Heavy sediment influx during early Holocene: Inference from clay mineral studies in a core from the western Bay of Bengal
IR@NIO: CSIR-National Institute Of Oceanography, Goa
View Archive Info| Field | Value | |
| Creator |
Reddy, N.P.C.
Rao, K.M. |
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| Date |
2006-08-28T07:48:19Z
2006-08-28T07:48:19Z 2001 |
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| Identifier |
Current Science, vol.81(10), 1361-1364pp.
http://drs.nio.org/drs/handle/2264/276 |
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| Description |
Clay mineral studies were carried out in a 650 cm long sediment core collected at a depth of 2200 m from the north-western Bay of Bengal. Illite is the predominant mineral, followed by montmorillonite and chlorite. Illite concentration varies from 49 to 65% from the core top to 380 cm and further down, increases to 85%. Montmorillonite content ranges from 22 to 36% above 380 cm, with a maximum in the upper 20 cm. Lowest values of montmorillonite (3– 8%) are observed below 380 cm. Chlorite values range from 12.8 to 29%. Kaolinite is present in traces. The changes in mineral composition at 380 cm in the core are interpreted to be a transitional period of Pleistocene– Holocene. This is substantiated by the lithological, foraminiferal and geochemical studies of the core. Very high content of illite below 380 cm of the core reflects glacial weathering products of crystalline metamorphic/ sedimentary rocks of Himalayas carried by Ganges–Brahmaputra rivers during the late Pleistocene, when the sea level was low. Increase of montmorillonite and kaolinite during the Holocene indicates that the Ganges–Brahmaputra province sediments were diluted with sediments from the peninsular rivers draining metamorphic gneisses, schists, Deccan Traps and Quaternary sediments. This distribution can be explained by circulation pattern and tectonics in the Ganges delta during early Holocene. The top 380-cm thick sediment deposition during Holocene is attributed to heavy sediment influx during Mid Termination (MT) (12,500–10,000 years BP), due to increased precipitation and run-off resulting from high intensity monsoonal regime.
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173056 bytes
application/pdf |
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| Language |
en
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| Publisher |
Indian Academy of Sciences
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| Subject |
Bay of Bengal
Clay mineral mineral composition sediment deposition |
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| Title |
Heavy sediment influx during early Holocene: Inference from clay mineral studies in a core from the western Bay of Bengal
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| Type |
Article
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