Melt-producing versus melt-consuming reactions in pelitic xenoliths and migmatites

Melt-producing reactions have operated both in pelitic xenoliths and in pelitic migmatites, but melt-consuming reactions, related to in situ melt crystallization, are largely restricted to migmatites. Hence, xenolith reaction textures may provide clues on the relative roles of both reaction types in migmatites. A comparison of xenoliths and migmatites results in a catalogue of textural and chemical features, some of which are argued to be diagnostic. The results have implications for the identification of restite in igneous rocks and for the relative importance of prograde and retrograde processes in different domains of layered migmatites.