| Title | Alteration Age Mapping of Some Japanese Geothermal Fields with Improved Thermoluminescence Dating Method |
|---|---|
| Authors | Takashima, Isao; Honda, Sakuro |
| Year | 1988 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Exploration; Japan; Hydrothermal Alteration; Mineralization; Chemical Analysis; Geochemistry; Thermal History |
| Abstract | Improved themoluminescence (TL) dating of altered rocks were carried out for three areas in northeast Japan. TL dating of altered rocks is unique and very useful because the heat sorted in the ground is directly estimated by the age of alteration. Obtained data are plotted to form an alteration age map. Based on this map, geothermal hopeful areas are identified and the relationship between the surface alteration age at the drilling site and subsurface temperature is identified. It also is used for the determination of thermal history of the are. Most of hopeful geothermal areas are located at the surface alteration ages younger than 0.3Ma. Subsurface temperatures differ from place to place even if the alteration ages are almost the same. Such different may attribute to the type and size of hydrothermal system. Overlapping of geothermal activities is identified at the Matsukawa area. |