Composition Of Thermal Waters Research Articles

Regional Hydro-Chemistry of Hydrothermal Springs in Northeastern Algeria, Case of Guelma, Souk Ahras, Tebessa and Khenchela Regions

Hydrothermal units are characterized by the emergence of several large-flow thermo-mineral springs (griffons), each with varying temperature and physico-chemical characteristics depending on the point of emergence. It seems, however, that there is variability between the different systems, although it is not easy to characterize it because the variability within each system is high. The regional dimension of the chemical composition of thermal waters is, therefore, an aspect that has received very little attention in the literature due to the lack of access to the deep reservoir. In this study, we investigated the spatial variability, on a regional scale, in the characteristics of thermal waters in northeastern Algeria, and more specifically the hydrothermal systems of Guelma, Souk Ahras, Khenchela and Tébessa. Thirty-two hot water samples were taken between December 2018 and October 2019, including five samples of low-temperature mineral spring water. Standard physico-chemical parameters, major anions and cations and lithium were analyzed. The data were log-transformed data and processed via principal component analysis, discriminant analysis and unsupervised classification. The results show that thermal waters are the result of a mixture of hot waters, whose chemical profile has a certain local character, and contaminated by cold surface waters. These surface waters may also have several chemical profiles depending on the location. In addition to the internal variability in each resource, there are differences in water quality between these different hydrothermal systems. The Guelma region differs the most from the other thermal regions studied, with a specific calcic sulfate chemical profile. This question is essential for the rational development of these regional resources in any field whatsoever.

Assessing magmatic contributions to rift-related geothermal systems in collisional orogens: Insights from the Sangri-Cona rift, southern Tibetan Plateau

Fault-controlled geothermal systems in the Himalayan-Tibetan orogen could receive heat and material from deep-seated magmas due to crustal anatexis in orogenic settings. The near N-S trending rifts in southern Tibetan Plateau host abundant geothermal systems but potential role of residual magmas remains less constrained. Here, we evaluate magmatic contributions to geothermal systems in Sangri-Cona rift (SCR), the youngest rift in southern Tibetan Plateau, based on chemical and isotopic compositions of thermal waters from a south-to-north sampling profile. Our results show that the thermal springs in the central SCR have significant inputs from magmatic fluids, which account for high B concentrations and positive shift in δ18OH2O, while those in the southern and northern SCR are dominated by recharge of meteoric water. Water-rock interaction constrained by 87Sr/86Sr, hydrochemistry, and geothermometry results, suggests a hotter or deeper groundwater circulation path beneath central SCR than that of the southern and northern SCR. The identified magmatic fluid inputs, higher reservoir temperature, and higher degrees of water–rock interaction in the central SCR agree well with the presence of high conductivity anomalies at crustal depths of ∼ 10–30 km revealed by magnetotelluric surveys. Our findings provide geochemical evidence for the impact of lithospheric extension and associated geological and geophysical expressions (e.g., extension-induced exhumation of genesis domes that recorded crustal anatexis and upwelling of partially molten crustal channel flows) on modern geothermal systems in collisional orogens.

СОСТАВ И УСЛОВИЯ ФОРМИРОВАНИЯ АЗОТНО-КРЕМНИСТЫХ ТЕРМ АМГИНСКОЙ ГРУППЫ (СЕВЕРО-ВОСТОК ПРИМОРСКОГО КРАЯ)

The article presents new data on the ionic, microcomponent and isotopic composition of thermal waters of the Amga group classified as sodium-bicarbonate waters characterized by low mineralization (up to 0.2 g/l), high contents of silica (up to 24 mg/l), lithium, tungsten and molybdenum, and pH = 8.5–9.7. The influence of neotectonics and Quaternary magmatism on the composition and conditions of formation of nitrogen-siliceous thermal waters is shown. Using δD and δ18O values in thermal and background waters, their atmogenic origin was proved, and the source area of mineral waters was identified. The calculated deep reservoir temperature of 77–81°С indicates the formation of resources in the crust at significant depths (as much as 2.5 km). The efficiency of using the multicomponent geothermometry method for low-temperature reservoirs is shown.

Hydro-geochemistry and Related Processes Controlling the Composition of Thermal Waters in the Lake Natron Basin, Northern Tanzania

Lake Natron Basin (LNB) forms part of the eastern branch of the East African Rift System (EARS) in Tanzania. The basin is endowed with thermal springs flowing towards the lake from the western, northwestern, southwestern and eastern parts. The western, northwestern and south-western thermal springs emanate from fractures in the basaltic rocks while in the east, they originate from the western flank of the Gelai volcano. There are limited studies on these springs, thus their geochemical differences and distributions of physicochemical parameters are not well understood. A hydrogeochemical study was conducted to interpret available geochemical data from the LNB springs, including cold and thermal water to allow their geochemical characterization. Results have shown that LNB water is dominated by sodium (Na+), chloride (Cl-) and bicarbonate (HCO3-) ions. Three hydro-chemical facies have been identified forming Na-Cl, Na-HCO3 and Ca-HCO3 water types. This study has also revealed that thermal water in the north-western part of the basin is highly mineralised and gradually becomes diluted toward south-west and south due to groundwater incursion. Water-CO2-rock interaction affects the overall chemistry of thermal water leading to HCO3- water, particularly in the east of the basin. While few springs from the western side of the basin indicated maturity of the thermal waters, other springs indicated mixed Cl-HCO3/peripheral water; while the cold waters are HCO3 type. It is recommended to take precautions when planning geothermal projects to avoid corrosion and scaling of production facilities. Similarly, mixing or dilution of thermal water with shallow groundwater can affect the temperature and the composition of Cl-.

Decadal Monitoring of the Hydrothermal System of Stromboli Volcano, Italy

AbstractIn active volcanoes, magmatic fluids rising toward the surface may interact with shallow waters, thereby forming hydrothermal systems that record variations in magma dynamics at depth. Here, we report on a data set comprising the chemical and isotopic composition of thermal waters and dissolved gases from Stromboli Island (Aeolian Volcanic Arc, Southern Italy) that spans 14 years (2004–2018) of continuous observations. We show that the shallow thermal aquifer of Stromboli results from variable mixing between meteoric water, seawater and magmatic fluids. Gas‐water‐rock interactions occur, which induce a large spectrum of variation in both water and gas chemistry. These shallow processes do not affect the 3He/4He of helium dissolved in thermal waters, which records a magmatic signature that varies in response to changes in magma supply at depth. We show that in periods of more intense volcanic activity, the helium isotopic composition of thermal waters approaches that of the gas emitted from the magma residing at 7–10 km depth. Investigation of hydrothermal waters at active volcanoes is a promising tool to examine magmatic fluids and their shallow circulation, as well as to evaluate the state of activity of a volcano, particularly when summit areas are inaccessible.

An integrated geochemical spatial and temporal survey of thermal springs to characterize the geothermal resource of a volcano (Piton des Neiges, Réunion Island)

Geothermal exploration can be challenging in the absence of obvious surface indicators of a high enthalpy geothermal resource such as geysers, fumaroles or thermal springs with temperatures near 100 °C. This is the case at the Piton des Neiges volcano (Réunion Island), which displays evidence of hydrothermal activity mostly as thermal springs with temperatures not exceeding 50 °C, affected by mixing and reequilibration, and emerging in a complex geological framework, resulting from the polygenic history of this dormant volcano. Yet, these thermal springs keep a partial record of the reservoir geochemistry. Here, we propose an exploration method to set this thermal signature apart from the contribution of other processes and trace back the equilibrium conditions, enabling us to locate thermal fluid circulations, and evaluate their temperature and availability. We report its application at Piton des Neiges volcano. We led an extensive geochemical survey which nearly doubled the number of thermal springs reported on the volcano and dramatically extended the existing geochemical database in space and time. In tandem, we also monitored δ18O and δD values in rainwaters and thermal springs over two years to compare their temporal variations.Our surveys show that the repartition of thermal springs is controlled by only one of the volcanic rift zones (the N30°E axis), which is thus identified as the heat source of hydrothermal circulations. This N30°E rift zone is also a preferential pathway for the degassing of mantellic CO2. In addition, the composition of thermal waters is influenced by syenite intrusions along the rim of the caldera, acting as drains for the uprise of hydrothermal waters. O, H and Sr isotopic signatures of springs show that the geothermal resource of Piton des Neiges is in fact made of two independent and unconnected hydrothermal systems on the northern and southern circular depressions of the volcano (the cirques of Salazie and Cilaos, respectively). Their recharge is meteoric, multi-year, and mostly achieved by cyclonic events. Thermal waters experience reequilibration during their ascent and various degrees of CO2 input or degassing. Last equilibrium temperatures of water/rock interaction, estimated by multicomponent geothermometry, reach up to 125 ± 6 °C in the cirque of Salazie, and up to 141 ± 15 °C in the cirque of Cilaos, with possibility for hotter waters before reequilibration. Taken together, our results suggest that the most promising target for future exploration is located in the cirque of Cilaos, along the caldera rim, and in proximity of syenite intrusions.With a thorough prospecting of thermal springs, a comprehensive geochemical study and a geochemical monitoring of the different water reservoirs, we improved our understanding of the geothermal resource and identified future exploration targets at Piton des Neiges volcano.A separation scheme for strontium and light rare earth elements and its application to the isotopic analysis of strontium and neodymium in silicate rocks are presented. This method benefits from the selectivity and high capacity of two newly introduced extraction Chromatographic materials, referred to as Sr.Spec and TRU.Spec, respectively. These afford a straightforward separation of Sr and Sm + Nd with high yield, good purity and satisfactory blank levels, on very small (0.25 ml) columns using small volumes of solutions of a single mineral acid, HNO3. The validity of the method is illustrated by the measurement of 87Sr/ 86Sr and 143Nd/144Nd ratios in twelve international standard reference materials.

Bacterial Communities in a Gradient of Abiotic Factors Near a Sulfide Thermal Spring in Northern Baikal

The structure and diversity of microbial communities developing in the combined gradient of temperature (44–19 °C), as well as concentration of oxygen (0–10 mg/L) and hydrogen sulfide (33–0.7 mg/L), were studied in the thermal sulfide spring on the coast of Northern Lake Baikal. The predominance of bacteria participating in sulfur and nitrogen cycles and significant changes in the composition of microbial communities were noted at changing physicochemical conditions. Thiovirga sp. (sulfur-oxidizing bacteria, up to 37%) and Azonexus sp. (nitrogen-fixing bacteria, up to 43%) were dominant at high temperatures and concentrations of hydrogen sulfide in two hydrotherms. In addition, a significant contribution of the Rhodocyclaceae family (up to 51%) which is involved in the denitrification processes, and Acetoanaerobium sp. (up to 20%) fixing carbon oxide were found in the spring water. In the stream, mainly oxygenic cyanobacteria (up to 56%) developed at a temperature of 33 °C, in the presence of hydrogen sulfide and oxygen. In addition, sulfur bacteria of the genus Thiothrix (up to 48%) found in epibiotic communities of benthic animals of Lake Baikal were present here. Thiothrix sp. formed massive fouling in the zone of mixing lake and thermal waters with a significant contribution of hydrogen-oxidizing bacteria of the genus Hydrogenophaga (up to 22.5%). As well as chemolitho- and phototrophic bacteria, chemoorganotrophs (phyla Firmicutes, Chloroflexi, Desulfobacterota, Nitrospirota, Fibrobacterota, etc.) have been identified in all communities. The chemical parameters of water in spring and coastal zones indicate a significant change in the composition of thermal waters occurring with the participation of diverse microbial communities that contribute to the assimilation of inorganic components of mineral thermal waters.

The Formation of the Composition of Thermal Waters of Present-Day Volcanoes Based on the Example of the Golovnin Caldera, Kunashir Island, Kuril Islands

The Formation of the Composition of Thermal Waters of Present-Day Volcanoes Based on the Example of the Golovnin Caldera, Kunashir Island, Kuril Islands

Calcium isotopic geochemistry of geothermal systems in the tectonically active southeastern Tibetan Plateau

