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Sunil Kumar ¹, S. K. Dash ¹, U. P. Sharma ¹, K. Ramadoss ¹, Rajendra Singh ², K. K. Dwivedy ²

Affiliations
1 Atomic Minerals Division, Department of Atomic Energy, Bangalore-560072, IN
2 Atomic Minerals Division, Department of Atomic Energy, Hyderabad-500016, IN

Abstract

Univariate and multivariate statistical analyses, especially correlation study and factor analysis of uranium and other major ions in the groundwater of Chenchalapalle-Mulapalle area, known for its fracture controlled uranium mineralization, in the southwestern crystalline margin of Middle-Upper Proterozoic Cuddapah basin have revealed - (i) several well defined and distinct anomaly zones of > 200, > 500, > 1000 ppb of uranium, (ii) enriching factors like TDS(Ec), HCO₃^-, Na⁺, K⁺, Ca⁺² , Mg⁺², Cl^-, SO₄^-2 have poor to negligible influence on high uranium content and (iii) factor-3, identified as "mineralization factor" has high loading for uranium (0.948). The study on saturation indices of several uranium and other minerals indicated undersaturation for most of the aqueous uranium species, except for a few hydroxides. Particularly, schoepite (2UO₃.5H₂O) has low to moderate degree of supersaturation in samples from major anomalous zones.

Based on the distinctive hydrogeochemical attributes and geological and structural favourability factors, the tracts in the vicinity of Varikuntapalle (VKP). Dapepalle (DPL) and Pulikunta (PLK) villages, between Chenchalapalle-Mulapalle area in the southwestern crystalline margin of Cuddapah basin, are designated as potential target areas for detailed exploration.

Keywords

Hydrogeochemistry, Uranium, Groundwater, Cuddapah Basin, Andhra Pradesh.

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Himadri Basu ¹, G. R. Gangadharan ¹, Suresh Kuman ¹, U. P. Sharma ¹, A. K. Rai ¹, Anjan Chaki ¹

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Nagarbhavi, Bangalore 560 072, IN

Abstract

Middle Proterozoic Gulcheru Quartzite marks the onset of sedimentation, after the Eparchaean unconforrnity, in the Cuddapah Basin. In the southwestern margin of the basin it is made up dominantly of orthoquartzites. On the basis of lithology, stratigraphic relationship, bedding characteristics, texture and colour of sediments and sedimentary structures, five lithofacies were recognized within Gulcheru Quartzite. The Gulcheru Quartzite, though dominantly of shallow marine origin, shows imprints of other depositional regimes. Detailed interpretation of the facies and study of their field relationships reveal that pink massive quartzite, the lowermost unit of Gulcheru Quartzite, is of fluvio-aeolian origin. Later marine transgression .led to the development of a moderate to low energy beach, which evolved with time into a barrier: spit complex.

Keywords

Depositional environment, Facies analysis, Fluvio-Aeolian, Barrier-Spit, Gulcheru Quartzite, Cuddapah Basin, Andhra Pradesh.

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S. Zakaulla ¹, K. Umamaheswar ², P. V. Tirupathi ¹, U. P. Sharma ¹, H. Basu ¹, M. A. Ali ¹

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Nagarabhavi, Bangalore, IN
2 Atomic Minerals Directorate for Exploration and Research, Nagarabhavi, Shillong, IN

