Development of unconventional method for mapping the surface hydrothermal alteration in wayang windu geothermal field

Abstract

The Wayang Windu geothermal field, a geothermal system zone that produces energy sources located in Pengalengan and Kertasari Districts, Bandung Regency, West Java, Indonesia. The interpretation of surface minerals considers the alterations in volcanic rocks that occur at the research site. The distribution of surface minerals is closely related to the fracture pattern and the position of manifestation. The testing method that we used is the X-Ray diffraction method, which aimed to identify surface minerals. Silica (cristobalite, quartz, tridymite, opal), sulfate (alunite), oxide minerals, and clay minerals (kaolinite, smectite) are minerals that are often found on the surface. Native sulfur is often found in the primary manifestation of the crater. X-Ray Fluorescence is used to determine the main elements and traces in a sample. Andesite and andesite-basaltic-rock are rock types that are found in the research area. The XRF analysis results show that the SiO2 distribution is inversely proportional to the Al2O3, Fe2O3, and K2O distributions.