HR: 09:15h
AN: OS11A-06    [PDF]
TI: Relationships Between Early Diagenetic Processes, Carbon Remineralization, and Sedimentary Dynamics in the Gulf of Papua Deltaic Complex
AU: * Aller, R C
EM: raller@notes.cc.sunysb.edu
AF: Marine Sciences Research Center, Stony Brook University, Stony Brook, NY 11794-5000 United States
AU: Blair, N E
EM: Neal_Blair@ncsu.edu
AF: Dept of Marine, Earth and Atmospheric Sciences, North Carolina State University, Raleigh, NC 27695-8208 United States
AU: Panzeca, C
EM: cpanzeca@hotmail.com
AF: Marine Sciences Research Center, Stony Brook University, Stony Brook, NY 11794-5000 United States
AU: Hannides, A
EM: hannides@soest.hawaii.edu
AF: Marine Sciences Research Center, Stony Brook University, Stony Brook, NY 11794-5000 United States
AU: Heilbrun, C
EM: cheilbrun@notes.cc.sunysb.edu
AF: Marine Sciences Research Center, Stony Brook University, Stony Brook, NY 11794-5000 United States
AB: A range of diagenetic environments is found within the central Gulf of Papua clinoform, each characterized by different balances between sedimentary dynamics, net accumulation, physical and biogenic transport processes, and biogeochemical properties. Sediments are generally diagenetically reactive, with $\Sigma$CO$_{2}$ production and benthic O$_{2}$ fluxes typically ranging between 10 - 40 mmol / m$^{2}$ / d (upper 20 cm). Highest remineralization rates occur within mobile inner topset and channel muds (1-20 m depth) and in the high accumulation rate rollover region of the topset - foreset beds (40-50 m). Lowest rates are found inshore along sandy channels, middle topset, and the deeper foreset (75 m). Topset deposits are typically suboxic, nonsulfidic over the upper $\sim$0.2 - 1 m, due to various combinations of physical reworking and deep bioirrigation. Pore water sulfate can be measureably depleted at depths $>$ 0.3 m, however dissolved sulfide remains below detection (upper $\sim$1-2 m). Sedimentary C / S ratios are $\sim$4 - 6 within the topset regions but decrease to $<$ 3 in offshore foreset beds and inshore mud banks where sulfidic diagenesis dominates. Remineralization patterns are independent of relative abundance of terrestrial or marine sedimentary carbon, both are efficiently remineralized. C$_{org}$ isotopic analyses ($^{13,14}$C) demonstrate that although terrestrial sources can be primary substrates at inshore sites, young marine C$_{org}$ preferentially dominates pore water $\Sigma$CO$_{2}$ relative to bulk C$_{org}$ in the upper foreset A small quantity of young, rapidly recycled marine organic material is often superimposed on a generally older, less reactive terrestrial background.
DE: 1050 Marine geochemistry (4835, 4850)
DE: 4219 Continental shelf processes
DE: 4804 Benthic processes/benthos
DE: 4805 Biogeochemical cycles (1615)
DE: 4806 Carbon cycling
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting