淮南新集矿区主要充水含水层水化学特征及成因

为探明新集矿区深层地下水离子组成及其演化特征,采集了研究区砂岩水和太灰水等共20个水样,测试分析常规离子和氢氧同位素数据,采用Piper三线图、相关性分析、离子比例系数与饱和指数等方法,探讨了研究区深层地下水水化学特征及其成因。结果表明:(1)研究区砂岩水为高矿化度水,平均矿化度为2 743. 73mg/L,水化学类型主要为Cl-Na型,太灰水多为中矿化度水,平均矿化度为1 468. 33mg/L,水化学类型主要为HCO3·Cl-Na型和Cl-Na型;(2)研究区地下水的补给不仅有大气降水和地表水,还有古气候条件下形成的古溶滤-渗入水,且由于矿物质与深层地下水的水岩作用使得氧同位素发生漂移;(3)含水层中主要发生的水岩相互作用有硅酸盐和蒸发盐岩的溶解及阳离子交替吸附作用,盐岩和石膏在研究区地下水中是反应性矿物,白云石和方解石的溶解在矿区地下水中呈过饱和状态。

Chemical Characteristics and Genesis of Deep Groundwater in the Xinji Mining Area

In order to find out the ion composition and the evolution characteristics of deep groundwater in the Xinji mining area, 20 water samples from the study area, such as sandstone water and limestone water in the Taiyuan formation, were collected, conventional ion and hydrogen and oxygen isotope analyses were conducted, Piper three-line diagram and correlation analyses were implied and ion ratio and saturation index methods were used to study chemical composition characteristics of these water and to investigate hydrogeochemical effects of ions on these waters. The results showed that:(1) the sandstone water is a high salinity water, mostly are the Cl-Na type water, the limestone water in the Taiyuan formation is a medium mineralization water, whose water chemical type is either the HCO₃·Cl-Na type or the Cl-Na-type; (2) the groundwater recharges in the study area included not only atmospheric precipitation and surface water, but also paleo-filtration-infiltration water formed under paleoclimate conditions, which caused the oxygen isotope drift due to the interaction of minerals and deep groundwater; (3) The main water-rock interactions in these groundwaters are the dissolutions of silicates and evaporating salt rocks and the alternating adsorptions of cations. The groundwater of the mining area is over-saturated in terms of dolomite and calcite.