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Relevance. In Kuzbass, a coalbed methane production project is being implemented for the first time in Russia. Formation water extracted together with coalbed methane plays an important role, since it has been in contact with the coal-bearing rocks for a long time, therefore it contains rich geochemical information. Over the period 2002–2022, new isotopic data were accumulated both on the waters of the region coal deposits and on overlying waters, including surface waters. Aim. Based on the material accumulated on the isotopic composition (δD, δ18O, δ13C, 34S, 3H, 14C) of natural waters in coal-bearing areas, create an evolutionary scheme for the formation of waters within the framework of the developed hypothesis on the interaction of water-rock-coal-methane. Objects. River, underground waters of the zone of active water exchange, upper and lower parts of the zone of slow water exchange (extracted together with coalbed methane). Methods. Studies of the isotopic composition of waters were carried out in several laboratories: in the Multielement and Isotope Research Center of the SB RAS, the Technical Branch of the Federal State Unitary Enterprise “SNIIGGIMS”, in the radiocarbon AMS laboratory based on the Center for Collective Use “Cenozoic Geochronology” and in the Pacific Oceanological Institute Far Eastern Branch Russian Academy of Sciences (POI) FEB RAS. Results and conclusions. The paper introduces the data on δD, δ18О, δ13С и δ34S for surface and groundwater in Kuzbass in coalbed methane production areas. It is shown that all the waters under consideration are infiltration based on their isotopic composition (δD and δ18О). The waters of the lower part of the slow water exchange, produced together with coalbed methane, are characterized by a positive oxygen shift and very light hydrogen. A diagram of the evolution of the isotopic composition of water-dissolved carbon in the region has been compiled according to the data obtained. It is noted that the atmospheric source of CO2 is characteristic only of river waters, and only biogenic carbon dioxide is present in groundwater. The wide range of δ13СDIC values of the latter is explained by the varying degrees of participation of light soil carbon dioxide and heavy biochemical carbon dioxide formed during methane formation in the coal seam. The heaviest values are typical for waters produced together with coalbed methane, which is associated with long-term interaction with coal and methane. The time of such interaction was determined using the radiocarbon method: 17–30 thousand years. In areas where coalbed methane is produced, an increase in δ13СDIC values for all natural waters is observed, which requires further study.

Relevance. The study of isotopic composition of water and dissolved substances makes it possible to determine not only their genesis, but also the fractionation processes occurring in the “water–rock–gas–organic matter” system over time, i. e. as different stages of the evolution of water composition pass through. Interest in the groundwater of the Arctic regions of Western Siberia is additionally associated with the widespread occurrence of oil deposits at the depths of formation waters and the possible influence of cryogenic metamorphization processes on composition of near-surface waters. Aim. To study and compare the isotopic composition of oxygen, hydrogen and carbon in natural waters of the Yamalo-Nenets autonomous region to identify conditional isotopic markers, as well as to be able to trace the evolution of the isotopic composition of waters along a vertical section in the area of the Taz oil and gas condensate field. Objects. Surface (river, soil and lake), underground waters of the active water exchange zone of the Yamalo-Nenets autonomous region and formation waters of oil and gas deposits of the Taz field. Methods. The study of the isotopic composition of oxygen, hydrogen, and carbon of water-dissolved carbon dioxide was carried out in the Research Equipment Sharing Center at the Institute of Geology and Mineralogy SB RAS using Isotope Ratio Mass Spectrometer FinniganTM MAT 253 equipped with H/Device and GasBench II for sample preparation. Results and conclusions. The paper introduces the data on isotopic composition of O, H and C for natural waters of the Yamalo-Nenets autonomous region. The authors have determined the characteristic trends in changes in the isotopic composition of water and dissolved carbon dioxide for various water bodies. Surface and underground waters with active water exchange in terms of isotopic composition (δD and δ18О) are infiltration. As water moves down the section, with an increase in the time of interaction of the “water–rock” system and increase in temperatures, the isotopic composition becomes significantly heavier with a slope from the GMWL to the right. The authors compiled the diagram of the evolution of water-dissolved carbon isotopic composition in the region according to the obtained and some literature data. Despite the wide range of δ13C values from –30.4 to 23.6 ‰, there are, obviously, only two sources of carbon dioxide in the region: biogenic and atmospheric, with biogenic being predominant for groundwater.

