QAP triangle

Updated About encyclopedia.com content Print Article Share Article
views updated

QAP triangle A three-component, modal classification scheme for igneous rocks of granitic affinity based on the relative proportions of: quartz (Q); alkali feldspar (including albite if the anorthite content is less than 5%) (A); and plagioclase feldspar (containing more than 5% anorthite (P).

More From Encyclopedia.com


MORE ON THIS TOPIC