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

M. N. Balasubrahmanyan ¹, P. K. Bishui ¹, K. C. Chandy ¹, S. N. Gupta ¹, N. K. Jana ¹, D. K. Paul ¹, R. Prasad ¹

Affiliations
1 Geochronology and Isotope Geology Division, Geological Survey of India, Calcutta, IN

Abstract

New Rb-Sr isotopic age is presented for the porphyritic phase of Kanara batholith of South Kanara, Karnataka. The porphyritic granite has a good spread of Rb/Sr ratio and indicates an isochron age of 2681 ± 236 Ma with an initial ratio of 0.7022 ± 0.004. The observed low initial Sr ratio suggests its derivation from mantle without much crustal contamination.

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R. Prasad ¹, S. Rai ¹, Alok Kumar ¹, G. N. Dwiyedi ², A. K. Tripathi ², M. L. Yadav ²

Affiliations
1 Mineral Physics Division, Geological Survey of India, Lucknow-226024, IN
2 Project Mineral Investigation (Peninsular), Geological Survey of India, Lucknow-226024, IN

Abstract

A rare mineral Beudantite PbFe₃ (AsO₄)(SO₄)(OH)₆had been identified by X-ray diffraction technique in a weathered mineralised quartz vein, emplaced in phyllitic sequence. Its cell parameters are a=7.32Å. and c=17.13Å that are comparable to those of JCPDS-ASTM standard. Its association with corkite suggests that the area may have potential for silver and gold.

Keywords

Mineralogy, Beudantite, Corkite, XRD, Sonbhadra, Uttar Pradesh.

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