広島県中帯古生層地域における花崗岩類と流紋岩類の岩石学的特性とその相互関係

Granitic and rhyolitic complexes are widely distributed in the Sanyo region, SW Japan. In the eastern part of Hiroshima Pref., granitic complexes have been classified by the author into four petrographic types, namely, the Mannari, Mikawa, Ashida and Hirotani types, and rhyolitic complexes into three types in his later works. As compared with granitic types distributed in the Southern Belt, the granitic complexes in the Middle Belt of the Palaeozoic Terrain are characterized by the presence of the Mannari type granitic complex, which is rich in highly perthitic potassic feldspar of idiomorphic habit. On the basis of interrelations between the granitic and rhyolitic complexes in the Middle Belt in Hiroshima Pref., it can be concluded that the Mannari type is the oldest, while the Hirotani type the youngest.