1984 Volume 93 Issue 4 Pages 191-201
The Mongolian and Chichibu geosynclines were confluent with each other at the Touman-Suifung area and the intrageosynclinal vulcanism was there repeated during the Palaeozoic era.
In the older Mesozoic age the Songnim and Akiyoshi folded mountains in North Korea and in the continental side of Japan respectively were probably on the same line and not very far from the Sikhota Alin. Following the late Jurassic Daebo orogeny in the Ogcheon zone, the Yoshimo embayment was brought to being on the east side of the Korean peninsula. Subsequently the Tsushima basin was produced on the southeast side of the Yongnam land. The folded mountains of W est Japan in the Wealden Oga phase were probably on the east side of the basin.
Later the Tsushima basin was destructed and still later the Miocene sea flooded into the hinter basin of the Sakawa folded mountains. The amount of the shifting of the islands arc of Japan since the late Cretaceous period was lessened in West Japan than North Japan. In my “Sakawa Cycle” of 1941, I attributed the difference of the shifting to the forelands i.e. subaqueous obstacles which are now often called oceanic plates.