HR: 16:30h
AN: OS44A-03    [Abstracts]
TI: Factors Leading to the Spatial Heterogeneity of Sediment-Transport Processes on the Fly River Clinoform, Gulf of Papua
AU: * Ogston, A S
EM: ogston@ocean.washington.edu
AF: University of Washington, Box 357940 School of Oceanography, Seattle, WA 98195
AU: Sternberg, R W
EM: rws@ocean.washington.edu
AF: University of Washington, Box 357940 School of Oceanography, Seattle, WA 98195
AU: Crockett, J S
EM: crockett@ocean.washington.edu
AF: University of Washington, Box 357940 School of Oceanography, Seattle, WA 98195
AU: Nittrouer, C A
EM: nittroue@ocean.washington.edu
AF: University of Washington, Box 357940 School of Oceanography, Seattle, WA 98195
AU: Goni, M A
EM: goni@geol.sc.edu
AF: University of South Carolina, Department of Geological Sciences, Columbia, SC 29208
AB: As part of the NSF Source-to-Sink program in the Gulf of Papua, the relationships between sediment transport processes, development of short-term sedimentary deposition, subsequent burial and long-term accumulation are being investigated. Sediment-transport processes were evaluated using both time-series observations from bottom-mounted tripods and repeated water-column profiling throughout the study area during three seasonal cruises. These observations are being evaluated in relation to the morphology of the clinoform that is offshore and to the northeast of the Fly River mouth. Channels across the clinoform feature off the river distributary mouths have been identified as active transport pathways delivering sediment to the deeper portions of the shelf. Tidal currents are focussed in the channels and there is potentially a direct supply of sediment from the river mouth. During the trade wind season, gravity-driven (fluid mud) flows were observed in this environment when waves added a critical component to the shear stress. Processes on the open clinoform differ from those in the channels. The open clinoform to the northeast appears to be a relatively smooth feature, yet measurements show that dramatically different sediment flux rates exist along the feature. On the open clinoform in the central part of the gulf, gravity flows were observed during trade-wind conditions, but were not seen closer to the Fly River mouth under similar energetic forcing. Factors that influence this heterogeneity include convergence of flow due to regional circulation and fresh water input, and variable sediment supply from a number of rivers entering the broad, shallow tidal region.
DE: 4211 Benthic boundary layers
DE: 4219 Continental shelf processes
DE: 4223 Descriptive and regional oceanography
DE: 3022 Marine sediments--processes and transport
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting