新疆焉耆盆地平原区地下水演化的主要水文地球化学过程分析  

Hydrogeochemical process of evolution of groundwater in plain area of Yanqi,Xinjiang

作　　者：赵江涛[1,2] 周金龙[2] 梁川[1,3] 尹钟[1] 鲍正德 钱立[1] 

机构地区：[1]四川大学锦城学院土木工程系,成都611731 [2]新疆农业大学水利与土木工程学院,乌鲁木齐830052 [3]四川大学水利水电学院,成都610065

出　　处：《环境化学》2017年第6期1397-1406,共10页Environmental Chemistry

基　　金：中国地质调查局项目(1212011220982);新疆自治区水文学及水资源重点学科基金(xjswszyzdxk20101202)资助~~

摘　　要：地下水资源是焉耆盆地生活、生产及生态用水的主要供水水源.深入研究焉耆盆地地下水演化特征及水文地球化学过程对合理开发地下水资源及保护地下水环境具有重要意义.利用Gibbs图阐明了焉耆盆地平原区地下水所经历的水文地球化学作用(大气降水、蒸发浓缩和岩石风化作用等),平原区采样点主要分布在Gisbbs图的右上角及中部左侧,表明平原区地下水受风化、蒸发浓缩作用影响,且受大气降水作用影响较小;方解石、白云石等碳酸盐矿物,以及岩盐、石膏等蒸发岩的风化溶解是平原区地下水主要离子来源,应用PHREEQC地球化学模拟软件计算了平原区各矿物饱和指数,大部分采样点方解石与白云石未达到饱和状态;随着平原区地下水中的TDS和Cl-浓度的逐渐升高,Mg^(2+)在地下水中的富集受到了白云石沉淀过程的限制,而Ca^(2+)的含量随TDS的增大而持续增加,并结合平原区2011年与2014年地下水水化学Piper三线图,平原区地下水大部分呈Ca·Na型或者Ca·Mg型;地下水ORP值均为正值,表明平原区地下水处于氧化状态;根据离子比例法,γNa+/γ(Na++Ca^(2+)+Mg^(2+))比值深层承压水>潜水>浅层承压水,表明平原区地下水阳离子交换作用由强到弱依次为深层承压水、潜水、浅层承压水.Groundwater is the dominant water supply source of domestic water,production water and ecological water in the Yanqi Basin. Study on the groundwater evolution characteristics and hydrogeochemical processes is of great significance in the exploitation of groundwater resources and protection of the groundwater environment. Gibbs diagram was used to simulate the hydrogeochemical processes（including hydrolysis, evaporation, cation exchange and oxidation-reduction） whichdecided the chemical characteristics of the plain area in the Yanqi Basin. The sampling sites in the plain area were mainly distributed in the upper right corner and the middle part of the Gisbbs diagram, which indicated that the groundwater was affected by weathering and evaporation concentration in the plain area,and was less affected by the precipitation.The weathering dissolution of calcite,dolomite,rock salt and gypsum were the main source of groundwater in plain areas,The saturation indices of the minerals in plain area were calculated by PHREEQC geochemical software.The calcite and dolomite of majorty points were not saturated. With the increase of TDS and Clconcentration in the groundwater, the enrichment of Mg^2＋of groundwater was limited by the precipitation of dolomite. And the content of Ca^2＋increased continuously with the increase of TDS.Combined with Piper three-line diagram of groundwater chemistry in plain area in 2011 and 2014,most of chemical types of groundwater in plain area were Ca·Na or Ca·Mg. The ORP of groundwater was positive,which indicated that the groundwater of plain areas was in the oxidation state.According to the ion proportion method,the ratio of γNa＋/γ（Na＋＋ Ca^2＋＋ Mg^2＋） was deep confined water phreatic water shallow confined water and showed that cation exchanged from strong to weak in order of deep confined water,phreatic water,shallow confined water. The main factors for the change of groundwater chemistry was the urbanization in plain area.

关 键 词：地下水 演化 水文地球化学过程 焉耆盆地平原区 新疆 

分 类 号：P641.3[天文地球—地质矿产勘探]