HR: 1330h
AN: OS12A-0184    [PDF]
TI: Biogeochemical and Sedimentary Processes in the Wet Tropics
AU: * Goni, M A
EM: goni@geol.sc.edu
AF: Department of Geological Sciences, University of South Carolina, Columbia, SC 29208 United States
AU: Monacci, N
AF: Department of Geological Sciences, University of South Carolina, Columbia, SC 29208 United States
AU: Gisewhite, R
AF: Department of Geological Sciences, University of South Carolina, Columbia, SC 29208 United States
AB: Surface sediments were collected from the clinoform of the Fly River (Papua New Guinea) as part of a multidisciplinary effort to understand the sources, transport and fate of sediments and organic matter. Sediments from the area northeast of the Fly River mouth, which appears to be a zone of temporary storage, were characterized by organic carbon contents (%OC) of 1.0 to 1.4 wt. %, atomic organic carbon:total nitrogen ratios ([C/N]a) of 14 to 24 and stable organic carbon isotopic compositions (d13Coc) of -26 to -27 per mil. The sediments from the delta front region adjacent to the Fly River Delta, on the other hand, displayed %OC values of 0.4 to 0.8 %, [C/N]a ratios of 12 to 24 and d13Coc values of -24 to -25 per mil. These compositions indicate that a large fraction of the organic matter in the surface sediments originated from terrigenous C3 plant sources, including vascular plant fragments from the delta and soil organic matter from the Fly River drainage basin. The contrasts between the northeast and the delta front regions suggest differential deposition and transport conditions between the two areas. On-going analyses of organic biomarkers (e.g. lignin phenols) and sediment characteristics (e.g. mineral surface area) will be used to further refine these initial interpretations.
DE: 3022 Marine sediments--processes and transport
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting