A high-resolution speleothem record of climatic variability at the Allerod-Younger Dryas transition in Missouri, central United States

Stable isotopic analysis and U-234/Th-230 mass spectrometry dating of a single calcite stalagmite from Onondaga Cave, east-central Missouri, reveal climatic variability between 13 200 and 12 400 yr BP coincident with the Allerod-Younger Dryas transition in the GISP2 Greenland ice cores. delta(18)O values of speleothem calcite mark decreasing temperatures between 13 200 and 13 000 yr BP while more rapidly decreasing delta(13)C values record a sharp shift toward C-3 vegetation at approximately 13 100 yr BP. Because of uncertainties in the chronological control of both this speleothem and the GISP2 record and the brevity of this speleothem record ( similar to 800 years), direct comparison of the two sequences is difficult. The interval preserved by this speleothem may span the inter-Allerod cold period (IACP) alone, both the IACP and the start of the Younger Dryas, or only the first half of the Younger Dryas. In any case, these data demonstrate that the climate of the North American interior deteriorated significantly and rapidly during the interval associated with the Allerod-Younger Dryas transition. (C) 2001 Elsevier Science B,V. All rights reserved.