Adakites are intermediate to felsic volcanic rocks that have geochemical characteristics of magma that have partially melted from the altered basalt that is subducted below volcanic arcs. Most magmas derived in subduction zones come from the mantle above the subducting plate when hydrous fluids are released from minerals that break down in the metamorphosed basalt, rise into the mantle, and initiate partial melting. However, Defant and Drummond recognized that when young oceanic crust (less than 25 millions years old) is subducted, adakites are typically produced in the arc. They postulated that when young oceanic crust is subducted it is "warmer" (closer to the mid-ocean ridge where it formed) than crust that is typically subducted. The warmer crust enables melting of the metamorphosed su