HR: 1340h
AN: OS53A-0985    [Abstracts]
TI: Sediment Transport Pathways in a High-Energy Source-to-Sink System: Results From the Submarine Topsets of the Ganges-Brahmaputra Delta, Bangladesh
AU: * Rogers, K G
EM: kimberly.g.rogers@vanderbilt.edu
AF: Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37235, United States
AU: Goodbred, S L
EM: steven.goodbred@vanderbilt.edu
AF: Department of Earth and Environmental Sciences, Vanderbilt University, Nashville, TN 37235, United States
AU: Khan, S R
EM: romugsb@gmail.com
AF: Geological Survey of Bangladesh, Segunbagicha, Dhaka, 1000, Bangladesh
AB: The transition between river and marine environments is the most complex and least understood component of coastal source-to-sink systems. The Ganges-Brahmaputra Delta, Bangladesh, represents an end-member in the continuum of estuarine environments, discharging the largest sediment load into a high energy canyon incised shelf. Toward the goal of understanding how fluvial, oceanographic and climactic processes interact to control sediment dispersal in this zone, a shallow high-resolution seismic survey was conducted on the inner shelf of the Bay of Bengal during the 2007 low-discharge winter monsoon. The data show that subsurface architecture within the river mouth estuary and adjacent to modern active distributaries includes extensive cut- and-fill features, "stair-step" reflective surfaces, and patches of acoustically transparent layers. Seismic facies bordering abandoned tidal channels in the westernmost part of the delta show comparatively little stratigraphic structure, implying limited penetration in sand. However, cross-shelf sections south of the abandoned distributaries and nearest the canyon head contain more complex cut-and-fill stratigraphy than along-shelf sections in the same area. Correlation of canyon feeder gullies with these infilled shelf features, which may be contiguous from the abandoned delta to areas of active sedimentation, may lead to a more precise understanding of transport mechanisms linking the river mouth and offshore depocenters.
DE: 3002 Continental shelf and slope processes (4219)
DE: 4219 Continental shelf and slope processes (3002)
SC: Ocean Sciences [OS]
MN: 2007 Fall Meeting