Migmatites are highly heterogeneous rocks found in high-grade metamorphic environments; they are commonly encountered in the continental crust. Until now, many geologists have been deterred from working with migmatites because of their complex appearance and an unhelpful non-genetic nomenclature. In his "Atlas of Migmatites", Dr. Edward Sawyer provides genetically based definitions and a system of nomenclature with which it will be possible to describe and map migmatites effectively and to understand how combinations of factors and processes produce a bewildering morphological diversity. Migmatites are produced by partial melting; to aid the reader in the identification of migmatites, the author describes and illustrates microstructures that can be used to infer the presence of melt or a melt-producing reaction. He also describes how geochemical data can be used to infer petrological processes involved in migmatite development. This book includes the results from two decades of researc