At the Core – October 2021 Keep up to date on what is going on at Utah FORGE. Read about it in the...
Basalt
Dark grey fine grained volcanic rock composed of plagioclase, pyroxene and olivine, with relatively low silica (45-52 wt %). The composition reflects an upper mantle origin. Basalt is the most common type of volcanic rock on Earth, and it erupts from mid-ocean spreading ridges and hot spots (e.g., Hawaii and Iceland). The intrusive coarsely crystalline igneous rock equivalent is called gabbro.
Geothermal Glossary
Word of the Week – Proppant
Proppant Sand-sized solid grains that are injected in a fluid suspension and used to hold open stimulated fractures in a geothermal reservoir.
Word of the Week – Propylitic Alteration
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),...
Word of the Week – Rhyolite
Rhyolite Light colored fined grained volcanic rock composed of glass, quartz, K-feldspar and plagioclase, with relatively high silica (69-77 wt %). The composition reflects partial melting of continental crust. Rhyolitic volcanism is a feature of both Yellowstone...