Investigation of alteration minerals and potential of geothermal energy on the Ambon Island

Abstract

An investigation of alteration minerals has been carried out using the XRD (X-ray diffraction) method in several geothermal areas on Ambon Island. There are 4 (four) regions that are mapped as potential areas for the development of geothermal energy in Ambon islands, including Hatuasa geothermal energy, TalangHaha, Suli, and Waiyari. The results of the investigation interpret that rock samples in the Hatuasa geothermal region are dominated by quartz wacke with rock fragments in this area in the form of quartz minerals, pyroxene, opaque minerals, and feldspar while the matrix is clay minerals. The interpretation of rock samples in the TalangHaha, Suli and Waiyari regions is almost the same which is dominated by feldspathic greywacke with fragments in the form of quartz minerals, opaque minerals, lytic, and feldspar, while the matrix is clay minerals. Those minerals are alteration mineralsfrom the original minerals. The appearance of mineral changes in these areas shows that the reservoir temperature in these areas is very high. In addition to changes in the appearance of minerals, the potential of geothermal energy in some areas of Ambon Island can also be interpreted from the results of measurements of flowrate. Flow discharge in the Hatuasa, TalangHaha, Suli and Waiyari regions ranged from 0.19 m3/second; 0.16 m3/second; 0.13 m3/second and 0.20 m3/second give the results of heat loss calculations which are 86.4 kW; 71.8 kW; 72.4 kW and 114.19 kW. Thus the Hatuasa, TalangHaha, Suli and Waiyari geothermal fields can be used as a basis for recommendations on the utilization of geothermal potential for local governments (indirect use), namely as information to meet the shortage of electricity in Ambon Island.