The relevance. When constructing various hydrogeochemical models of basins, accurate data on the temperature of formation waters are required. In the case of thermal waters, where it is difficult to measure temperatures at depth, calculated or empirical expressions – geothermometers – have long been used. For formation waters of sedimentary basins, they are rarely used, since temperatures are lower here, water salinity and pressure are higher. However, even here it is necessary to check the data of deep-seated thermometers, the accuracy of which varies greatly, and, in the absence of data on temperature or the impossibility of measuring it, to reliably calculate them. To do this, it is necessary to select the most suitable geothermometers in these conditions. The main aim: get acquainted with a wide range of geothermometers used, calculate several varieties from the available database of the chemical composition of formation waters in the Tomsk region, compare these calculations with each other and between actually measured data from deep thermometers, identify and justify the most suitable for specific conditions. Objects: formation waters taken during the development of oil fields, mainly waters of Cretaceous and Jurassic deposits, with a depth from near surface conditions to 4,5 km. Methods. When processing the database on the chemical composition of formation waters, basic statistical methods were used; as a result, samples with abnormally high and abnormally low concentrations of components were rejected, as well as those that did not comply with the law of electrical neutrality. The formulas for calculating geothermometers are taken from numerous literary sources. The calculation results were compared with the available data on actually measured temperatures, among themselves, with the depths of water circulation and the geothermal gradient of the region. Results. The types of geothermometers and the conditions for their use were studied in detail according to numerous literary sources. The most suitable in these conditions were selected. As a result, nine different chemical geothermometers were calculated for the first time using the available database of the chemical composition of formation waters in the Tomsk region. It is shown that classical geothermometers (Si, Na-K, Na-K-Ca, K-Mg) do not work in these waters, they do not correlate well with the actually measured data of deep thermometers. Mg-Li and Na-Li geothermometers are recommended, as well as Na-K-Ca geothermometer with Mg correction. These geothermometers filled in the gaps in the database of 650 missing temperatures. It is concluded that it is necessary to further develop geothermometers for formation waters of oil fields, taking into account more modern and accurate data. As a practical result of this work, the possibility of using the obtained temperatures in calculating equilibria in the water-rock system and other calculations is indicated.

The relevance of the work is related to the issues of the groundwater’s chemical composition formation in environmental conditions, the solution of which, within the framework of the considered hypothesis of the interaction of water with rocks, is impossible without understanding the stage of water’s equilibrium with minerals of host rocks. This problem is particularly specific due to the wide distribution of fissured volcanogenic structures and salt lakes in the territory, as well as the dry climate. At the same time, existing hypotheses single out evaporation processes as the key factor leading to water salinization, ignoring all others. Meanwhile, this is not obvious for groundwater. The general theory of interaction in the water–rock system can reveal the mechanism of water’s different composition formation, distinguish different stages of salt accumulation, including the soda stage, which cannot be explained only by evaporation processes. To do this, it is necessary to calculate the degree of water saturation relative to the minerals of the host rocks. The aim of the research is to assess the equilibrium-nonequilibrium state of the natural waters in the territory with minerals of host rocks at different stages of evolutionary development, to determine the possible set of secondary minerals at each stage and to identify necessary hydrogeochemical parameters for their formation. In the future, the results will be used to study the mechanisms of groundwater formation. Objects. During chemical composition formation, groundwater goes through several stages of its development, among them: atmospheric (atmospheric waters as a source of nutrition), lithogenic (when interacting with host rocks) and evaporative (when interacting with lake waters that undergo evaporation). In order to trace the entire evolution of the composition, in addition to the directly groundwater of the upper dynamic zone (springs, wells and boreholes up to 70 m deep, 69 samples in total), atmospheric (6 samples), river (9 samples) and lake (10 samples) waters were also studied. Methods. Water’s macrocomponent composition was determined by modern standard methods: titrimetric, potentiometric, photometric, atomic absorption spectrometry with flame atomization and flame atomic emission spectrometry at the INREC SB RAS (Chita), microcomponent – by the ICP-MS method at TPU (Tomsk). Petrographic and mineralogical studies of host rocks were carried out using scanning electron microscopy at TSU (Tomsk). Physico-chemical modeling of equilibria in the water–rock system was calculated using the HydroGeo software package. Then the calculation results were compared with natural observations. Results. Thermodynamic calculations in the water–rock system showed that all natural waters of the Torey Lakes area from atmospheric precipitation to salt lakes are nonequilibrium with respect to primary aluminosilicates (especially basalts, which are found in the north of the study area), which they continuously dissolve throughout this interaction, and are in equilibrium with respect to secondary minerals they form (gibbsite, kaolinite, montmorillonites, various carbonates, chlorites, albite, microcline, muscovite, etc.). The paper introduces the main physicochemical parameters (chemical composition, pH and salinity of water) obtained by the authors in the calculations, which control the formation of a certain secondary mineral.

