宁夏海原盆地地下水淡水——微咸水分布规律  

Distribution law of ground freshwater-brackishwater in the Haiyuan basin,Ningxia

作　　者：李海学[1] 程旭学[1] 李林阳 王雨山[1] 刘伟坡[1] 张梦南[1] LI Haixue;CHENG Xuxue;LI Linyang;WANG Yushan;LIU Weipo;ZHANG Mengnan(Center for Hydrogeology and Environment Geology,China Geological Survey,Baoding 071051,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,保定071051

出　　处：《干旱区资源与环境》2019年第4期182-188,共7页Journal of Arid Land Resources and Environment

基　　金：中国地质调查局地质大调查项目"陕甘宁革命老区1:5万水文地质调查"(项目编码:121201012000161311)资助

摘　　要：结合地质调查成果,基于88组水化学数据分析了研究区地下水矿化度与主要离子的相关性特征、圈定了淡水-微咸水的分布范围、总结了淡水-微咸水分布规律及其成因。结果表明:海原盆地淡水-微咸水面积共计544. 2km2,淡水资源主要分布在南华山断陷洼地、古洪积扇及河谷阶地等第四系松散含水层和古河道附近浅部第三系含水层,微咸水主要分布在洪积扇前缘和西安州洼地;地下水矿化度与Na+、Mg2+、SO2-4、Cl-相关性显著,沿地下水流向地下水矿化度逐渐增大,地形坡降大、地下水循环交替强烈、水岩作用时间短的区域地下水矿化度一般相对较小;适度的人类开采可以改善浅层地下水水质,过度开采导致深层咸水顶托补给造成上部潜水矿化度升高。Combining with the results of the China Geological Survey,88 hydrochemical samples from the Haiyuan basin were analyzed in order to study the correlation characteristics between groundwater salinity and major ions,and to define the distribution and formation mechanisms of freshwater-brackishwater.The results showed that freshwater-brackish groundwater covered an area of 544.2 km^2 in the Haiyuan basin,and freshwater distributed in Quaternary loose aquifers of the Nanhua Mountain’s Cenozoic Fault Basin,alluvial fan and river valley terraces.In addition,freshwater was also found in shallow Tertiary aquifers near Palaeochannel.And brackish water mainly dispersed in the front of alluvial fan and in Xi’an Township.The correlation between groundwater mineralization and Na^+,Mg^2+,SO4^2-and Cl^-was significant in those areas.The degree of mineralization increased along the groundwater flow routine;however,with the increase of terrain slopes,the stronger groundwater circulation and the shorter water-rock interaction time,mineralization generally showed relatively low.The moderate human exploitation of groundwater improved the phreatic water quality,nevertheless overexploitation led to the recharge of deep salty water and increased the mineralization of the upper groundwater layers.

关 键 词：地下水 分布规律 矿化度 淡水-微咸水 

分 类 号：P641[天文地球—地质矿产勘探]