Abstract
The Mataloko geothermal field is situated east of Bajawa, the capital city of Ngada District. The field is bordered by several volcanoes; Ebulobo in the east, Inelika in the northwest and Inerie in the south-southwest. The local surface geology was affected by volcanic activities of some eruption centers during Tertiary to Quaternary ages. At least two periods of volcanic activities were identified. One is the Tertiary volcanic basement composed of the Maumbawa lava flow and Green Tuff; the other is the Quaternary volcanic rocks characterized by Watumanu, Rotogesa and young volcanic cones. Based on the lithologic logs of the MTL-01, MT-1 and MT-2 shallow wells, the stratigraphic sequences of the MT-1 and MT-2 are nearly the same, but the well MTL-01 is characterized by dacitic ash tuff. In general, subsurface geology of the Mataloko geothermal field consists of Quaternary ash tuff of dacitic composition, pyroxene andesite intercalated with hornblende andesite and pyroclatic deposits.
