lakes in Crimea: Sasyk-Sivash, Oiburg, Konrad, and Sakskoe (eastern basin) in 2017. The migration pathways of biogenic elements in the hypersaline lakes are determined depending of natural and anthropogenic factors. The role of the elements in

The higher accumulation of Mo, W, Cu and Re by soils and organisms in the Baksan River basin owing to the anthropogenic contamination by the former Tyrnyauz W–Mo industrial complex and migration of the metals with natural waters are discovered during biogeochemical studies of W–Mo mining landscapes of the North Caucasus and background territories. The man-made transformed soils of the Baksan River

Pallasite Seymchan contains three morphological types of olivine grains, which occur in a FeNi matrix and have rounded, angular, and fragmental shape. Sometimes the rounded grains form clusters. The texture and mineralogical features of the olivine cluster in pallasite Seymchan were studied by optical microscopy, EMPA, and SEM. The data obtained indicate an imposed impact event in the Seymchan history

Abstract—The Karasu Stream is located in the province of Sakarya in Turkey. It flows into the Black Sea with an output of 10 m3/s. Chemical compositions of surface and ground waters change following interaction with geological units and chemical weathering at the surrounding rocks. This change may be realized as passing of the ions mobilized from the rocks and soil into the water. Hence, concentrations

Abstract—The authors have previously developed the separation principles of filtering water samples rich in colloids into size fractions by the method of cascade filtration and by studying the migration of trace elements with them. Data acquired by studying the migration of a great number (forty to sixty) elements and organic matter (OM) of riverine runoff show that the method is highly promising for

Ore-bearing rocks and natural waters of the Pitkäranta ore district (near the “Arsenic” shaft, the Hopunvaara mine field) were sampled and analyzed. The permanganate value as well as iron and manganese contents in surface water are higher than MPC values, while water samples from the “Arsenic” shaft have the elevated contents of zinc, copper, and arsenic. The Fe, Mn, Cu, Zn, Cr, As, and Ni speciation

Abstract—Data obtained on carbonates and metaterrigenous rocks of the Devonian complex of the Sultan-Uizdag Range, northwestern Uzbekistan, which are carbonized in local deformation zones, are used in a generalized interpretation of the genesis of carbonaceous matter by means of decomposition of carbonates under the effect of seismogenic movements. The release of free carbon is facilitated by synchronous

Comparison of trace element distribution in bulk samples from the North-Western Caucasus mud volcanoes with PAAS (average Australian post-Archean shale) showed their depletion in many elements. The contents of most elements in sediments of the mud volcanoes are comparable with those of the Middle Maikopian clay. Compared to the Upper Maikopian clay, most of the studied samples have much higher concentrations

The bismuth distribution was studied in the landscape of the Sherlova Gora ore district and in the organs of congested cinquefoil (Potentilla acervata Sojak). The bismuth content in all landscape components is much higher than its average content in the Earth’s crust, soils and plants. In soils of the Sherlova Gora ore district, its average content is 95.11 mg/kg, which is 475.5 times higher than the

Based on geological, geochemical, and isotope-geochronological studies, the geodynamic nature of the island-arc magmatic associations of the Predivinsk terrane of the Yenisei Ridge has been established. It is shown that the Predivinsk terrane consists of two blocks, which differ in age and composition of rock associations. The Eastern Block is composed of the following associations: (1) typical island-arc

This paper addresses the vertical distribution of total mercury and its thermoforms in the Holocene–Upper Pleistocene sedimentary rocks from the Dead Dog active hydrothermal field in the Middle Valley, Juan de Fuca Ridge, Pacific Ocean. Sediment samples were taken from the core of Hole 858B drilled during ODP leg on the top of a sulfide hill, in a zone of ascending hydrothermal fluid, in the vicinity

The distribution of dissolved major- and trace elements in the mixing zone of the Ural River and the North Caspian waters was studied based on the natural observations data from 2016–2017. Conservative behavior was established for most of major ions (Na, K, Mg, SO4) and some trace elements (Li, Rb, Cs, Sr, Co, Ni, Cu, Zn, Sb, Ga, Y, U, B, F, Cr, Ge, Mo, W) with common parameters of relationships between

AbstractThe paper presents data on the chemical composition of waters and bottom sediments in lakes variably affected by liquid wastes from facilities of the Olkon Joint-Stock Company in Olenegorst, Murmansk oblast, which mines and processes iron ores. Since Olkon started operating, the composition of water in nearby water bodies has underwent significant changes. The mineralization (TDS) and pH of

The natural hydrous sodium−magnesium sulfate blödite (astrakhanite) Na2Mg(SO4)2 · 4H2O from sediments of saline Lake Bai Shagyr (Russia) is studied. The stages of its decomposition on heating are distinguished using thermal analysis, X-ray diffraction, IR and Raman spectroscopy. The enthalpy of formation of blödite from elements (\({{\Delta }_{f}}H_{{el}}^{0}\) (298.15 K) = –3845 ± 13 kJ/mol) is determined

