Thermal Groundwater Research Articles

Hydrogeological uniqueness of groundwater in the Cherkashinsky area of the Tobolsk district of the Tyumen region

Intensive development of the Tyumen region, where the largest West Siberian megabasin is located (the Tyumen groundwater deposit is the largest in Russia), violates the natural state of ecosystems, in particular groundwater, which is the basis of an ecosystem vital to the health of the planet. Currently, the significance of groundwater is often underestimated. Professor Robert Reinecke from Johannes Gutenberg University Mainz emphasizes that groundwater should be considered as a crucial ecosystem. This is because groundwater is a major ecosystem itself, also it plays a critical role in the earth surface. So what is the hydrogeological uniqueness of the groundwater of the Cherkashinsky area in the Tobolsk district of the Tyumen region?Mineral and thermal groundwater, historically termed "medicinal water," are essential. In the early 20th century, "mineral water" was synonymous with "medicinal water." Today, groundwater is utilized not only as a mineral resource for extracting valuable components like bromine and iodine but also as technical water. Technical water have special requirements. This is due to the need to assess the geochemical compatibility of formation fluids and injected fluids, because forecasting equilibrium can help prevent problems of salt deposition in oil fields. The difficult procedure for determining the compatibility of injected water and formation water complicates the operational use of hydrochemical data, in especially in monitoring calcite precipitate.The aim of this article is to present the groundwater composition and evaluate the geochemical compatibility of formation fluids and injected fluids in the Cherkashinsky area. Studying this science topic, we mostly used method of atomic-absorption analysis and the geochemical compatibility of formation fluids and injected fluids. This study examines the value of concentration and potential accumulation of micro-components (bromine and iodine) in groundwater, defined by the geological and hydrogeological conditions of this area. Additionally, we have identified a computational method of compatibility of mixed waters based on calcite and gypsum. Also, we showed the dependency of calcium salt solubility in a multi-component mixture on temperature, pressure, and the partial pressure of carbon dioxide.

Stereochemistry of phosphatidylglycerols from thermotolerant bacteria isolated thermal springs

Phosphatidylglycerol (1,2-diacyl-sn-glycero-3-phospho-glycerol) (PG) is one of the most abundant lipids in biological membranes. However, the chirality of the carbon atom in glycerol phosphate differs among the three kingdoms: bacteria, archaea, and eukaryotes. It is commonly assumed that archaea, as well as bacteria and eukaryotes, produce only one isomer of PG. Archaeal membranes consist of phospholipids with glycerol-1-phosphate in the S configuration, while the phospholipids of the other two kingdoms contain glycerol-3-phosphate with (R) stereochemistry. Another chiral atom is found in glycerol with non-esterified hydroxy groups. Considering the high temperatures that accompanied the origin of life on Earth, it becomes obvious that it is necessary to clarify the importance of membrane lipids in early evolutionary times. To reconstruct the effect of high temperatures on membrane lipids, it is ideal to use microorganisms originating from a thermophilic environment analogous to the early Earth, such as the thermal groundwater of the famous spa town of Karlovy Vary. Here, we prepared all four isomers of PG, i.e., (R,S, R,R, S,R), and (S,S), by organic synthesis and analyzed the representation of individual molecular species in seven bacteria isolated from the Karlovy Vary thermal springs using chiral chromatography - mass spectrometry. Our results provide evidence that five of these strains produce all four isomers of PG and that this production is highly dependent on the cultivation temperature. Subsequent analysis by chiral chromatography revealed that the ratio of isomers, enantiomers, and diastereoisomers depends on the cultivation temperature of individual strains.

GEOCHEMISTRY OF GROUNDWATERS AND SURFACE WATERS, AND GROUND ICE OF THE OKA PLATEAU (Eastern Sayan, Russia)

