The Chemistry Characteristics of Ranang-Kasimbar Hot Springs, Parigi Moutong Regency, Central Sulawesi Province, Sulawesi, Indonesia

The Ranang-Kasimbar area is located in the West Mandala of Sulawesi which is influenced by the tectonic activity of the Palu-Koro fault. The lithology of the study area consists of Cretaceous-Eocene metamorphic rocks, Tertiary breakthrough rocks and Quaternary sedimentary rocks. The structure that developed consists of a horizontal fault with a north-south trend, and a normal fault with a southwest-northeast, northwest-southeast and west-east trending which causes the formation of a depression zone in the middle of the study area and controls the appearance of the Ranang hot spring manifestation. This data was conducted in 2011 and identifying the geothermal manifestations in the Ranang area are hot springs as a result of the interaction process of geothermal fluids flowing by convection to the surface with the temperature about 55-61oC, chloride type (indication of fluid from geothermal reservoir/from depth), neutral pH tends to be alkaline (around 9), and indicates fluid interaction with igneous rock at depth. The dominance of surface water is also seen in the results of the isotope analysis, the enrichment of oxygen-18 is only slightly. This shows that only a partial equilibrium process occurs in the process of interaction of the hot fluid with the surrounding rock. The minimum temperature of the geothermal reservoir in Ranang is estimated at 130 oC. There are also Lambani hot springs which is the distance about 7km from the Ranang hot springs, the temperature about 34-55oC, netural pH, and interpreted has different system with Ranang hot springs.