Petrogenetic grid for metapelites (click to zoom).[1][2] Each line represents a metamorphic reaction. Metamorphic facies included are: BS = Blueschist facies, EC = Eclogite facies, PP = Prehnite-Pumpellyite facies, GS = Greenschist facies, EA = Epidote-Amphibolite facies, AM = Amphibolite facies, GRA = Granulite facies, UHT = Ultra-High Temperature facies, HAE = Hornfels-Albite-Epidote facies, Hbl = Hornblende-Hornfels facies, HPX = Hornfels-Pyroxene Facies, San = Sanidinite facies