Informatics Publishing Limited

V. P. Saxena ¹, R. M. Sinha ¹, O. R. Yadav ¹, R. V. S. Sesha Rao ²

Affiliations
1 AMD Complex, Begumpet, Hyderabad - 500 016, IN
2 AMD Complex, Civil Lines, Nagpur - 440 001, IN

Abstract

Signatures of concealed Unconformity-Related uranium mineralization at the contact of Chhotanagpur Granite Gneissic Complex [CGGCJ/Mahakoshal and Lower Vindhyan Semri sequence have come to light at Baskati, in Vindhyan- Mahakoshal Basin, following a multipronged exploration strategy. Systematic lithogeochemical sampling brought out uranium halos and most significant signals with concentration sufficiently above the normal background closely associated with breccias along reactivated faults and fractures occurring parallel and also oblique to the unconformity contact extending for a strike length of 17 km. Alteration halos and signatures like hematitisation, chloritisation and ilhtisation characterize the vicinity of these reactivated faults and fractures Geochemical study indicates a hypogene source for mineralizing fluids supported by geology, structure and lithogeochemistry and an 'Unconformity-Related uranium mineralization model' has been envisaged with the target area narrowed down for subsurface exploration.

Keywords

Geochemical Modelling. Uranium Mineralization, Unconformity, Alteration Halos, Baskati Area, Madhya Pradesh.

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R. V. S. Sesha Rao ¹, M. S. M. Deshpande ¹, K. Shivkumar ¹

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Central Region Civil Lines, Nagpur - 440 001, IN

Abstract

Uranium mineralisation associated with phosphatic ferruginous breccia has been located for the first time within the Lower Vindhyan Semri Group of basal sediments in Son Valley around Baskati, Sidhi district, M.P. The phosphatic ferruginous breccia occurs along the reactivated basement fracture that follows the structural grain of Son-Narmada megalineament, and also marks the tectonic contact zone between Vindhyans to the north and Crystallines/Mahakoshals to the south. Detailed geological investigations at Baskati reveal uranium enrichment intermittently over a stretch of 2500 m at Baskati block and 400 m in Paniha block further east with an average width of 3 to 5 m. Samples from radioactive horizon analysed upto 670 ppm U and 36. 87% P₂O₅. Petromineralogical studies reveal that the association of uranium is mostly with the phosphatic phase.

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