Item talk:Q41640
From geokb
Mindat Description
A field term for coarse-grained crystalline rocks with <90% mafics, and calcic plagioclase dominant
Geoscience Ontology Description
Phaneritic crystalline igneous rock that contains less than 90 percent mafic minerals, and up to 20 percent quartz or up to 10 percent feldspathoid in the QAPF fraction. The ratio of plagioclase to total feldspar is greater than 0.65, and anorthite content of the plagioclase is greater than 50 percent. Includes rocks defined modally in QAPF fields 9 and 10 and their subdivisions.
