HR: 0800h
AN: OS51B-1304    [Abstracts]
TI: Initial Chronostratigraphic and Paleoclimatic Framework for Sediment Cores From the Mixed Siliciclastic-Carbonate System of the Gulf of Papua New Guinea
AU: * McFadden, M A
EM: melanymcfadden@hotmail.com
AF: Rosenstiel School of Marine and Atmospheric Science, MGG, University of Miami, Miami, FL 33149 United States
AU: Peterson, L C
EM: lpeterson@rsmas.miami.edu
AF: Rosenstiel School of Marine and Atmospheric Science, MGG, University of Miami, Miami, FL 33149 United States
AU: Bentley, S J
EM: sjb@lsu.edu
AF: Coastal Studies Institute, Louisiana State University, Baton Rouge, LA 70803
AU: Dickens, G R
EM: jerry@rice.edu
AF: Department of Earth Science, Rice University, Houston, TX 77251
AU: Droxler, A W
EM: andre@rice.edu
AF: Department of Earth Science, Rice University, Houston, TX 77251
AU: Opdyke, B N
EM: bno@ems.anu.edu.au
AF: Department of Earth and Marine Science, The Australian National University, Canberra, ACT 0200 Australia
AB: The goal of the MARGINS Source-to-Sink (S2S) study in the Papua New Guinea (PNG) focus area is to develop an integrated and quantitative understanding of sediment production, transport, and accumulation in the Gulf of Papua. The PNG S2S focus area was selected for several reasons including large production and rapid transport of sediments in a mixed siliciclastic-carbonate system, clearly defined sources and sinks, variable fluxes over a range of timescales, and a relatively pristine environment. A total of 76 gravity, box, and jumbo piston cores were collected aboard the R/V Melville in spring 2004 from the slope and basin region of the Gulf of Papua. These cores will be used to understand sedimentation dynamics (production, transport, and accumulation) in this region on a range of time-scales and in the context of changes in sea level and climate. The PNG study area is centrally located in the Western Pacific Warm Pool and experiences strong seasonal changes in rainfall associated with the Monsoon which affects sediment delivery to the Gulf. The PNG region is also dramatically affected by the El Nino-Southern Oscillation phenomenon. We report here preliminary stratigraphic results from a number of jumbo piston cores collected from the Eastern Plateau region. This topographically elevated feature was targeted to avoid the rapid siliciclastic sedimentation that dominates the deeper troughs and to sample carbonate-rich pelagic sediments for purposes of generating continuous isotope and microfossil-based records of climate change. Even at sample locations most distant from the major riverine sources and removed from direct transport pathways, the carbonate content of cores rarely exceeds 40%, attesting to the huge input of terrestrial siliciclastic sediments to the Gulf of Papua over the last several glacial-interglacial cycles. Preliminary foraminiferal oxygen isotope stratigraphies indicate sedimentation rates of $\sim$ 6 cm/kyrs at plateau sites expected to have the lowest bulk accumulation rates in the study area. Sedimentation rates should be higher and more variable in slope and trough cores closer to the major siliciclastic sources. The chronostratigraphic record provided by oxygen isotopes in the plateau cores is currently being used to develop the framework by which age models can be applied to the complete set of cores, thus facilitating our overall objectives of assessing the dynamics of sedimentation in this important mixed-sediment region.
DE: 4267 Paleoceanography
DE: 3000 MARINE GEOLOGY AND GEOPHYSICS
DE: 3022 Marine sediments--processes and transport
DE: 1035 Geochronology
DE: 1050 Marine geochemistry (4835, 4850)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting