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Origin and significance of high-grade phosphorite in a sediment core from the continental slope off Goa, India

DRS at CSIR-National Institute of Oceanography

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Title Origin and significance of high-grade phosphorite in a sediment core from the continental slope off Goa, India
 
Creator Rao, V.P.
Rao, Ch.M.
Thamban, M.
Natarajan, R.
Rao, B.R.
 
Subject sediments
geochemistry
phosphorite
continental slope
 
Description A phosphorite crust was found at 380-390 cm depth interval of a sediment core collected from the topographic high occurring on the continental slope off Goa. This crust is fragile and grey to light brown in colour. Carbonate fluorapatite is the predominant mineral followed by minor pyrite. Thin section studies indicate that it is mostly homogeneous with a few bone fragments and shows porous microstructure. SEM studies show that it contains agglomerated 1-2 mu m size apatite globules resembling phosphatized bacteria and coalesced bacteria. Microprobe geochemistry of the phosphorite indicates that is contains 33% P sub(2)O sub(5) and 50% CaO with other major elements (Si, Al, Ti, Fe, Mg, Na and K) amounting to only 1.8%. The mode of the phosphorite crust formation is discussed in relation to Quaternary phosphorites in upwelling and non-upwelling regions. It is suggested that the initial substrate for the phosphorite crust was most probably a fish coprolite which phosphatized under lower rates of terrigenous sedimentation and calm environmental conditions during the Pleistocene
 
Date 2009-01-25T06:12:51Z
2009-01-25T06:12:51Z
1995
 
Type Journal Article
 
Identifier Current Science, Vol.69; 1017-1022p.
http://drs.nio.org/drs/handle/2264/2376
 
Language en
 
Rights Copyright [1995]. 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 Current Science Association, Bangalore, India