Adularia Hydrothermal potassium bearing feldspar that forms in volcanic hosted geothermal reservoirs and is a favorable indicator of boiling and permeable conditions.

Aquifer Porous and permeable rock unit or unconsolidated layer in the subsurface in which all the pores and voids are filled with water. Water supply for wells comes from aquifers.

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...