乌梁素海及其周边地区水源补给关系同位素研究

Isotope study of recharge relationships of water sources in Wuliangsuhai Lake and its surrounding areas

野外采集乌梁素海及其周边区域的水样和土壤样品,测定样品的δD、δ18O和ρ(TDS),并以采自南京燕子矶的黄土为样本进行室内降水入渗试验,测试每个土壤样品的含水率和ρ(TDS)。根据试验结果,对乌梁素海以北的色尔腾山地区的降水入渗情况进行分析,对乌梁素海湖水补给来源进行同位素分析,对乌梁素海湖泊周围地下水进行TDS分析。结果表明,乌梁素海以北的色尔腾山地区的大气降水在入渗的过程中大量蒸发,无法有效入渗补给地下水,降水并不是当地地下水的主要补给源,而比当地降水中的氘氧同位素值更负的稳定外部补给源是当地地下水的主要补给源;泉水、井水的δD和δ18O值比当地降水明显贫化,也表明大气降水并非是地下水的补给源;地下水是乌梁素海的主要补给源,河套灌区排水渠中的水的主要来源是深循环地下水,狼山—日喀则隐伏断裂带中可能存在渗漏通道,西藏内流区的渗漏水通过该通道补给到了内蒙古高原。

Water and soil samples were collected in the field at Wuliangsuhai Lake and its surrounding areas. The δD, δ180, and p （TDS） of these samples were measured, and an indoor rainfall infiltration test was conducted with loess collected from Yanziji in Nanjing City. The moisture content and p （TDS） of each soil profile were tested. Based on the experimental results, the infiltration of precipitation in the Seerteng Hill areas on the north side of Wuliangsuhai Lake was analyzed, and an isotope analysis of the sources of Wuliangsuhai Lake water and the p（TDS） analysis of surrounding groundwater of Wuliangsuhai Lake were conducted. The results show that the meteoric water of the Seerteng Hill areas evaporates greatly and cannot effectively recharge groundwater; precipitation is not the main recharge source of the local groundwater; the main source of the local groundwater is the stable external supply source where deuterium and oxygen isotope values are more negative; the δD and δ180 values of spring water and well water are significantly depleted compared with local precipitation, also indicating that the precipitation is not a recharge source of groundwater; groundwater is the main recharge source of Wuliangsuhai Lake; the main source of water in the drains in the Hetao irrigation district is the deep circulating groundwater; and in the Lang Mountain-Rikaze buried fault zone, there may exist a leakage channel, through which the percolating water in the inner flow area of Tibet flows to the Inner Mongolia Plateau.