Isotopic characteristics of the main hot springs in southern Gaoligong Mountain

Abstract：The origins of the main hot springs in southern Gaoligong Mountain and the cyclic characteristics were analyzed by using water chemistry isotope techniques, and some important results were achieved. The hot springs in the area was low-mineralized, alkaline, Na-HCO3 type water,which originated in the rainfall,with characteristics of fast cyclic rate,incomplete water-rock interaction,and flowing in a relatively open oxidation environment. These characteristics are especially outstanding in the Huangcaoba spring and the Sanguan spring. Groundwater recharge areas are mainly located at the elevation of 1800 m and near the spring that is recharged by atmospheric precipitation in the vicinities. There exist two kinds of mixing processes, i.e., shallow and deep mixing processes. Mixing ratio of modern water is above 90% in the Huangcaoba spring and the Sanguan spring. Hot spring thermal reservoir temperature is between 100 and 200℃, and the circular depth is 2000-4000 m.