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P. V. Ramesh Babu ¹

Affiliations
1 Atomic Minerals Division, Department of Atomic Energy, Nagpur 440 001, IN

Abstract

The Bastar-Koraput Pegmatite Belt (BKPB) in southeastern part of the Bastar Craton of Penisular India extends over 80km in a NW-SE direction from Dantewada in the Bastar District of Madhya Pradesh to Salimi in thc Koraput District of Orissa. The pegmatites of BKPB are typically associated with tin and rare metal (Nb, Ta, Be and Li) mineralisation in the form of cassiterite, columbite-tantalite, beryl, lepidolite and amblygonite. Based on the study of over 200 pegrnatites in the Tongpal-Mundval-Dammoguda sector, the pegmatites of BKPB are characterised in terms of mode of occurrence, size, shape, internal zoning and mineralisation. Considering the mineralogy, internal zoning and associated mineralisation, the pegmatites of BKPB are classified into five types, viz., I-Simple, unzoned biotite or muscovite-microcline prgmatiles without tin and rare metal minerals, II-Partly differentiated, muscovite-microcline pegmatites with beryl, III-Fully differentiated muscovite-microcline pegmatites with beryl, columbite-tantalite and cassiterite, IV-Replaced lepidolite-albite-muscovite pegmatites with amblygonite, cassiterite, beryl anti colurnbite tantalite and V-Replaced muscovite-albite pegmatites with cassiterite and beryl. The five types of pegmatites have diagnostic sizes and shapes and form a paragenetic sequence with increasing internal evolution from types-I to V. Such a classification aids in prospecting for tin and rare metal minerals since pegmatitcs of types-III to V in BKPB are highly potential for these metals.

Keywords

Tin-Rare Metal Pegmatites, Economic Geology, Bastar Craton, Madhya Pradesh, Orissa.

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A. K. Dwivedi ¹, Joydip Sen ¹, C. Murugan ¹, G. Bairwa ¹, A. K. Bhatt ¹, P. V. Ramesh Babu ¹, S. A. Pandit ²

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Jamshedpur-831002, IN
2 Atomic Minerals Directorate for Exploration and Research, Hyderabad-500016, IN

Abstract

Hydrogeochemical exploration were earned out over an area of 700 sq km in Barabazar-Manbazar area of Purulia district, West Bengal, in order to identify target areas for the uranium mineralization. Water samples were collected from 504 borewells in the Singhbhum Group meta-Sediments and Chhotanagpur Granite Gneissic Complex (CGGC) including South Purulia Shear Zone (SPSZ). For individual Iithological domains, univariate and multivariate statistical techniques were applied to the analytical data on 10 variables, i.e. U, Na⁺, K⁺ , Mg⁺², Ca⁺², SO₄^-2, HCO₃, Cl^-, conductivity and pH. Five hydro uranium anomalous zones withm CGGC were delineated at Raghunathpur, Tentla, Chepua-Dighi, Ban and Jitujon areas. However, distinct pattern of high uranium values along with uranium/Conductivity are observed only in Raghunathpur-Tentla and Chepua-Dighi areas in the proximal tectonized zones of SPSZ. Based on the distinctive hydrogeochemical attributes, and favourable geology and structure, the areas in the vicinity of Raghunathpur-Tentla and Chepua-Dighi in the northern proximal contact of SPSZ, are designated as potential target areas for detailed geological and geophysical exploration.

Keywords

Hydrogeochemistry, Uranium, SPSZ, CGGC, Singhbhum Group, Purulia, West Bengal.

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S. Viswanathan ¹, P. Jagadeesan , K. S. Mishra , P. V. Ramesh Babu

Affiliations
1 Hyderabad - 500 016, IN

Abstract

No Abstract.

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K. K. Pandey ¹, K. S. Mishra ¹, U. K. Pandey ², P. V. Ramesh Babu ²

Affiliations
1 Atomic Minerals Directorate for Exploration & Research, CR, Nagpur - 440001, IN
2 Atomic Minerals Directorate for Exploration & Research, Hyderabad - 500016, IN

Abstract

Whole-Rock isochron dating of granite gneiss, hosting rare element-Bearing pegmatites from Jharsuguda district, Orissa defines an isochron age of 2762±±200Ma with initial ⁸⁷Sr/⁸⁶Sr ratio of 0.7082 ± 0.0027 (MSWD = 36.8). High ⁸⁷Sr/⁸⁶Sr ratio indicates involvement of crustal source for its formation. Petrography of the granitoids characterizes them as 'hornblende granite gneiss'. The ASI of the granite gneiss reveals its meta-Aluminous nature. It is a significant host to the zoned and complex type of 'Rare Elements-Bearing Pegmatites' , containing columbite-Tantalite (oxide of Nb + Ta) and beryl. Based on the whole-Rock isochron data, the granite gneiss of the Jharsuguda area can be equated with the Bamra and Tamparkola granite and phase III of the Singhbhum granite. Further, it postdates the Bonai and Kaptipada granite but is older to the Nilgiri and Ramapahari granite, with all these forming part of the Singhbhum North Orissa Craton.