AbstractThe paper presents data on the involvement of local populations of bank vole (Clethrionomys glareolus) in the biogeochemical cycles of Cu, Zn, Cd, and Pb at territories strongly chemically polluted by large nonferrous metallurgical plant in the Middle Urals (in 1990–1992) and after a significant decrease in its emissions (in 2015–2017). At maximally polluted areas (impact zone), the animal-controlled

AbstractThe paper presents data on dolerite dikes in the Murmansk block in the northeastern Kola Peninsula. The dikes belong to a Middle Paleozoic flood-basalt association, which is a principal element of the large-scale plume–lithospheric process in the area of the Barents Sea. According to their geological, petrological, and geochemical features, the dolerite dikes are classified into two groups:

Concentrations and carbon isotope composition of dissolved inorganic carbon (DIC) and isotope composition (δD, δ18O) of waters were studied in the eastern East Siberian Sea, along two submeridional sections extending from the Indigirka and Kolyma mouths to the edge of perennial ice. Estimated contents of river waters, sea ice meltwater, and modified waters showed that the eastern part of the shelf

AbstractThe paper presents data on the composition of organic matter (OM) in the surface layer of bottom sediments (BS) in two small estuaries in the southwestern part of the Tatar Strait (as of summer of 2014 and 2016). The concentration of hydrocarbons (HC) varied from 0.01 to 2.0 mg/g. The HC content in the uniform silt–psammite sediments (0.55–1.47 mg/g) was higher than the biogenic background

AbstractUnderstanding the chemical composition of gases trapped in rocks is important in a wide variety of earth science studies and gases are often extracted from rock samples and analyzed. Gas chromatography (GC) and mass spectrometry (MS) are the most frequently used analytical techniques for measuring gases extracted from rock samples, but these techniques have rarely been coupled except for gas

The element distribution is analyzed in the “atmospheric precipitation–crown waters–soil waters–lake” system of the Lake Gusinoe drainage system in the Valdaysky National Park. The chemical composition of the atmospheric precipitations, crown, soil, and lacustrine waters, as well as soils is determined. The input and output element fluxes in genetic soil horizons are calculated by months and their

Aliphatic hydrocarbons (HCs) were studied in water and bottom sediments sampled during cruises 67th and 68th (August–September 2016 and July–August 2017, respectively) of the R/V Akademik Mstislav Keldysh in the Barents Sea to determine the lateral and interannual variability of their concentrations and composition. It has been established that the HC distribution in water was mainly determined by

AbstractGabal El Fereyid area, represents a promising area for monzogranite and pegmatites hosted rare-metal mineralization. Microscopically, monzogranite and pegmatites consist of K-feldspar, albite, and quartz with few biotite +/– hornblende. The radiometric studies of anomalous pegmatite samples show that their eU-contents reached up to 149 ppm while their eTh-contents reached up to 375 ppm, in

AbstractThe paper discusses water–rock interaction in areas where wastes of tungsten ore processing are stored, as exemplified by the Dzhida and Bom-Gorkhon mining and processing complexes. Pore waters at the tailing dumps become acidic, and the solutions are enriched in decomposition products of the sulfide minerals and rocks. When the wastes are stored for a long enough time, interaction between

AbstractInteraction between amphibole and H2O–HCl fluid was experimentally studied in an internally heated pressure vessel (IHPV) at 650–800°C and 5–7 kbar. The stability of the anorthite–amphibole association was approved to be constrained at T = 650–800°C, (P = 5–7 kbar) within a range of HCl fugacity (fHCl) 50 < fHCl < 400 bar. At higher fHCl, the amphibole is replaced by gedrite (or cordierite

AbstractThe paper presents petrochemical, geochemical, and mineralogical data on rocks of the phoscorite–carbonatite complex in the Kovdor alkaline–ultramafic massif, Kola Peninsula, Russia. In contrast to what is usually thought, trace elements were determined to be concentrated not in the carbonatites themselves but in the related phoscorites. The paper presents data on the evolution of the compositions

The results of electron-probe and spectrophotometric study of five porous micrometeorites found on the Novaya Zemlya glacier are presented. Their reflectance spectra are compared with those of terrestrial serpentines and several carbonaceous chondrites. The possibility of discovery and identification of mineralogical absorption bands in the reflectance spectra of micrometeorite particles is demonstrated

Abstract—The paper considers the content and geochemical mobility of 226Ra in surface waters, bottom sediments, and radioactively contaminated soils (podzolic and alluvial–soddy) of the northern taiga subzone in the area of former radium production site. It is established that the level or radioactive contamination and specific activity of geochemically mobile radium in the podzolic soil is higher

Abstract—A set of experiments was carried out in the system NaAlSi3O8–FeO–NiO–CoO–SiC–NaH2PO4 at 1550°C, 4 GPa, and oxygen fugacity (fO2) 0.5–2.9 log. units below the iron–wüstite (IW) buffer to estimate how C–O–H components can affect Ni, Co, and P partition between silicate melt and a liquid metallic phase at redox conditions under which the metallic phase is segregated into melting products of the