Transition From the LGM to the Holocene, the View From a West Virginia Cave

A stalagmite collected from a West Virginia cave provides a continuous high resolution record of climate change during the transition from the last glacial maximum (LGM) to the Holocene. The chronology is based on 14 dates obtained using U/Th dating techniques developed for carbonates and adapted for measurement on mass spectrometer. Stable isotopes were measured on a GasBench II coupled to a ThermoFinnigan DeltaPlusXP IRMS. After correcting for the ice volume effect on source water, the residual oxygen isotopic signal shows a glacial period drier than the Holocene, with numerous abrupt changes in the record, likely a response to changing circulation patterns. The Bolling-Allerod was characterized by fast growth rates, and wetter conditions than during other periods in the record. The observed variations are likely due to changes in atmospheric circulation in response to a retreating ice sheet, imposed upon a long-term warming trend. Carbon isotopes provide an additional constraint on changing moisture conditions, although there is also some evidence of changing vegetation structure during the Younger-Dryas, pre-boreal, and early Holocene.