The Mineral Assemblages of Hydrothermal Alteration in Slate Formation Area - Chingshui Geothermal Field, Taiwan

Abstract

A 3-MWe geothermal energy power plant was installed in Chingshui Geothermal Field, Ilan of Taiwan in 1981. The geothermal energy power plant of Chingshui Geothermal Field is one of few metamorphic geothermal fields in the world. The majority of bedrocks are argillites, slate and metasandstone. We have systematically analyzed samples taken along the two creeks, Chishui and Chilukeng, of the region to understand the spatial distribution of mineral assemblages under the influence of alterations by using XRD. We have found the existence of montmorillonites, a typical product of hydrothermal alteration, is tightly associated with surface hot springs. Kaolinite, Illite and quartz are observed in argillites areas while Kaolinite, Illite, Chlorite and quartz are found in slate formation.