Geothermal Systems Characteristics in Pesanggrahan Area, Bawang Distric, Batang Regency, Based on Geology and Geochemistry Analysis

Abstract

Research conducted at Pesanggrahan area, Sangubanyu Village, Bawang District, Batang Regency with geographical coordinates at 7°5'00 "00 S - 7°7'30" 00 S, and 109 ° 56'00 "E-109°58'30"E, with an area of around 25 Km². Research methods used quantitative and qualitative methods with descriptive analysis, geological and geochemical analysis. Geochemical fluid samples were taken in manifestations hot springs Pesanggrahan and hot water samples in Sibanteng and Sileri Crater to determine the relationship with geothermal systems in this area. Geomorphology divided into two geomorphology units, they are steep slope and sloping hill. Stratigraphy can be divided into three lithologies, which are andesite breccia, tuff breccia, and tuff sandstone. Based on fluid geochemical characteristics of manifestations, it can be interpreted that hot spring of Pesanggrahan area is outflow zone with bicarbonate-chloride water type, Sibanteng Crater and Sileri Crater, include upflow zone with water type sulfate for Sibanteng Crater, bicarbonate-sulfide water type for Sileri Crater. Environmental source geothermal fluid Pesanggrahan from the magmatic volcanic process. Sources geothermal fluid in Pesanggrahan, Sibanteng and Sileri Crater from meteoric water. Estimated temperature Pesanggrahan in the interval 50-100°C, Sileri Craters 160-180°C, and Sibanteng Craters 140-150°C. The Conceptual model of Pesanggrahan includes a geothermal system that associated with volcanic system and high relief liquid dominated system.

Keywords

• geothermal system
• manifestation
• geochemical
• conceptual model