Tectonic Evolution of the Japanese Island Arc System

■ Abstract Growth of the Japanese arc system, which has mainly taken place along the continental margin of Asia since the Permian, is the result of subduction of the ancient Pacific ocean floor. Backarc basin formation in the Tertiary shaped the presentday arc configuration. The neotectonic regime, which is characterized by strong eastwest compression, has been triggered by the eastward motion of the Amur plate in the Quaternary. The tectonic evolution of the Japanese arc system includes formation of rock assemblages common in most orogenic belts. Because the origin and presentday tectonics of these assemblages are better defined in the case of the Japanese arc system, study of the system provides useful insight into orogenesis and continental crust evolution.