The global Calcium (Ca) cycle is closely coupled to the carbon cycle, and Ca isotopes have potential in tracing it. Even though groundwater is one of the main reservoirs of Ca at the Earth's surface, few data are available for groundwater, and the behavior of Ca and its isotopes in geothermal systems remains unknown. Here we analysed the stable Ca and radiogenic Sr isotope compositions of thermal waters distributed along the Jinsha and Yalong river valleys in the southeastern Tibetan Plateau. The Ca isotopic composition of the thermal water ranges from 0.45 to 2.16 ‰ (δ44/40Ca values relative to SRM 915a). The thermal waters collected from carbonate aquifers have higher δ44/40Ca values than bedrocks, which was attributed to secondary carbonate precipitation accompanied by CO2 degassing. In contrast, δ44/40Ca values in thermal waters collected from clastic and igneous rocks are similar to bedrock. Despite some thermal waters undergoing secondary silicates formation and CaNa ion exchange, such processes maybe not play a significant role in governing the Ca isotopic composition of these thermal waters. This suggests that Ca isotopes can be used to trace secondary carbonate precipitation driven by CO2 degassing (e.g. travertine) in geothermal systems located in tectonically active areas.

Volcanic Activity of Usu Volcano and Fluctuations of Groundwater Level, Temperature, and Chemical Composition of Thermal Water at Toyako Onsen, Hokkaido, Japan

The relationships between eruptive activities and changes in groundwater level, temperature, and chemical composition of thermal water at Toyako Onsen are discussed in relation to the 1977-1978 and 2000 eruptions of Usu volcano, Hokkaido, Japan. The temperature and chemical composition of thermal water observed since the 1977-1978 eruption are found to have changed after the eruptions. The groundwater levels in the hot spring wells, observed before the 2000 eruption, are found to have changed approximately six months before the eruption. Changes of groundwater level, which reflect pore water pressure, are generally faster than those of the temperature and chemical composition of thermal water attributed to fluid flow. However, thermal water flow during the 2000 eruption of Usu volcano was probably triggered as fast as propagation. Because the thermal water at Toyako Onsen is affected by the eruptive activities of Usu volcano, understanding the relationship between volcanic activity of Usu volcano and changes in temperature, chemical composition and groundwater levels of the thermal water is useful for inferring volcanic eruption and activity of Usu volcano.

Formulation and rheological evaluation of liposomes-loaded carbopol hydrogels based on thermal waters

The aims of this study were to develop topical liposomal hydrogels based on thermal waters (TWs) acquired in the region of Biskra (Northeast Algeria) and also to investigate their rheological properties. Liposomes containing two highly mineralized thermal waters, Baraka (BTW) and Salhine (STW), were prepared by probe sonication using phosphatidylcholine (PC) and cholesterol (Chol), plain or mixed with phosphatidylglycerol (PG). Based on their lipid composition, obtained liposomes presented vesicle sizes of 60 nm, a low polydispersity index, and various negative zeta potentials. It was noted that with increasing counterions charge in TWs the zeta potential of liposomes decreased toward neutral values. Carbopol (1%, w/w) hydrogels prepared with BTW, STW, and also demineralized water (placebo hydrogel) showed a non-Newtonian behavior, pseudoplastic fluid adjusted to Carreau model. The composition of thermal waters influenced highly the rheological properties of Carbopol hydrogels. Liposomal hydrogels were prepared by dispersing liposomes in hydrogels formulated with the same encapsulated thermal water. Regardless of composition or lipid concentration of added liposomes, the viscosity and viscoelastic parameters of Carbopol hydrogels changed negligibly. Indeed, liposome composition and lipid concentration seemed to have no effect on the rheological properties of Carbopol hydrogel in the presence of an important charge of cations. Hence, hydrogels and liposomal hydrogels based on thermal waters had suitable rheological properties for topical application and delivery of minerals in the skin.

Hydrogeochemical characteristics and evaluation of the geothermal fluids in the Gazlıgöl geothermal field (Afyonkarahisar), Western Anatolia, Turkey

The Gazlıgöl geothermal field located in 20 km northern of Afyonkarahisar in Western Anatolia region of Turkey is one of the most important geothermal areas in the Afyon-Akşehir Graben on the basis of potential. The present study has been performed to investigate the hydrogeochemical and isotopic characteristics and evaluate the origin, reservoir temperature and processes controlling the chemical composition of thermal waters of the Gazlıgöl geothermal field. Discharge temperature, electrical conductivity and pH of the thermal waters vary from 58.5 to 74 °C, 3910 µS/cm to 4050 µS/cm and, 7.05 to 7.54, respectively. The Gazlıgöl thermal waters are chemically of Na-HCO3 type, with high salinity, while the cold waters have mainly Ca-Mg-HCO3, Ca-Na-HCO3 and Ca-Mg-HCO3-SO4 types, with low salinity. Geochemical processes controlling chemical composition of the thermal waters are mainly water-rock interactions including dissolution and/or weathering of mostly silicates and partially carbonates and ion-exchange reactions. Besides, the bacterial sulfate reduction is another main process leading to the depletion of SO4 in the thermal water. Higher contents of some minor elements in the thermal waters, such as F, B, Li, As and Sr, are probably derived from enhanced water-rock interaction, and the minor elements can be regarded as indicator of residence times and flow paths.Geothermometer applications including quartz geothermometers and SiO2-K2/Mg, mineral saturation state and silica enthalpy mixing models provide the most reliable estimations of reservoir temperature in the varying of 100-150 °C for the Gazlıgöl thermal waters. Accordingly, the Gazlıgöl geothermal system can be classified as a low-moderate geothermal resource. The isotope data (δ18O, δ2H and 3H) of the thermal waters point to their deep circulating meteoric origin, and let estimating of recharge elevation varying from 1300 to 1400 m.a.s.l. These elevations suggest the mountainous region in the north-northeastern of the study area as the recharge area of the geothermal system. Long-term circulation of meteoric waters within the aquifer is confirmed by low tritium ratios (< 1 TU) of the thermal waters although the fluids do not achieve thermodynamic equilibrium. Based on the all gathering data, a conceptual model of the functioning of geothermal system has been constructed. Accordingly, geothermal fluid is heating at deep zones due to the high geothermal gradient caused by active fault systems and heated waters rise toward the shallow levels through faults and fractures. During moving to the surface, they undergo conductive cooling by mixing with the cold groundwater at shallow depths and during contacting with the colder rocks.

Hydro-geochemical criteria of thermal waters in Guba-Khachmaz region

Beginning from 1970-1980s as a result of the studies carried out in Guba-Khachmaz region, the thermal waters with the temperature of more than 80 оC were revealed on the Earth surface. These waters are characterized with high recovery rate and have natrium-chloride chemical composition. The chemical composition of thermal waters change appropriately depending on the zone and depth. Thermal waters of Mesozoic (Cretaceous) complex with natrium-chloride composition in Cenozoic sedimentary complex (Upper Productive Series) transfer to the waters with sulfate-natrium composition. Such a geochemical approach is clearly reflected towards the deepening of the sedimentary complex of Productive Series of Khachmaz upland with regard to both anions and cations. Based on the indexes of high temperature and recovery rate, as well as on the parameters of permanent and temporary condition in touristic purposes, the construction of a health resort complex in the territory of Nabran on shore of the Caspian Sea is possible.

Stable isotope and anthropogenic tracer signature of waters in an Andean geothermal system

In the present study, we combined stable isotopes and anthropogenic tracers to investigate the origin, residence times, and evolution of thermal waters in the Lonquimay-Tolhuaca Volcanic Complex (LTVC) of the southern Chilean Andes. A total of 20 water samples from springs discharging at a broad range of temperatures (8–96 °C) were collected and analyzed for major ion geochemistry, stable isotope ratios (δ2H, δ18O, δ13CTDIC), dissolved chlorofluorocarbons (CFCs) and sulfur hexafluoride (SF6). In addition, we compiled all available data on the isotopic composition of precipitation in the region to derive the local meteoric water line. Coupled with a Rayleigh-fractionation model of precipitation, we provide constraints on the elevation at which infiltration and recharge to the system is produced. δ13CTDIC values are consistent with the bulk of dissolved inorganic carbon being derived from the addition of soil CO2 to an atmospheric source, while magma degassing and boiling processes are evidenced in samples discharging directly on the flanks of volcanoes. The isotopic composition of thermal water, once heated at depth, is further modified by CO2 degassing and carbonate precipitation during ascent. All geothermal samples contain low but detectable concentrations of CFC-11, CFC-12, CFC-113, and SF6, suggesting the addition of only a small fraction (2–22%) of modern meteoric water. The discharge temperature of naturally outflowing springs in the LTVC correlates directly with the age distribution of the water samples. This difference in residence times is attributed to the distinct subsurface circulation pathways of each water type—i.e., the shallow, diffuse flow of cold groundwater vs. the deep, focused circulation of thermal water along fault zones. Conduit flow along high vertical permeability networks allows hydrothermal fluid to remain relatively unmixed with shallow meteoric water during ascent. Data from this study confirm that fault-fracture meshes with different orientations exert a first order control on the residence times, ascent, and mixing rates of thermal waters in this segment of the Andean Cordillera, thus modulating their chemical and isotopic signature. Additionally, our results show that the combined use of conventional hydrogeochemical and isotopic data with environmental tracers, including anthropogenic CFCs and SF6, is a powerful tool to better understand the dynamics of geothermal systems.

КРЕМНИЕВЫЕ ТЕРМАЛЬНЫЕ ВОДЫ И ИХ ВЛИЯНИЕ НА ЗДОРОВЬЕ ЧЕЛОВЕКА

The unique mineral thermal water has been researched. The composition of thermal water has been studied, its effect on human health has been described. This thermal water belongs to the hydrocarbonate-silicon type. The total silicate content is more than 120 mg/l, which is one of the highest rates for thermal springs in our country. The low solubility of silicic acid is compensated by the ability of silicon to form positively charged colloids, which neutralize microorganisms and promote the precipitation of heavy metals. Perhaps this factor is responsible for the insignificant presence of heavy metals in water. The medical indications and contraindications for this type of balneological treatment are described.

НОВЫЕ ИЗОТОПНО-ГЕОХИМИЧЕСКИЕ ДАННЫЕ ПО ТЕРМАЛЬНЫМ ВОДАМ ТАЛЬСКОГО МЕСТОРОЖДЕНИЯ (МАГАДАНСКАЯ ОБЛАСТЬ)

In this paper, we summarize new data on the chemical and isotopic composition of thermal wa-ters of the Talskoye deposit in the Magadan Oblast. We were the first to obtain the data on the content of stable oxygen (δ18O) and hydrogen (δD) isotopes in thermal and background waters, as well as oxygen (δ18O) and carbon in bicarbonate ion (δ13C), even though this is the largest ex-ploited deposit of low-mineralized alkaline nitric thermal waters in the region. The thermal water is fresh (M = 980 mg/l), alkaline (pH = 8.9), hydrocarbonate-chloride-sulphate sodium with a high content of fluorine (up to 17 mg/l) and silicic acid (up to 152 mg/l). The deposit is fed by atmospheric precipitation; we did not find traces of melting underground ice supply. A sequential scheme for calculating the temperature of a deep reservoir was applied, which allowed the temperature of water formation to be constrained at 108 °C suggesting an input of fluids rich in potassium and sulfate ion.

ЭКОТУРИСТИЧЕСКОЕ ЗНАЧЕНИЕ ТЕРМАЛЬНЫХ И МИНЕРАЛЬНЫХ ВОД ЮЖНОГО СКЛОНА (МЕЖДУРЕЧЬЕ МАЗЫМЧАЙ И ШИНЧАЯ БОЛЬШОГО КАВКАЗА)

In the article, in the socio-geographical direction, issues are discussed about the territory of mineral and thermal waters on the southern slope of the Greater Caucasus, the chemical composition of waters, temperature, the possibility of using it in the treatment of some diseases, ecotourism value and rational use of thermal waters. Ecotourism can provide real financial support for nature conservation and increase the importance of natural sites that should be preserved in their original form. For the rational use of thermal waters in the research area, targeted measures should be taken at the state level, in order to eliminate the shortages in this area and to ensure its further development, entrepreneurs should be provided with very low interest rates, long-term loans. In the study of thermal and mineral waters, the merit of geologists, hydrogeologists and balneologists was great; in the modern period, scientists and specialists mainly refer to information obtained 50-100 years ago. There are very few innovations in this area. Favorable climatic conditions of the region, ecotourism conditions, large forests, natural and historical monuments, high seismicity of the territory, deforestation processes, and so on. according to specifications differ. The study area (especially the Gakh region) is the region with the richest thermal and mineral water resources in Azerbaijan, as well as ecotourism and balneological tourism. The Gakh region in the northwestern part of Azerbaijan, along with other natural benefits, is distinguished by its thermal and mineral springs and balneological value. The well-known hydrogen sulfide, hydrocarbonate groups of the Ilisu thermal waters, as well as the resort-tourist and balneological significance of the mineral springs on the left and right banks of the Kurmukh River near the village of Alibeyli and in the so-called boiling zone have not yet been fully utilized. Thermal and mineral waters, with the exception of a few, were used in a very primitive form mainly by the local population. The use of such waters should be carried out under the supervision of a physician for his purpose, and the taking or not taking medicinal baths should be especially controlled. Therefore, the chemical composition of thermal waters must be periodically checked by professional specialists.

НОВЫЕ ИЗОТОПНО-ГЕОХИМИЧЕСКИЕ ДАННЫЕ ПО ТАВАТУМСКИМ ТЕРМАЛЬНЫМ ВОДАМ (МАГАДАНСКАЯ ОБЛАСТЬ)

The article presents the results of isotope-chemical research of the Tavatum thermal water deposit (coast of the Sea of Okhotsk, Magadanskaya Oblast), as well as surrounding underground and surface waters. For the first time, data on the content of isotopes of oxygen and hydrogen in the underground and surface waters were obtained, and the analysis of trace elements was performed. The results show that the chloride sodium-calcium mesohalinous thermal waters of the Tavatum deposit are atmogenic; two processes can be considered as the main processes of the chemical composition formation: 1) involvement of deep brines (including cryopeg waters) and 2) cationic exchange in the interaction of sea waters (buried during marine transgressions in the Holocene) with rocks. In the chemical composition of thermal waters, there are indicator chemical elements reflecting the impact of deep high-temperature processes. The temperature of the deep fluid estimated by different geothermometers is 117 to 128°C, and the depth of formation is at least three kilometers.

Hydrogeochemistry and Related Processes Controlling the Formation of the Chemical Composition of Thermal Water in Podhale Trough, Poland

The most promising Polish region in terms of its geothermal resource potential is the Podhale Trough in the Inner West Carpathians, where the thermal water occurs in the Eocene-Mesozoic strata. The origin and conditions of formation of the chemical composition of the thermal water are different in a regional scale due to the impact of infiltrating water on the chemical compounds present in nearby thermal intakes, chemical processes responsible for the concentration of major elements and residence time. The article presents the regional conceptual model in regard to the factors controlling the chemistry of thermal water from Podhale Trough and the conditions of its exchange. It was allowed by performing the hydrogeochemical characteristics of studied water and analyzing its changes according to flow direction from HCO3-Ca-Mg type to SO4-Cl-Na-Ca and SO4-Ca-Mg types. The hydrogeochemical modelling was also made allowing identification of the impact of reservoir rocks on the formation of the chemical composition. For confirmation of the theories formulated and for more accurate interpretation of the results obtained from hydrogeochemical modelling, hydrochemical indices were calculated, i.e., rHCO3−/rCl−, rNa+/rCl−, rCa2+/rMg2+, rCa2+/(rCa2+ + rSO42−) and rNa+/(rNa+ + rCl−). The results revealed the most important processes evolving the chemistry of thermal water are progressive freshening of the thermal water reservoir, which in the past was filled with salty water, dissolution of gypsum, and ongoing dolomitization. Conducted research presents the important factors that in the case of increased exploitation of thermal water in the Podhale Trough, may influence the quality of thermal water in terms of its physical and chemical parameters.

Hydrochemical features of thermal waters in Kur-Gabyrry and Ganykh-Ayrichay interfluve region

Studied areas are characterized with complicated geological structure. The formation of thermal waters in Mesozoic-Cenozoic sediments is impacted by a number of factors, particularly tectonic penetration of Ganykh-Ayirichay deep fault. By their chemical composition the thermal waters in Kur-Gabyrry and Ganykh-Ayrichay interfluves are predominantly of natrium-chloride and potassium-chloride type. The gas composition of thermal waters in the territory differs by the depth and distribution area of separate components (nitrogen, methane, hydrogen sulfide etc.). The concentration of thermal waters in the territory is also quite various. The temperature of thermal waters in Kur-Gabyrry and Ganykh-Ayrichay interfluves on the Earth surface reaches up to 50 оС and is characterized with high recovery rate and dynamic regime. In this view, thermal waters can be used as an alternative source of thermal energy in the regions’ economy. Moreover, thermal waters have industrial significance. In a modern sanatorium-resort complex they may be used medicinally.