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Himalayan sedimentary pulses recorded by silicate detritus within a ferromanganese crust from the Central Indian Ocean

DRS at CSIR-National Institute of Oceanography

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Title Himalayan sedimentary pulses recorded by silicate detritus within a ferromanganese crust from the Central Indian Ocean
 
Creator Banakar, V.K.
Galy, A.
Sukumaran, N.P.
Parthiban, G.
Volvaiker, A.Y.
 
Subject sediments
concretions
palaeoceanography
detritus
mineralogy
neodymium isotopes
strontium isotopes
silicates
 
Description A Central Indian Ocean deep-water seamount hydrogenous ferromanganese crust (SS663-Crust) contains variable (7-23%) amounts of detrital material (silicate-detritus). Taking into account the growth rate of the authigenic component, the accumulation rate of the silicate-detritus has been calculated, which shows an overall decrease during the past 25 plus or minus 2 Ma growth history of the specimen. This silicate-detritus displays epsilon Nd(0) between -7.7 and -12.7, and u87Sr/ u86Sr between 0.7083 and 0.7215. The Sr-Nd isotopic compositions record the variation in the mixture of two detrital end-members throughout the growth history of the SS663-Crust. While one end-member clearly appears to be Himalayan-derived material, the other component is less well defined, but could be related to the volcanogenic component from the Indonesian back-arc basin. We have unscrambled the proportion of these two components in the silicate-detritus of the SS663-Crust to quantify the variation in the accumulation rate of the Himalayan-derived silicate-detritus during the last 25 Ma. The result shows three periods of high accumulation rates (modern, around 10 Ma and prior to 16 Ma). These sedimentary pulses have already been recognised and described in the turbidites from the distal Bengal Fan, which is located more than 1000 km away from the SS663-Crust location, suggesting that these sedimentary pulses are of regional significance rather than of local importance. The timings of elevated contents of the Himalayan-derived silicate-detritus in the specimen during the Neogene closely superimpose the periods of the Himalayan uplift along the Main Central Thrust, the Main Boundary Thrust, and the Main Frontal Thrust. This further emphasises the tectonic control of the sediment production by the erosion of an active orogenic range and its distribution over a vast area. Additionally, close superimposition of the Early Miocene detritus pulse in the SS663-Crust on the riverine Sr isotopic positive excursion suggests that the physical and chemical weathering of the Himalaya was strongly coupled during the Early Miocene, while the spatial decoupling appears to have taken place only around 12-14 Ma
 
Date 2008-07-18T05:45:16Z
2008-07-18T05:45:16Z
2003
 
Type Journal Article
 
Identifier Earth and planetary science letters, Vol.205; 337-348p.
http://drs.nio.org/drs/handle/2264/1250
 
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