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Preliminary Assessment of the Geothermal System of the Tiris Volcanic Area, East Java, Indonesia
- Publisher: European Association of Geoscientists & Engineers
- Source: Conference Proceedings, 74th EAGE Conference and Exhibition incorporating EUROPEC 2012, Jun 2012, cp-293-00050
- ISBN: 978-90-73834-27-9
Abstract
Indonesia, with 15 % of the world´s active volcanoes, hosts a total estimated geothermal potential of 27000 MW, where only 800 MWe is installed. Exploration of magmatic remote areas is therefore important. Our investigation area is located at the volcano Lamongan, Tiris East Java, Indonesia, which is part of the modern Sunda arc region, characterized by extensional regime. Warm springs (temperature 35-45 °C) are the evidence of geothermal potential of the area. Numerous maars and cindered cones have been located and studied here, some of them with a NW –SE lineament similar to the Tiris fault (only observed in satellite images). In this first exploration stage we characterized the geochemistry of the springs and investigated the petrology of the rocks. The cation and anion concentration suggests that the fluids derive from sea water intrusion. The high permeable pyroclasites, overlain by low permeable basalt – andesitic basalt, may have channeled the sea water from the coast to the Tiris area. A structural lineament, NW – SE, may control the water intrusion as the lineament of the springs confirm. The high HCO3- concentration has probably a magmatic source, as no carbonate rocks are known in the area.