paired metamorphic belts

views updated

paired metamorphic belts Juxtaposed zones of metamorphic rocks; a high pressure—low temperature (blueschist facies) zone which lies parallel to a low pressure–high temperature (greenschist facies) zone. Paired metamorphic belts were first recognized in Japan, where the greenschists facies is nearer the subduction zone, and similar belts in different Phanerozoic orogenic belts have been identified and are thought to indicate destructive margins. Recently it has been suggested that the Japanese belts are not contemporaneous and are separated by a major transcurrent fault.