AMS-14C ages of Japan Sea cores from the Oki Ridge

Abstract

In this study only shells of a planktonic foraminifera, Globigerina umbilicata, were used for the 14C dating. The AMS-14C ages at the last glacial maximum period are about 4500 yr younger than the 14C ages obtained by the previously used method. The age difference is due to the presence of dead carbon in bulk carbonate, accounting for as much as 40% of the total carbonate, and presumably derived from eolian dusts drifting into the Japan Sea during the last glacial age. From the new AMS dating, the age of the lowest salinity of the surface water in the Japan Sea is about 15 000 yr BP. -from English summary