广安市平行岭谷区地下水化学特征及控制因素分析

Groundwater chemical characteristics and analysis of the controlling factors in parallel ridge valley area of Guang an City

广安市渠江以东是川东典型的平行岭谷区,具有独特的水文地质条件,为探寻该区域地下水化学特征及控制因素,运用Piper三线图、Gibbs图、Phreeqc软件、离子比例系数图及Pearson相关性分析等方法,结合区域水文地质条件综合分析区域地下水化学组分空间分布特征、水岩作用类型、地下水化学组分来源及其主控因素。研究结果表明:研究区内浅层地下水主要为低溶解性总固体(total dissolved solids,TDS)的淡水,浅层地下水阴离子主要为HCO_(3)^(-)、SO_(4)^(2-),阳离子以Ca^(2+)、Na^(+)为主,地下水类型以HCO_(3)^(-)-Ca^(2+)型、HCO_(3)^(-)-Ca^(2+)·Mg^(2+)型和HCO_(3)^(-)-Ca^(2+)·Na^(+)型为主;地下水水化学组分主要来源于碳酸盐岩及硅酸岩溶滤,盐岩对地下水影响小;地下水中的钾盐、石膏、硬石膏、盐岩、萤石均处于非饱和状态中,地层中相关矿物是地下水中相关离子的主要来源;地下水化学组分主要受到溶滤作用、正向阳离子交换、煤矿开采及农业活动控制。研究结果可为研究区水资源合理开发利用、生态环境保护以及成渝区域经济发展提供科学依据。

The eastern Qujiang of Guang an City is a typical paralleled ridge valley area with unique hydrogeological conditions.The Piper triplex map,Gibbs map,Phreeqc software,ion proportional coefficient map and Pearson correlation analysis methods were used to study the chemical characteristics and the controlling factors of groundwater.And the spatial distribution of groundwater chemical components,water-rock interaction types and groundwater chemical components source and its controlling factors were comprehensively analyzed combined with regional hydrogeological conditions.The results show that shallow groundwater in the study area is low TDS fresh water.The shallow groundwater anions are mainly HCO_(3)^(-),SO_(4)^(2-),and the cations are mainly Ca^(2+),Na^(+).The groundwater types are mainly HCO_(3)^(-)-Ca^(2+),HCO_(3)^(-)-Ca^(2+).Mg^(2+)and HCO_(3)^(-)Ca^(2+)·Na^(+).The groundwater hydrochemical component mainly comes from the weathering of carbonate rock and silicate karst filtration,and salt rock has little effect on groundwater.The potassium salt,gypsum,anhydrite,salt rock and fluorite in groundwater are all in the unsaturated state,and the related minerals in the strata are the sources of related ions in groundwater.The chemical components of groundwater are mainly controlled by leaching,positive cation exchange,coal mining and agricultural activities.The research results could provide some scientific basis for the rational development and utilization of water resources in the study area,ecological environmental protection,and economic derelopment of Chengdu-Chongqiang region.