14C plateaus and global stratigraphic correlation during Termination IA

In search of a global 14C reference record for Termination IA, we analyzed three published 14C records with centennial-scale resolution, that provide independent evidence for calibrating the 14C time scale: (1) A sediment record from Cariaco Basin (ODP Site 1002) correlated to the U/Th-dated Hulu Cave record (Hughen et al., 2006), (2) a U/Th dated speleothem record from the Bahamas (Beck et al., 2001, 2006), and (3) a set of U/Th-dated coral ages (IntCal04 plus Fairbanks et al., 2005) that unfortunately lack data from 18-15 cal. ka. All these records exhibit significant changes in the slope of 14C vs. calendar ages, allowing us to define a suite of major and minor "14C plateaus" in each record, that in total occupy >70% of the 14C record between 19 and 14 cal. ka. Despite their different origin the three records are largely consistent. When dating resolution is sufficient, most plateaus show a characteristic internal structure incorporating 14C inversions, in particular near the onset of a plateau. Plateau boundary ages for the Cariaco record have a total range of uncertainty of 150-450 yr due to uncertainties with age calibration (Hughen et al., 2006), in addition to the range of dating resolution. During Termination IA, a period of dramatic climate change, these boundary ages should serve as datums for the global correlation of marine sediment records. Moreover, they are employed to deduce apparent paleoventil-ation ages and thus circulation patterns of surface and bottom water masses, as demonstrated for example from the northern Pacific and the Icelandic Sea.