DEVELOPING HIGH PRECISION TIME SERIES OF ISOTOPIC RECORDS ON SPELEOTHEMS FROM EASTERN TENNESSEE

Speleothem-based records of paleo-environmental changes have been developed in many karst regions around the globe. However, no such records exist from Tennessee’s world-renown cave systems. Eastern Tennessee probably has the highest cave density in North America. The climatic fluctuations in the region would reflect cyclic glacial advances and retreats. Recently, we started to process speleothems from Morril's Cave (aka Worley's Cave), eastern Tennessee. Twenty five speleothem samples were collected from the cave. The chronology of 16 samples was determined by U-Th dates. Preliminary uranium-series ages demonstrated that these speleothem samples probably continuously grew during ~400 ka to ~340 ka and ~230 ka to ~50 ka. Stable isotopic analyses were done with a sampling interval of 0.5 mm on one speleothem spanning continuously from ~400 ka to ~340 ka. The isotopic record is consistent with marine and ice core records, but also featured with prominent millennial-scale variations. The primary objective of this research project is to assemble a calibrated, highly-resolved composite record of decadal- to centennial-scale climate change from the mid-latitudes of eastern North America that extends across the last six interglacial/glacial cycles.