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Clay minerals and Sr-Nd isotopes of the sediments along the western margin of India and their implication for sediment provenance

DRS at CSIR-National Institute of Oceanography

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Title Clay minerals and Sr-Nd isotopes of the sediments along the western margin of India and their implication for sediment provenance
 
Creator Kessarkar, P.M.
Rao, V.P.
Ahmad, S.M.
Babu, G.A.
 
Subject clay minerals
stromium isotopes
neodymium isotopes
sediments
continental margins
provenance
 
Description Mineralogy and Sr-Nd isotopic composition of the less than 2-m fraction of the Holocene and late Pleistocene sediments from 12 gravity cores collected along the western margin of India were used to delineate the provenance and understand the response of isotopes with respect to the source rock composition. Holocene sediments show distinct clay mineral associations representing three major sources: illite, chlorite-rich sediments from the Indus, smectite-dominated sediments from the Deccan Traps, and kaolinite and smectite-enriched sediments from gneissic rocks. The mixing of Indus-derived sediment with the Deccan Traps-derived sediment or the Deccan Traps-derived sediment with gneissic rock-derived sediment occurs in the deeper water cores. Sr isotopes are very sensitive to weathering and laterization. Weathering does not influence Nd isotopes. The u87Sr/ u86Sr ratios of the Holocene sediments in shallow water cores are higher and fluctuated widely than those in deeper water cores.epsilondNd correlates well with the clay mineral associations, indicating source rock composition or mixing of source sediments. Kaolinite-enriched sediments coupled with high Sr ratios and low epsilondNd on the SW margin of India suggest intense chemical weathering in the hinterland. The influence of the sediment from the Ganges-Brahmaputra, transported by the Bay of Bengal waters during the NE monsoon surface current or SW monsoon underwater current, on the composition of the sediments of the SW Indian margin is insignificant. The late Pleistocene sediments reflect a decrease of hydrolytic processes resulting in decrease of smectite and Sr isotopic ratio. Clay minerals and epsilondNd values suggest that the provenance and transport pathways of the late Pleistocene sediments are the same as those of the Holocene for each region.
 
Date 2008-07-18T05:41:38Z
2008-07-18T05:41:38Z
2003
 
Type Journal Article
 
Identifier Marine Geology, Vol.202; 55-69p.
http://drs.nio.org/drs/handle/2264/1244
 
Language en
 
Rights Copyright [2003]. It is tried to respect the rights of the copyright holders to the best of the knowledge. If it is brought to our notice that the rights are violated then the item would be withdrawn.
 
Publisher Elsevier