在分析关中盆地水文地质背景的基础上，根据地下水的水文地球化学特征，讨论了研究区潜水的形成机理。结果表明：地下水水动力和水化学类型具有明显的水平分带特征，水动力场对水化学类型的分布起着控制性作用；Cl-浓度与TDS的大小可用来表征研究区的蒸发强度；研究区内地下水离子交换作用主要发生在高矿化度的地下水中。PHREEQC模拟结果显示，沿地下水流向，路径1、2以方解石和石膏的沉淀为主，离子交换方式主要是Na+-Ca2+交换；而路径3则以方解石沉淀、白云石和石膏溶解为主，除发生Na+-Ca2+离子交换外，还存在着Ca2+-Mg2+交换现象。

Based on the hydrogeological conditions in of the Guangzhong Basin and, the regional hydrochemical evolution characteristics of groundwater, the formation mechanism of unconfined groundwater wasere analyzed. The results showed that (1) aht from diving contour and hydrochemical type map, the types of groundwater chemisty and groundwater dynamic have horizontal zoning characteristics, and groundwater dynamic field plays a controling rollcontrols the distribution ofon groundwater chemistry; (2). Cl- concentration and TDS can reflect the intensity of evaporation in the study area; and (3)intensity. Chloride alkaline indices reflect the ion exchange occurs mainly appear in high concentration of groundwater with high salinity in study area. The results of PHREEQC simulation showed that aAlong groundwater flow direction, it mainly occurs the precipitation of calcite and gypsum and the cation exchange of Na+ and Ca2+ occur at paths 1 and 2; whereas. However, at path 3, it mainly occurs the precipitation of calcite and dissolution of gypsum and dolomite, and it also has the exchange of Mg2+ and Ca2+ in addition to Na+ and Ca2+ occur at path 3.

“地方病严重区地下水勘查与供水安全示范综合研究”（1212010634700）