HR: 10:35h
AN: PP42B-02    [Abstracts]
TI: Sea Ice Entrainment and Sediment Sources
AU: Miles, S
EM: smiles@odu.edu
AF: Dept. of Ocean, Earth, and Atmospheric Sciences, Old Dominion University, Oceanography and Physical Sciences Building, 4600 Elkhorn Avenue, Norfolk, Va 23529-0276, United States
AU: * Darby, D A
EM: ddarby@odu.edu
AF: Dept. of Ocean, Earth, and Atmospheric Sciences, Old Dominion University, Oceanography and Physical Sciences Building, 4600 Elkhorn Avenue, Norfolk, Va 23529-0276, United States
AU: Jakobsson, M
EM: martin.jakobsson@geo.su.se
AF: Dept. of Geology and Geochemistry, Stockholm University, SE-106 91 Stockholm University, Stockholm, SE-106 91, Sweden
AU: Rigor, I
EM: ignatius@apl.washington.edu
AF: Applied Physics Laboratory, University of Washington, 1013 NE 40th Street, Box 355640, Seattle, Wa 98105-6698, United States
AB: More than 20 sea ice sediment samples collected during the Healy-Oden Trans-Arctic Expedition (HOTRAX-'05) and the Lomonosov Ridge off Greenland Expedition (LOMROG-'07) along with 18 dirty ice samples from previous expeditions back to the early 1970's show a consistent trend of several sources especially the Laptev and Kara Seas and northern Canada. Modern sea ice back-trajectories from the coordinates of the dirty sea ice samples using past drifts of this ice from the International Buoy Drift Program indicate a close match to the Fe grain sources. Comparison with several sediment cores from across the Arctic and in Fram Strait indicate that Holocene sediment that is primarily transported by sea ice contains the same sources based on Fe oxide grain chemical fingerprint matches with circum-Arctic source areas previously characterized. Observations of encounters with dirty ice by HOTRAX and LOMROG icebreaker expeditions indicate that while a small percentage of sea ice contains sediment, this dirty ice is concentrated in bands extending several kilometers and consisting of irregularly spaced patches of dirty ice that are usually less than a 100 meters in width. Also, sea ice containing coarse sediment and/or large shells due to anchor ice are less than 10 percent of dirty sea ice but that they may contain much higher concentrations of sediment than sea ice containing finer sediment from suspension freezing.
DE: 0750 Sea ice (4540)
DE: 3022 Marine sediments: processes and transport
DE: 4524 Fine structure and microstructure
DE: 4550 Ocean influence of Earth rotation (1223)
DE: 4558 Sediment transport (1862)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting