New 14C calibration data set for the last deglaciation based on marine varves

摘要

Varved sediments of the tropical Cariaco basin provide a new (sup 14)C211u001ecalibration data set for the period of deglaciation (10,000 to 14,500 years 211u001ebefore present: 10-14.5 cal ka BP). Independent evaluations of the Cariasco Basin 211u001ecalendar and (sup 14)C chronologies were based on the agreement of varve ages 211u001ewith the GISP2 ice core layer chronology for similar high-resolution paleoclimate 211u001erecords, in addition to (sup 14)C age agreement with terrestrial (sup 14)C dates, 211u001eeven during large climatic changes. These assessments indicate that the Cariaco 211u001eBasin (sup 14)C reservoir age remained stable throughout the Younger Dryas and 211u001elate Alleroed climatic events and that the varve and (sup 14)C chronologies 211u001eprovide an accurate alternative to existing calibrations based on coral U/Th 211u001edates. The Cariaco Basin calibration generally agrees with coral-derived 211u001ecalibrations but is more continuous and resolves century-scale details of (sup 211u001e14)C change not seen in the coral records. (sup 14)C plateaus can be identified 211u001eat 9.6, 11.4, and 11.7 (sup 14)C ka BP, in addition to a large, sloping plateau 211u001eduring the Younger Dryas ((approximately)10 to 11 (sup 14)C ka BP). Accounting 211u001efor features such as these is crucial to determining the relative timing and 211u001erates of change during abrupt global climate changes of the last deglaciation.