An introduction to orogenic andesites and crustal growth

Abstract

AbstractThis chapter provides an overview of the current state of research on orogenic andesites. While their importance as proxies to the evolution of the continental crust has long been recognized, andesite genesis has remained highly controversial with a broader consensus yet to be reached. The controversy is fuelled by the question of whether orogenic andesites are primary melts of slab and mantle materials, or instead derivative products of basaltic mantle melts that differentiate in the overlying crust. These hypotheses are addressed in three sections of the book devoted to slab–mantle processes, the complexities of melt differentiation at crustal levels, and models pertaining to arc crustal growth. We believe that cross-fertilization and discussion among seemingly opposite and irreconcilable hypotheses will smooth the pathway towards a holistic communal model of andesite petrogenesis.