Studies of geothermal waters in Jiangxi Province using isotope techniques

Abstract

Isotope hydrogeological studies of thermal waters conducted in the Lushan hotspring area, northern Jiangxi Province, the Maanping hotspring area, central Jiangxi, and the Henjing hotspring area, southern Jiangxi Province show that the local meteoric water line of Jiangxi Province is similar to the Craig line. The δD and δ¹⁸O values of geothermal waters in the province are roughly in accord with the local meteoric line, which implies that the thermal waters are of meteoric origin. Variations of isotopic composition of natural waters in the study areas reveal that the recharge areas of the geothermal fields are the adjacent mountains. The ages of geothermal waters measured by different dating methods, such as Ra/Rn dating and tritium dating, range from several decades to several hundred years in the Province which suggests that the geothermal waters are undergoing active circulation. The³He/⁴He ratios of gases from the hotsprings in the Hengjing hotspring area show that the hotspring gases originate from the depth, and probably partly from the mantle source.