Millennial-scale Climate Variability During the Last Interglacial Recorded in Two Speleothems from Eastern North America

Thursday, 18 December 2014
Yongli Gao1, Harold Dale Rowe2, Zhiguo Rao3, Jessica A Buckles1, Xianfeng Wang4, Hai Cheng5 and R. Lawrence Edwards6, (1)University of Texas at San Antonio, San Antonio, TX, United States, (2)University of Texas at Austin, Bureau of Economic Geology, Austin, TX, United States, (3)LZU Lanzhou University, Research School of Arid Environment and Climate Change, Lanzhou, China, (4)Earth Observatory of Singapore, Singapore, Singapore, (5)University of Minnesota Twin Cities, Dept. of Earth Sciences, Minneapolis, MN, United States, (6)University of Minnesota, Minneapolis, MN, United States
Two speleothems from eastern North America grew throughout the warmest part of the Last Interglacial (128 –120 ka BP). High-resolution stable isotope δ18O and δ13C records are constrained by 20 230Th age dates. The high-resolution speleothem records from Morril's Cave (aka Worley's Cave) in the eastern North America region demonstrate millennial-scale climate variability. ‘‘Warmer–wetter’’ periods are interspersed with ‘‘cooler–drier’’ periods at millennial-scale based on shifts of stable isotope values. Between 123.8 to 123.6 BP, both δ18O and δ13C values dropped more than 2‰ in the TNMOR1-12 speleothem record. The abrupt negative excursions of δ18O and δ13C values indicate the transition from the “coolest-driest” to the “warmest-wettest” in the middle of MIS 5e. Overall, the isotope record is anti-phasing with a stalagmite record from southwestern France (BDinf), which may indicate that orbitally driven western Europe and eastern North America anti-phasing precipitation occurred during the warmest period of the Last Interglacial.