Hydrogeochemical properties of CO2-rich thermal–mineral waters in Kayseri (Central Anatolia), Turkey

The present study highlights the hydrogeological and hydrogeochemical characteristics of the CO₂-rich thermal–mineral waters in Kayseri, Turkey. These waters of Dokuzpınar cold spring (DPS) (12–13°C), Yeşilhisar mineral spring (YMS) (13–16°C), Acısu mineral spring (ACMS) (20–22.5°C), Tekgöz thermal spring (TGS) (40–41°C), and Bayramhacı thermal-mineral spring (BTMS) (45–46.5°C) have different physical and chemical compositions. The waters are located within the Erciyes basin in the Central Anatolian Crystalline complex consisting of three main rock units. Metamorphic/crystalline rocks occur as the basement, sedimentary rocks of Upper Cretaceous-Quaternary age form the cover, and volcanosedimentary rocks Miocene-Quaternary in age represent the extrusive products of magmatism acting in that period. All these units are covered unconformably by terrace and alluvial deposits, and travertine occurrences have variable permeability. Dokuzpinar cold spring, YMS and ACMS localized mainly along the faults within the region have higher Na⁺ and Cl⁻ contents whereas TGS and BTMS have higher amounts of Ca²⁺ and HCO ₃ ⁻ . The high concentrations of Ca²⁺ and HCO ₃ ⁻ are mainly related to the high CO₂ contents resulting from interactions with carbonate rocks. Whereas the high Na⁺ content is derived from the alkaline rocks, such as syenite, tuff and basalts, the Cl⁻ is generally connected to the dissolution of the evaporitic sequences. These waters are of meteoric-type. BTMS deviates from meteoric water line. The content is related to the increases in the δ¹⁸O compositions due to mineral–water interaction (re-equilibrium) process. CO₂-dominated YMS and ACMS with low temperatures have higher mineralizations. Yeşilhisar mineral spring, ACMS, TGS and BTMS are oversaturated in terms of calcite, aragonite, dolomite, goethite and hematite, and undersaturated with respect to gypsum, halite and anhydrite. Yeşilhisar mineral spring, ACMS and BTMS are also characterized by recent travertine precipitation. Dokuzpınar cold spring is undersaturated in terms of the above minerals. The higher ratios of Ca/Mg and Cl/HCO₃, and lower ratios of SO₄/Cl in BTMS than TGS suggest that TGS has shallow circulation compared to BTMS, and/or has much more heat-loss enroute the surface. The sequence of hydrogeochemical and isotopic compositions of the waters is in an order of DPS>YMS>ACMS>TGS>BTMS and this suggests a transition period from a shallow circulation to a deep circulation path.     

Isotopic composition and origin of mineral and geothermal waters from Tuşnad Băi Spa, Harghita Mountains, Romania

Different types of free water have been analysed for their deuterium and chemical composition in order to evaluate their source, mixing phenomena, and the underground dynamics. All types of ground water (mineral, geothermal and wellhead water) display δD values (− 82.6‰ to − 72.6‰) similar to surface waters from the studied area (− 77.1‰ to − 73.6‰). The global salt content varies from 1102 to 8707 mg/l for the groundwater, and from 46 to 392 mg/l for the surface water. From the co-variation between the δD values and the chemical composition of the waters, as well as from the seasonal variation of these two parameters, it is evident that the free water from Tuşnad Băi are meteoric in origin. The mineralization of the mineral water took place by means of an intense underground circulation, probably in the fault system developed within the Neogene magmatites.     

Genesis of the mineral groundwaters of the Razdol’nenskii occurrence in Primorye

Original isotopic and chemical data are reported on the groundwater and gases from the unique occurrence of mineral water in the coastal zone of southern Primorye. Results of the δ¹⁸O and δ²H analysis of the underground and surface water of the area integrated with their δ¹³C composition made it possible to solve the problem of the genesis and evolution of groundwater and gases in the coastal part of the Sea of Japan. It was established that meteoric waters penetrate into the Mesozoic terrigenous rocks and changed their chemical composition under the influence of transformation of organic matter from the host rocks. CO₂ released owing to reactions provides multiple enrichment of the water in HCO₃ and stimulates Na influx via dissolution of aluminosilicates.     

Geochemistry of the mineral waters and gases of the Mukhen deposit,Far East

This work reports new hydrochemical data on the two types of cold high p CO₂ groundwaters from the Mukhen deposit (Khabarovsk district). The first type is classed with HCO₃-Ca-Mg waters with a relatively low TDS (up to 1.7 g/l) and high concentrations of Fe²⁺, Mn²⁺, Ba²⁺, and SiO₂. The second type is of HCO₃-Na composition with high TDS (up to 14 g/l) and elevated Li⁺, B, Sr²⁺, Br^?, and I^?. New oxygen (δ¹⁸O) and hydrogen (δD) isotopic data on the waters and carbon (δ¹³C) isotopic data on the gas phase, together with a detailed geological and hydrogeological analysis of the study area, allowed us to decipher the origin of both the mineral waters. Based on the tritium content (³H) in the ground and surface waters of the area, the duration of the mineral water circulation was estimated. It was established that the both types of groundwaters were formed during interaction of meteoric water with bedrock under active influence of CO₂, however HCO₃-Na groundwaters have longer residence time than HCO₃-Ca-Mg groundwaters.     