Link for citation: Lepokurova O.E., Ivanova I.S., Pyrayev A.N. Stable isotopes of hydrogen, oxygen and carbon when interpreting formation conditions of surface water bodies of Yamalo-Nenets autonomous region. Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 6, рр.7-19. In Rus. The relevance. Stable isotopes are widely used in geochemistry for solving various genetic problems, which is associated with the assumption of the constancy of the original isotopic composition of any element, subsequently changed under the influence of various processes. In the practice of surface water studies, isotope methods are used for solving not only direct genetic problems, but also for various related problems. In arctic regions affected by permafrost, water isotopes are increasingly being used to assess the contribution of melt water to the balance of total river flow, especially in conditions of accelerated melting, which leads to changes in the hydrological regime and the overall structure of the landscape. The analysis of the isotope composition of dissolved inorganic carbon is of particular research interest, since it gives an idea of the participation of organic matter released during the thawing of permafrost peat in isotope exchange with water. The joint use of the chemical and isotopic characteristics of water bodies will make it possible to study in detail the genesis, features of the formation and interaction of these waters with the environment. The main aim: clarification of the genesis and conditions of formation of surface water bodies in the Arctic regions of Western Siberia, subject to the influence of permafrost, using the composition of stable isotopes H, O, C. Objects: surface water bodies of the tundra and forest-tundra natural zones of the Yamalo-Nenets Autonomous Region. Field work took place in August 2020. Water samples for the isotopic composition were taken from three large rivers – Ob, Taz, Pur, and in the right tributary of Pur River – Ngarka-Khadytayakha, 7 large lakes (from 2500 to 300000 m2), 1 small thermokarst lake (12 m2) and from 3 depressions (the initial stage of formation of thermokarst lakes); and 2 soil cross sections. A total of 17 water samples. In addition, 5 peat samples were taken from one soil cross section from five depth intervals up to 55 cm. Methods. Chemical composition of water was analyzed by standard methods (titration, inductively coupled plasma mass spectrometry, photometry, ion chromatography and high-temperature catalytic oxidation method) at the Problematic Research Laboratory of Hydrogeochemistry of Tomsk Polytechnic University. The study of the isotopic composition of oxygen, hydrogen and carbon of water-dissolved carbon dioxide was carried out in the Analytical Center for multi-elemental and isotope research SB RAS using Isotope Ratio Mass Spectrometer FinniganTM MAT 253 equipped by H/Device and GasBench II for sample preparation. Results. Isotope composition of oxygen, hydrogen and carbon in waters and dissolved inorganic carbon for surface waters of the tundra and forest-tundra zones of the YaNAO are presented. It is shown that each object (soils, depressions, lakes and rivers) is characterized by individual intervals of δD, δ18О, δ13С (dissolved inorganic carbon) values, which indicates different specifics of their formation and allows them to be differentiated. Comparison with the already available data on δD, δ18O of atmospheric precipitation, surface water and snow in the region revealed that river and soil waters, in comparison with other water bodies, were formed in colder conditions. The δ13CDIC values indicated the presence of two sources of carbon in the surface waters of the region: biogenic (light) and soil diffusion, which inherits the isotopic composition of the atmosphere (heavy). The first one is dominates in soil waters, depressions, shallow lakes and, apparently, in stagnant river waters. In large lakes and in the active course of the river, soil diffusion CO2 is more pronounced. The effect of permafrost thawing in the region is demonstrated by lighter δD and δ18O values (thawed waters), as well as by lighter δ13СDIC values (additional biogenic carbon is released from soils and peat). A scheme of possible distribution and exchange of stable isotopes H, O and C in natural waters and dissolved inorganic carbon for investigated region was developed. The obtained results can be used for determining genesis of the region natural waters; for clarifying conditions of waters and dissolved inorganic carbon formation; for identifying permafrost degradation processes and evaluating its rate; for paleoclimate reconstructions etc.

The relevance. The river and lake waters of the Arctic regions of Western Siberia are enriched with dissolved organic matter, primarily humic acids, which are characterized by a good ability to form stable organomineral complexes. When studying the formation of the chemical composition of such waters, it is necessary to take into account the complex compounds that shift the equilibrium in geochemical processes (in dissolution, leaching, sedimentation and co-precipitation, etc.) towards the aqueous phase, thereby directly affecting the composition of waters. In the case of humic acids, a sufficient data on thermodynamic constants have been accumulated which made it possible to conduct numerical modeling. The main aim is to consider the features of the distribution of humic substances (fulvic and humic acids) in the surface waters of the region and to calculate the migration forms based on the available new data on the chemical composition. Other issues are to study in what quantity and what elements are bound by humic substances; and whether there are differences between the waters belonging to different river basins. We also determine the role of organic matter, mainly humic substances, in the formation of the chemical composition of waters. Objects: surface water bodies of the tundra and forest-tundra natural zones of the Yamalo-Nenets Autonomous District. The authors tried to cover the main stages of the surface water evolution in the direction of depression – large lakes – rivers, as well as consider the water bodies of different drainage basins of four main rivers – Taz, Pur, Ob, Nadym. As a result, 23 watercourses (large and small rivers) and 24 reservoirs (20 lakes of different sizes and 4 depressions) were studied. Methods. Chemical composition of water was determined by standard methods at the Basic Research Laboratory of Hydrogeochemistry of the Tomsk Polytechnic University, the analysis of fulvic acids and humic acids was carried out by titration to account for bichromate consumed for the oxidation of carbon of fulvohumic acids. The migration forms of humic substances and chemical elements were calculated using the HydroGeo software. Results. The features of distribution of humic substances in the direction of depression–lake–river in the main drainage basins of rivers in the north of Western Siberia were studied. The dissolved migration forms of humic acids relative to their concentrations were determined by thermodynamic calculations, and the forms of migrations of the main ions and trace elements were determined taking into account the content of humic acids, i. e. it is shown which part of them binds into organomineral complexes. It was determined that compounds with fulvohumic acids are the most common in all the described waters, but their maximum proportion is typical for depressions. Some of the trace elements are more prone to form organomineral forms than others: Cu, Ni, Mn, Li, Zn, Fe. Fulvic acids are more susceptible to complex formation. The patterns obtained must be taken into account when considering the conditions for the formation of these waters.

The relevance. When studying the formation of the composition of organic-rich waters, it is necessary to take into account organomineral compounds that shift the equilibria in geochemical processes (dissolution, leaching, precipitation and co-deposition, sorption, ion exchange, oxidation-reduction) towards the aqueous phase, thereby directly affecting the composition of waters. The main aim of the research is to calculate the forms of migration of basic ions and some micro-components, with an emphasis on organomineral complexes, based on available data on the composition of waters, including concentrations of fulvic and humic acids. Objects: groundwater of Permian terrigenous-coal-bearing deposits (Kolchuginskaya formation) Naryksko-Ostashkinskaya areas located at depths of 0,4–1,2 km in the zone of delayed water exchange, as well as overlying fresh underground zones of active water exchange, river and lake waters. Methods. The chemical and organic composition of water was determined by standard methods in the Problem Research Laboratory of Hydrogeochemistry of Tomsk Polytechnic University, the determination of fulvic acids (FA) and humic acids (GA) was carried out by titration based on bichromate consumed for carbon oxidation of fulvohumic acids. The forms of humic acid migration were calculated using the HydroGeo software package. Results. The migration forms of the main ions and, for the first time, humic acids contained in high concentrations in the natural waters of the Naryk-Ostashkin territory (Kuzbass) were determined by thermodynamic calculations. It was established that cations migrate in a simple ionic form, but in the zone of delayed water exchange at high concentrations of bicarbonate ion (soda water), a significant part (up to 50 %) begins to take their carbonate forms. Only iron forms compounds with fulvic acids in significant amounts (more than 1 %), but under specific geochemical conditions. Humic acids themselves, relative to their content in waters in % proportion, bind well into complex compounds. Fulvic acids are almost completely consumed, giving preference to Na, even in calcium waters. However, this has little effect on the general substance of Na itself. Humic acids mainly migrate with Mg and Ca, but the more soda composition of the waters, the more their amount remains in free form.

The relevance of the work is associated with the problem of fresh water resources shortage in arid regions, the solution of which is impossible without understanding the conditions and mechanisms of water’s chemical composition formation in the natural environment. The aim of the research is to supplement information on the origin and conditions of groundwater’s formation using the basis of new data on water’s stable isotopes (δ18О, δD) and dissolved carbon and sulfur (δ13C, δ34S). Study objects are groundwaters of the upper dynamic zone of the Torey Lakes (eastern Transbaikal region) – springs, boreholes and wells depth (no more than 70 m), partly rivers’ and lake’s waters. Methods. Isotopic studies of water and dissolved C and S were carried out using an isotope mass spectrometer Finnigan-MAT 252 (Germany) at the FEGI FEB RAS Analytical Centre; water’s chemical composition – using modern standard methods: potentiometric titration, atomic absorption, flame emission, potentiometric method, titration method at the INREC SB RAS. Results. New data on the isotopic composition (H and O) of groundwater in the upper dynamic zone of the Torey Lakes area, as well as dissolved C and S are presented. Altitudinal zonality is noted in isotope's distribution The conclusions related to the origin and formation conditions were presented based on the results obtained, as well as the data on partially lake’s and meteoric waters: water of infiltration with little influence of evaporation processes (mixing with lake waters). A fairly uniform isotopic composition of groundwater was noted, despite the differences in chemical composition. No relationships were found between isotopic composition and salinity, basic ions and pH within groundwater, however, the general evolution of the composition in the direction of «atmospheric–groundwaters–lake waters» is characterized, in addition to the increase in salinity and pH, by enrichment in isotopes 18О, 2Н, 13C.

