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New C-14 Calibration Data Set for the Last Deglaciations Based on Marine
Varves
Hughen, K.A., J.T. Overpeck, S.J. Lehman, M. Kashgarian, J.R. Southon 1998 Radiocarbon 40: 483-494 ABSTRACT Varved sediments of the tropical Cariaco Basin provide a new C-14 calibration data set for the period of deglaciation (10,000 to 14,500 years before present: 10-14.5 cal ka sp). Independent evaluations of the Cariaco Basin calendar and C-14 chronologies were based on the agreement of varve ages with the GISP2 ice core layer chronology for similar high-resolution paleoclimate records, in addition to C-14 age agreement with terrestrial 14C dates, even during large climatic changes. These assessments indicate that the Cariaco Basin C-14 reservoir age remained stable throughout the Younger Dryas and late Allerod climatic events and that the varve and C-14 chronologies provide an accurate alternative to existing 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 C-14 change not seen in the coral records. C-14 plateaus can be identified at 9.6, 11.4, and 11.7 C-14 ka BP, in addition to a large, sloping "plateau" during the Younger Dryas (similar to 10 to 11 C-14 ka sp). 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. | Mailing
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Studies Laboratory, Department of Geosciences, The University of Arizona Last updated
August 11, 2003
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