Hot spring activity in the Dakongbeng geothermal area, China

Abstract

The Dakongbeng geothermal area, whose hot springs reach a temperature of up to 96°C, has been considered one of the potential high-temperature hydrothermal systems in south-west China. The concentration of dominant cations and anions indicates an NaHCO 3 type of thermal water, whose major constituents in decreasing order are: Na>K>Ca>Mg, HCO 3>SiO 2>Cl>SO 4. On the basis of the silica geothermometer, cation geothermometers, gas geothermometer and activity diagram, the reservoir temperature is estimated at about 200°C. All the thermal waters have originated from meteoric water of a higher altitude that circulated as ground water at considerable depth along faults. The stability of their contents of Cl, SiO 2, δD, δ 18O and of the Cl B , Na Li ratios suggests that the main heat loss process is through steam loss. The geochemistry of the initial liquid has been estimated by single and continuous steam loss. On the basis of its geologic and geographic setting, the Dakongbeng geothermal area appears to belong to the Himalayan geothermal belt and is thus regarded as an area of interest for further study.