Relationship between Clinopyroxene Composition and the Formation Environment of Volcanic Host Rocks

This work presents new binary and ternary diagrams based on the chemical composition of volcanic clinopyroxenes that distinguish the tectonic environments in which their host rocks were formed. The present work identifies the following tectonic environments: intraplate calc-alkaline volcanism (IP), alkaline volcanism in a thinned continental crust (CI), alkaline volcanism in islands over an oceanic crust (OI), calc-alkaline volcanism in subduction zones (SU), calc-alkaline volcanism originating in crustal anatexis (AX), and ulrapotassic volcanism (UP). The SU field was subdivided into andesitic (AN) and trachyandesitic (TA) compositions.