西部典型侏罗系富煤区地下水补径排的同位素特征
Characteristics of groundwater circulation condition and complementary diameter in typical Jurassic coal-rich area of western China
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摘要: 以位于吐哈盆地的大南湖矿区为例,结合该区侏罗系含煤地层渗透性好、富水性强、静储量大等典型水文地质特征,通过野外调查,沿区域主要补给方向共采取了9个地表水及地下水样,开展了氢氧同位素及水化学分析与测试;在获取研究区水样氢氧同位素特征并首次构建哈密地区氢氧同位素降雨线的基础上,系统研究了天山东段南麓区域地下水的补径排条件;结合研究区所处的干旱区域特征及主要构造的控水作用研究,基本阐明了大南湖凹陷特殊地下水系统的形成原因及水循环条件。研究结果表明:天山东段南麓雪融水是区域地下水的惟一远程补给水源,通过深渗透方式进行补给,主径流方向为由北东向南西,补给途径长;受研究区北部沙尔湖隆起、西部及南部觉罗塔格隆起、东部边界断层等隔水构造的控制,研究区总体水文地质条件较为封闭,地下水循环交替差,进而形成了大南湖矿区上侏罗系含水层具有以静储量为主、高矿化度的特殊水文地质特征。Abstract: This paper takes the Dananhu mining areas as an example,which is located in TurPan-Hami Basin. Com- bined with the typical hydro-geologic characteristics in its Jurassic containing coal formation such as good permeabili- ty,water rich,static large reserves,through the method of field investigation,the nine water samples taken along the main groundwater recharge direction were used to conduct the isotopes analysis and chemical tests. Based on the water isotopic characteristics obtained in the study area and the precipitation line of hydrogen and oxygen isotopes construc- ted in Hami area for the first time,the authors systematically studied the conditions about groundwater recharge in east- ern Tianshan area. Considering the characteristics of arid area and water controlling function of main structure in the study area,the authors clarified the forming reasons in the water cycle conditions of the special groundwater system in the Dananhu depression. The results of this study show that the snow melting water in the eastern Tianshan foothill is the only one source to supply for regional groundwater by replenishing of the deep penetration. Its main flow direction is from northeast to southwest. Controlled by same geotectonic movements,such as North schallsee uplift,the rise of the Western and Southern Jueluotag,and eastern boundary fault and others faults,the general hydro-geological conditions of the study area are relatively closed and the groundwater circulation is poor. Then the Jurassic aquifer formation in the area is characterized by its static reserves and high salinity.