Fluids Chemistry of Low Temperature Geothermal System at Bantarkawung Geothermal Area, Brebes, Central Java

Abstract

Indonesia has many geothermal areas which are associated with non-volcanic environment. One of them is Bantarkawung, Brebes, Central Java.Characteristic of the Bantarkawung hot springs is described in this paper. The methodology using in this study are field observation, taking samples, laboratory analysis and data interpretation. The geothermal manifestations are only Pangebatan hot springs, Buaran, Muara, and Parasi warm springs. The temperatures are about 39,5-56,7 oC with neutral pH. Geologycally, it is consisted of igneous rock, sedimentary rock, volcanic rock, and aluvial. Bantarkawung manifestation has chloride-bicarbonate type of water based on Cl-SO4-HCO3 diagram and plots in partial equilibrium zone based on Na-K-Mg diagram. The temperature of reservoir is about 100-120oC from Na-K geothermometry (low temperature).