新疆哈密地区三塘湖北地下水水—岩作用模拟

新疆哈密地区三塘湖北承压水从上游到下游水化学类型演化特点是SO4·HCO3-Na→SO4-Na·Ca→SO4·Cl-Na·Ca→SO4·Cl-Na或SO4-Na·Ca,具有水文地球化学分带性。用PHREEQC软件中反向模拟的方法对此演化机理做了水-岩作用模拟。模拟结果表明:研究区上游→中游→下游的演化过程中基本以石膏、岩盐等矿物的溶解;钙蒙脱石和硝石等的沉淀为主。从研究区上游往下,水中矿物相迁入、迁出的数量逐渐增大,水-岩作用逐渐增强。得到的结论有:矿物相的溶解析出和阳离子交换作用共同控制着演化,从研究区上游往下水-岩作用增强是由于含水介质颗粒逐渐变细所致。

Water rock interaction simulation of groundwater in north Santang lake of Hami district of Xinjiang

Abstract： The evolution of confined groundwater chemical type from upstream to downstream is SO4·HCO3-Na→SO4-Na·Ca→SO4·Cl-Na·Ca→SO4·Cl-Na SO4-Na·Ca, which has the hydro- geochemical zonality. The water- rock interaction simulation has been applied by method of reverse sim- ulation in PHREEQC software to study its mechanism. The simulation results indicate that the process of confined groundwater evolution from upstream to downstream mainly contains the dissolution of gypsum and halite, the sediment of Ca - montmorillonite and niter. The dissolution/precipitation amount of min- erals in groundwater increases gently in study area from upstream to downstream. The water - rock interac- tion gradually increases. It got the two conclusions that the dissolution/precipitation of minerals and posi- tive ion exchange control the evolution, the reason that the water- rock interaction strengthens from up- stream to downstream area is that the particles of water - bearing medium becomes fine gradually.