nav2.gif (5736 bytes) title.gif (3369 bytes)
Hughen, K.A., Overpeck, J.T., Lehman, S.J., Kashgarian, M., Southon, J. and Peterson, L.C., 1998, Radiocarbon 39, 483-494.
Konrad A. Hughen1
Jonathan T. Overpeck2,3
Scott J. Lehman2
Michaele Kashgarian4
John Southon4
Larry C. Peterson5
Please also see updated calibration in Hughen et al. (Science, 2000)

titleill2.gif (10215 bytes)

Abstract  Varved sediments of the tropical Cariaco Basin provide a new 14C calibration data set for the period of deglaciation (10,000 to 14,500 years before present - 10-14.5 cal kyr BP). Cariaco Basin calendar and 14C chronologies were both assessed for accuracy, using a comparison of Cariaco Basin varve ages to the GISP2 ice core layer chronology, as well as comparisons of Cariaco Basin 14C ages to terrestrial 14C dates. These assessments show that the Cariaco Basin varve chronology agrees, within 20-50 years, with GISP2 layer ages for abrupt, decade-to-century-scale climatic changes throughout most of the deglacial period. In addition, comparisons with terrestrial 14C dates indicate that the Cariaco Basin 14C reservoir age has remained stable since the late Allerød and throughout the Younger Dryas climatic event. This evidence demonstrates that the varve and radiocarbon chronologies together provide an accurate alternative to existing 14C calibrations based on coral U/Th dates. The Cariaco Basin calibration generally agrees with coral-derived calibrations but is more continuous and resolves century-scale details of 14C change not seen in the coral records. Radiocarbon plateaus can be identified at 9.6, 11.4, and 11.7 14C kyr BP, in addition to a large, sloping ‘plateau’ during the Younger Dryas (between 10.0 and 10.4 14C kyr BP). Accounting for features such as these is crucial to determining the relative timing and rates of change during abrupt global climate changes of the last deglaciation.

1Dept. of Earth and Planetary Sciences, Harvard University, Cambridge, MA 02138

2INSTAAR and Dept. of Geological Sciences, Univ. of Colorado, Boulder, CO 80309

3NOAA Paleoclimatology Program, NGDC, Boulder, CO 80303

4CAMS, Lawrence Livermore National Laboratory, Livermore, CA 94551

5RSMAS, University of Miami, Miami, FL 33149