Characterization and Timing of Sediment Fluxes to Continental Slopes of the Coral Sea during the Late Quaternary

Jason M. Francis
Rice University, Department of Earth Science
Houston, Texas
[email protected]

Tropical mixed siliciclastic-carbonate depositional systems receive large amounts of sediment from rivers and shallow marine organisms. The flux and composition of sediment shed from the northeast Australian shelf to surrounding slopes and basins varies with latitude and over the late Quaternary. The reason for this variance remains poorly understood. Previous studies conducted on this margin between 15ºS and 18ºS have determined that the greatest siliciclastic sediment flux to the slope and basin occurs during transgression, not during lowstand as predicted by sequence stratigraphy. Researchers have proposed that regional climate and/or shelf physiography may have caused the deviation from sequence stratigraphic models. This study looks to decipher the major control on sedimentation over the last sea-level cycle by extending this investigation across physiographic boundaries and regional climate bands. This study will determine the composition and flux of carbonate and siliciclastic components along the Papua New Guinea / northeast Australian margin from the Gulf of Papua (8°S) to the Queensland Plateau (18ºS). The methods used to characterize the properties of the sediment will include: mineralogy using an XRD, carbonate bomb measurements to determine carbonate %, magnetic susceptibility, δ¹⁸O measurements, and ¹⁴C dating to establish a high resolution age model. The sediment composition coupled with the age model will then be used to quantify the flux of sediment to the slope. This study will expand on recent work to extend our understanding of mixed systems through space and time and provide a broad view of the world’s foremost tropical mixed system.

AAPG Search and Discovery Article #90033©2004 AAPG Foundation Grants-in-Aid