内蒙古呼伦湖流域地表水与地下水氢氧同位素特征及湖水来源分析

Characteristics of Hydrogen and Oxygen Isotopes of Surface and Ground Water and the Analysis of Source of Lake Water in Hulun Lake Basin, Inner Mongolia

以内蒙古呼伦湖流域为研究对象,对其湖水、河水和井水样品中的氢氧同位素特征、地下水中的总溶解性固体含量与氘盈余值的关系,进行了研究,并分析了呼伦湖湖水的来源。结果表明,呼伦湖流域的蒸发趋势线方程为δD=5.53δ18O-27.39(n=31,R2=0.98),蒸发线明显偏离全球大气降水线(GMWL),表明呼伦湖流域干旱的气候特征。湖水中的氘盈余值偏负程度最大,表明湖水的蒸发最强烈。除采样点W9和W15外,其它各采样点地下水中总溶解性固体含量与氘盈余值负相关,说明呼伦湖流域的地下水也存在蒸发作用。在蒸发强烈的夏季,呼伦湖的湖水来源为大气降水、河流水和地下水。

The characteristics of hydrogen and oxygen isotopes of lake, rivers and well water as well as the re- lationship between total dissolved solids and deuterium surplus of ground water were analyzed in Hulun Lake basin, Inner Mongolia. The results showed that the equation of evaporation trend was 8D=5.53δ^18O-27.39（n= 31, R2=0.98）. The evaporation line indicated that the Hulun Lake basin was of arid climatic characteristics as that the line deviates significantly from the global atmospheric precipitation line （GMWL） and falls on the lower right. The deuterium surplus of the lake water was negative maximum, which illustrated the evaporation was most strong due to the open water area and their local climate characteristics. Except the sampling sites of W9 and W15, the total dissolved solids decreased as deuterium surplus increasing of all other ground water sampling sites, which was of a negative correlation relationship, and indicated the presence of groundwater evaporation in Hulun Lake basin. Besides the precipitation and river recharge, the ground water was also the main recharge source of the lake water which could maintain the open water area in summer season.