鄂尔多斯沙区天然水体水化学组成及其成因

天然水体水化学组成及其成因分析既有助于重塑和预测区域水文地质环境及水文地球化学发展历史,也是水资源评价的基础。本文基于鄂尔多斯沙区天然水体水化学数据和前人在该地区的研究成果,利用多种水化学分析方法,对该地区天然水体的水化学组成及其成因进行分析。结果表明：鄂尔多斯沙区毛乌素沙地和库布齐沙漠虽然具有不同的沙漠景观,但其相同类型的天然水体具有相似的水化学性质和成因,该现象的出现可能和两者具有相似的蒸发量有关。鄂尔多斯沙区受蒸发影响较小的深层地下水水化学类型以Ca²⁺-HCO₃^-型为主,其水化学组成主要受控于岩石风化;湖水蒸发较强烈,水化学类型为Na⁺-Cl^-型,其水化学组成主要受控于蒸发—结晶过程的影响;浅层地下水和河水的水化学类型及其成因均处于两者之间,具有过渡特征。离子比例关系显示,蒸发岩风化、碳酸盐岩风化和硅酸盐岩风化在不同程度上影响着深层地下水、浅层地下水和河水的水化学组成。鄂尔多斯沙区地下水和河水虽然能满足灌溉水要求,但由于蒸发强烈,长期使用可能会引起盐碱化。本研究结果可为区域水资源可持续开发利用提供科学依据。     

IAGC and IAEA Interlaboratory Comparisons of Geothermal Water Chemistry: The Propagation of Uncertainty in the Reservoir pH Calculation

A statistical evaluation of the results of geochemical analyses of geothermal waters during interlaboratory comparison programmes of the International Association of Geochemistry and Cosmochemistry (IAGC) and International Atomic Energy Agency (IAEA) was performed to estimate the uncertainty of measurement of pH, electrical conductivity, Na⁺, K⁺, Ca2⁺, Mg²⁺, Li⁺, Cl^?, HCO₃^?, SO₄^2?, SiO₂ and B. The uncertainty of measurement was found to increase exponentially with decrease in value (concentration) for all the parameters except for pH, electrical conductivity and SiO₂ and was of the same order of magnitude as the concentrations for values of less than 1 μ ml^?1. There was an overall uncertainty of ± 2.5% in the measurement of pH and ± 30% in SiO₂. For all the other chemical species the uncertainty data were modelled by exponential curves. The sample IAEA14 was prepared by dissolving commercial reagents (i.e., represents a solution of known composition). Thus, the calculated values are considered to be the conventional true values for each chemical parameter. The difference between the measured mean of the data submitted by participating laboratories and the conventional true value for each parameter (i.e., bias of submitted measurements) for the species Na⁺, K⁺, Ca²⁺, Mg²⁺, Cl^? and SO₄^2? was ‐3.5, ‐1.1, ‐13.3, ‐53.6, ‐12.6 and ‐86.6%, respectively. The observed bias was of the same order of magnitude as statistical fluctuations (1s) for Na⁺ and K⁺, but significantly higher for Ca²⁺, Mg²⁺, Cl^? and SO₄^2?. Two methods, uncertainty interval and GUM (“guide to the expression of uncertainty of measurement”) were used to propagate uncertainty in the pH calculation of geothermal reservoir fluid. The application of the methods is illustrated by considering the IAEA10 and IAEA11 samples analysed in the interlaboratory comparisons as separated geothermal waters at atmospheric pressure.     

Chlorine transport processes through a 2000 m aquifer/aquitard system

In the Paris Basin, in France, the Callovo-Oxfordian (COx) is currently studied over a 250 km² surface area by the French national radioactive waste management agency in order to assess the feasibility of long-term underground nuclear waste repository. The COx is a 140 m thick clay-rich layer, which is part of the 2000 m aquitard/aquifer system constituting the sedimentary cover. In such sedimentary context, the transport processes of potential contaminants can be represented by both vertical diffusion and horizontal advection through the most permeable layers.Chloride is used as a natural conservative tracer, and is monitored in term of concentrations and isotopic composition (δ³⁷Cl) for both pore and groundwater. During this study, the samples were collected from three boreholes located in the center of the studied zone, one of them (EST433) going down to 2000 m depth. The main solute transport process is shown to be vertical diffusion from the massive Keuper halite level to the rest of the sedimentary pile. This global diffusive system can be occasionally disturbed by horizontal circulation of groundwater occurring in the Oxfordian and Dogger limestone formations. Therefore, these circulations cut the global diffusive system in a succession of independent diffusive systems. In this study the data set was implemented in a simplified 2D solute transport model and scenarii reproducing known history in term of paleo circulations inside the system, were applied and allowed to obtained a good fit of the data. Model results showed that paleo circulations, occurring between −145 Ma and −110 Ma, still have an impact on current distribution of chloride in the system, especially for δ³⁷Cl. The model highlights the need of the presence of a circulation spatially limited at the base of the Liassic formation to fit the data. The best fit obtained indicated current residence time of 500 ka in the Dogger and Oxfordian, with respective onset of the circulations at −20 Ma and −5 Ma.     

山东半岛黄海沿岸强壮箭虫丰度的季节变化和分布特征

于2006年8月~2007年11月对山东半岛黄海沿岸海域进行的春、夏、秋、冬4个航次的调查,根据强壮箭虫的个体丰度分析其季节变化、水平分布、垂直分布特征,并运用聚集度指标法分析其聚集特征。结果表明,山东半岛黄海沿岸海域4个季节强壮箭虫的平均丰度为63.2ind·m3,呈现秋季冬季夏季春季的变化规律。水平分布上,春夏两季形成的丰度密集中心多于秋冬两季,但高丰度区分布范围小于秋冬两季;春夏两季丰度密集中心主要分布于近岸海域,而秋冬两季则以远岸海域为主。垂直分布上,春夏季强壮箭虫表层平均丰度高于底层,而秋冬季表层平均丰度则低于底层;强壮箭虫存在一昼夜内2次上升和2次下沉的垂直移动现象,其上升和下沉的时间随季节不同而有所变化。强壮箭虫在山东半岛黄海沿岸海域呈现聚集分布。强壮箭虫的分布与多种环境因子变化有关,其中温度、盐度、桡足类分布是影响强壮箭虫分布的重要因素。     

A POSSIBLE IMPACT OF EL NIO MODOKI ON SEA SURFACE TEMPERATURE OF CHINA'S OFFSHORE AND ITS ADJACENT REGIONS

El Nio Modoki,similar to but different from canonical El Nio,has been observed since the late1970s.In this paper,using HadISST and NCEP/NCAR wind data,we analyze the relationship between El Nio Modoki and Sea Surface Temperature(SST)in the offshore area of China and its adjacent waters for different seasons.Our results show a significant negative correlation between El Nio Modoki in summer and SST in autumn in the offshore area of China and its adjacent waters,particularly for regions located in the east of the Kuroshio.It is also found that during El Nio Modoki period,anomalous northerlies prevail over the regions from the northern part of the Philippines to the offshore area of China,indicating that the northerlies are unfavorable for the transport of warm water from the western tropical Pacific to the mid-latitude area.Consequently,El Nio Modoki in summer may play a substantial role in cold SST anomalies in the offshore area of China and its adjacent waters in autumn through the influence of the Kuroshio,with a lagged response of the ocean to the atmospheric wind field.     

Remote quantification of phycocyanin in potable water sources through an adaptive model

Cyanobacterial blooms in water supply sources in both central Indiana USA (CIN) and South Australia (SA) are a cause of great concerns for toxin production and water quality deterioration. Remote sensing provides an effective approach for quick assessment of cyanobacteria through quantification of phycocyanin (PC) concentration. In total, 363 samples spanning a large variation of optically active constituents (OACs) in CIN and SA waters were collected during 24 field surveys. Concurrently, remote sensing reflectance spectra (R_rs) were measured. A partial least squares–artificial neural network (PLS–ANN) model, artificial neural network (ANN) and three-band model (TBM) were developed or tuned by relating the R_rs with PC concentration. Our results indicate that the PLS–ANN model outperformed the ANN and TBM with both the original spectra and simulated ESA/Sentinel-3/Ocean and Land Color Instrument (OLCI) and EO-1/Hyperion spectra. The PLS–ANN model resulted in a high coefficient of determination (R²) for CIN dataset (R² = 0.92, R: 0.3–220.7 μg/L) and SA (R² = 0.98, R: 0.2–13.2 μg/L). In comparison, the TBM model yielded an R² = 0.77 and 0.94 for the CIN and SA datasets, respectively; while the ANN obtained an intermediate modeling accuracy (CIN: R² = 0.86; SA: R² = 0.95). Applying the simulated OLCI and Hyperion aggregated datasets, the PLS–ANN model still achieved good performance (OLCI: R² = 0.84; Hyperion: R² = 0.90); the TBM also presented acceptable performance for PC estimations (OLCI: R² = 0.65, Hyperion: R² = 0.70). Based on the results, the PLS–ANN is an effective modeling approach for the quantification of PC in productive water supplies based on its effectiveness in solving the non-linearity of PC with other OACs. Furthermore, our investigation indicates that the ratio of inorganic suspended matter (ISM) to PC concentration has close relationship to modeling relative errors (CIN: R² = 0.81; SA: R² = 0.92), indicating that ISM concentration exert significant impact on PC estimation accuracy.