Geochemistry analysis of geothermal water in Tulabolo Timur, Sulawesi, Indonesia

Gorontalo has several geothermal manifestations, such as Lombongo, Pangi, Libungo, Hungayono and Tulabolo Timur. Research on geothermal areas must be carried out to obtain surface and subsurface information, then the geothermal areas can be further developed. The purpose of this study was to analyse the geochemistry water of the geothermal water in Tulabolo Timur, Bone Bolango Regency, Gorontalo Province, Sulawesi, Indonesia. The research method is divided into field observations and laboratory analysis. Data processing using Atomic Absorption Spectrophotometer (AAS) for cation and anion test. Data processing using Picaro Water Isotope Analyzer for isotope test. Subsurface temperature is determined using the geothermometer Na-K Giggenbach formula. The results of this research show that the fluid type of Tulabolo Timur geothermal area is chloride and the origin of fluid is from deep reservoir. Geothermal fluid when it approaches the surface is not affected by surrounding rocks. Tulabolo Timur geothermal fluids are categorized in the upflow zone. Geothermal fluid when it reaches the surface is diluted with meteoric water. Meteoric water is infiltrated below the surface in the recharge area, which is located in the north and south of the study area. The subsurface temperature of Tulabolo Timur is included in the high-temperature system.