Orogenic Andesites and Crustal Growth

Book excerpt: Orogenic andesites have long intrigued scientists because of their remarkable compositional similarities to the continental crust. The significance of orogenic andesites as proxies to continental crust formation has been recognized for over 30 years, but no consensus model of andesite genesis exists. Much of the controversy revolves around whether orogenic andesites are primary mantle melts of slab and mantle materials, or instead evolve from basaltic mantle melts at shallower crustal levels. In three sections, this book provides an overview of andesite genesis at convergent margins that focuses on the slab–mantle interaction, crustal processing and andesite evolution through the life of volcanic arcs. Without favouring a particular view, the books aims to engender cross-fertilization and discussion that will smooth the pathway towards a holistic communal model of andesite petrogenesis and its role within the broader geochemical cycles of the Earth.