From the Bureau of Economic Geology, The University of Texas at Austin (www.beg.utexas.edu).
For more information, please contact the author.

Bureau Seminar, March 20, 2009

From River Mouth to Remote Depocenters: Transport Processes
and Sediment Dispersal across the Bengal Margin

Kimberly G. Rogers
Earth and Environmental Sciences, Vanderbilt University

The Ganges-Brahmaputra delta in Bangladesh is an end-member example of a high-volume river system that debouches onto a rapidly accreting, canyon-incised margin. The combined sediment discharge of these rivers delivers more than 750 million metric tons of sediment annually to the world ocean through a highly energetic coastal zone, where sediments are reworked daily by tides, winds, waves, and annually by seasonal monsoons and cyclones. Sediment delivery to the coast has kept pace with sea level rise since the mid-Holocene, allowing subaerial and subaqueous growth of the delta. However, the spatial and temporal distribution of these sediments has been only partially quantified. Under the threat of global and regional sea level changes, it is imperative to more completely understand how oceanographic, fluvial and climatic processes interact to control sediment transport and storage in this dynamic system. Radioisotope geochronology, sedimentological analyses and high-resolution sub-bottom sonar surveys have been conducted to identify dispersal mechanisms and transport pathways on the understudied inner shelf of the Bay of Bengal, and to determine how sediments exiting the active river mouth are delivered to offshore and onshore depocenters.