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Facies, dissolution seams and stable isotope compositions of the Rohtas Limestone (Vindhyan Supergroup) in the Son valley area, central India

DSpace at IIT Bombay

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Title Facies, dissolution seams and stable isotope compositions of the Rohtas Limestone (Vindhyan Supergroup) in the Son valley area, central India
 
Creator BANERJEE, S
BHATTACHARYA, SK
SARKAR, S
 
Subject combined flow
carbonate
evolution
diagenesis
sequences
oxygen
basin
age
geochemistry
systematics
dissolution seams
rohtas limestone
stable isotopes
diagenesis
 
Description The early Mesoproterozoic Rohtas Limestone in the Son valley area of central India represents an. overall shallowing-upward carbonate. succession. Detailed facies analysis of the limestone reveals outer- to inner-shelf deposition in an open marine setting. Wave-ripples, hummocky cross stratifications and edgewise conglomerates argue against a deep marine depositional model for the Rohtas Limestone proposed earlier. Stable isotope analysis of the limestone shows that delta(13)C and delta(18)O values are compatible with the early Mesoproterozoic open seawater composition. The ribbon limestone facies in the Rohtas Limestone is characterized by micritic beds, each decoupled in a lower band enriched and an upper band depleted in dissolution seams. Band-wise isotopic analysis reveals systematic short-term variations. Comparative enrichment of the heavier isotopes in the upper bands is attributed to early cementation from sea water and water derived from the lower band undergoing dissolution because of lowering of pH at depth. The short-term positive shifts in isotopic compositions in almost every upward gradational transition from a seamed band to a non-seamed band support the contention that dissolution seams here are of early diagenetic origin, although their formation was accentuated under overburden pressure.
 
Publisher INDIAN ACADEMY SCIENCES
 
Date 2011-08-02T03:37:52Z
2011-12-26T12:53:40Z
2011-12-27T05:40:26Z
2011-08-02T03:37:52Z
2011-12-26T12:53:40Z
2011-12-27T05:40:26Z
2005
 
Type Article
 
Identifier JOURNAL OF EARTH SYSTEM SCIENCE, 114(1), 87-96
0253-4126
http://dx.doi.org/10.1007/BF02702011
http://dspace.library.iitb.ac.in/xmlui/handle/10054/8642
http://hdl.handle.net/10054/8642
 
Language en