While enjoying the first days of 2025, we’ve taken a moment to reflect on everything that Utah FORGE accomplished during the past year. There’s a lot to be proud of!
Propylitic Alteration
A term borrowed from studies of hydrothermal ore deposits that refers to an assemblage of secondary hydrothermal minerals which forms in igneous rocks. This assemblage is made up of chlorite, illite, feldspar (both Na and K-rich varieties), epidote, calcite and pyrite, imparting a dark green tint to the appearance of altered rocks. It is commonly developed in volcanic-plutonic sequences that host high-temperature geothermal reservoirs.
Geothermal Glossary
Word of the Week – Cement Bond Log
Cement Bond Log A geophysical well log that is obtained using a sonic-type tool on a wireline. The result helps to confirm the integrity of the hardened cement that was injected to form a bond between well casing and the adjacent rock formation.
Word of the Week – Chemical Geothermometer
Chemical Geothermometer A temperature that is calculated based on the chemical composition of a hydrothermal fluid and involves knowing a ratio (e.g., Na/K) or knowing the absolute concentration of a species (e.g., SiO2). Temperature is computed using a simple...
Word of the Week – Chlorite
Chlorite A micaceous mineral that is commonly green-colored, composed of iron and/or magnesium, and forms due to hydrothermal alteration of amphiboles, pyroxenes, and feldspars.