基于水化学与环境同位素的额济纳平原区域地下水循环规律解析  

Groundwater circulation in the Ejina Plain:Insights from hydrochemical and environmental isotope studies

作　　者：徐蓉桢 魏世博 李成业 程旭学[1] 周翔宇 XU Rongzhen;WEI Shibo;LI Chengye;CHENG Xuxue;ZHOU Xiangyu(Center for Hydrogeology and Environmental Geology Survey,China Geological Survey,Baoding 071051,China;Inner Mongolia First Hydrogeology and Engineering Geology Exploration Company,Hohhot 010020,China;No.9 Geological Brigade,Hebei Bureau of Geology and Mineral Resources Exploration,Xingtai 054000,China)

机构地区：[1]中国地质调查局水文地质环境地质调查中心,河北保定071051 [2]内蒙古第一水文地质工程地质勘查有限责任公司,内蒙古呼和浩特010020 [3]河北省地质矿产勘查开发局第九地质大队,河北邢台054000

出　　处：《地学前缘》2023年第4期440-450,共11页Earth Science Frontiers

摘　　要：额济纳平原生态环境脆弱,地下水在维持当地生态方面发挥着重要作用。然而,对具有重要生态水文意义断面上地下水循环过程关注不够,阻碍了对额济纳平原地下水循环规律的深入认识。本研究采用水化学与同位素方法解析额济纳平原关键界面地下水循环特征,归纳区域地下水循环模式。结果表明:沙漠区降雨在入渗补给地下水过程中受到过强烈的蒸发影响,研究区中部降雨对地下水补给微弱;额济纳平原北部白垩系潜水接受侧向径流补给,自北向南径流,至东、西居延海一带与南部第四系地下水流系统交汇,白垩系承压水径流滞缓,与上覆潜水水力联系微弱;黑河渗漏强烈影响深度30~50 m,强烈影响宽度10 km,平原中部地下水接受黑河渗漏补给后驱动两侧年龄较老的地下水缓慢侧向径流,在古日乃湖至天鹅湖一带与东部沙漠区地下水流系统交汇,黑河河水与沙漠区地下水不存在补排关系。该研究深化了对额济纳平原地下水循环的认识,对当地生态环境保护与修复、地下水合理开发利用具有指导意义。The Ejina Plain has a fragile ecoenvironment and groundwater plays an important role in maintaining an ecological balance in the region.However,an in-depth understanding of groundwater circulation in the Ejina Plain is lacking due to limited knowledge of groundwater circulation in eco-hydrologically important sections.In this study,the characteristics of groundwater circulation at key aquatic interfaces are investigated through hydrochemical and environmental isotopic analyses,and the regional groundwater circulation patterns are revealed.In the desert area rainfall is strongly affected by evaporation during groundwater recharge via infiltration,while in the central part of the study area rainfall only contributes weakly to groundwater recharge.The Cretaceous phreatic water system in the northern Ejina Plain is recharged by lateral runoff flowing from north to south,and intersects the southern Quaternary groundwater system in the eastern and western Juyanhai areas;whereas stagnant Cretaceous confined water runoff has limited interaction with the overlying phreatic water system.In the central part of the plain groundwater is recharged by seepage from the Heihe River over an effective area of 3050 m deep and 10 km wide,and groundwater recharge drives slow surface runoff on both sides of the river to flow to the Gurinai-Swan Lake district,where it meets the desert groundwater system in the east;the Heihe River has no impact on groundwater recharge/discharge in the desert area.This study deepens our understanding of groundwater circulation in the Ejina Plain and helps to guide local ecological environmental protection and restoration as well as rational development and utilization of groundwater.

关 键 词：地下水循环 水化学 环境同位素 额济纳平原 

分 类 号：P641.3[天文地球—地质矿产勘探] X142[天文地球—地质学] P597[环境科学与工程—环境科学]