HR: 0800h
AN: PP41D-0775    [Abstracts]
TI: Cyclicity in the Central Arctic Ocean Middle Eocene Sediment Record: Orbital Forcing and Environmental Response
AU: * Sangiorgi, F
EM: f.sangiorgi@uu.nl
AF: Palaeoecology, Institute of Environmental Biology, Utrecht University, Laboratory of Palaeobotany and Palynology, Budapestlaan 4, Utrecht, 3584CD, Netherlands
AU: * Sangiorgi, F
EM: f.sangiorgi@uu.nl
AF: Royal Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, PO Box 59, Den Burgh, Texel, 1790 AB, Netherlands
AU: van Soelen, E E
EM: e.e.vansoelen1@students.uu.nl
AF: Palaeoecology, Institute of Environmental Biology, Utrecht University, Laboratory of Palaeobotany and Palynology, Budapestlaan 4, Utrecht, 3584CD, Netherlands
AU: Spofforth, D J
EM: djas@noc.soton.ac.uk
AF: School of Ocean & Earth Science, University of Southampton, Waterfront Campus, Southampton, SO14 3ZH, United Kingdom
AU: Palike, H
EM: heiko@noc.soton.ac.uk
AF: School of Ocean & Earth Science, University of Southampton, Waterfront Campus, Southampton, SO14 3ZH, United Kingdom
AU: Stickley, C E
EM: catherine.stickley@npolar.no
AF: Norwegian Polar Institute, Polar Environmental Centre, Tromso, N-9296, Norway
AU: St. John, K
EM: stjohnke@jmu.edu
AF: Department of Geology and Environmental Science, James Madison University, 7125 Memorial Hall, 395 S. High St, Harrisonburg, VA 22807, United States
AU: Koc, N
EM: nalan.koc@npolar.no
AF: Norwegian Polar Institute, Polar Environmental Centre, Tromso, N-9296, Norway
AU: Koc, N
EM: nalan.koc@npolar.no
AF: Department of Geology, University of Tromsų, Dramsveien 201, Tromso, N-9037, Norway
AU: Schouten, S
EM: schouten@nioz.nl
AF: Royal Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, PO Box 59, Den Burgh, Texel, 1790 AB, Netherlands
AU: Sinninghe Damste', J S
EM: damste@nioz.nl
AF: Royal Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, PO Box 59, Den Burgh, Texel, 1790 AB, Netherlands
AU: Brinkhuis, H
EM: h.brinkhuis@uu.nl
AF: Palaeoecology, Institute of Environmental Biology, Utrecht University, Laboratory of Palaeobotany and Palynology, Budapestlaan 4, Utrecht, 3584CD, Netherlands
AB: Continuous X-ray fluorescence (XRF) scanning of middle Eocene (ca 46 Ma) ACEX (Arctic Coring Expedition, IODP 302) core 2A-55X revealed a strong cyclic signal in some of the major and trace geochemical elements. XRF (e.g., Fe, K, Ti, Al, Si) and physical properties (GRA, MagSus, PWL, and NGR) evidenced cyclicity with periods of about 50 cm and 100 cm. Using the age model of Backman et al. (Paleoceanography, accepted, 2007) and the derived sedimentation rate of 24.3 m/Myr, these frequency components are compatible with a Milankovitch type orbital forcing, with the oscillations at 50 cm and at 100 cm representing precession and obliquity, respectively. The longer 100 cm cyclicity is also present in the biological (pollen, dinocysts and siliceous microfossil) proxies and in the sedimentological (IRD) proxy. Results show that biological proxies seem to respond stronger to seasonal darkness (length of the growing season), whereas the terrigenous components, partly linked to sea-ice and/or glacial ice formation and extent, respond more directly to seasonal insolation.
DE: 0750 Sea ice (4540)
DE: 1065 Major and trace element geochemistry
DE: 1859 Rocks: physical properties
DE: 4944 Micropaleontology (0459, 3030)
DE: 4952 Palynology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting