Holocene stratigraphy of the lower Ganges-Brahmaputra river delta in Bangladesh

Research Article

DOI: 10.1007/s11707-008-0051-8

Cite this article as:
Khan, S.R. & Islam, B. Front. Earth Sci. China (2008) 2: 393. doi:10.1007/s11707-008-0051-8

Abstract

Major part of the Holocene Ganges-Brahmaputra delta occupies the southern and southwestern part of Bangladesh with a smaller part extending beyond the international boundary in the west. Five facies assemblages are documented in the lower deltaic plain in five different depositional environments: levee or levee complex, bil or depression, abandoned meander belt, interdistributary plain and estuarine plain. The thickness of the Holocene sediments ranges from 30 m to 70 m in the deltaic plain, usually floored by the Pleistocene stiff clays, with the exception of the abandoned meander belt deposit where Holocene channel sand deposited directly on the Pleistocene sand. Radiocarbon dates indicate that low-rate sedimentation has occurred in the northern part, where 4-6 m thick sediments were deposited since the mid-Holocene, whereas 10-30 mthick sediments were deposited in the southern part during the same span of time. In addition, significant coastal subsidence (3 mm/a on average), added by sea-level rise (1.5 mm/a, conservative rate) occurs in the study area, which serves as a negative factor in degrading the coastal plain of Bangladesh in the future, while taking into consideration the weaker sedimentation in the area.

Keywords

levee bil/depression abandoned meander belt interdistributary plain estuarine plain Holocene sediment thickness 

Copyright information

© Higher Education Press and Springer-Verlag GmbH 2008

Authors and Affiliations

  1. 1.Geological Survey of Bangladesh 153 Pioneer RoadSegunbagichaDhakaBangladesh
  2. 2.Department of Geology and MiningUniversity of BangladeshRajshahiBangladesh

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