中新世古地理からみた中国山地の準平原問題

抄録

In the Chilgoku Mountains, the geological and geomorphological relations between Backbone Ridge surface and Kibi Highland surface as elevated peneplain in the post-Miocene age, have been discussed many times over the past years.
It is noteworthy that IMAMURA et al. newly found out a remnant of the marine Miocene Bihoku group, from the erosion surface on the crest of Mt. Azuma, which is one of the Backbone Ridge surface. The IMAMURA's data is considered to indicate that both Backbone Ridge and Kibi Highland surfaces had been formed by the same post-Miocene peneplanation contemporaneously.
In this article, the significance of its discovery is discussed from the Miocene paleogeographic and post-Miocene geotectonic points of view.