HR: 0800h
AN: PP51C-0607    [Abstracts]
TI: Cenozoic Ridge Crest Sediments From the Central Arctic Ocean Yield cm/ka-Scale Sedimentation Rates
AU: * Backman, J
EM: backman@geo.su.se
AF: Stockholm University, Department of Geology and Geochemistry, Stockholm, SE-106 91 Sweden
AU: Moran, K
EM: kate.moran@gso.uri.edu
AF: University of Rhode Island, Graduate School of Oceanography, Narragansett, RI 02882 United States
AU: Moore, T
EM: tedmoore@umich.edu
AF: University of Michigan, Geological Sciences, Ann Arbor, MI 48109-1063 United States
AU: King, J
EM: jking@gso.uri.edu
AF: University of Rhode Island, Graduate School of Oceanography, Narragansett, RI 02882 United States
AU: Gattacecca, J
EM: gattacceca@cerege.fr
AF: Universite de Aix-Marseille 3, Department of Geophysics, CEREGE (CNRS), Aix-en-Provence, 13545 France
AU: Brinkhuis, H
EM: h.brinhuis@bio.uu.nl
AF: Utrecht University, Laboratory of Paleobotany and Palynology, Utrecht, 3484 CD Netherlands
AU: Matthiessen, J
EM: jmatthiessen@awi-bremerhaven.de
AF: Alfred Wegener Institute, Department of Geosystems, Bremerhaven, D-27515 Germany
AU: Jakobsson, M
EM: martin.jakobsson@geo.su.se
AF: Stockholm University, Department of Geology and Geochemistry, Stockholm, SE-106 91 Sweden
AU: Paelike, H
EM: heiko@noc.soton.ac.uk
AF: University of Southampton, Southampton Oceanography Center, Southampton, SO14 3ZH United Kingdom
AU: O'Regan, M
EM: oregan@gso.uri.edu
AF: University of Rhode Island, Graduate School of Oceanography, Narragansett, RI 02882 United States
AU: Frank, M
EM: mfrank@ifm-geomar.de
AF: University of Kiel, Leibniz Institute for Marine Science, Kiel, D-24148 Germany
AU: Kubik, P
EM: kubik@phys.ethz.ch
AF: Swiss Federal Institute of Technology, ETH Hoenggerberg, Zuerich, CH-8093 Switzerland
AB: Estimates of long-term sedimentation rates derived from total sediment thickness and bedrock ages based on current tectonic models consistently yield cm/ka-scale average sedimentation rates in the central Arctic Ocean, including the Lomonosov Ridge. The physiographic setting of the Arctic Basin is that of a small basin surrounded by huge landmasses since its initial opening during Early Cretaceous times, a setting that has contributed to yielding 2-6 km thick sediment deposits on Arctic's abyssal plains at average rates of about 4-5 cm/ka. This as sedimentation rate scenario is in contrast to the long-held belief that central Arctic Plio-Pleistocene sedimentation rates have been on the mm/ka-scale, or even sub-mm/ka-scale, estimated from numerous short gravity or piston cores. ACEX drilled through a nearly 410 m thick latest Paleocene to Recent sediment section on the Lomonosov Ridge near 88°N at about 1200 m water depth, with a recovery of 68 %. A combination of paleomagnetic, biostratigraphic and 10-Be data derived from the ACEX cores finally solved the Arctic Basin sedimentation rate ambiguity, in showing an average middle Miocene to Recent rate of about 1.3 cm/ka and Pleistocene rates of nearly 2 cm/ka. The ACEX record is interrupted by a hiatus encompassing the interval between about 17 Ma and 43 Ma. Average middle Eocene through latest Paleocene rates are on the order of about 1.5 cm/ka.
DE: 3036 Ocean drilling
DE: 4999 General or miscellaneous
DE: 9604 Cenozoic
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005