CLASSIFICATION OF REGIONAL METAMORPHIC FACIES AND CRITERIA FOR THE CLASSIFICATION

Metamorphic facies aims at studying mineral assemblages of metamorphic rocks and their formative conditions by applying physico-chemical concepts and principles.In regional surveys,mineral prospecting and research work in metamorphic terranes,metamorphic facies has become the major content in the study of metamorphic conditions of rocks. Metamorphic facies and metamorphic facies series are now also the major content of the metamorphic maps already compiled or being compiled at home and abroad. The concept of metamorphic facies introduced by Eskola（1915）has been widely applied by geologists both at home and abroad,but there are a lot of controversies regarding some problems of metamorphic facies,and there are divergent opinions on the number,nomenclature and classification criteria of metamorphic facies. In response to the demand for the compilation of the Metamorphic Map of China, the author analysed and studied relevant data both at home and abroad,and in consideration of the cases in some metamorphic terranes in China, the author has proposed a scheme of classification and nomenclature of regional metamorphic facies.In this scheme, regional metamorphic facies is divided into 1aumontite facies,prehnite-pumpellyite facies,lower greenschist facies,higher greenschist facies,lower amphibolite facies,higher amphibolite facies,granulite facies,glaucophae schist facies and eclogite facies.The discussion focuses on the criteria for classfication of the above-mentioned. regional metamorphic facies.