The Shimanto Terrane

The Shimanto Terrane, middle to late Cretaceous melange terrane of accretion origin, occurs in the outer zone of Southwest Japan just south of the Jurraso-Cretaceous melange terrane (called the Chichibu Terrane); both terranes form narrow belts trending ENE-WSW almost parallel to the Median Tectonic Line in the Kii Peninsula, Shikoku and Kyushu. The Shimanto Terrane is composed principally of middle Cretaceous siliceous shale which contains abundant radiolarian fossils, and of the middle to late Cretaceous clastic formations; however, it sometimes contains many isolated slivers of older rock-formations derived from the Chichibu Terrane.