Dynamic characteristics and genesis of hydrogen and oxygen stable isotopes in Hot Water Wells in Xiaxian County, Shanxi Province

Through analyzing the test data of hydrogen and oxygen isotope and SiO₂ temperature scale of hot water well in Xiaxian County, Shanxi Province, the characteristics of stable hydrogen and oxygen isotopes, the groundwater recharge source and the depth of circulation are studied. The results show that: ① δ¹⁸O ranges from −10.10‰ to −9.47‰, and δD ranges from −72.75‰ to −71.32‰ in Xiaxian hot water well. ② Stable hydrogen and oxygen isotopes in hot water wells in Xiaxian County are located near the atmospheric precipitation line, but shift to the right of it, showing that the recharge source of hot water well in Xiaxian County is mainly atmospheric precipitation, and there is a certain degree of water-rock interaction. ③ The reservoir temperature of Xiaxian hot water well is 63.7 ~ 96.0 ℃, the circulation depth is 0.95 ~ 2.4 km, and the recharge elevation is 1 370 m. ④ The characteristics of stable hydrogen and oxygen isotopes, the characteristics of water-rock interaction and the depth of circulation reveal that the hot water well in Xiaxian County is caused by the infiltration of atmospheric precipitation from Zhongtiaoshan Mountain along the fault. Through deep circulation, it is heated in the underground thermal reservoir and enriched through the Zhongtiaoshan fault to form hot water. The results provide a scientific basis for the hot groundwater recharge cycle and seismic monitoring in Xiaxian County.