利用环境同位素识别共和盆地地下水补给特征及其环境指示意义  

Identify Groundwater Recharge Characteristics and Environmental Implications in Gonghe Basin Using Environmental Isotopes in Gonghe Basin

作　　者：刘春雷[1,2] 杨会峰 曹文庚[1] LIU Chunlei;YANG Huifeng;CAO Wengeng(The Institute of Hydrogeology and Environmental Geology,Chinese Academy of Geological Science,Shijiazhuang 050061,Hebei,China;Key Laboratory of Groundwater Sciences and Engineering,Ministry of Natural Resources,Shijiazhuang 050061,Hebei,China)

机构地区：[1]中国地质科学院水文地质环境地质研究所,河北石家庄050061 [2]自然资源部地下水科学与工程重点实验室,河北石家庄050061

出　　处：《西北地质》2022年第2期227-236,共10页Northwestern Geology

基　　金：中国地质调查局“共和盆地水文地质环境地质调查评价”(1212011220944)。

摘　　要：共和盆地地处黄河流域生态保护“一带五区多点”空间布局的水土保持区,地下水是盆地的主要供水水源,也是维持盆地脆弱生态系统的关键因子。针对该区域地下水补给路径不清、深层与浅层地下水相互作用机理认识不够深入的问题,笔者利用氢、氧同位素与^(14)C同位素,探讨了区域地下水补给机理及其对生态环境的指示作用。研究结果表明,盆地地下水补给源主要为哇洪山和青海南山山区河流侧向入渗补给;潜水主要为1952年以后降雨入渗补给,循环交替较快。承压水^(14)C年龄最高达19384.7 a,盆地西部边界和东部排泄区地下水δ^(18) O和δD特征相似,^(14)C测年年龄相近,其补给来源主要为形成于距今10000~60000 a冰期时古水,反映共和盆地与西部茶卡盆地没有明显的水力联系。中部承压水受山区降雨侧向入渗和沙珠玉河入渗补给,地下水年龄较盆地西部边界和东部排泄区年轻。该研究揭示了共和盆地地表水、潜水和承压水之间的补给排泄相互转化关系,对盆地水资源开发和生态环境保护具有重要意义。Gonghe basin is located in the soil and water conservation zone of the Yellow river basin ecological reserve.Groundwater is the main water supply source and also the key factor for maintaining the fragile ecosystem in this basin.However,the path of regional groundwater recharge and the mechanism of deep and shallow groundwater interaction are still unclear.Using hydrogen,oxygen and ^(14)C isotopes,the mechanism of regional groundwater recharge and its indicative effect on ecological environment are discussed in this paper.Results show that lateral infiltration recharge of rivers from Wahong Mountain and Qinghai South Mountain is the main groundwater recharge.The recharge of unconfined groundwater is mainly from infiltration of rainfall after the year 1952 with rapid cyclic alternation and the ^(14)C age of the confined groundwater is up to 19384.7a.The groundwater characteristics ofδ^(18)O,δD and the ^(14)C age are similar both in the western boundary of the basin and the eastern drainage area,and its recharge source is mainly from ancient water formed during the ice age of 10000-60000a ago,which reflecting that there is no obvious hydraulic connection between the Gonghe Basin and the western Chaka Basin.The age of the confined groundwater in the middle of the basin is younger than that in the western boundary and the eastern drainage area.For the middle part of the basin,rainfall and Shazhuyu river infiltration are the main recharge.This study reveals the mutual transformation of recharge-discharge among surface water,unconfined groundwater and confined groundwater in Gonghe basin and is of significance for developing and managing groundwater in this area.

关 键 词：同位素 地下水年龄 地下水循环 共和盆地 

分 类 号：P641[天文地球—地质矿产勘探]