This study, initiated in 1997, examines the nature of floodplain sedimentation
and deltaic evolution for one of the world's largest river systems. The
Ganges-Brahmaputra river system carries a billion tonnes of sediment annually,
yet the fate of this material past the upstream gauging stations, as in
most of the world's rivers, is not known. The study will test the hypothesis
that at least half of the rivers' sediment load is being sequestered in
the floodplain and delta plain, resulting in an evolution and facies architecture
significantly different from classic deltaic models. Such magnitude of
sediment sequestering, in the Ganges Brahmaputra as well as in other river
systems, has important implications for our understanding of the global
flux of riverine particulates to the world ocean.
Three field efforts in Bangladesh will be undertaken to obtain sediment
core and geophysical data. The specific objectives of this study are to:
1) Construct a sediment budget for the Holocene floodplain/delta plain;
2) Detail the stratigraphic architecture and history of infilling for the
Sylhet, a large tectonic basin along the previous course of the Brahmaputra;
3) Characterize the nature and magnitude recent floodplain sedimentation
in other portions of the Bengal Basin, including small sub-basins, bil
(wetland) areas; 4) Determine the stratigraphic architecture and magnitude
of delta plain sedimentation, focusing on the tidal distributary channels
of the Ganges; and, 5) Link results from 1-4 above with our previous offshore
studies to develop a holistic conceptual model for G-B delta evolution
during the late Holocene. In addition to its scientific relevance, this
study would contribute to a rational strategy for development of one of
the most densely populated, low-lying areas of the world.
FUNDING AGENCY: National Science Foundation
STUDENTS: Steven Goodbred, David Heroy
P.I.: Steven Kuehl