Hydrogeochemical Characterization and the Origin of Hot Springs in the Cidanau Geothermal Field, West Java, Indonesia

Abstract

The Cidanau geothermal field is situated in Banten province, West Java. Nine water samples from hot spring and well bore were collected and analyzed for their chemical composition and stable isotopes of water. Hot springs are mainly discharging at the northern foot and on the northern slope of Mt. Parakasak. Water temperature, pH, EC were measured in situ, and HCO©ý was analysed with the titration method soon after the sampling. Cation, anion and stable isotopes of hot springs were analyzed in laboratory. On the basis of analysis the hot spring water was divided into three types: HCO©ý, Cl-HCO©ý and SO©þ types. The stable isotope values for ¥ä©ö⁸O and ¥äD range from -7.1¢¶ to -6.7¢¶ and from -43¢¶ to-41¢¶, respectively. These are plotted on the meteoric water line, implying meteoric water origin. Geochemical geothermometry gave estimated reservoir temperature in the range 147-172⁰C.