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Growth response of a deep-water ferromanganese crust to evolution of the Neogene Indian Ocean

DRS at CSIR-National Institute of Oceanography

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Title Growth response of a deep-water ferromanganese crust to evolution of the Neogene Indian Ocean
 
Creator Banakar, V.K.
Hein, J.R.
 
Subject palaeoceanography
miocene
oligocene
concretions
radiometric dating
beryllium isotopes
carbonate-compensation depth
 
Description A deep-water ferromanganese crust from a Central Indian Ocean seamount dated previously by sup(10)Be and sup(230) Th sub(excess) was studied for compositional and textural variations that occurred throughout its growth history. The sup(10)Be/ sup(9)Be dated interval (upper 32 mm) yields an uniform growth rate of 2.8 plus or minus 0.1 mm/Ma which gives an extrapolated age of approx. 26 Ma for the base of the crust at 72 mm and is comparable to the maximum age derived from the Co-model based growth rate estimates. This study shows that Fe-Mn oxyhydroxide precipitation did not occur from the time of emplacement of the seamount during the Eocene (approx. 53 Ma) until the late Oligocene (approx. 26 Ma). This paucity probably was the result of a nearly ovelapping palaeo-CCD and palaeo-depth of crust formation, increased early Eocene productivity, instability and reworking of the surface rocks on the flanks of the seamount, and lack of oxic deep-water in the nascent Indian Ocean. Crust accretion began (older zone) with the formation of isolated cusps of Fe-Mn oxide during a time of high detritus influx, probably due to the early-Miocene intense erosion associated with maximum exhumation of the Himalayas (op. cit.)
 
Date 2009-01-09T08:08:12Z
2009-01-09T08:08:12Z
2000
 
Type Journal Article
 
Identifier Marine Geology, Vol.162; 529-540p.
http://drs.nio.org/drs/handle/2264/1650
 
Language en
 
Rights Copyright [2000]. All efforts have been made to respect the copyright to the best of our knowledge. Inadvertent omissions, if brought to our notice, stand for correction and withdrawal of document from this repository.
 
Publisher Elsevier