HR: 0800h
AN: PP41D-0783 [Abstracts]
TI: Paleogene Record of Orbital Variations, Time Scales and Elemental Distribution in Sediments from the Arctic Ocean Obtained by XRF Analyses.
AU: * Spofforth, D J
EM: djas@noc.soton.ac.uk
AF: School of Ocean and Earth Science, National Oceanography Centre, University of
Southampton, Southampton, SO14 3ZH, United Kingdom
AU: Pälike, H
EM: heiko@noc.soton.ac.uk
AF: School of Ocean and Earth Science, National Oceanography Centre, University of
Southampton, Southampton, SO14 3ZH, United Kingdom
AU: O'Regan, M
EM: oregan@gso.uri.edu
AF: Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882,
United States
AU: Gattacceca, J
EM: gattacceca@cerege.fr
AF: Geophysics and Planetology, CEREGE (CNRS / University of Aix-Marseille), BP80, Aix-en-
Provence, 13545, France
AU: Green, D
EM: drhg@noc.soton.ac.uk
AF: School of Ocean and Earth Science, National Oceanography Centre, University of
Southampton, Southampton, SO14 3ZH, United Kingdom
AB:
We present a high resolution X-Ray Fluorescence (XRF) core scanner record for the expanded middle Eocene
section from IODP Expedition 302 (ACEX) drilled on the Lomonosov Ridge. The division of the middle Eocene into
two units (sub-unit 1/6 and unit 2) is seen in both cyclical behavior of the elements and the changing inter-
elemental correlations and their relationship to physical properties. Al, Ti and K strongly correlate throughout the
record while the behavior of Fe, Mn and Si seems to be more complex. These variations in elemental
concentrations, which occur on depth scales from decimeters to meters, correspond to the varying contribution of
detrital minerals and biogenic silica in a likely euxinic basin setting. We also highlight the diagenetic effect on Fe
within the record reflecting the decoupling of this record from the other elements. Additionally we show a coherent
and cross-correlated pattern between physical property data and our XRF derived elemental concentrations for
calculating sedimentation rates for selected intervals in the early and middle Eocene. We confirm and refine
sedimentation rates obtained independently through bio- and magnetostratigraphic means to be of the order of
10 to 25 m/Myr, and observe a strong imprint of astronomically forced cycles, particularly through climatic
precession which allows us to test recently proposed new insolation calculations.
DE: 1030 Geochemical cycles (0330)
DE: 1051 Sedimentary geochemistry
DE: 4910 Astronomical forcing
DE: 4946 Milankovitch theory
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting