Carbon and oxygen isotopic variations in stromatolitic dolomites of Palaeoproterozoic Vempalle Formation, Cuddapah Basin, India

• Autores: Gopal Chakrabarti, Debasish Shome, Subhasish Kumar, John S. Armstrong Altrin, Alcides N. Sial
• Localización: Carbonates and Evaporites, ISSN 0891-2556, Vol. 26, Nº. 2, 2011 (Ejemplar dedicado a: Dr. Gerald Friedman, Founder of Carbonates and Evaporites.), págs. 181-191
• Idioma: inglés
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• Resumen

  • The marine stromatolitic dolomites of Palaeoproterozoic Vempalle Formation, of Cuddapah Basin, South India show significantly depleted [delta]18O (-8.19 to -18.25%o) and [delta]13C (-0.03 to -5.74) values and are consistent with the global Proterozoic data. A comparison of the stable isotope values from major localities of Proterozoic Basins of India has also been attempted in this study. Significantly depleted [delta]18O values of Vempalle carbonate samples could not be considered to be post-depositional modifications as there exists an inverse correlation relationship between C and O isotopic values. The Vempalle stromatolitic dolomite is likely to be precipitated in equilibrium with marine waters significantly depleted in oxygen isotopes (-10 to -15%o SMOW) with respect to modern sea water. The negative [delta]13C values of the Vempalle carbonates are likely to be interpreted at the backdrop of global "icehouse" as there is an indication of dropstone-like features in the lower part of the Vempalle Formation just 2 km, southwest of the study area.