HR: 14:40h
AN: OS43C-05    [Abstracts]
TI: Tropical Climate Variability During Marine Isotope Stage 3: Results from the Cariaco Basin
AU: * McConnell, M
EM: mmcconnell@geol.sc.edu
AF: University of South Carolina, Department of Geological Sciences, Columbia, SC 29208,
AU: Thunell, R
EM: thunell@geol.sc.edu
AF: University of South Carolina, Department of Geological Sciences, Columbia, SC 29208,
AU: Peterson, L
EM: lpeterson@rsmas.miami.edu
AF: University of Miami Rosenstiel School of Marine and Atmospheric Science, 4600 Rickenbacker Causeway, Miami, FL 33149,
AU: Black, D
EM: david.black@stonybrook.edu
AF: Stony Brook University, School of Marine and Atmospheric Sciences, Stony Brook, NY 11794,
AU: Lea, D
EM: lea@geol.ucsb.edu
AF: University of California, Santa Barbara, Department of Earth Science, Santa Barbara, CA 93106,
AB: The last glacial period is characterized by a number of well-defined, millennial scale stadial and interstadial events that have been documented in climate records from low to high latitudes. We combine detailed oxygen isotope and Mg/Ca records for the planktonic foraminifera G. ruber from Cariaco Basin core MD03-2621 in order to assess the magnitude of sea surface temperature, and to reconstruct seawater δ¹⁸O variations and sea surface salinity changes associated with 10 stadial/interstadial oscillations during MIS3. The lowest oxygen isotope values \{~0.25‰\} occur during interstadials \{IS\} with the highest values reaching 0.85‰ during stadial periods. The δ¹⁸O of G. bulloides is also measured in MD03-2621 and covaries well with G. ruber δ¹⁸O, though, the G. bulloides δ¹⁸O values are slightly lighter than G. ruber during stadials events. The variability in the oxygen isotopic composition for G. ruber \{white and pink\} and G. bulloides along with the δ¹³C record of G. bulloides correlates very well with sediment color reflectance data, which is considered a proxy for marine productivity. The Mg/Ca results for G. ruber across several of these stadial/interstadial oscillations tend to co vary with the δ¹⁸O data. Mean Mg/Ca values range from a minimum of ~3.0 mmol/mol during stadial periods just prior to and immediately after IS-7 and IS-12, to a maximum of ~4.9 mmol/mol during IS-12. Interestingly IS 12 exhibits a double peak in both the δ¹⁸O and Mg/Ca records with the trace element record leading by about 400 years. The Mg/Ca and δ¹⁸O records for G. ruber begin to diverge during the latter part of IS 13 and shortly after interstadials 9 and 6 suggesting warmer, saltier conditions during these stadial periods. We are comparing this record with a Greenland and Antarctic ice cores to further evaluate of the role the tropics play in millennial scale climate change.
DE: 3344 Paleoclimatology (0473, 4900)
DE: 4200 OCEANOGRAPHY: GENERAL
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4926 Glacial
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting