Pyroxenite melting at subduction zones

Abstract Arc magmatism is thought to be driven by peridotite melting in the mantle wedge. Yet pyroxenites are ubiquitous region beneath magmatic arcs. Because they typically have lower solidi temperatures and higher melt productivities compared peridotite, likely play a significant role magma generation. Here, we use Zn/Fe ratios of global database Pliocene–Holocene primitive arc magmas show that, as crustal thickness overlying plate increases, so does proportion pyroxenite-derived melts relative peridotite-derived melts. In fact, at arcs with thicknesses >40 km, majority sourced from pyroxenite. Major trace element geochemistry pyroxenite consistent derivation mafic frozen en route surface. We hypothesize continental crust wedge displaced toward pressures cooler temperatures, thereby lowering extent allowing pyroxeniteveined dominate budget.