|
|
|
Holocene stratigraphy of the Lower Ganges-Brahmaputra
River delta in Bangladesh |
| Khan Sirajur Rahman1, Islam Md Badrul2 |
| 1.Geological Survey of Bangladesh; 2.Department of Geology and Mining, University of Bangladesh; |
|
|
|
|
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 m thick 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.
|
|
Issue Date: 05 December 2008
|
|
| 1 |
Alam M, Alam M M, Curray J R, et al. (2003). An overview of the sedimentarygeology of the Bengal Basin in relation to the regional tectonic frameworkand basin-fill history. Sedimentary Geology, 155(3–4): 179–209.
doi:10.1016/S0037-0738(02)00180-X
|
| 2 |
Banerjee M, Sen P K (1987). Paleobiologyin understanding the change of sea level and coast line in BengalBasin during Holocene period. Indian Journalof Earth Sciences, 14: 307–320
|
| 3 |
Banerjee M, Sen P K (1988). Paleobiologyand environment of deposition of Holocene sediments of the Bengalbasin, India. The Palaeoenvironment of East Asia from the mid-Tertiary, Proceedings of the 2nd Conference. Hong Kong: Centre of Asian Studies, University of Hong Kong, 703–731
|
| 4 |
Blanchon P, Shaw J (1995). Reefdrowning during the last deglaciation: Evidence for catastrophic sea-levelrise and ice-sheet collapse. Geology, 23: 4–8.
doi:10.1130/0091-7613(1995)023<0004:RDDTLD>2.3.CO;2
|
| 5 |
Curray J R, Emmel F J, Moore D G, et al. (1982). Structure, tectonics andgeological history of the northestern Indian Ocean. In:: Naim A E M, StehliF G, eds. The Ocean Basins and Margins. The Indian Ocean, vol 6. New York: Plenum, 399–450
|
| 6 |
Fairbanks R G (1989). A 17 000-year glacio-eustatic sea level record: influenceof glacial melting rates on the Younger Dryas event and deep-oceancirculation. Nature, 342: 637–642.
doi:10.1038/342637a0
|
| 7 |
Goodbred S L, Kuehl S A (1999). Holoceneand modern sediment budgets for the Ganges-Brahmaputra river system:Evidence for highstand dispersal to floodplain, shelf, and deep-seadepocenters. Geology, 27(6): 559–562.
doi:10.1130/0091-7613(1999)027<0559:HAMSBF>2.3.CO;2
|
| 8 |
Goodbred S L, Kuehl S A (2000). LateQuaternary evolution of the Ganges-Brahmaputra River delta: Significanceof high sediment discharge and tectonic processes on margin sequencedevelopment. Sedimentary Geology, 133: 227–248.
doi:10.1016/S0037-0738(00)00041-5
|
| 9 |
Khan S R, Kudrass H R (1999). Holocenesedimentation of the lower Ganges-Brahmaputra river delta, Bangladesh. SONNE–SO126 cruise Final Report, Federal Institute for Geosciences and Natural Resources, Germany
|
| 10 |
Milliman J D, Syvitski J P M (1992). Geomorphic/tectoniccontrol of sediment discharge to the ocean: The Importance of smallmountainous rivers. Journal of Geology, 100: 525–544
|
| 11 |
Umitsu M (1987). Late Quaternary sedimentary environment and landformevolution in the Bengal lowland. GeographicalReview of Japan, 60: 164–178
|
| 12 |
Umitsu M (1993). Late Quaternary sedimentary environments and landformsin the Ganges delta. Sedimentary Geology, 83: 177–186.
doi:10.1016/0037-0738(93)90011-S
|
| 13 |
Weber M E, Wiedicke M H, Kudrass H R, et al. (1997). Active growth of the Bengalfan during sea-level rise and highstand. Geology, 25: 315–318.
doi:10.1130/0091-7613(1997)025<0315:AGOTBF>2.3.CO;2
|
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
