喀什平原区地下水硫同位素分布特征及其硫酸盐来源研究

Distribution characteristics of sulfur isotopes and source of sulfate in groundwater of Kashi plain

喀什平原区是沙漠与戈壁交界的绿洲平原,属于典型的水质型缺水地区,地下水的化学特征主要表现为高硫酸盐、高硬度、高矿化度。本文针对喀什平原区300 m以浅钻孔中完成的地下水样品硫同位素进行测试,结果显示,地下水中δ34S值均为正值,δ34S值范围为2.1‰~13.6‰之间。采用统计、对比分析的方法 ,研究了喀什平原区地下水中硫同位素分布特征及其硫酸盐来源,表明研究区地下水中的硫酸盐主要来自于不同沉积相蒸发岩的溶解以及大气降水的补给。从区域分布看,南部盖孜河地下水流亚系统的地下水中硫酸盐浓度相对较低,北部克孜勒河地下水流亚系统的地下水硫酸盐浓度较高,沿水流方向,SO42-的浓度逐渐增加,而δ34S值变化不大,是蒸发浓缩和沿程累积共同作用的结果。研究结果为喀什平原区水质典型缺水地区的地下水资源开发、利用与保护提供科学依据。

Kashi plain is the oasis plain between desert and Gobi. It belongs to typical water quality water shortage area.The chemical characteristics of groundwater are mainly high sulfate,high hardness and high salinity. In this paper,the sulfur isotope of groundwater samples from shallow boreholes in 300 meters in Kashi plain is tested. The results show that the values of delta δ34 S in groundwater are positive,and the range of delta δ34 S is between 2. 1 and 13. 6 per thousand. By using the method of statistics and comparative analysis,study the distribution characteristics and sources of sulfate sulfur isotopes of groundwater in plain area in Kashgar,indicated that sulfate ingroundwater mainly comes from different sedimentary facies evaporite dissolution and precipitation recharge. From the regional distribution,the South River Sub System of underground water cover Zi in groundwater sulphate concentration is relatively low,high concentration sulfate Groundwater groundwater flow in northern qezel subsystem,along the flow direction,the concentration of SO42-increased,while34 S values changed little,is along the cumulative evaporation and the result of joint action. The results provide scientific basis for the development,utilization and protection of groundwater resources in typical water shortage areas of Kashi plain.