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Nannostructure and significance of fish coprolites in phosphorites

DRS at CSIR-National Institute of Oceanography

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Title Nannostructure and significance of fish coprolites in phosphorites
 
Creator Lamboy, M.
Rao, V.P.
Ahmed, E.
Azzouzi, N.
 
Subject Geology and Geophysics
Geology and Geophysics
 
Description Phosphatic coprolites (0.5-2 cm long) occurring in Cretaceous-Eocene phosphorites of Tunisia, Morocco, Mauritania, Senegal, and Egypt were investigated for their petrology by using SEM. They exhibit a homogeneous porous apatite structure with a few fish remains. The nonnostructures of the coprolites consist of inframicron-sized and botryoid-type apatite microparticles. Spherical cavities and cavity-infilled inframicron-sized apatite globules are typical in the coprolites and are apparently formed by extracellular precipitation of phosphate around microbial organisms. We presume that the coprolites studied here may belong to fishes, whose, excrements contain abundant organic matter and phosphate. Phosphatization of excrements appears to be a microbial process controlled by the microenvironment. The nannostructures observed in the coprolites investigated here differ significantly from the nannostructures of other studied phosphatic grains (pellets and coated grains) in the same samples which are mostly heterogeneous and consist of ovoid-type apatite particles. In the case they are not reworked, the centimetre to decimetre thick coprolite beds in phosphorites indicate a lack of detrital input and strong bottom water currents at the sediment-water interface during deposition and subsequent phosphatization of the excrements
 
Date 1997-07-05T10:06:29Z
2017-09-30T01:55:44Z
1997-07-05T10:06:29Z
2017-09-30T01:55:44Z
1994
 
Type Journal Article
 
Identifier Marine Geology, vol.120(3-4); 1994; 373-383
0025-3227
http://drs.nio.org/drs/handle/2264/7400
 
Language en
 
Relation Mar Geol
SCI
 
Publisher Elsevier