| Abstract |
Xianyang geothermal field is one of the largest areas for the development of geothermal energy in Guanzhong Basin, China. This paper mainly discusses the isotope characteristics of geothermal fluids in Xianyang geothermal field, including the 2H, 18O and 14C in geothermal water and noble gas isotopes in dissolved gases. The isotope 18O content of geothermal water in Xianyang geothermal field has obvious oxygen shift tendency, which is the result of temperature, water-rock ratio and groundwater residence time. The isotope 14C content of geothermal water in Xianyang geothermal field is mostly low, the highest is 23pmc, and some water samples are lower than the detection limit. After correction, the age of Xianyang geothermal water is more than 10,000 years, generally more than 20,000 years. At the same time, according to the ratio of 3He / 4He and 4He / 20Ne of the noble gas isotope in geothermal water dissolved gas, it is proved that the Weibei fault in the Xianyang geothermal field only takes the thermal material of the crust. The circulation depth of the fluids is only within the depth of the crust. |