Geology and Geochemistry of Mataloko Geothermal Area Central Flores-East Nusa Tenggara

Abstract

The Mataloko geothermal Field is situated in the East of Bajawa, the capital city of Ngada District, East Nusatenggara. The thermal features associate with post volcanic activity and the area is surrounded by active volcanoes of Inerie in the southwest, Inelika in the northwest and Ebulobo in the East. Base on volcanism activities, the local stratigraphy sequence can be divided into three main parts of volcanic product : the Tertiary volcanic rocks (3.7-2.4 ma) as basement, Old volcanic rocks of Quaternary (1.1-1.6 ma) and younger Quaternary volcanic rock (0.17-0.2 ma) The Mataloko thermal feature are likely controlled by the northwest-southeast trending Waeluja normal fault. These include fumaroles, steaming grounds, mud-pools, high temperature of acid sulfate water and argillic-advanced argillic type of alteration rocks. The high sulfate, low chloride spring water type and high anomaly of Hg and CO2 gas around this area suggest that the feature area is probably as an up flow zone of the Mataloko geothermal system. The Mataloko geothermal heat sources were deduced from Wolo Belu lava dome and some volcanic cones which are located at the surrounding of the Mataloko geothermal manifestation