PREFACE

Turner (1948) attempted to summarize the mineral paragenesis of metamorphic rocks in terms of Eskola’s facies concept. Since that date a considerable mass of experimental data bearing on metamorphic reactions and stability ranges of some of the simpler metamorphic minerals has appeared in various journals. Theoretical treatment of metamorphic problems from the thermodynamic standpoint, initiated by Johnston and Niggli in their classic paper (1913), has progressed notably. It is no longer satisfactory to interpret metamorphic mineral assemblages as products of reactions in a closed system determined by a single physical variable such as temperature or confining pressure. Rather we envisage...