HR: 0800h
AN: OS41D-0512    [Abstracts]
TI: High Frequency Time-series of the Dynamic Sedimentation Processes on the Western Shelf of the Mississippi River Delta
AU: * Dail, M B
EM: mbd0707@mail.ecu.edu
AF: East Carolina University, Department of Geology 101 Graham, Greenville, NC 27858
AU: Corbett, D R
EM: corbettd@mail.ecu.edu
AF: East Carolina University, Department of Geology 101 Graham, Greenville, NC 27858
AU: McKee, B
EM: bmckee@tulane.edu
AF: Tulane University, Department of Earth and Environmental Sciences, New Orleans, LA 70118
AU: Duncan, D
EM: dduncan@tulane.edu
AF: Tulane University, Department of Earth and Environmental Sciences, New Orleans, LA 70118
AB: Rivers annually transport billions of tons of organic and inorganic sediment to coastal environments, making them an extremely important part of global biogeochemical cycles. However, the majority of the freshwater and suspended materials are delivered to the coastal ocean by only a few rivers. In these river-dominated ocean margins (RiOMar), sediments are deposited and re-suspended repeatedly before stable deposition. This sediment cycling is poorly understood and is critical to understanding how deltas and continental shelves, considered to be major repositories of organic carbon in marine sediments, manipulate the global carbon cycle and biogeochemical processes affecting coastal environments. During six cruises in the fall of 2003 (October, November, and December) and spring of 2004 (March, April, and May), on the shelf west of the Mississippi River Delta, sediment samples collected from cores were analyzed for particle reactive radionuclides (210Pb, 137Cs, and 234Th) to create a quantitative high frequency time-series of sediment deposition and erosion processes and evaluate the transport and fate of material on the shelf. Based on previous work completed by Corbett et al. (2004), seasonal variations in short-lived tracers could be explained by river flow and weather conditions. Inventories of the tracers collected during the fall cruises suggest increased deposition during the late summer months and that most sediment reworking and export occurs during the winter months, typically a period of low/increasing river discharge and increased weather forcing.
DE: 4835 Inorganic marine chemistry
DE: 4850 Organic marine chemistry
DE: 1030 Geochemical cycles (0330)
DE: 1035 Geochronology
DE: 1050 Marine geochemistry (4835, 4850)
SC: Ocean Sciences [OS]
MN: 2004 AGU Fall Meeting