Photo by Jennifer Boyer: Geothermal Greenhouses in Hveragerði, Iceland. Geothermal Greenhouses: A...

Depressions filled with hot bubbling mud commonly associated with steaming ground. The mud is mostly made up of clay minerals which form as an alteration product and interaction between acidic condensed steam and rock-forming minerals.
Epidote Alumino-silicate hydrothermal mineral having a distinctive yellow-green color that is used a mineral geothermometer, forming at temperatures above ~230°C. The first down hole occurrence of epidote commonly coincides with the top of a high-temperature...
Felsic A geological term referring to igneous rocks that are equivalent to rhyolite and granite in composition.
Flowback Return flow of slickwater that was injected during a stimulation. This is a highly controlled process in which well head pressure is reduced to allow managed fluid recovery. Fluids are commonly sampled and chemically analyzed to determine the effects of...