HR: 0800h
AN: PP21C-1566    [Abstracts]
TI: Mid Pleistocene Climate Instability in the Subtropical Northwestern Atlantic
AU: * Billups, K
EM: kbillups@udel.edu
AF: University of Delaware, 700 Pilottown Road, Lewes, DE 19958 United States
AU: Gibbons, F
EM: ferng@uchicago.edu
AF: University of Chicago, 5734 S. Ellis Avenue, Chicago, IL 60637 United States
AU: Martin, P
EM: pmartin@uchicago.edu
AF: University of Chicago, 5734 S. Ellis Avenue, Chicago, IL 60637 United States
AB: We have constructed Globigerinoides ruber, G. sacculifer and Neogloboquadrina dutertrei oxygen isotope records from northwestern subtropical Atlantic Site 1058 spanning the mid Pleistocene (~650 to 400 kyr). The high temporal resolution of these records (~800 years) allows us to compare millennial-scale climate signals during one of the most extreme glacial periods of the Pleistocene (Marine Isotope Stage, MIS, 12) to earlier, less extreme glacial periods (MIS 14), as well as to two full interglacial intervals (MIS 13 and 15). On the longer term, we observe excellent agreement between the oxygen isotope records of the surface dwelling species G. ruber and G. sacculifer and Northern Hemisphere insolation patterns, but only until MIS 12. During glacial MIS 12 Northern Hemisphere insolation remains relatively high, but planktonic foraminiferal oxygen isotope records increase towards the extreme maximum characterizing MIS 12. The thermocline dweller N. dutertrei records comparatively little variability during the entire interval of time. On the millennial-scale, all three species display their highest amplitude oxygen isotope variations (with a period between 4-6 kyr) during glacial MIS 12. Suborbital-scale variability is also statistically significant during glacial MIS 14, but the amplitude is smaller. These results support hypotheses linking millennial-scale climate fluctuations to the extent of continental glaciation (McManus et al., 1999). We speculate that the relatively high degree of subtropical Atlantic sea surface instability during one of the most extreme glacial periods of the Pleistocene (MIS 12) arises from the interplay between strong atmospheric winds related to the presence of a large ice sheet to the north and persistently high incident solar radiation.
DE: 1605 Abrupt/rapid climate change (4901, 8408)
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005