Gneiss metamorphic rock

Gneiss

Metamorphic rock that forms under intense pressure and high temperature and that is made of quartz, feldspar, amphibole and mica. Gneiss represents the highest grade of metamorphic rock, which is characterized by alternating bands of dark and light-colored minerals, foliation (i.e., parallel alignment of planar minerals) and tight folding. This rock type is common at mid to deep levels of continental crust.

Geothermal Glossary

Word of the Week – Spudding In

Word of the Week – Spudding In

Spudding In Denotes the start of the well. The term originated from cable tool drilling where spudding is the act of hoisting the drill pipe and letting it fall freely so that the drill bit strikes the bottom of the well bore with sufficient force to break the...

Word of the Week – Stable Isotopes

Word of the Week – Stable Isotopes

Stable Isotopes Refers to non-radioactive isotopes of elements, including those of oxygen, hydrogen, carbon, sulfur, and nitrogen. In geothermal geochemistry, the stable isotope ratios of oxygen (18O/16O) and hydrogen (2H/1H) in thermal waters are used to trace its...

Utah FORGE

Advancing innovative technologies to unlock Earth’s limitless geothermal energy.