The study area is located in the Eastern Sayan hydrogeological folded area. The objects of the study were groundwaters, surface waters and ground ice in the Sentsa River basin on the Oka Plateau. Cold and thermal groundwaters are associated with Proterozoic and Paleozoic metamorphic and igneous rocks. Their discharge as springs occurs in the river valleys along fault zones. Ground ice was studied in mineral frost mounds (lithalsas) composed of clays, clayey silts and silts of lacustrine-alluvial and fluvioglacial genesis. It has been established that thermal and cold groundwaters have HCO3 Ca-Na compositions, river and lake waters, as a rule, have HCO3 Ca-Na compositions, and ground ice melts – HCO3, SO4-HCO3 and NH4-HCO3 Ca. Thermal waters are largely enriched in Li, Be, B, Si, Mn, Ga, Ge, Se, As, Br, Rb, Sr, Cs, Ba and all REE relative to river and rain waters, and have the highest values of trace elements enrichment factor (EFREE). The latter shows that atmospheric precipitation participates in the formation of the composition of groundwaters (cold and thermal) and surface waters. The specificity of the geochemistry of ground ice is determined by the composition of precipitation, the injection of ice-forming groundwater from taliks, the interaction in the water-rock system, and the presence of organic matter in unconsolidated sediments. The participation of river water and groundwater in the formation of the frost mound ice core is also evidenced by similar values of stable isotopes (δ18O, δD) in surface water, groundwater and ground ice. The 3He/4He ratio points to a possible influx of mantle helium into thermal waters, and δ13С points to the magmatic and thermometamorphic mechanisms of carbon dioxide accumulation in thermal waters. The 87Sr/86Sr ratio in travertines indicates a significant contribution of intrusive rocks to the formation of fluid composition.

Spatial analysis of thermal groundwater use based on optimal sizing and placement of well doublets

Spatial analysis of thermal groundwater use based on optimal sizing and placement of well doublets

Hydrogeological Characteristics of the Makaresh Carbonate Karst Massif (Central Albania)

Carbonate rocks cover about 23% of Albania, with exploitable karst water resources estimated at 2.84 × 109 m3/year (about 65% of the total exploitable groundwater resources in the country). The Kruja tectonic zone is characterized by the presence of SE–NW-oriented carbonate structures, rich in fresh and thermal groundwaters. More than 80% of the thermal springs in Albania are present in this tectonic zone. One of its most interesting carbonate structures, with the presence of both cold and thermal waters, is the small karst structure of Makaresh, with a surface of 22 km2. The purpose of this article is to describe the hydrogeological characteristics of this massif; based on the physico-chemical characteristics, groundwaters of the study area are classified as cold waters (belonging to the local flow system) and thermal waters (originating in intermediate/deep flow systems). The former are mainly of HCO3-Ca or HCO3-Ca-Mg type (electrical conductivity 580–650 μS/cm, Temperature 13.9–16.6 °C). Thermal waters are mainly of the Cl-Na-Ca type (EC 7200–7800 μS/cm, T 18.5–22.5 °C); they are further characterized by high hydrogen sulfide concentration, up to about 350 mg/L. The presence of two groundwater types in the Makaresh massif is connected to the presence of two groundwater circulation systems. The main factors of the groundwater physico-chemical quality are the dissolution of rocks and minerals contained therein, the presence of hypogenic speleogenesis, and the mixing of the groundwater of the two systems. The hydrogeological studies proved that karst rocks contain considerable freshwater resources, partly used for water supply. Thermal waters are not currently exploited due to their temperature, but they are potentially suitable for thermal uses by drilling boreholes to a depth of about 1000 m.

Lithium Distribution in Thermal Groundwater: A Study on Li Geochemistry in South Korean Deep Groundwater Environment

Lithium Distribution in Thermal Groundwater: A Study on Li Geochemistry in South Korean Deep Groundwater Environment

Lithology controls on the mixing behavior and discharge regime of thermal groundwater in the Bogexi geothermal field on Tibetan Plateau

Lithology controls on the mixing behavior and discharge regime of thermal groundwater in the Bogexi geothermal field on Tibetan Plateau

Hydrogeochemistry and isotopic assessment of a new geothermal prospect in rancho Nuevo (Guanajuato-Central Mexico)

Hydrogeochemistry and isotopic assessment of a new geothermal prospect in rancho Nuevo (Guanajuato-Central Mexico)

A multidisciplinary geochemical approach to geothermal resource exploration: The Spezzano Albanese thermal system, southern Italy

A multidisciplinary geochemical approach to geothermal resource exploration: The Spezzano Albanese thermal system, southern Italy

GROUNDWATER OVEREXPLOITATION OF THE CONTINENTAL INTERCALACRY AQUIFER. A CASE STUDY FROM GHARDAIA, ALGERIA

Since the late 1999, extensive groundwater extraction within the Sahara aquifer system has been investigated. In this study we analyze the overexploitation of the thermal groundwater stored in the Continental Intercalary aquifer in the Algerian province of Ghardaia. The Saharan aquifer system is recognized by a large number of over 8800 boreholes and springs, on which 3500 operate the Continental Intercalary series and 5300 operate the Terminal complex. This work describes the groundwater order problem of overexploitation and the flows that exploit this hydrothermal system to be identified and analyzed. We have negative impacts on groundwater in that region due to the practice of certain activities which directly affect the quantity causing the water level of the aquifer to be lowered. Using theoretical context, water quality status can be assessed and recommendations suggested. Results show that we have 387.86 million m3/yr of flow today which is determined 30 m drawdowns. Measures need to be taken until the effects of the appeal become irreversible and the legal system instruments need practical applicability to prevent this context from extending to other areas.

Hydrochemical Indicator Analysis of Seawater Intrusion into Coastal Aquifers of Semiarid Areas

Saltwater intrusion into groundwater systems is a problem worldwide and is induced mainly by human activities, such as groundwater overexploitation and climate change. The coastal Los Planes aquifer in the southern part of the Baja California Peninsula (Mexico) is affected by seawater intrusion due to more than 40 years of groundwater overexploitation. A dataset of 55 samples was compiled, including 18 samples from our campaigns between 2014 and 2016. Several methods exist to define the impact of seawater in a coastal aquifer, such as the “seawater fraction”, the “Chloro-Alkaline Indices”, the “Hydrochemical Facies Evolution Diagram”, and the “Saltwater Mixing Index”. These methods provide reasonable results for most of the coastal zone of the Los Planes aquifer. A slight increase in mineralization was observed from 2014 to 2016 compared with the situation in 2003. However, in its northwestern part, samples from hydrothermal wells were not recognized by these methods. Here, the aquifer is affected mainly by thermal water with elevated mineralization, introduced through the El Sargento fault, a main fault, which cuts through the study area in the north–south direction. By considering known hydrothermal manifestations in the interpretation, samples could be classified as a combination of four end-members: fresh groundwater, seawater, and the composition of two types of thermal water. One thermal endmember with very low mineralization coincides with the thermal water described from the Los Cabos Block, where meteoric water represents the source (found in the Sierra la Laguna). The second endmember is comparable to coastal thermal manifestations where seawater represents the main source. Therefore, the higher mineralization in the northwestern zone is the result of the mobilization of thermal groundwater and direct mixing with seawater, which is introduced locally at the coast due to overextraction. This finding is important for future management strategies of the aquifer.

ღრმად განლაგებული სითხის გეოთერმული პირობები კოლხეთის არტეზიულ აუზში: წყლის ქიმიური შედგენილობა და გეოთერმომეტრია

Among the most important issues to be characterized is the temperature of the aquifer in any geothermal system. Fluids located deep within a hydrothermal system provide heat, and they control thermal groundwater temperature changes in aquifers. Geothermometers based on water chemistry have been used to estimate groundwater temperatures in various complexes. However, the average temperature measured by hydrochemical geothermometers is often variable, and it is difficult to assign a corresponding average geothermal fluid temperature because temperature and pressure change as the geothermal fluid moves upward. Different geothermometers cover different temperature ranges. Some hydrochemical geothermometers are suitable for high temperature geothermal systems, while others are suitable for medium and low temperature. Based on these geothermometers, it is difficult to assign a temperature that is close to the actual temperature of the geothermal system, because the influence of atmospheric precipitation, which causes a decrease in the concentration of chemical components and dilution due to mixing with shallow groundwater.

