Hydrochemical characteristics and genesis of geothermal water in Bangor geothermal area, Tibet

The Bange area of Tibet is rich in hot spring geothermal resources. In this study, 11 hot springs with good outcrops in Bange County were selected to collect and analyze hydrochemical and isotope data. Geochemical methods were used to quantitatively analyze the hydrochemical characteristics, reservoir temperature, recharge and hot water age of geothermal systems. The chemical type of geothermal water in the study area is mainly HCO₃-Na water, and the water-rock interaction is the main salt source of geothermal water in the area. The trace elements F and Li are enriched and have a strong positive correlation with Cl, indicating that the hot water is more likely to be mixed with deep fluid. The reservoir temperature is 32~161°C after the cold water is mixed in the study area. The original reservoir temperature of the reservoir is 85~260°C, and the proportion of cold water is 54~95%. The hydrogen and oxygen isotope data show that the main recharge of hot water comes from atmospheric precipitation, and there is a slight ' oxygen drift ' phenomenon. The elevation of the recharge area is 5954~ 6707 m ; the tritium content is generally < 1 TU, which can be qualitatively judged that the geothermal water is mainly recharged by sub-modern water before 1952. The research results provide some basic data for later drilling exploration and provide scientific basis for the rational development and utilization of regional geothermal resources.