Development of database on circular abandoned channel in Japan
Takatori, Ryoichi; Yasue, Kenichi; Tanikawa, Shinichi*; Ninomiya, Atsushi*; Tanase, Atsushi*
To develop a method for estimating late Quaternary uplift rates of inland mountainous terrains where fluvial terraces are poorly developed, we focused on "circular abandoned channels", formed by meander cut-offs or river capture of an incised meandering river. We studied about 1,000 circular abandoned channels distributed throughout the Islands of Japan, and developed GIS database on circular abandoned channel in Japan. This database contains formation process, relative heights, degree of dissection and bedrocks of circular abandoned channels. Circular abandoned channels are distributed in inland mountainous terrains, where late Quaternary uplift rates are unknown, and indicate different relative heights along the same river. Relative heights tend to correlate with degree of dissection of the circular abandoned channels, which may indicate that degree of dissection correlate with ages of abandonment of circular abandoned channels.