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

概要

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Geological structures of the Mikabu greenstones and northern margin of the Chichibu Terrainwere studied in the Kamidoi and Oda Areas in Central to West Shikoku. It has been thought that theMikabu 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, clarifiedthat the Mikabu greenstones composed of tuff and tuff breccia occur in a narrow zone there. TheMikabu greenstones are intercalated in the Jurassic accretionary complex as a layered unit, and arefolded by the Kamiyakawa-Ikegawa antiform. The Mikabu greenstones of the Oda Area are alsointercalated in the Jurassic complex and form the Odagawa antiform, which is the same as theKamiyakawa-Ikegawa antiform. There is no large thrusts along the southern margin of the Mikabugreenstones. The Jurassic complexes under the Mikabu greenstones of the Kamidoi and Oda Areashave undergone the pumpellyite-actinolite facies metamorphism, like as the Mikabu greenstones andthe overlying Jurassic complex. The Kiyomizu Tectonic Line, which runs along the northernmargin of the Mikabu greenstones, is probably a large fault, dividing the Sanbagawa Terrain from theMikabu greenstones and the Nortner Chichibu Terrain.
徳島大学の論文