HR: 0800h
AN: PP11A-0227    [Abstracts]
TI: Shaking up an Old Standard: The Paleocene-Eocene Boundary Through the Eyes of DSDP Site 401
AU: * Lyman, J
EM: jalyman@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0208, United States
AU: Norris, R
EM: rnorris@ucsd.edu
AF: Scripps Institution of Oceanography, 9500 Gilman Dr., La Jolla, CA 92093-0208, United States
AB: Ocean Drilling Program (ODP) Site 690 (Weddell Sea) has been the standard against which all other Paleocene- Eocene Thermal Maximum (PETM) carbon and oxygen isotope records are measured. Deep Sea Drilling Program (DSDP) Site 401 (Bay of Biscay) has a nearly complete record, and despite having a shorter section containing the PETM, contains a detailed record of the carbon isotope excursion (CIE). Site 401 contains no collapse of the carbon isotope gradient between planktic and benthic foraminiferal species, indicating there was no rapid oceanic turnover in the North Atlantic at this time. A negative dip in δ¹³C is observed prior to the main CIE in Morozovella subbotinae, Acaranina soldadoensis and Subbotina patagonica, and is a potential precursor to the main CIE. Records of δ¹⁸O in planktic foraminifera show no recovery to pre- excursion levels at Site 401, indicating the rise in sea surface temperature in the North Atlantic was not a transient event. Additionally, there is a change in habitat of the species A. soldadoensis, which migrates from shallow dwelling to thermocline dwelling and returns to shallow dwelling during the recovery phase of the CIE.
DE: 4870 Stable isotopes (0454, 1041)
DE: 4948 Paleocene/Eocene thermal maximum
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting