2017 Volume 123 Issue 5 Pages 321-333
We conducted an organic carbon analysis of flood sediments from the 2003 typhoon no. 10 off Hidaka, southern Hokkaido. Flood-induced sediments from the river mouth, inner shelf, outer shelf, and upper slope are rich in terrigenous organic carbon. Four years after the typhoon, flood sediments were found preserved in a topographic depression on the inner shelf, within an area protected from waves and currents. Stratigraphic variations in terrigenous organic carbon ratios in flood sediments from the depression reflect changes in river discharge with rainfall during the flood. Our results indicate that terrigenous material from the river mouth was continuously supplied and deposited on the shelf. These stratigraphic variations in the terrigenous organic carbon ratio could be significant in ongoing attempts to discriminate flood sediments from ancient turbidite successions.
