| Abstract |
Microthermometry is an analytical technique to determine the physical - chemical changes (mostly phase transitions) that occur within the fluid inclusions in a crystal. This technique has been a valuable tool in strengthening geological and geochemical interpretations in El Salvador’s geothermal projects. The Geology laboratory of LaGeo acquired for the first time the fluid inclusion system in 2012, where several samples from different geothermal fields in the country have been analyzed to determine the thermal evolution of the geothermal system, as well as to support in updating the conceptual models of different geothermal fields. Likewise, the equipment serves as an educational support to the regional diploma course for Latin America held yearly in El Salvador. Homogenization temperatures (Th) and melting temperatures (Tm) were measured in fluid inclusions of crystals present as vein minerals in core samples of wells at reservoir depths. Quartz and calcite crystals were usually the host minerals of fluid inclusions in samples that were analyzed. Most of the Th measurements were in equilibrium with the reservoir temperatures of the wells and the mineralogical facies established during drilling of the wells. Furthermore, different geochemical processes were observed within the geothermal system such as boiling, conductive cooling and dilution. At present, fluid inclusion studies are being undertaken in core samples obtained during the first few years (1980s – 1990s) of development of Ahuachapan and Berlin geothermal fields, as part of geological and geochemical investigations and to help update the conceptual models, as well as a tool in deep exploration especially during drilling in new areas in El Salvador. |