RESPONSE TO (91 - 45 KA) CLIMATE CHANGE IN A SPELEOTHEM FROM SOUTHEAST TENNESSEE, USA

Very little is known about the climate of the SE North American continent during the oxygen isotope stages (OIS) 3-5c, a period formerly known as the early- to mid-Wisconsin glacial period. To reconstruct the paleoclimate of the region and investigate the possible drivers that lead to its variability during this interval, we produced a speleothem-derived 46 ky climate record for SE Tennessee (TENN1). Despite the limitations of our age model, a cross-correlation of our speleothem record and that of GISP2 finds that the chronology is justified. The correspondence of our paleoclimate reconstruction for TENN1 and other hemispheric proxies demonstrates common drivers of the climate variability during the OIS 3-5c. The long term trend of our record, most clearly illustrated in our δ¹³C values, is a derivation of the 100 ky eccentricity solar cycle and short term events such as Heinrich Event #6 (H6) and advances in the polar front explain millennial-scale events. In addition to the presence of the H6 event, the rapid shift in climate from 55-50 ka is clearly displayed in the speleothem record which is indicative of an advance in the polar front. Finally, hemispheric changes in atmospheric methane levels appear in the δ¹³C values of TENN1 which suggests that our paleoclimate reconstruction does not simply reflect local climate changes but those occurring at the global scale.