Hydrogeochemistry Of Hotsprings In Northwest Jiangxi Province

The solute-mineral equilibrium and subsurface temperature of three geothermal fields in the northwest of jiangxi province are thoroughly analyzed on the basis of their hydrochemistry and δ18O 、 δD 、3H. The three geothermal fields include Bailing area, Tangqiao area and Jiuxiantang area. The mineral-fluid equilibria are estimated by PHREEQC program,and the mixing of the underground hot water during its upward migration are evaluated by AQUACHEM program.The results showed that geothermal waters from all the three hot spring fields are of meteoric origin, and their recharge elevation are 849-1167 m for Bailing Kangri hotspring of Xiushui County, 829-1014 m for Tangqiao hotspring of Xiushui County, and 657-906 m for Jiuxiantang hotspring of Fengxin County respectively. According to tritium analysis, the age of hotsprings are 5-67 a for Bailing Kangri hotspring, 22-70 a for Tangqiao hot spring, and 4-26 a for Jiuxiantang hot spring respectively. The hydrochemical types of all the thermal waters are HCO3-Na and Na-HCO3-SO4.Solute-mineral equilibrium studies suggest that all the three geothermal fields are departure from equilibrium, only a few minerals such as quartz, chalcedony, calcite convergent at a similar temperature. Because there lack data of aluminium contents in Fengxin Jiuxiantang JX2 hot spring, the lost of aluminosilicate in the process of equilibrium simulation affect the reliability of equilibrium calculation result.Various geochemical geothermometers calculation results show that the chalcedony geothermometer gives subsurface temperature reflecting the real situation of deep thermal storage temperature in the low-mid temperature geothermal systems of Jiangxi province The Na-K geothermometer and Na-K-Ca geothermometer are not suitable for Jiangxi province.The chalcedony geothermometer gives subsurface temperature between 82~1062℃ for Bailing areain Xiushui, 115℃ for Tangqiao areain Xiushui, and 73~85℃ for Jiuxiantang area inFengxin respectively.Integrating the above results and the local conditions, all the three geothermal hot springs can be found have good development prospect.