The relevance of the research is related to the regional specificity of the coal deposit load and objects of the coal complex on water bodies. The data obtained make it possible to expand the understanding of the general regularities in the element’s distribution in the «water – coal bearing rock» system and further use them in various ecological and exploration studies. The aim of the research is to study the features of the component maximum amount distribution in the natural waters of the region and the composition of the host rocks, to estimate the rate of chemical element leaching from the rocks. Objects: surface and groundwater of the Naryksko-Ostashkinskaya area in the Kemerovo region, the most promising for coalbed methane production. Methods: modern methods for determining the water and rock chemical composition, including inductively coupled plasma mass spectrometry, as well as standard hydrogeochemical methods for calculating the concentration factors and water migration. Results. The paper introduces the data on 59 elements, including the micro-components of rivers, lakes and groundwater of different water exchanges: active, upper part and lower part (coal bearing rocks) of passive. When the water–rock interaction time increases, the salinity and the major ion and trace element concentrations increase as well. The calculated concentration coefficients relative to the average for groundwater leaching in a moderate climate made it possible to distinguish elements with a high level of accumulation: from major components, these are C, Na, Cl, Fe and the trace elements are Ga, Ba, Li, Zr, Pb, B, Sc, Ni, Br, Rb, Sr, Nb, Mo, I, Ag, Cd, Cs, Hg. The paper introduces as well the data on 48 elements of the coal bearing sandstones and siltstones, which, together with the literature data on some other elements, made it possible to obtain interesting relationships. For example, in a percentage relative to the total salinity, groundwaters of active water exchange contain 1–2 orders of magnitude more than in rocks: Cu, Ag, Cd, Sr, Sn, Sb, I, Cs, Hg, Pb. Taking into account water and rock composition, the coefficients of water migration were calculated, the series of migration of different types of waters were compiled, which did not reveal any fundamental differences. In all natural waters, they are highly mobile: Na, C, Cl, I, B, N, Br, Sr, Cd, Cu, Li, Mo, Ge, Zn; weakly mobile: Al, Ti, Zr, V, Nb, Eu, Mn, Si, Cr, Co, Fe, Rb.

Relevance. Dissolved organic matter almost always presents in waters and plays an important role in the formation of their chemical composition, while until recently it has received little attention. For the Kuznetsk Basin, the study of dissolved organic matter is very important due to the presence of coal deposits, which determines the regional specifics of the loads on water systems. The aim of the research is to study the dissolved organic matter distribution in the surface and groundwaters of the region. Methods. Chemical and organic composition of water was determined by standard methods in the Research Laboratory for Hydrogeochemistry of Tomsk Polytechnic University: dissolved organic carbon – by the method of high-temperature catalytic oxidation, oxygen demand chemical oxygen demand, biochemical oxygen demand – by titration methods. Fulvic acid and humic acid were determined by the titration method to account dichromate consumed for the fulvic and humic acid carbon oxidation. Results and conclusions. The paper introduces the data on dissolved organic matter indicators and fulvic acid and humic acid concentrations in river, lake and ground waters of the Kuzbass Naryksko-Ostashkinskaya area. It was shown that fulvic acids prevail, from 69 to 100 %, in all waters in composition of humic substances. The humic ones have a subordinate significance. Groundwater in zones with intensely fractured rocks is distinguished by the minimum values of all dissolved organic matter indicators (dissolved organic carbon, oxygen demand, chemical oxygen demand, biochemical oxygen demand) and relatively heterogeneous humic substances composition. River and lake waters have more homogeneous humic substances composition and narrow dissolved organic matter range values, despite differences in chemical composition and pH. For groundwater in zone of damped fracturing circulating within the coal deposits at depths of 400–1200 m, the highest dissolved organic matter indicators and relatively homogeneous fulvic and humic acid composition are characteristic. At the first stage of the research, there is no the relationship between the organic matter concentration and the salinity and all the waters chemical composition, pH and depth.