新安江流域上游地区地下水化学特征及水文地球化学作用研究

Study on the chemical characteristics and hydrogeochemistry process of groundwater in the upper reaches of Xin'an River Basin

新安江流域上游地区地下水水化学成分复杂,水与含水介质间发生的各种溶解、沉淀、吸附等水-岩相互作用在地下水复杂成分形成和演化过程中发挥重要功能。文章采用数理统计、主成分分析和聚类分析、Gibbs模型、硅酸平衡、主要离子比例系数等方法,研究了新安江流域上游地区地下水水化学特征和水文地球化学作用,分析了水化学组分来源。结果表明:研究区地下水阳离子以Ca^(2+)、Na^(+)为主,阴离子以HCO_(3)^(-)为主,还存在少量Cl^(-)、SO_(4)^(2-),地下水主要水化学类型为HCO_(3)-Ca型、HCO_(3)-Na·Ca型、HCO_(3)-Ca·Mg型;地下水水化学组分主要来自碳酸盐矿物和硅酸盐矿物的风化溶解,其次来源于蒸发岩的风化溶解。地下水的溶滤作用、阳离子交替吸附作用以及人类生产生活等活动共同影响地下水水化学特征。

The chemical composition of groundwater in the upper reaches of Xin'an River Basin is complex.Water-rock interactions such as dissolution,precipitation and adsorption between water and water-bearing medium play an important role in controlling the formation and evolution of complex groundwater components.In this paper,mathematical statistics,principal component and cluster analysis,Gibbs model,silicic acid balance,proportion coefficient of major ions and other methods are used to study the hydrochemistry characteristics and hydrogeochemical process of the groundwater in the upper reaches of Xin'an River Basin,also analyzed the sources of hydrochemical components.The results show that the cations in groundwater in the study area are mainly Ca^(2+)and Na^(+),the anions are mainly HCO_(3)^(-),with a small amount of Cl^(-)and SO_(4)^(2-).The main hydrochemical types of groundwater are HCO_(3)-Ca,HCO_(3)-Na·Ca and HCO_(3)-Ca·Mg.The hydrochemical components of groundwater are mainly derived from the weathering and dissolution of carbonate and silicate minerals,followed by the weathering dissolution of evaporite.The water chemical characteristics of groundwater are affected by the leaching of groundwater,the cation alternating adsorption and human activities.