シコク チュウオウブ セイブ カミドイ チイキ ト オダ チイキ ニオケル ミカブ リョクショク ガンルイ ノ チシツ コウゾウ
Geological structures of the Mikabu greenstones of the Kamidoi and Oda Areas, Central to West Shikoku
犬房, 陽一 アース環境サービス株式会社
前川, 寛和 大阪府立大学大学院理学系研究科物理科学教室
Northern Chichibu Terrain
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.
徳島大学総合科学部自然科学研究 = Natural Science Research, The University of Tokushima
LID201104191003.pdf 486 KB