运城盆地漏斗区水文地球化学演化规律研究

Geochemical Evolution of Groundwater Filler in Yuncheng Basin of Shanxi Province

该文通过对运城盆地漏斗区浅层水文地球化学系统的分析,利用反向地球化学反应路径模型NETPATH模拟盆地漏斗区浅层水文地球化学演化规律。从模拟结果可以看出,在整个模拟的水流路径上,石膏和石盐的溶解在多数情况下占据主导地位,萤石和云母接近平衡状态。这种水文地球化学演化规律说明,从漏斗区边缘到漏斗中心,地下水沿途溶蚀含水层中的石膏、石盐等含盐矿物,地下水中氯化物、硫酸根和钠离子含量沿水流路径逐渐升高,地下水水质逐步恶化。受人类活动的影响,在较短的时间尺度内盆地漏斗区的水文地球化学演化规律有明显的变化,地下水对方解石有从溶解状态向沉淀方向演化的趋势,整个水流路径上,方解石总交换量由1990年的+14 565变为2000年的-10 145。

Yun Chen Basin is located at the southwest of Shanxi province. Because of its special hydrogeological and climatic condition, the groundwater quality is not so good in many place of Yuncheng Basin. Salt water and semi-salt water is detected in some observation wells. And the groundwater fill is forming and extending with the excess exploitation of groundwater in the past two decades. In the groundwater fill areas, the hydrodynamic condition is changed largely, which make the geochemical reaction path become more complexity in these areas. The hydro-geochemical system of aquifer in the groundwater fill area of Yun Cheng Basin is analyzed in this paper. The hydro-geochemistry is affected and by dissolution and evaporation on the groundwater flow path. The chemistry types of groundwater are multiplex. The geochemical modeling software NETPATH models the hydro-geochemical evolution process, which is in most common use in recent years. The calculate result shows that the dissolution of gypsum and rock salt in the aquiferous play a dominant role in the hydro-geochemical evolution process on the whole flow path, and the dissolution is equal to precipitation of the fluorite and talc, which indicates the groundwater dissolves the gypsum and rock salt in the aquiferous along the flow path. And the concentration of chloride, sulphate, and sodium arising from edge to center of the groundwater fill, and the groundwater quality is worse and worse. The calculation result also indicates that the hydro-geochemical evolution rule of the groundwater fill area is change distinctly in a shorter time scale by the disturbing of human activity. The calcite in the aquiferous has the trend from dissolution to precipitation on the modeling flow path. The total change volume of calcite is +14.565 in 1990, while which is become -10.145 in 2000.