HR: 0800h
AN: PP51A-0185    [Abstracts]
TI: Late Pleistocene biomarker records from the central Arctic Ocean (ACEX Hole M0004C and HOTRAX HLY0503-08JPC)
AU: * Yamamoto, M
EM: myama@ees.hokudai.ac.jp
AF: Faculty of Environmental Earth Science, Hokkaido University, Kita-10, Nishi-5, Kita-ku, Sapporo, 060-0810, Japan
AU: Polyak, L
EM: polyak.1@osu.edu
AF: Byrd Polar Research Center, Ohio State University, 1090 Carmack Rd., Columbus, OH 43210, United States
AB: Biomarkers were investigated in late Pleistocene sediments collected from the Integrated Ocean Drilling Program (IODP)-Arctic Coring Expedition (ACEX) Hole M0004C (87°52.1'N, 136°11.3'E) from the Lomonosov Ridge and the 2005 Healy-Oden Trans Arctic Expedition (HOTRAX) HLY0503-08JPC (79°35.6'N, 172°30.1'W) from the Mendeleev Ridge in the central Arctic Ocean. In Hole M0004C, the major biomarkers were long-chain n-alkanes, n-fatty acids, and n-alkan-1-ols, indicating fresh organic matter derived predominantly from higher plants. No concrete evidence for phytoplankton biomarkers was found at the study site. The dominance of terrestrial biomarkers is attributed to the severe degradation of organic matter caused by slow sedimentation in oxygen-rich benthic water and/or low primary production due to permanent sea-ice coverage. Hopane concentrations correlated well with ice-rafted debris (IRD) data, suggesting that they are a tracer of mature sedimentary organic matter and may encode the same information as IRD. High organic carbon content was present in the IRD-rich dark gray layer deposited during MIS-6. The layer contained a significant amount of branched GDGTs, suggesting ice erosion of organic-rich continental soils followed by transportation to the central Arctic by drifting ice. We also present the results from Core HLY0503-08JPC and discuss the correlation with ACEX M0004.
DE: 0732 Icebergs
DE: 1055 Organic and biogenic geochemistry
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4926 Glacial
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting