四国中央部～西部，上土居地域と小田地域における御荷鉾緑色岩類の地質構造

Geological structures of the Mikabu greenstones and northern margin of the Chichibu Terrain were studied in the Kamidoi and Oda Areas in Central to West Shikoku. It has been thought that the Mikabu greenstones did not occur in the Kamidoi and Nishi-ishihara Areas in Central Shikoku, because of the existence of the Nishi-ishihara and Ikegawa thrusts. This study, however, clarified that the Mikabu greenstones composed of tuff and tuff breccia occur in a narrow zone there. The Mikabu greenstones are intercalated in the Jurassic accretionary complex as a layered unit, and are folded by the Kamiyakawa-Ikegawa antiform. The Mikabu greenstones of the Oda Area are also intercalated in the Jurassic complex and form the Odagawa antiform, which is the same as the Kamiyakawa-Ikegawa antiform. There is no large thrusts along the southern margin of the Mikabu greenstones. The Jurassic complexes under the Mikabu greenstones of the Kamidoi and Oda Areas have undergone the pumpellyite-actinolite facies metamorphism, like as the Mikabu greenstones and the overlying Jurassic complex. The Kiyomizu Tectonic Line, which runs along the northern margin of the Mikabu greenstones, is probably a large fault, dividing the Sanbagawa Terrain from the Mikabu greenstones and the Nortner Chichibu Terrain.