| Abstract |
The homogenization temperature of fluid inclusion in hydrothermal quartz, anhydrite and calcite from some geothermal fields in Kyushu, Japan, ahs been measured. In the very active Hatchobaru geothermal field, it has revealed that the homogenization temperature concentrates on temperature near the boiling point curve of water, and agrees well with the present reservoir temperatures. On the other hand, in the less active Kirishima geothermal field, inclusions have a wide range of homogenization temperature, and the minimum values of them are quite close to the present underground temperatures. This may indicate that the geothermal field has cooled down to some extent, and also that the fluid inclusion have been formed at various stages of the cooling process. Some considerations suggest that not only the primary inclusions but also the secondary ones can be useful, when they contained only liquid at the time of trapping. |