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

R. Dhana Raju ¹, R. N. Prasad ², D. D. Pandey ², A. V. Jeyagopal ², R. D. Deshmukh ¹

Affiliations
1 Atomic Minerals Division, Department of Atomic Energy, Bangalore - 560072, IN
2 Atomic Minerals Division, Department of Atomic Energy, Hyderabad - 500016, IN

Abstract

Baryte at Vemula near to the southwestern margin of Cudapah Basin occurs as a vein-type deposit discordant to both the carbonate rocks of Vempalle formation and its intrusive dolerite. S-isotopic data on the baryte have a range of δ³⁴S_CDT between +16.2‰ and +23.3‰ whereas the coexisting chalcopyrite has a restricted range between +10.9‰ and +11.4‰. The average value of δ³⁴S of Vemula baryte (+20.8‰) differs much from that of magmatic rocks (0‰ to +2.5‰), metamorphic rocks (+3‰) and sediments of continental margins, platform areas and geosynclines (-12.5‰ -17,1‰), but is similar to that of sea water (+20‰) which appears to be the source for sulphur. The narrow range of δ³⁴S of baryte and chalcopyrite points to a uniform source with their sulphur possibly derived from sea water sulphate by bacteriogenic reduction.

Keywords

Economic Geology, Baryte, Sulphur Isotope, Cuddapah Basin, Andhra Pradesh.

Full Text