内蒙古达里诺尔湖水体稳定同位素空间分布特征指示的区域补给差异  

Regional groundwater recharges based on the characteristics of stable isotope distribution in Dali-nor Lake in Inner Mongolia

作　　者：李文宝[1] 杜蕾 王旭阳 杨旭 史小红[1] LI Wenbao;DU Lei;WANG Xuyang;YANG Xu;SHI Xiaohong(Inner Mongolia Agricultural University IMAR Key Laboratory of Water Resources Protection and Utilization,Hohhot 010018,P.R.China)

机构地区：[1]内蒙古农业大学水资源保护与利用自治区重点实验室

出　　处：《湖泊科学》2019年第5期1334-1343,共10页Journal of Lake Sciences

基　　金：国家自然科学基金项目(51669021,51469025);内蒙古自治区自然科学基金项目(2016MS0552)联合资助

摘　　要：基于内蒙古寒旱区达里诺尔湖(简称"达里湖")无河流外泄、冬季湖面冰封、水体流动缓慢等典型区域水文气象特征,对夏、冬季湖泊底层、表层水(冰)、入湖河水、浅层地下水(井水、泉水)等样品中稳定氢、氧同位素(δD、δ^18O)值的变化进行对比分析,结果显示湖区不同水体δD和δ^18O平均值均存在湖泊水体(水、冰体)>大气降水>入湖河水>浅层地下水的变化特征.在达里湖,夏、冬季底层水δD、δ^18O值均比表层水(含湖冰)中δD、δ^18O值偏负且季节变化幅度较小.此外,冬季不同采样点底层水δD、δ^18O平均值的区域差异性比夏季明显,这反映了湖泊底层水体相对封闭、稳定的储存环境,也说明地下水补给过程存在一定程度的区域差异.而基于不同区域底层水δD、δ18O值及氘盈余指数(d)值和水深变化间相互关系的分析,发现水深变化可能是影响达里湖底层水δD、δ^18O值分布区域差异及补给过程的主要因素之一:东北部水体较浅(水深小于8m)区域采样点水体δD、δ^18O平均值多数比达里湖整体平均值偏负且d值偏正,指示浅层地下水输入及二次蒸发作用的影响;西南部水体较深(水深超过8m)区域采样点水体δD、δ^18O平均值多数比达里湖整体平均值偏正且d值偏负,说明水体相对稳定,受二次蒸发作用的影响较弱.The Dali-nor Lake is a typical closed lake in Inner Mongolia,the cold and arid area in Northern China,which has no surface water discharges by rivers.In particular,the surface water of the lake would be frozen with very slowly water flows in winter.The lake can be regarded as nearly sealed and only influenced by groundwater recharges in winter.According to regional hydrologic and meteorological characteristics,the winter is an ideal stage to study the recharge process of bottom water in Dali-nor Lake.Therefore,we collected samples of lake water,lake ice,river water,shallow groundwater and rainfall,and analyzed the values of hydrogen and oxygen isotopes (δD and δ^18 O) of these water samples from the lake.The results show that the average values of δD and δ^18 O are the heaviest in samples from the lake water and ice,and the average values of δD and δ^18 O in shallow groundwater are the lightest,relatively.Meanwhile,the average values of δD and δ^18 O are about -31.51 ‰ and -2.05 ‰ in bottom water and about -32.77 ‰ and -2.51 ‰ in surface water in winter,respectively.But the average values of δD and δ^18 O in bottom water are lighter than those in surface water and ice,with values of about -29.12 ‰ and -1.84 ‰.In summer,the average values of δD and δ^18 O in bottom water are also lighter than those in surface water,with values of about -32.95 ‰ and 2.13 ‰ in bottom water and -32.61 ‰ and -1.99 ‰ in surface water,respectively.It's likely that the different δD and δ^18 O values between bottom and surface water had been influenced by seasonal changes and frozen processes in Dali-nor Lake.As a whole,the values of δD and δ^18 O in bottom water are lighter than those in surface water,and the regional differences of δD and δ^18 O values are also more distinct than those in summer bottom water.On the other hand,the relationships between water depth and lake water stable isotopes had shown that changes in the water depth were one primary factor that influenced the value changes of δD

关 键 词：氢-氧同位素 空间分布 湖泊水体 补给特征 达里诺尔湖 

分 类 号：P342[天文地球—水文科学] X143[天文地球—地球物理学]