Keywords

Rb-Sr Geochronology, Granite Gneiss, Rare Metals, Jharsuguda, Orissa.

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S. Viswanathan ¹, P. Jagadeesan ², K. S. Misra ², P. V. Ramesh Babu ³

Affiliations
1 Flat B-203, Block-B, United Avenue Apartments, South End, 7- 1-29, Ameerpet, Hyderabad- 500 016, IN
2 Atomic Minerals Directorate for Exploration and Research, Civil Lines, Nagpur -440 001, IN
3 Atomic Minerals Directorate for Exploration and Research, Begumpet, Hyderabad - 500 016, IN

Abstract

No Abstract.

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P. Jagadeesan ¹, K. S. Mishra ¹, P. V. Ramesh Babu ²

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Civil Lines, Nagpur - 440 001, IN
2 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Begumpet, Hyderabad - 500 01 6, IN

Abstract

Manganocolumbite in the pegmatites of Bhurpidungri(Lat: 21°51'30": Long: 84°15'52", T.S.No.73C/5) in the Jharsuguda district of Orissa is reported for the first time from the pegmatites of India. It contains upto 18.46% MnO, with an average (n=8) of 14.52% MnO, 7.26% FeO^(T), 60.18% Nb₂O₅ and 14.33% Ta₂O₅. A swarm of pegmatites is exposed, intruding at the contact of granite gneiss and amphibolite/Charnockite near the Bhurpidungri village. These pegmatites are well-Zoned with prominent quartz core, intermediate zone and wall zone. About 4 tonnes of manganocolumbite has been estimated in the gravels of these pegmatites for exploitation. Apart from this, beryl is also found in sufficient quantity.

Keywords

Manganocolumbite, Pegmatites, Jharsuguda District, Orissa.

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Ajay Kumar ¹, S. N. S. Birua ¹, Dheeraj Pande ¹, A. R. Nath ¹, P. V. Ramesh Babu ¹, S. A. Pandit ¹

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Khasmahal, Jamshedpur - 831 002, IN

Abstract

Several radioactive quartz-pebble conglomerate (QPC) occurrences at the western margin of Archaean Bonai granite and overlying Iron Ore Group (IOG) rocks have recently been located over a total strike length of 8-10 km intermittently in a NE-SW to E-W trend with steep dips due north- west to north in parts of Sundargarh district of Orissa. The QPC samples have analysed up to 0.039% U₃O₈ and 0.035% ThO₂ with high concentration of Y (74 to 518 ppm), La (<100 to 880 ppm), Cr (126 to 633 ppm), Zr (137 to 1250 ppm) and Pb (31 to 581 ppm). Cellulose Nitrate (CN) film studies of few QPC samples indicated adsorbed uranium over goethite and infiltrated ferruginous material (limonite), secondary uranium as encrustation and fracture filling and discrete sub-rounded grains of monazite, zircon, allanite and rare xenotime in the matrix of QPC as radioactive phases. Higher content of Th over U, elevated concentration of Y and La in QPC eliminates the possibility of its low temperature product by epigenetic processes. Poor correlation of U with elements like Pb, Y, Zr, La and Cr can be explained due to surficial leaching of uranium from QPC after its deposition as reflected by adsorbed U over iron- oxides and low U/Th ratio in QPC in the area.

Keywords

Quartz-Pebble Conglomerate, Bonai Granite, Radioactive Minerals, Orissa.

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Kalyan Chakrabarti ¹, N. R. R. Ecka ¹, B. Mishra ¹, P. V. Ramesh Babu ², P. S. Parihar ²

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Jamshedpur - 831 002, IN
2 Atomic Minerals Directorate for Exploration and Research, Hyderabad - 500 016, IN

Abstract

Ground Radiometric survey of Paleoproterozoic pyritiferous quartz-pebble conglomerate (QPC) occurring to the north of Pallahara area led to the discovery of a QPC type uranium mineralisation near Mankarhachua village. Significant radioactivity is recorded in three sub-parallel uraniferous QPC horizons with metamorphosed pebbly to medium grained recrystallised massive sandstones. Detrital grains of uranothorite, thorite, radioactive allanite, monazite, zircon, minute uraninite grains in carbonaceous matter and thucolite contributes to the radioactive phases present in QPC matrix. Adsorbed U on limonite and goethite, secondary uranyl minerals in matrix, along bedding planes and fractures are commonly observed. This discovery has opened up a new horizon for future exploration for QPC type uranium mineralization in the area. The paper presents observations on geology, radioactivity, petrological and geochemical nature of the uraniferous QPC horizons.

