HR: 0800h
AN: PP51C-0620    [Abstracts]
TI: High Resolution Multi Proxy Deep-Sea Records of Eocene/Oligocene Climate Change From the Equatorial Pacific Ocean
AU: * Coxall, H K
EM: hkc@gso.uri.edu
AF: School of Earth, Ocean and Planetary Sciences, Cardiff University, Cardiff, CF10 3YE United Kingdom
AU: Wilson, P A
EM: paw1@noc.soton.ac.uk
AF: National Oceanography Centre, Southampton University, European Way, Southampton, SO14 3ZH United Kingdom
AB: The initiation of major ice-sheets on Antarctica at the Eocene/Oligocene (E/O) boundary (~34 Ma) was rapid (<100 kyr) and step-wise and occurred synchronously with a significant deepening (~1 km) of the oceanic calcite compensation depth (CCD) in the Pacific Ocean and a perturbation to the global carbon system. Correspondence between climate proxy data and an astronomical template describing fluctuations in Earth's orbit back to the late Eocene indicate that the glaciation and CCD deepening occurred faster than previously documented and in two `steps' (~40 kyr each) during an interval when Earth's orbit of the Sun favoured cool austral summers. In order to further integrate the observations of CCD and carbon system shifts with our understanding of E/O climate change we have produced a high-resolution dual-species benthic foraminifera δ¹⁸O and δ¹³C record using Cibicidoides spp. and Oridorsalis umbonatus from equatorial Pacific ODP Site 1218. In addition, we present bulk sediment δ¹⁸O, δ¹³C and CaCO₃ as proxies for surface water conditions. Changes in the δ¹³C differences between the ecologically partitioned benthic taxa and surface-to-deep records in the first 3-4 million years of the Oligocene provide information about the strength of the biological pump and imply changes in the surface to deep organic flux associated with the climatic transition.
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4924 Geochemical tracers
DE: 4944 Micropaleontology (0459, 3030)
DE: 9604 Cenozoic
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005