INTEGRATION OF THE OLD AND NEW LAKE SUIGETSU (JAPAN) TERRESTRIAL RADIOCARBON CALIBRATION DATA SETS

Abstract

<p>The varved sediment profile of Lake Suigetsu, central Japan, offers an ideal opportunity from which to derive a terrestrial record of atmospheric radiocarbon across the entire range of the C-14 dating method. Previous work by Kitagawa and van der Plicht (1998a,b, 2000) provided such a data set; however, problems with the varve-based age scale of their SG93 sediment core precluded the use of this data set for C-14 calibration purposes. Lake Suigetsu was re-cored in summer 2006, with the retrieval of overlapping sediment cores from 4 parallel boreholes enabling complete recovery of the sediment profile for the present "Suigetsu Varves 2006" project (Nakagawa et al. 2012). Over 550 C-14 determinations have been obtained from terrestrial plant macrofossils picked from the latter SG06 composite sediment core, which, coupled with the core's independent varve chronology, provides the only non-reservoir-corrected C-14 calibration data set across the C-14 dating range. Here, physical matching of archive U-channel sediment from SG93 to the continuous SG06 sediment profile is presented. We show the excellent agreement between the respective projects' C-14 data sets, allowing the integration of 243 C-14 determinations from the original SG93 project into a composite Lake Suigetsu C-14 calibration data set comprising 808 individual C-14 determinations, spanning the last 52,800 cal yr.</p>