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

Stable isotopic analysis and 234U/230Th 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 Allerød–Younger Dryas transition in the GISP2 Greenland ice cores. δ18O values of speleothem calcite mark decreasing temperatures between 13 200 and 13 000 yr BP while more rapidly decreasing δ13C values record a sharp shift toward C3 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 (∼800 years), direct comparison of the two sequences is difficult. The interval preserved by this speleothem may span the inter-Allerød 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 Allerød–Younger Dryas transition.