Informatics Publishing Limited

G. S. Sharma ¹, R. K. Purohit ¹, Minati Roy ¹, B. Sengupta ¹, Jagmer Singh ²

Affiliations
1 Atomic Minerals Division, Department of Atomic Energy, New Delhi-110066, IN
2 Atomic Minerals Division, Department of Atomic Energy, Hyderabad-500016, IN

Abstract

Radioactive alkali feldspar granite (alaskite) occurs as dykes within the Proterozoic granite gneiss around Dhanota. Samples have assayed 0.011 to 0.16% U₃O₈ and 0.005 to 0.16% ThO₂. Yttrium values range from 250 to 800 ppm. Uranothorite occurs in association with zircon, xenotime, magnetite, hematite, sphene and goethite. The U-Th-Y mineralisation in alaskites of Dhanota is disseminated syn-magmatic intrusive type.

Keywords

Economic Geology, Geochemistry, Petrography, Alaskite Dyke, Xenotime, Uranothorite, Dhanota, Haryana.

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Bikash Sengupta ¹, Madhuparna Roy ², R. K. Purohit ¹, A. K. Paul ¹

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Hyderabad-500 0 16, IN
2 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, New Delhi - 110 066, IN

Abstract

The Precambrian migmatites around Kudri host uranium, rare earth and zirconium mineralization, manifested, respectively in the form of discrete uraninite, allanite and zircon. Mineralization is mostly in the biotite-Rich melanosome (restite), albite-Rich leucosome and mesosome (mobilizate). Uraninite with UO₂ content of 79.93-82.45% (av.81.36%), and content of high Th (ThO₂:2.98-5.71%, av.4.37%) and high REE (RE₂O₃: 0.82-2.11, av.1.41%) and chemical age (736-929 Ma, av.824 Ma) of uraninite (n=14) point towards its origin during Neoproterozoic (av. 824 Ma) probably by epigenetic, high-Temperature, synmagmatic origin which later subjected to dissolution and alteration by hydrothermal process. However, textural evidence of corrosion of erstwhile euhedral uraninite suggests its subsequent dissolution and alteration, together with expulsion of REE, possibly by a saline, moderately acidic hydrothermal (100-300°C), reducing solution at a lower pressure, related to regional tectonic episode.

Keywords

Petrography, Mineral Chemistry, Migmatite, Uraninite Dissolution, Kudri, U.P.

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U. P. Sharma ¹, S. Shukla ¹, P. K. Sinha ¹, R. K. Purohit ¹, A. Majumdar ¹, A. K. Rai ²

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, AMD Complex, Civil Lines, Nagpur 440 013, IN
2 Atomic Minerals Directorate for Exploration and Research, AMD Complex, Begumpet, Hyderabad 500 016, IN

Abstract

No Abstract.

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B. Nagabhushanam ¹, S. Durai Raju ², K. L. Mundra ³, S. D. Rai ¹, R. K. Purohit ¹, M. B. Verma ¹, L. K. Nanda ¹

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Hyderabad 500 016, IN
2 Atomic Minerals Directorate for Exploration and Research, Beach Sand and Offshore Investigations, Thiruvananthapuram 695 012, IN
3 Atomic Minerals Directorate for Exploration and Research, Western Region, Jaipur 302 033, IN

Abstract

The Ambadongar sub-volcanic carbonatite alkali complex is located about 140 km east of Vadodara, Chhota Udepur district, Gujarat, India and falls in Survey of India Toposheet No. 46 K/1. The complex intrudes Bagh sandstone (Cretaceous) and overlying Deccan basalts (Eocene) and is situated in the Narmada rift zone. The carbonatites came into prominence in the early 1960s with significant discoveries of fluorite and conspicuous radioactivity located near Chhota Udepur, at Ambadongar, the erstwhile Baroda district, Gujarat. Earlier workers have clarified many aspects of the carbonatite complex.

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