GSA Connects 2021 in Portland, Oregon

Paper No. 21-2
Presentation Time: 9:00 AM-1:00 PM


CARNEY, Hannah, Department of Geological Sciences, San Diego State University, 5500 Campanile Dr, San Diego, CA 92182, BOVA, Samantha, Deparment of Geological Sciences, San Diego State University, 5500 Campanile Dr, San Diego, CA 92182 and ROSENTHAL, Yair, Department of Marine and Coastal Sciences, Rutgers University, 71 Dudley Road, New Brunswick, NJ 08901

Approximately 501 million tons/yr. of sediment is delivered to the Bismarck Sea and dispersed on a narrow continental shelf off the coast of Northern Papua New Guinea (NPNG) (Milliman, 1995). Thirty NPNG watersheds are analyzed for their slope, relief, lithology, and rainfall to determine prominent source regions of the load carried offshore. Terrestrial sediments in this region are rich in iron, manganese, and aluminum and are carried from the narrow continental shelf offshore into the deep sea, where sediments are then carried by the New Guinea Coastal Undercurrent (NGCU).The NGCU and the New Ireland Coastal Undercurrent are primary sources of nutrients to the Eastern Pacific, which are carried by the Equatorial Undercurrent (EUC) (Slemons et. al 2010, Qin et. al 2016). Elemental compositions and grain size of core top sediments (n=25) derived from IODP Expedition 363 and RR1313 reveal where the sediment is mobilized within watersheds and how sediment is dispersed along the ocean floor in recent years (<300yrs). Samples are prepared with a flux fusion method (derived from Murray et. al 2000) and elemental concentrations are measured via ICP-OES. A multivariate statistical analysis of the geochemistry of samples determines if endmembers can be determined to identify source regions of sediment from the contributing watersheds. Elevation of delivery of modern sediments to the Bismarck Sea provides supplemental information on the efficacy of terrestrial proxies like titanium variations used to develop long term paleoclimate records (Tachikawa et. al 2011).