Keywords

Conglomerate, Uranium Mineralization, Orissa.

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A. K. Dwivedi ¹, U. K. Pandey ¹, C. Murugan ¹, A. K. Bhatt ², P. V. Ramesh Babu ¹, Mallikarjun Joshi ³

Affiliations
1 Atomic Minerals Directorate for Exploration and Research (AMD), Hyderabad - 500629, IN
2 Atomic Minerals Directorate for Exploration and Research (AMD), Jamshedpur - 831 002, IN
3 Banaras Hindu University, Varanasi - 221005, IN

Abstract

The Barabazar granite, exposed at the northern margin of Singhbhum craton, Eastern India, occurs along the South Purulia Shear Zone (SPSZ) and is emplaced into the Palaeoproterozoic metapelites and felsic volcanics of Singhbhum Group. Geochemical, petrographical and geochronological studies on the Barabazar granite addressed in the work have wide implications on understanding the geodynamics of SPSZ during Palaeoproterozoic to Mesoproterozoic. Geochemically, Barabazar granite displays limited range of major oxides, alkali enrichment and highly fractionated features (SiO₂ > 75%; Eu/Eu^* = 0.16-0.33; enrichment of K, Rb, Th, U and Nb; depletion of Ba, Sr, P and Ti). It is predominantly peraluminous (molar Al₂O₃/CaO+Na₂O+K₂O (A/CNK) = 1.14-144) and contains abundant alkali feldspar, perthite, and minor plagioclase, biotite and accessory minerals. Geochemical and petrological data indicates that it is A-type granite, which formed in 'Within plate granite' tectonic set up. The Barabazar granite was emplaced at ca. 1771 Ma (Pb-Pb) in rift related environs and evolved by partial melting of stabilized lower/middle crust (initial ⁸⁷Sr/⁸⁶Sr = 0.7302 ± 0.0066 and μ₁ = 8.5 ± 0.5). Subsequently, the shear zone (SPSZ) developed during the closure of the riftogenic basin and was reactivated during the Grenvillian orogeny (Ca. 900-1300 Ma), resulting in rehomogenisation of the strontium isotopes and thereby yielding younger whole-rock Rb-Sr isotope age of c. 971 Ma for the Barabazar granite. Probably during this tectonic event, the Singhbhum craton (Southern India Shield) would have finally juxtaposed with Northern Indian Shield along Central Indian Tectonic Zone (CITZ) during the global Grenvillian orogeny.

Keywords

A-Type Barabazar Granite, Geochemistry, Geochronology, Grenvillian Orogeny, Singbhhum Craton, SPSZ, West Bengal.

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Ajay Kumar ¹, A. S. Venkatesh ², P. V. Ramesh Babu ³, S. Nayak ³

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Jamshedpur-831002, IN
2 Atomic Minerals Directorate for Exploration and Research, Department of Applied Geology, Indian School of Mines, Dhanbad-826004, IN
3 Atomic Minerals Directorate for Exploration and Research, Hyderabad-500016, IN

Abstract

Petrographic and EPMA studies reveal the presence of discrete grains of uraninite and pyrite are being reported for the first time in quartz-pebble conglomerates from western margin of Bonai granite pluton, Sundargarh district, Orissa. Uraninite grains (2-3 μ in size) are subrounded to muffin shaped which show variation in UO₂ (63.86 to 71.73 wt %), ThO₂ (5.48 to 6.42 wt %) and RE₂O₃ (1.57 to 2.23 wt %). Pegmatitic source of uraninite is revealed by comparing UO₂, ThO₂, PbO, CaO content and ratios of UO₂/ThO₂ and CaO/ThO₂ in uraninites from pegmatite and other environments and areas. Subrounded to muffin shape of uraninite, their association with subrounded pyrite and heavies like zircon, tourmaline, chromite, monazite, magnetite and their comparable chemistry with well established quartz-pebble conglomerates of India and world are indicative of their detrital origin. Pyrite, minor chalcopyrite and rare galena are observed as sulphide phases in conglomerate. Variable shapes of pyrite, their low Co (up to 0.16 wt %) and Ni contents (up to 0.09 wt %) and Co/Ni ratio less than 1.0 (mean = 0.63) favours sedimentary/diagenetic origin.

Keywords

Quartz-Pebble Conglomerate(QPC), Uraninite, Pyrite, Bonai Granite Pluton (BGP), Orissa.

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