Investigation on Long-term Offshore Sedimentation and Sediment Transport Using Radiocarbon Dating

Abstract

Sediment deposition and the origins at water depths of 9 to 19 m at Kashima-nada Sea were investigated by radiocarbon dating the age of shells contained in the seabed core samples. The older-than-normal shells were used as tracers, which was included in sediments dumped into the sea from 1965 to 1977, to estimate the offshore sedimentation and sediment transport history. The results showed that the influence of the dumped sediments was observed even at a water depth of 19 m, and it was also indicated that the dumped sediments were not moved in relative deepwater points after the deposition and the dumped sediments eroded after the deposition in relative shallow-water points would be transported and be redeposited.