苏干湖盆地地下水氢氧稳定同位素特征及其意义

Characteristics and significance of stable hydrogen and oxygen isotopes in groundwater of Sugan Lake basin

苏干湖盆地位于疏勒河流域西端,是西北干旱区独立的内流盆地。文中利用盆地内不同水体的氢氧稳定同位素样品,分析了盆地内不同水体氢氧同位素特征,揭示了盆地内水资源形成与水环境演化规律,对干旱区水资源研究有重要意义。盆地中部泉水及地下水接受出山河水大量入渗补给,地下水循环交替迅速,氢氧同位素组成与出山河水相似,是地下水的主要径流通道;党河南山、阿尔金山、安南坝山及赛什腾山山前戈壁带地下水接受山区季节性洪流补给,地下水循环交替缓慢,具贫重同位素特征;大苏干湖西端地下水同位素组成介于苏干湖湖水与山前戈壁带地下水,具富集重同位素的特征,表明大苏干湖西端地下水接受湖水的渗漏补给。受强烈蒸发影响的水体,具高矿化、富集重同位素的特征,同位素组成与盐分含量呈正相关变化,未受蒸发影响的水体,具贫重同位素的特征,同位素组成与盐分含量呈负相关变化。

The Sugan Lake basin is located at the western end of the Shule river basin,it is an independent inland basin in the arid area of Northwest China.In this paper,the characteristics of hydrogen and oxygen isotopes in different water bodies in the basin were analyzed,the formation of water resources and the evolution water environment were revealed,which is of great significance for the study of water resources in arid areas.Spring water and groundwater in the middle of the basin are supplied by a large amount of infiltration from the mountain river water,the groundwater circulation is rapid,and the hydrogen and oxygen isotopic composition is similar to that of the river water.The middle of basin is the main runoff of groundwater.The groundwater in the Gobi belt in front of the mountain,such as the south the mountain of Danghe River and the Altun mountain,is recharged by the flood in the mountain area,the groundwater circulation is slow and has the characteristics of poor heavy isotopes.The isotopic composition of groundwater in the western part of Dasugan Lake is between that of the lake and that of the Gobi belt in front of the mountain,which indicates that the groundwater in the western part of Dasugan Lake is supplied by the leakage of the lake water.The water affected by strong evaporation has the characteristics of high mineralization and enrichment of heavy isotopes.The isotopic composition is positively correlated with salt content.The water body not affected by evaporation has the characteristics of poor heavy isotope,and the isotopic composition is negatively correlated with salt content.