Stable isotope ratios and nodular limestone of the Proterozoic Rohtas Limestone: Vindhyan basin, India
DSpace at IIT Bombay
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Title |
Stable isotope ratios and nodular limestone of the Proterozoic Rohtas Limestone: Vindhyan basin, India
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Creator |
BANERJEE, S
JEEVANKUMAR, S SANYAL, P BHATTACHARYYA, SK |
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Subject |
carbonates
supergroup evolution oxygen age geochemistry systematics diagenesis deposition sequences nodular limestone stable isotopes early diagenesis rohtas limestone microbial mat |
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Description |
The Proterozoic Rohtas Limestone succession in the Vindhyan basin, central India depicts a transition from outer shelf to inner shelf depositional setting. The succession comprises of seven facies viz., black shale, crinkly-laminated limestone, nodular limestone, thinly-laminated heterolithic, grey shale, plane-laminated limestone and wavy-laminated limestone. From field and petrographic features the nodular limestone is identified as early diagenetic product of crinkly-laminated limestone. delta C-13 and delta O-18 values of the limestone bear essentially the 'primary' seawater composition of late Paleoproterozoic to early Mesoproterozoic time and rules out any postdepositional resetting. delta C-13 and delta O-18 compositions of the nodular and non-nodular portions when analysed separately reveals that the nodular portions are invariably enriched in heavier oxygen and carbon isotopes. Enrichment in oxygen and carbon isotope values in the same nodular limestone, although negligible, suggest preferential cementation within the nodular portion. Nodules were possibly generated by dissolution of carbonate sediments and subsequent reprecipitation of carbonate cements close to the sea floor.
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Publisher |
NORTHEASTERN SCIENCE FOUNDATION INC
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Date |
2011-08-19T10:01:46Z
2011-12-26T12:56:11Z 2011-12-27T05:44:28Z 2011-08-19T10:01:46Z 2011-12-26T12:56:11Z 2011-12-27T05:44:28Z 2006 |
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Type |
Article
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Identifier |
CARBONATES AND EVAPORITES, 21(2), 133-143
0891-2556 http://dspace.library.iitb.ac.in/xmlui/handle/10054/10312 http://hdl.handle.net/10054/10312 |
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Language |
en
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