HR: 0800h
AN: PP41C-0691    [Abstracts]
TI: Millennial-Scale Climate Variability During the Mid Pleistocene
AU: * Billups, K
EM: kbillups@udel.edu
AF: University of Delaware, 700 Pilottown Road, Lewes, DE 19958, United States
AU: Weirauch, D
EM: danw@UDel.Edu
AF: University of Delaware, 700 Pilottown Road, Lewes, DE 19958, United States
AU: Martin, P
EM: martin@geosci.uchicago.edu
AF: University of Chicago, 5734 S. Ellis Avenue, Chicago, IL 60637, United States
AB: We use the oxygen isotopic composition of planktonic foraminifera Globigerinoides ruber (white) from Ocean Drilling Program ODP Site 1058 in the subtropical northwestern Atlantic to construct a high-resolution (~800 year) climate record spanning the mid-Pleistocene transition (~0.41 Ma to 1.35 Ma). We test the hypothesis that millennial-scale climate instabilities are associated with the extent of continental glaciation. We apply two age models in order to assess the effect of the chronology on the timing of suborbital variations. The first age model is derived by tuning the isotope record to the G. ruber record from ODP Site 677, and the second by tuning to Northern Hemisphere (NH), summer insolation. Independent of age control, results indicate the appearance of significant (95% level) millennial-scale (4-8 kyr) variability at ~880 Ka (Marine Isotope Stage (MIS) 20). These types of instabilities show the largest amplitude during MIS 12 supporting the idea that millennial-scale fluctuations are associated with the presence of a large NH ice sheet. Higher frequency (2-4 kyr), but lower amplitude, variations occur during glacial and interglacial intervals throughout the mid Pleistocene.
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4926 Glacial
DE: 4940 Isotopic stage
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting