HR: 0800h
AN: PP11B-0567    [Abstracts]
TI: Paleoceanographic changes in the western tropical Atlantic during the late Paleocene (59-55 Ma): high-resolution stable isotope records from ODP Leg 207 Site 1258
AU: * Romano, M
EM: mromano1@gc.cuny.edu
AF: Graduate School & University Center, City University of New York, 365 Fifth Avenue, New York, NY 10016 United States
AU: Pekar, S F
EM: spekar@qc1.qc.edu
AF: Queens College, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367 United States
AU: Pekar, S F
EM: spekar@qc1.qc.edu
AF: Lamont-Doherty Earth Observatory of Columbia University, Route 9W, Palisades, NY 10964 United States
AU: Jenning, N
EM: nfj2003@columbia.edu
AF: Columbia University, 3244 Lerner Hall, New York, NY 10027 United States
AU: Taitt-Finch, N
EM: mzfinch@earthlink.net
AF: Queens College, CUNY, 65-30 Kissena Blvd., Flushing, NY 11367 United States
AB: High-resolution isotopic records are being developed for the late Paleocene (59-55 Ma) from cored materials from ODP Leg 207 Site 1258 to evaluate oceanographic changes leading up to the Paleocene/ Eocene Thermal Maximum (PETM). Site 1258 is located on the western slope of the Demerara Rise, $\sim$380 km north of Suriname. It was drilled in 3,192 meters of water and is the deepest water site of the paleoceanographic transect drilled for Leg 207. Site 1258 contains an exceptional sedimentary archive of late Paleocene oceanographic and climate changes based on high sedimentation rates and pristinely preserved benthic foraminifers, providing the requisite material to study deep-sea changes in the western equatorial Atlantic. The late Paleocene $\delta$$^{18}$O record at Site 1258 contains low values from 58 Ma until near the PETM at Site 1258, which are consistent with bottom water temperatures of up to 10$\deg$ to 12$\deg$C. These low $\delta$$^{18}$O values result in a significant gradient (up to $\sim$1$\permil$) between the equatorial Atlantic and the southern ocean (e.g., Site 690) bottom waters. This suggests at least two bottom water sources existed during this time, one originating from the southern ocean region and another from either the Tethys Sea or somewhere near the equatorial Atlantic regions. A number of isotopic excursions occur in both the $\delta$$^{13}$C and $\delta$$^{18}$O records between 57 Ma and before the PETM. These are characterized by $\delta$$^{13}$C changes of over 1$\permil$ and $\delta$$^{18}$O changes of up to $\sim$0.7$\deg$ (equivalent to $\sim$ 3$\deg$ C). Similar events were previously identified in records from the North Pacific Ocean Site 577, which were interpreted to be restricted to the Pacific basin. Although limitations in age control cannot unequivocally show whether these events were synchronous at both sites, these results indicate that these brief abrupt deep-sea warming events occurred in both the Atlantic and Pacific basins, indicating that they were global in nature.
DE: 9604 Cenozoic
DE: 4870 Stable isotopes
DE: 4267 Paleoceanography
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting