应用环境同位素水文地球化学方法,结合区域沉积演化史,对关中盆地固市凹陷、咸阳-礼泉断阶和西安凹陷深部地下热水成因类型进行了探讨,并就残存沉积水存在的可能性,寻找氢氧同位素关系、硫氧同位素关系、碳氧同位素关系、N(87Sr)/N(86Sr)与古盐度的关系等环境同位素证据,rNa/rCl值、ρ(Cl-)/ρ(Br-)、rBr/rI值与ρ(Cl-)的关系等水文地球化学证据以及沉积演化史证据。结果表明:固市凹陷华阴地下热水的同位素、水文地球化学特征已基本符合沉积水的特征,推测其为混有古入渗水的残存沉积水;固市凹陷华阴之外的其他构造单元、咸阳—礼泉断阶和西安凹陷地下热水的同位素和水文地球化学特征部分接近沉积水的特征,部分介于古入渗水和沉积水之间;咸阳—礼泉断阶东部地下热水可能为古入渗水或残存沉积水与后期入渗水的混合;西安凹陷及咸阳—礼泉断阶西部地下热水属于现代入渗水与古入渗水的混合水。
Combined with the regional sedimentary evolution history,the genetic types of deep geothermal water in Gushi depression,Xianyang-Liquan fault terrace and Xi’an depression of Guanzhong Basin were discussed by the environmental isotope and hydrogeochemistry methods;environmental isotope evidences including the relationships between hydrogen and oxygen isotopes,sulfide and oxygen isotopes,carbon and oxygen isotopes,and N(87 Sr)/N(86 Sr)and paleosalinity,hydrogeochemistry evidences including the relationships of rNa/rCl,ρ(Cl-)/ρ(Br-),rBr/rI toρ(Cl-),and sedimentary evolution evidences were used to find the remaining sedimentary water in the deep geothermal water. The results show that the isotope and hydrogeochemistry characteristics of geothermal water from Huayin in Gushi depression are similar with that of sedimentary water,so that the geothermal water is remaining sedimentary water mixed with paleo-leaching water;the isotope and hydrogeochemistry characteristics of geothe