Hydrogeochemical characteristics and evolution of the aquifer systems of Gonghe Basin,Northern China

We present the first systematic hydrogeological analysis to grain insights on the evolution of the Gonghe Basin in North China. Two hundred and forty seven water samples were collected from the Gonghe East Basin, Gonghe West Basin and Chaka Basin. The three groundwater systems of Gonghe Basin from west to east display different geochemical signatures. Based on Na/Cl ratios and Langelier-Ludwig diagram, it is inferred that the groundwater recharge potential of the Gonghe East Basin is much prosperous than the other areas. The renewability of the aquifers in alluvial-proluvial fan of Wahonghe and Gonghe East Basin margin is much faster than in the other basins. The groundwater quality in Chaka Salt Lake,Shazhuyu and Qiabuqia River Valley plains is low due to strong evaporation and cation exchange. The groundwater quality of the phreatic aquifers in the Qiabuqia River Valley plain is further deteriorated by mixing of high-arsenic and high-mineralization water from the deep fault structures.     

Identification of sources and groundwater recharge zones from hydrochemistry and stable isotopes of an agriculture-based paleo-lacustrine basin of drought-prone northeast Mexico

Over exploitation for agricultural activities and consumption has depleted the groundwater resources of drought-prone northeast Mexico. Major ion concentrations along with δ¹⁸O_H2O, δ²H_H2O and d-excess values of shallow groundwater from the Cieneguilla Basin (near Tula) located at a distance of ∼200 km from coast of the Gulf of Mexico helped to contribute new data about drought vulnerability in this region through identification of the moisture source and groundwater recharge zone. Different degrees of rock-water interaction through gypsum, anhydrite and halite dissolutions and minor silicate weathering controlled the hydrochemistry. Stable isotopes yielded a least square regression and slope similar to the local as well as global meteoric water lines, indicating minimal effect of evaporation during the recharge as well as in the subsoil. Isotopic fractionations along with a digital elevation model demarcated the recharge zones at north and east of the basin, with altitudinal difference of ≥1000 m, and indicated that the recharge occurred through warm season moisture sourced from the Gulf of Mexico. Less frequent landfalling of tropical storms caused by warmer sea surface temperature, however, has reduced this rainfall over the last few decades. If the trend of global warming continues unabated, the depleted groundwater resources would trigger reduction in agricultural activities in this drought-prone region and lead to enhanced socio-economic challenges.     

洋北饮用天然矿泉水形成的水文地球化学机理的初步研究

在浙江省象山县洋北村石英霏细斑岩的断层蓄水构造中发现了锶偏硅酸复合型优质饮用天然矿泉水，该矿泉水中还含有所有人体必需的微量元素和对人体健康有益的微量元素，而其放射性元素、有毒组分、污染物和微生物指标均符合我国饮用天然矿泉水的标准，具有开发利用价值。对该矿泉水形成的水文地球化学机理的研究，为浙江省寻找新的同类饮用天然矿泉水指出了方向。     

Variation of dispersion of radon content in the groundwater and short-term and imminent precursors of earthquakes

A lot of observational data both at home and abroad suggested that before some strong earthquakes anomalous variations of radon concentration appear in the chemical composition of groundwater. In order to further study these anomalies and get reliable precursory anomalies, a special packet of precursory data processing has been developed recently. By using a computer program of first-order difference method, it is discovered that the scatter of radon content increased systematically before earthquakes at some observation posts where observational conditions are fairly good. This change may be a new criterion for evaluating short-term and imminent earthquake precursors.     

湖南保靖县白岩洞地下河流域水文地球化学特征研究

白岩洞地下河系统工程主要是解决保靖县城供水水源问题。本文通过三个时段的大量野外实测数据,分析了白岩洞地下河流域内岩溶泉、地表水体和地下河水的岩溶水文地球化学特征及其动态变化。结果显示,该流域内岩溶泉可分为两个主要类型,一类是与深循环有关、沿区域断层带分布,其水文、水化学动态相对稳定,水化学变化受深源CO2 浓度控制; 另一类为岩溶表层带泉,受地表环境、降雨量影响大,水化学动态变化较大。而地下河及其支流水的水化学变化特征介于表层带岩溶泉和地表水之间,其三个时段的变化规律跟表层带泉相似,主要水化学指标枯季( 12月) > 雨季1(次年4月)> 雨季2(次年7月) ,说明明显受降雨的稀释作用控制。      

Chemical and geological control of spring water in Eastern Guaniguanico mountain range, Pinar del Rìo, Cuba

Flows of different hierarchy, which travel through limestone, schist, sandstone and ultra-basic rocks, with ages from the Paleocene to the Jurassic, at Sierra del Rosario, Pinar del Río, Cuba, were characterized. The waters were sampled from 1984 until 2004 and the data were statistically processed by means of chemical equilibrium and physico-chemical models, under a flow system view of interpretation. Results demonstrate that the physico-chemical properties of the water are controlled by water–rock interaction resulting from residence time since rainwater infiltrate and the path it follows to the discharge zone and the type of aquifer material the different groundwater flows are in contact with. Geochemical indices allow the definition of the different types of flow (local, intermediate, regional) to be characterized, permitting a further definition of the different flow systems and rock type involved, as well as its use for water supply and medical use. The main geochemical processes which control the chemical composition acquisitions mode are: congruent dissolution of calcite, dolomite, and halite; incongruent dissolution of plagioclase and microcline minerals; pyrite oxidation, sulphate reduction, and silica dissolution at the surface or silica precipitation at deep saturation and circulation zones.