Informatics Publishing Limited

Mary K. Kumar ¹, D. Veera Baskar ², Mithilesh Sharma ³, T. Chabria ⁴, R. Dhanar Raju ³

Affiliations
1 Atomic Minerals Division, Department of Atomic Energy, Bangalore - 560 072, IN
2 Atomic Minerals Division, Department of Atomic Energy, Nagpur - 440 001, IN
3 Atomic Minerals Division, Department of Atomic Energy, Bangalore - 560 072, IN
4 Atomic Minerals Division, Department of Atomic Energy, Hyderabad - 500 016, IN

Abstract

Sulphur-isotopic dataon fifteen samples of baryte from the quartz-baryte rock occurring along a shear zone east of the Elagiri Syenite pluton at Andiyappanur, Tamil Nadu have shown a narrow range of +5.1‰ to +9.5‰, with an average of +6.70‰, for δ³⁴S_CDT. The data, in conjunction with the field and petromineralogical characteristics, indicate hydrothermal-type mineralisation of baryte. Association of relatively earlier formed sulphides like pyrite, molybdenite and galena, and later formed sulphates like baryte and jarosite in this quartz-baryte rock is attributed to dual behaviour of sulphur in the magmatichydrothermal system, with formation of sulphides at depth under reducing conditions and of sulphates in the shallower oxidised zones.

Keywords

Baryte, Geochemistry, Andiyappanur, Tamil Nadu.

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Yamuna Singh ¹, T. Chabria ¹

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Begumpet, Hyderabad - 500 016, IN

Abstract

Whole-rock Rb-Sr analysis of ten granite samples from Kawadgaon, Bastar craton, yield an isochron corresponding to an age of 2497±152 Ma (2σ) and initial ⁸⁷Sr/⁸⁶Sr ratio of 0.7142±0100(2σ). The data suggest emplacement of Kawadgaon granite during the ca. 2500 Ma Archaean-Proterozoic transitional event in the craton.

Keywords

Geochronology, Rb-Sr, Granite, Bastar Craton, Madhya Pradesh.

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