HR: 0800h
AN: PP41B-0549    [Abstracts]
TI: Extraterrestrial 3He Based Age Models for the PETM and ETM-2 Events from ODP Leg 208 Depth Transect Sites
AU: * Murphy, B H
EM: bmurphy@es.ucsc.edu
AF: UC Santa Cruz, Earth and Planetary Sciences Dept. 1156 High St., Santa Cruz, CA 95064, United States
AU: Farley, K A
EM: farley@gps.caltech.edu
AF: California Institute of Technology, Division of Geological and Planetary Sciences, MS 170- 25, Pasadena, CA 91125, United States
AU: Zachos, J C
EM: jzachos@es.ucsc.edu
AF: UC Santa Cruz, Earth and Planetary Sciences Dept. 1156 High St., Santa Cruz, CA 95064, United States
AU: Periat, N E
EM: nperiat@ucsc.edu
AF: UC Santa Cruz, Earth and Planetary Sciences Dept. 1156 High St., Santa Cruz, CA 95064, United States
AB: The early Eocene is marked by several short-lived global warming events, or hyperthermals, that were triggered by rapid, massive release of carbon. In each case, the release of carbon acidified the ocean triggering widespread dissolution of seafloor carbonates, thereby producing condensed intervals over much of the deep sea. The amount of time represented in these condensed intervals must be determined in order to reconstruct changes in various biogeochemical and climate parameters including carbonate and clay accumulation rates. Traditional stratigraphic techniques, however, have proved to be inadequate for this purpose. As a solution, a constant flux proxy, extraterrestrial helium-3 (3HeET) is being applied to a number of pelagic early Eocene sections. Here we present 3HeET records of the Paleocene-Eocene Thermal Maximum (PETM) and the second Eocene thermal maxima (ETM-2) from ODP Sites 1262, 1263, 1266, and 1267 located on Walvis Ridge in the South Atlantic (water depths between 2600 and 4800 m). By correcting for long-term changes in the local accretion rate of 3HeET we are able to construct high-resolution age models for both the PETM and ETM-2. Our results confirm a transient rise in carbonate sedimentation rates during the late phase of recovery first reported by Farley & Eltgroth (2003) for the PETM. Additionally, the duration between PETM and ETM-2 has been determined to be ~1.827 Ma by orbital calibration by Westerhold et al. (2007) allowing us to test the constant flux hypothesis.
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4912 Biogeochemical cycles, processes, and modeling (0412, 0414, 0793, 1615, 4805)
DE: 4948 Paleocene/Eocene thermal maximum
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting