用同位素方法研究额济纳盆地承压含水层地下水的补给

Study of Groundwater Supply of the Confined Aquifers in the Ejin Basin Based on Isotopic Methods

本文通过环境同位素、温度、电导率和人工示踪等方法研究了黑河下游古日乃和额济纳盆地深部承压水的补给源 ,初步揭示了额济纳盆地承压水来自于祁连山的降水 ,是部分祁连山西端雪水直接渗入山前的深大断裂 ,在玉门宽滩山一带注入与之相交的阿尔金断裂 ,然后继续向东补给至巴丹吉林沙漠 ,并顺着古日乃断层补给到额济纳盆地。通过蒸发量计算得到的补给量为 5× 10 8m3/a。黑河流域承压水中的 T(氚 )为 17.8～ 0 .1TU ,地下水的年龄与取样孔的位置有关 ,靠近强渗漏带附近的地下水的年龄只有 2 0～ 30 a。古日乃、拐子湖的湖泊、泉、沼泽等消失的主要原因是由于 5 0 a来温度升高、蒸发量增加和下游抽水量增大的原因。该项研究对于重新认识额济纳盆地、古日乃、巴丹吉林沙漠的地下水补给与黑河下游水资源调度。

This paper studies the deep confined water replenishment sources in the lower reaches of the Heihe River in the Gurinai and Ejin Basin area by using environmental isotope, temperature, electric conductivity, artificial tracer method etc, and reveals that the confined groundwater in the Ejin Basin came from precipitation over the Qilian Mountains. We found that the snow water from the Qilian Mountains flows into the Altyn fault through the large deep fault and lake groups were formed in the Badain Jaran Desert due to the rupture of the surface. There is a great fault around the Muji Lake and the lake groups, through which groundwater in the Altyn fault can be directly supplied to the Gurinai and Ejin areas to form confined aquifers. The groundwater was supplied from deep to shallow aquifers with a supply amount of 6×10 8 m 3/a. The tritium from the confined groundwater of the Heihe River catchment is between 17.8 and 0.1 TU. The age of the groundwater is related to the distance between the water sampling position and the confined aquifer. At the center of the leakage aquifer the age is only between 20 and 30 a, but some groundwater is far from the leaky conformation and the age is thousands of years. The reason for the disappearance of lakes, springs, marshes or rivers in the Gurinai and Jinsutuhaizi area is not related to the discontinuity of the Heihe River, but is the increasing temperature, evaporation and downstream pumping in the past 50 years. The discovery of the large deep fault in the Qilian Mountains and the great transmissibility of the Altyn fault under the Ejin Basin, Gurinai, Badain Jaran Desert is very important for the management, development and utilization of the water resources of the Heihe River.