摘要
西藏是我国重要的生态安全屏障,拉萨地区地下水化学特征及形成机制研究,对揭示青藏高原现代表生过程变化机理具有重要作用,对服务国家生态安全建设具有重要意义。本文通过拉萨地区地下水调查、水样采集与分析,综合运用Gibbs模型模拟、水化学分析方法分析了地下水化学特征及水岩作用机理。结果表明:地下水电导率介于38.80~1193.00μS/cm,平均值为123.99μS/cm,总溶解性固体(total dissolvedsolids,TDS)含量介于44.05~1050.55 mg/L,平均值为150.75 mg/L,pH值大于7,属弱碱性水,地下水化学类型为HCO_(3)-Ca型和Cl-Na型,其中Cl-Na型水为地下温泉水。地下水形成过程主要是碳酸盐岩和硅酸盐岩的溶解、阳离子交换等作用下的结果,且受到一定程度的人为因素影响;地下水中的Na^(+)、K^(+)和Cl^(-)主要来自盐岩矿物的风化溶解,过量的Na^(+)、K^(+)来源于钠长石和钾长石等硅酸盐矿物的溶解,HCO_(3)^(-)、Ca^(2+)、Mg^(2+)和SO_(4)^(2-)主要来自方解石、白云石、石膏以及其他含钙镁矿物的溶解。
Tibet is an important ecological barrier in China.Studies on the chemical characteristics and formation mechanism of groundwater in the Lhasa area play an important role in revealing the mechanism of current epigenetic changes on the Qinghai-Tibet Plateau,and they are of great significance in building ecological security in the nation.In this paper,we analyzed the chemical characteristics of groundwater and the mechanism of water-rock interaction by means of groundwater survey and water sample collection and analysis in the Lhasa area,combined with Gibbs model simulation and hydrochemical analysis.The results showed that the groundwater conductivity ranged from 38.80 to 1193.00μS/cm,averaging at 123.99μS/cm;the TDS ranged from 44.05 to 1050.55 mg/L,or 150.75 mg/L on average;the pH level of groundwater was greater than 7,weakly alkaline;and groundwater is HCO_(3)^(-)-Ca and Cl-Na types,with the latter attributed to underground spring water.The groundwater formation process is mainly associated with the dissolution of carbonate and silicate rocks,cation exchange,and so on,and affected by human factors to a certain extent.The Na+,K+and Cl-in groundwater are mainly from the weathering of salt minerals;the excess Na+,K+are from the dissolution of silicate minerals,such as sodium and potassium feldspars;and HCO_(3)^(-),Ca^(2+),Mg^(2+)and SO_(4)^(2-) come mainly from the dissolution of calcite,dolomite,gypsum and other calcium-magnesium minerals.
作者
林聪业
孙占学
高柏
华恩祥
张海阳
杨芬
高杨
蒋文波
姜心月
LIN Congye;SUN Zhanxue;GAO Bai;HUA Enxiang;ZHANG Haiyang;YANG Fen;GAO Yang;JIANG Wenbo;JIANG Xinyue(State Key Laboratory of Nuclear Resources and Environment,East China University of Technology,Nanchang 330013,China;School of Water Resources and Environmental Engineering,East China University of Technology,Nanchang 330013,China;Yangtze River College,East China University of Technology,Fuzhou 344100,China)
出处
《地学前缘》
EI
CAS
CSCD
北大核心
2021年第5期49-58,共10页
Earth Science Frontiers
基金
国家自然科学基金项目(41162007,41362011)
江西省重点研发计划(2018ACG70023)
江西省科技厅项目(21203000051)
江西省科技厅“三援”专项“气候变化和人类活动下拉萨河水文地球化学特征及其环境影响研究与技术示范”。
关键词
拉萨地区
地下水
水化学特征
水岩模型
离子比值
Lhasa area
groundwater
hydrochemical characteristics
water-rock model
ion ratios
