达里诺尔湖水体稳定氢、氧同位素组成变化对结冰过程的响应  

Changes of Stable Oxygen and Hydrogen Isotopes and Their Responses to Freezing Process in Dali-Nor Lake in Cold-Arid Areas of China

作　　者：李文宝[1] 李畅游[1] 刘晓旭[1] 甄志磊[1] 胡其图 刘志娇 

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,内蒙古呼和浩特010018 [2]内蒙古赤峰市克什克腾旗这里诺尔湖国家级自然保护区生态旅游有限公司,内蒙古赤峰025373

出　　处：《地球科学（中国地质大学学报）》2015年第12期2081-2090,共10页Earth Science-Journal of China University of Geosciences

基　　金：国家自然科学基金重点项目(No.51339002);国家自然科学基金项目(Nos.51269013,51469025);中国博士后科学基金资助项目(No.2014M562495XB);内蒙古自治区自然基金项目(No.2012MS0615)

摘　　要：利用自然界中广泛分布的环境同位素进行湖泊水体演化过程分析已经成为现代湖泊科学的重要研究方向.通过采集内蒙古达里诺尔湖(简称"达里湖")2013年1月份的湖冰、湖水,2012年夏季湖水与湖区大气降水等,共分析了77个样品中稳定氢(H)、氧(O)同位素值的变化情况,在此基础上对达里湖水体稳定H、O同位素组成变化及其对结冰过程的响应进行了详细分析,结果显示:(1)伴随结冰过程的完成,各站点深层冰体(厚度~65cm)中δD、δ^(18) O值比表层冰体(厚度~15cm)中的值出现不同幅度的偏重.而冰下水体中δD、δ^(18) O平均值则比冰体中的平均值分别偏轻约13.85‰、2.23‰.在冰层形成的快速与稳定阶段,δD、δ^(18) O值的变化幅度也存在差异.同时,冬季外源水体的输入对各站点间同位素值差异的影响比夏季更明显;(2)夏季湖水、冬季湖水与湖冰的同位素值均落在全球大气降水线与湖区大气降水线之外,显示湖泊冰封之前,蒸发对湖泊水体同位素偏移存在一定程度的影响;而冬季湖水与湖冰的同位素值基本位于同一斜率区间,且全部落在夏季湖水同位素值的右侧,显示两者之间并不存在明显的蒸发分馏作用,造成上述现象的因素只能归结于结冰过程.Utilizing the environmental isotopes,which exist widely as one proxy of lake water evolution process,has become one important direction in lake sciences.In this paper,a total of 77 samples of lake water,ice and precipitation water were collected in Dali-Nor Lake,which locates in cold-arid areas of Inner Mongolia;and changes of δD and δ^（18） O and their responses to freezing process in Dali-Nor Lake are analyzed.The comparison of the changes ofδD andδ18 O among lake ice,lake water and precipitate water shows that：（1）Following the freezing process,the values of ΔδD,Δδ^（18） O between bottom（65cm）and surface（15cm）ice layers are both above zero.But in fast stage and stable stage during lake ice forming,the change range of water stable isotopes is different.Meanwhile,the values of δD and δ^（18） O in water under the ice are about 13.85 ‰ and 2.23 ‰ lighter than those in lake ice.In addition,the river inflows have more obvious influence on value changes of δD and δ^（18） O among different sites in winter than in summer.（2）The δD and δ^（18） O values of water（both summer and winter）and ice are both in right side of the global meteoric water line（GMWL）and local meteoric water line（LMWL）,which shows that the evaporationprocess has certain influence on the fractional distillation of water stable isotopes before the lake ice formed.On the other hand,the values of δD and δ^（18） O in lake ice and winter lake water have the same slope range and both in right side of the values of δD and δ^（18） O in summer lake water,which shows that the freezing process has obvious influence on the fractional distillation of water stable isotopes during the lake ice forming process.

关 键 词：氢同位素 氧同位素 结冰过程 达里诺尔湖 寒旱区 地球化学 

分 类 号：P592[天文地球—地球化学]