HR: 0800h
AN: OS51B-1301    [Abstracts]
TI: Sediment Flux to the Gulf of Papua Continental Slope Using Pb-210 Geochronology, Source to Sink Papua New Guinea Focus Area
AU: * Muhammad, Z
EM: zmuham1@lsu.edu
AF: Coastal Studies Institute, Louisiana State University, Baton Rouge, LA 70803 United States
AU: Bentley, S J
EM: sjb@lsu.edu
AF: Coastal Studies Institute, Louisiana State University, Baton Rouge, LA 70803 United States
AU: Droxler, A W
EM: andre@rice.edu
AF: Department of Earth Science, Rice University, Houston, TX 77251-1892 United States
AU: Dickens, G R
EM: jerry@rice.edu
AF: Department of Earth Science, Rice University, Houston, TX 77251-1892 United States
AU: Opdyke, B
EM: bno@ems.anu.edu.au
AF: Department of Earth and Marine Sciences, Australian National University, Canberra, ACT 0200 Australia
AU: Peterson, L C
EM: lpeterson@rsmas.miami.edu
AF: Rosenstiel School of Marine and Atmospheric Science, University of Miami, Miami, FL 33149 United States
AB: The Gulf of Papua is a mixed siliciclastic/carbonate environment where terrigenous sediments from New Guinea rivers are supplied to shelf and slope where they mix with carbonate sediments from pelagic and platform sources. During a March-April 2004 cruise of the R/V Melville, we recovered multicores from a range of depositional settings on the upper and middle slope of the Gulf of Papua. Cores were navigated using dynamic positioning, and a multibeam bathymetric mosaic collected during the cruise. These multicores have been examined using Pb-210 radiochemistry, x-radiographs and granulometry, in order to constrain carbonate and terrigenous sediment flux to the slope over century timescales. Preliminary results support the hypothesis that terrigenous sediments are reaching the slope from the northeast Gulf of Papua shelf break, where a core from a shelf-edge clinoform revealed an apparent Pb-210 accumulation rate of 0.4 cm/y. Southwestwards along the upper slope, toward the northern edge of the Great Barrier Reef, sedimentation rates appear to be lower, and carbonate platform influence appears to increase. In the Moresby Trough, a major sediment conduit from the upper Gulf of Papua slope to the Coral Sea Basin, we have documented modern turbidite sedimentation through x-radiographs and Pb-210 analyses of one multicore. The depositional sedimentary fabric of the Moresby Trough turbidite contrasts sharply with the intensely bioturbated fabric of hemipelagic sediments identified elsewhere.
DE: 4850 Organic marine chemistry
DE: 4851 Oxidation/reduction reactions
DE: 3022 Marine sediments--processes and transport
DE: 3045 Seafloor morphology and bottom photography
DE: 1815 Erosion and sedimentation
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting