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Genesis of early Cambrian phosphorite of Krol Belt, Lesser Himalaya

DRS at CSIR-National Institute of Oceanography

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Title Genesis of early Cambrian phosphorite of Krol Belt, Lesser Himalaya
 
Creator Mazumdar, A.
Banerjee, D.M.
 
Subject GEOLOGY AND GEOPHYSICS
GEOLOGY AND GEOPHYSICS
 
Description Early Cambrian phosphogenesis in the lesser Himalaya is represented by a well-developed sequence of phosphorite, black shale and black chert with interbedded phosphatic dolomite in the Krol Belt. Prevalence of shallow marine depositional structures support shallow subtidal to intertidal depositional environment. Similar shallow marine character for Late Vendian and Early Cambrian phosphorites have been recorded from Yangtze Basin (South China), Khubshugul Basin (Mongolia), Karatau Basin (Kazakhstan), Soltaniah Basin (Iran), Tal Basin (Lesser Himalaya, India), Hazara Basin (Pakistan) and Georgia Basin (Australia). We have characterized the Tal Phosphorites of Krol Belt, Lesser Himalaya in terms of mineralogy and petrography. The phosphogenic model for the modern Peru–Chile shelf–slope phosphorite is inadequate to explain the genesis of Cambrian phosphorite. Physicochemical characters of the Cambrian phosphorites demand a shallow marine phosphorous source. Based on the available early Cambrian oceanographic models, we envisage a repeated influx of P and 12C rich water on to the shallow platform. Amorphous calcium phosphate (ACP) precipitated from the shallow water column overlying the sediment water interface and subsequently modified to microsphorite (micritic phosphorite). Influx of P resulted in proliferation of algal mat and stromatolites, which are found in abundance in Tal phosphorites. The algal and mudstone phosphorites were the parent material for granular phosphorites
 
Date 2015-08-24T09:42:32Z
2015-08-24T09:42:32Z
2015
 
Type Journal Article
 
Identifier Current Science, vol.108(7); 2015; 1247-1252
http://drs.nio.org/drs/handle/2264/4760
 
Language en
 
Rights Copyright [2015]. 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