Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

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Carbon, Oxygen and Uranium Isotopic Study of Uraniferous Dolostone from Cuddapah Basin, Southern India : Implications to Depositonal Environment and Uranium Alteration


Affiliations
1 Physical Research Laboratory, Ahmedabad 380 009, India
2 Atomic Minerals Division, Dept. of Atomic Energy, Hyderabad - 500 016, India
3 Atomic Minerals Division, Dept. of Atomic Energy, Bangalore 560 072, India
     

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The dolostones show a narrOw range of δ13C values but a large range of δ13O values. The small spread of δ13C from 0.1‰ to -0.9‰ is typical of marine carbonates, whereas the large range of δ13O from -7‰ to -14‰ represents characteristic Proterozoic marine carbonates some of which were exposed to alteration by fresh continental waters. A diagenetic environment of mixed marine and fresh water for the dolostone alteration is also supported by earlier studies in sedimentary structures and petrography. The 234U/238U activity ratio of 0.7 in some of the mineralised samples shows the effect of ongoing chemical leaching of uranium from discrete uranium minerals like pitchblende and coffinite.
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  • Carbon, Oxygen and Uranium Isotopic Study of Uraniferous Dolostone from Cuddapah Basin, Southern India : Implications to Depositonal Environment and Uranium Alteration

Abstract Views: 198  |  PDF Views: 2

Authors

S. K. Bhattacharya
Physical Research Laboratory, Ahmedabad 380 009, India
M. M. Sarin
Physical Research Laboratory, Ahmedabad 380 009, India
Minati Roy
Atomic Minerals Division, Dept. of Atomic Energy, Hyderabad - 500 016, India
R. Dhana Raju
Atomic Minerals Division, Dept. of Atomic Energy, Bangalore 560 072, India

Abstract


The dolostones show a narrOw range of δ13C values but a large range of δ13O values. The small spread of δ13C from 0.1‰ to -0.9‰ is typical of marine carbonates, whereas the large range of δ13O from -7‰ to -14‰ represents characteristic Proterozoic marine carbonates some of which were exposed to alteration by fresh continental waters. A diagenetic environment of mixed marine and fresh water for the dolostone alteration is also supported by earlier studies in sedimentary structures and petrography. The 234U/238U activity ratio of 0.7 in some of the mineralised samples shows the effect of ongoing chemical leaching of uranium from discrete uranium minerals like pitchblende and coffinite.