HR: 0800h
AN: PP41B-0550    [Abstracts]
TI: Characterizing the Timing and Scale of Late Paleocene to Early Eocene Carbon Cycle Oscillations, Site 1262, Walvis Ridge
AU: * McCarren, H K
EM: hmccarren@pmc.ucsc.edu
AF: Department of Earth and Planetary Sciences, UC Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
AU: Rohl, U
EM: uroehl@marum.de
AF: Center for Marine Environmental Sciences (MARUM), Bremen University, Leobener Strasse, Bremen, 28359, Germany
AU: Westerhold, T
EM: tho@uni-bremen.de
AF: Center for Marine Environmental Sciences (MARUM), Bremen University, Leobener Strasse, Bremen, 28359, Germany
AU: Zachos, J C
EM: jzachos@pmc.ucsc.edu
AF: Department of Earth and Planetary Sciences, UC Santa Cruz, 1156 High Street, Santa Cruz, CA 95064, United States
AB: ODP Site 1262, drilled at Walvis Ridge in the S Atlantic, 3600m paleo water depth, provides a continuous record of sedimentation through the Late Paleocene and Early Eocene. The interruption of regularly paced carbon cycle oscillations by transient and extreme climate change events (e.g., the Paleocene Eocene Thermal Maximum (PETM or ETM-1), ETM-2, and ETM-3) allows for in depth study of the interactions between long- and short-term geochemical cycles, perturbations of the global carbon system, and the mechanistic relationship between orbital periodicity and climate variability. Here we present the first stratigraphically continuous, orbital-scale stable isotope and Fe records (obtained by XRF scanning) spanning the entire upper Paleocene and lower Eocene (~52 to 59 Ma). All records shows distinct periodicity. Furthermore, spectral analysis of stable isotope (δ¹³C, δ¹⁸O) and Fe intensity data reveals strong variance in primary orbital bandwidths. Coherence is prominent in eccentricity bands (100kyr, 405kyr), as well as precessional bands (21kyr). Orbital variations in the Fe intensity record, most likely related to carbonate dissolution events, were used to develop an orbitally calibrated age model (Westerhold et al., 2007). Fe intensity cycle peaks are anti-phased with respect to eccentricity controlled δ¹³C and δ¹⁸O cycles in the Atlantic Ocean, and coincide with eccentricity maxima. The data suggest that modulation of the precessional cycle by eccentricity creates a general climate state conducive to periodic shifts in carbon fluxes and reservoir partitioning. Additionally, we will investigate the lead-lag phase relationships between these geochemical and climate parameters.
DE: 4924 Geochemical tracers
DE: 4946 Milankovitch theory
DE: 4948 Paleocene/Eocene thermal maximum
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting