Carbon and oxygen isotope geochemistry of Neoproterozoic limestones of the Shahabad Formation, Bhima basin, Karnataka, southern India

Petrography, major (including four trace elements), stable isotopes (carbon and oxygen), and 87Sr/86Sr geochemistry of limestones of the Shahabad Formation, Bhima basin, Karnataka, southern India are reported. These limestones show a narrow range of δ13C (~1.34−1.96‰) and δ18O (~ -6.04 to -7.61‰) v...

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Main Authors: Ramasamy Nagarajan, Alcides N. Sial, John S. Armstrong-Altrin, Jayagopal Madhavaraju, Raghavendra Nagendra
Format: Article
Language:English
Published: Universidad Nacional Autónoma de México 2018-01-01
Series:Revista Mexicana de Ciencias Geológicas
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Online Access:https://rmcg.unam.mx/index.php/rmcg/article/view/654
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Summary:Petrography, major (including four trace elements), stable isotopes (carbon and oxygen), and 87Sr/86Sr geochemistry of limestones of the Shahabad Formation, Bhima basin, Karnataka, southern India are reported. These limestones show a narrow range of δ13C (~1.34−1.96‰) and δ18O (~ -6.04 to -7.61‰) values. The petrographic study reveals the presence of microsparite and micro- and macrostylolites. The δ13C and 87Sr/86Sr values indicate that these limestones were deposited during the late Neoproterozoic age and the δ18O values also are very similar to the average Proterozoic carbonate values. Mn and Sr concentrations and low Mn/Sr ratio (<1) together with the stable and radiogenic isotope data suggest that the studied samples are well-preserved or scarcely altered limestones and probably have retained their primary isotopic signatures.    
ISSN:1026-8774
2007-2902