HR: 1330h
AN: OS12A-0185    [PDF]
TI: Carbon Cycling And Diagenetic Carbonate Formation in the Gulf of Papua, Papua New Guinea
AU: * Fang, T
EM: taofang99@hotmail.com
AF: Tao Fang, Robert Aller, Geoscience Department, SUNY Stony Brook, Stony Brook, NY 11790 United States
AU: Aller, R
EM: raller@notes.cc.sunysb.edu
AF: Tao Fang, Robert Aller, Geoscience Department, SUNY Stony Brook, Stony Brook, NY 11790 United States
AU: Aller, R
EM: raller@notes.cc.sunysb.edu
AF: Robert Aller, Marine Science Research Center, SUNY Stony Brook, Stony Brook, NY 11794 United States
AU: Blair, N
EM: neal_blair@ncsu.edu
AF: Neal Blair, Department of Marine, Earth and Atmospheric Sciences, NC State University, Raleigh, NC 27695 United States
AB: The Gulf of Papua, Papua New Guinea, receives roughly 350 million tons of sediment each year, comparable to the largest river depocenters in the world. Although the proportion of carbonate is low ($<$5%), Fe - carbonate authigenesis, cycling and burial in this tropical deltaic system could be important due to rapid net sedimentation and a dominance of nonsulfidic diagenetic conditions. Most carbonate, however, is present as calcite (~40-540 æmol/g, average 165æmol/g), with less than 35% siderite (~25-40æmol/g). Carbon isotope analyses were performed on pore water and operationally separated carbonate minerals. The del-13C of pore water total CO2 varies from ~0?near the surface to -25 at depth (~1-2m), reflecting the progressive contribution of diagenetic CO2 from the decomposition of marine and terrestrial organic matter during burial. Both terrestrial and marine derived organic matter are effectively remineralized, with the decomposition of marine organic material dominating the upper few decimeters. Biogenic carbonate has del-13C values near that of overlying seawater whereas del-13C of diagenetic siderite varies from -2.5 to -12.5 Isotopic patterns of pore water profiles and carbonate fractionation factors indicate that most siderite forms in the upper 10 - 20 cm of Gulf deposits. Compared with the tropical Amazon delta system, authigenic carbonate formation in the Gulf of Papua deposits is not well developed.
DE: 1050 Marine geochemistry (4835, 4850)
SC: Ocean Sciences [OS]
MN: 2003 Fall Meeting