Natural radioactivity due to uranium and radon in thermal groundwaters of Central Brazil

Natural radioactivity due to uranium and radon in thermal groundwaters of Central Brazil

Structural controls of the northern Red River Fault Zone on the intensity of hydrothermal activity and distribution of hot springs in the Yunnan-Tibet geothermal belt

Deep, large faults are well-developed in the Red River Fault Zone in Yunnan in southwest China. This study uses a classification approach and macro-scale analysis of faults and hot springs with data from the literatures and field work. By examining 68 hot springs, 6 faults, and 12 Quaternary basins in this area, controls of the northern Red River Fault Zone on the intensity of hydrothermal activity (temperature and flow rates) and distribution of hot springs are summarized. The results show that topography-related hydraulic gradients can cause geothermal water to rise after circulation. The hot springs are easy to occur along the active faults (76%), especially at fault intersections (37%). The circulation depth and elevated temperature of hot springs in the study area are positively correlated. The highest temperature hot springs correspond to low flow rates, and hot springs with the highest flow rate have low temperatures. The results are of practical significance for the search for thermal groundwater and for understanding geothermal resources potential in this area and similar areas.

Three-Dimensional Thermal Groundwater Analysis by Localized Meshless Method and Method of Characteristics

Three-Dimensional Thermal Groundwater Analysis by Localized Meshless Method and Method of Characteristics

Geographic Information System (GIS) as a basis for the next generation of hydrogeological models to manage the geothermal area Waiwera (New Zealand)

Abstract. The geothermal hot water reservoir below the small town of Waiwera in New Zealand has been known to the indigenous Māori for many centuries. Overproduction by European immigrants led to a water level decrease and consequently artesian flow from the wells and the seeps on the beach ceased. The Te Kaunihera o Tāmaki Makaurau Auckland Council established the Waiwera Thermal Groundwater Allocation and Management Plan to allow the geothermal system to recover. For a sustainable operation, the management regime can be informed by hydrogeological models based on monitoring data. The underlying geological model has been revised according to field observations and an existing numerical model transferred to the newly developed software package TRANSPORTSE. Monitoring and digitally derived data have been integrated in a geographic information system (GIS).

The Possible Source of Abnormally High Sodium Content in Low-Salinity Geothermal Water.

The dissolution of sodium-containing minerals in high-temperature geothermal systems can cause Na+ to exceed 400 mg/L with high salinity. But the Na+ of low-salinity geothermal water is mostly less than 100 mg/L in medium-low temperature geothermal systems. However, geothermal water with Na+ up to 325.4mg/L and total dissolved solids less than 650 mg/L was found in the Huangshadong geothermal field, which is a typical medium-low temperature hydrothermal system in South China. The water chemistry results indicate that thermal groundwater is uniformly HCO3 -Na type with high sodium content (average 240.06 mg/L). All the thermal groundwater and shallow groundwater have the same meteoric origin based on δD and δ18 O. According to water chemical geothermometers and multicomponent mineral equilibrium (MME) method, the reservoir temperature is estimated to be 100 to 130 °C at a maximum depth of 2.43 km. The estimation of the Cl- mixed indicator suggests that geothermal water has mixed with 51% to 72% of shallow groundwater, resulting in the reduction of Na+ content in real geothermal water (Na+ up to 685.2mg/L). The simulated results of water-rock interactions indicate that mineral dissolution and ion exchange have minor contributions to Na+ enrichment in geothermal water. Hydrochemical simulations and Gibbs diagrams suggest an additional source of high sodium: granite fluid inclusions are fractured into geothermal water at high temperatures. Granite fluid inclusions may only account for 3% to 5% of geothermal water, but they provide the main source of Na+ in geothermal water.

Geochemical Characteristics of Geothermal Fluids of a Deep Ancient Buried Hill in the Xiong’an New Area of China

The Xiong’an New Area is one of the areas with the richest geothermal resources in the east-central part of China. However, the genesis of the geothermal water in Jixianian carbonate reservoirs in this area is still unclear. This study conducted systematical geochemical and isotopic analyses of the geothermal water in the Jixianian carbonate reservoirs in the Rongcheng geothermal field and summed up the genetic mechanisms of geothermal fluids in deep geothermal reservoirs. The results are as follows: the geothermal water in the study area has a hydrochemical type of Cl·HCO3-Na and originates from meteoric water in the Taihang Mountains. The age of the geothermal water increases from 22 ka in the west to 45 ka in the east, and its transport rate is approximately 1.02 m/a. The Sr concentration and 87Sr/86Sr ratio of the geothermal fluids increase along their runoff direction and are related to the dissolution and filtration of minerals such as dolomite and gypsum and the decay of 87Rb in the Earth’s crust. The geothermal water is involved in deep circulation and occurs in a closed system. These results are consistent with those obtained using the PHREEQC inverse model. The reverse hydrogeochemical simulation results exhibited the precipitation of gypsum and halite, the dissolution of anorthite and quartz, and desulfurization. The geothermal reservoir temperatures were estimated to be 92–113 °C using a SiO2 geothermometer, and the thermal groundwater may have undergone deep circulation, with a prolonged retention time. Moreover, the groundwater occurs in a closed environment, strong water-rock interactions occur between the groundwater and related minerals, and the groundwater absorbs the heat from the deep heat source, thus forming geothermal water.

Active degassing of crustal CO2 in areas of tectonic collision: A case study from the Pollino and Calabria sectors (Southern Italy)

Carbon dioxide (CO2) is released from the Earth’s interior into the atmosphere through both volcanic and non-volcanic sources in a variety of tectonic settings. A quantitative understanding of CO2 outgassing fluxes in different geological settings is thus critical for decoding the link between the global carbon budget and different natural processes (e.g., volcanic eruption and earthquake nucleation) and the effects on the climate evolution over geological time. It has recently been proposed that CO2 degassing from non-volcanic areas is a major component of the natural CO2 emission budget, but available data are still sparse and incomplete. Here, we report the results of a geochemical survey aimed at quantifying CO2 emissions through cold and thermal springs of the tectonically active Pollino Massif and Calabrian arc (Southern Italy). The chemical ad isotopic (He and C) composition of fifty-five dissolved gas samples allows to identify two different domains: 1) a shallow system dominated by gas components of atmospheric signature (helium, hereafter He) and biogenic origin (C), and 2) a deeper system in which crustal/deep fluids (CO2 and He) are dominant. The measured He isotope ratios range from 0.03 to 1.1 Ra (where Ra is the He isotopic ratio in the atmosphere) revealing a variable atmospheric contamination. Furthermore, the He isotopic data indicate the presence of traces of mantle He contributions (2%–3%) in the thermal groundwater. The prevailing low R/Ra values reflect the addition of crustal radiogenic 4He during groundwater circulation. Using helium and carbon isotope data, we explore the possible sources of fluids and the secondary processes (dissolution/precipitation) that act to modify the chemistry of pristine volatiles. For the thermal springs, we estimate a deep C output of 2.3 x 107 to 6.1 x 108 mol year−1. These values correspond to deep CO2 fluxes per square km comparable with those estimated in several active and inactive volcanic areas and in continental regions affected by metamorphic CO2 degassing (e.g., the southern margin of the Tibetan Plateau).

Combining 14CDOC and 81Kr with hydrochemical data to identify recharge processes in the South German Molasse Basin

• Combination of 14 C DOC and 81 Kr provides new insight of recharge dynamics in the UJA. • Groundwater dating with 14 C DOC and 81 Kr proves to be useful for deep aquifers. • Groundwater dating revealed high spatial heterogeneity in groundwater ages. • The main recharge area of the UJA may be located at the southern border of the SGMB. • Glaciations may be the driving force for groundwater recharge. To face the challenges of ongoing climate change, renewable energy sources are needed to reduce CO 2 emissions to the atmosphere. The South German Molasse Basin (SGMB) contains an important geothermal aquifer in Germany; however, an enhanced understanding of the flow regime at the basin scale remains a fundamental limiting factor in assessing a long-term and sustainable strategy for using this green energy source. Here we report 14 C DOC and 81 Kr groundwater dating results together with hydrochemical data, stable water isotopes, noble gases and out-diffusion experiments that indicate that the thermal groundwater consists of at least two groundwater sources: a formerly unknown young groundwater component with apparent water ages between 9,800 and 18,700 a and an old groundwater component, which shows an apparent water age of up to approximately 300 ka. The results of the out-diffusion experiments with core material from the Upper Jurassic aquifer (UJA) suggest that diffusion processes between rock-matrix water and more mobile fracture water represent a controlling mechanism for groundwater flow and the observed extended apparent groundwater ages within the UJA. The observed elevated 14 C DOC activities and the high spatial heterogeneity in groundwater ages close to the southern margin of the SGMB were interpreted as a recharge zone of the system. The combination of the 14 C DOC and 81 Kr methods shows the potential as a powerful groundwater dating tool for deep aquifers.