Geochemical characterization and origins of the thermal springs in southern Gaoligong Mountains, China

Hydrogeochemistry and environmental isotope data were utilized to understand origins and characteristics of the thermal springs in southern Gaoligong Mountains, China. The groundwater at the thermal springs has low values of total dissolved solids, and its main water types are Na-HCO₃. The thermal springs are mainly recharged from meteoric precipitations. The recharge areas are located near the springs at an approximate elevation of 1,800 m. The groundwater of the thermal springs is immature and partially equilibrated with a strong mixture of the shallow cold waters during the flow process. The shallow cold water accounts for more than 90 %. The temperatures of thermal reservoir that feed the springs are between 146 and 260 °C, and the calculated groundwater circulation depths range from 2,000 to 5,700 m below ground surface.