Geological structures of the Mikabu greenstones were studied in the Uchiko-Oda Area in West
Shikoku. Greenstones near Mt. Takamori, to the east of Ikazaki, consist of basaltic tuff breccia, tuff and
gabbro. They continue eastward, through Umezu, to the widely distributed Mikabu greenstones near
Mt. Rohgajo and Mimido. Therefore, the greenstones near Mt. Takamori and Umezu can be correlative
with the Mikabu greenstones. The Mikabu greenstones of the Uchiko-Oda Area are intercalated in the
Jurassic accretionary complex as a sheet-like unit, and are folded by the Utsumukiyama and Odagawa
antiforms. The Mikabu greenstones should be included in the northern Chichibu Terrain in the sight of
geological structures. 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 Northern
Chichibu Terrain
