The significance of experimental studies for the formation of migmatites.

Abstract

This chapter 1) summarizes the results of experimental studies, which have been used to explain the formation of migmatites; 2) evaluates the significance of these results; 3) discusses cotectic melting of granitic and tonalitic assemblages and explains the detected unstable melting in experiments with plagioclases of intermediate composition; 4) gives a reasonable explanation for the very similar observed composition of plagioclases in the different layers of a migmatite; and 5) makes suggestions for further experimental and petrological investigations. These aims are achieved by descriptions of experimental studies in the haplogranite system Q-Or-Ab-H2O, the tonalite system Q-Ab-An-H2O and the granite system Q-Or-Ab-An-H2O, together with a discussion of plagioclase compositions and suggestions for future research. -J.M.H.