Abstract

Gulcheru Formation constitutes 200 m-250 m thick siliciclastic sediments Based on grain size texture and colour of the sediments, four distinct facies are demarcated They are pink massive quartzite, cross bedded grey quartzite, purple siltstone and pitted quartzite The ratios of Si/Al is higher (62 9 to 292 18) in pitted quartzite and lowest (2 122 - 18 247) in siltstone, where as grey quartzite has wide range of 3 78 - 8637 67 Ths difference is essentially due to higher quartz content in pitted quartzite and dominance of clays/shaly component in siltstone The wide range of Si/Al ratio in grey quartzlie is due to interlayering of siltstone/shale laminations/bands Distribution of uranium indicates grey quartzite (av U₃0₈= 9 9 ppm) and siltstone (av 15 42 ppm) have higher intrinsic uranium than that of pitted quartzite (average 5 6 ppm) and pink massive quartzite (average 7ppm) which is considered very high in comparison to normal sandstone (av = 0 5ppm, Taylor, 1965) Trace elements like Mo, V, Ni, Cu and Pb are enriched in mineralised grey quartzite Pitchblende is the man uranium mineral in grey and pitted quartzite unlts It occurs as fracture fillings and also as interstital material, associated intimately with chlorite Close association between pitchblende and sulphides like pyrite, chalcopyrite and galena is seen when pitchblende occurs as fracture fills Uranium in siltstone, is generally in adsorbed form with ferruginous material, where as associated trace elements like Mo (r = 0 515), V (r = 0 806), Nt (r = 0 4) and even Ti0₂, (r = 0 87) are well correlated with Al₂0₃, suggesting their clays/phyllosilicates U/Pb dating of uraniferous grey quartzite indicated ages of 1336k±4 Ma and 446±29 Ma suggesting remobilisation and concentration of intrinsic uranium.

Keywords

Gulcheru Formation, Cuddapah Supergroup, Siliciclastic Sediments, Uranium incidence, Gandi Area, Andhra Pradesh.

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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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Santu Patra ¹, Jitu Gogoi ¹, U. P. Sharma ¹, Rahul Banerjee ¹, D. K. Sinha ²

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Shillong 793 019, IN
2 Atomic Minerals Directorate for Exploration and Research, Hyderabad 500 016, IN

Abstract

No Abstract.

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Dheeraj Singh ¹, U. P. Sharma ², G. B. Rout ³

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Central Region, Civil Lines, Nagpur 440 001, IN
2 Atomic Minerals Directorate for Exploration and Research, North Eastern Region, Nongmynsong, Shillong 793 00, IN
3 Atomic Minerals Directorate for Exploration and Research, Begumpet, Hyderabad 500 016, IN

Abstract

Disequilibrium in the uranium series is a vital parameter to ascertain the state of equilibrium between uranium group (parent uranium) and its daughters, i.e. radium group of elements. The ²³⁸U isotope of uranium is the parent of 14 daughter isotopes forming the uranium series. The first five isotopes of ²³⁸U series, i.e. ²³⁸U, 234Th, 234Pa, 234U and 230Th form uranium group and the sixth to last isotopes of ²³⁸U series, i.e. ²²⁶Ra, ²²²Rn, ²¹⁸Po, ²¹⁴Pb, ²¹⁴Bi, ²¹⁴Po, ²¹⁰Pb, ²¹⁰Bi, ²¹⁰Po and ²⁰⁶Pb form radium group. Isotopes in the uranium and radium group usually remain in equilibrium within the group, but disequilibrium commonly exists between the two groups. In an open system, the mobility of radium is significant due to radon gas produced as a daughter element in the radium series. Anomalies with excess radium are commonly found around springs and seepages, whereas uranium anomalies are usually found under reducing environments. A study was carried out in Devri area, Surajpur district, Chhattisgarh, India, to decipher the state of disequilibrium in the area by analysing the drill core samples (n = 4470) from 43 boreholes. This study has revealed a strong disequilibrium (65%) in favour of the parent uranium. This disequilibrium is due to cycles of dissolution and deposition of parent uranium; aided by the movement of groundwater and diverse geochemical behaviour of different radionuclides. In addition, loss of radon from the system might have also contributed to the disequilibrium in favour of the parent uranium. Linear regression coefficient between U₃O₈ (parent uranium) and RaEq.(U₃O₈) was calculated to be 0.82. Strong disequilibrium in favour of the parent uranium will enhance the uranium ore reserve in Devri area.

Keywords

Beta-Gamma Method, Disequilibrium Factor, Linear Regression Coefficient, Radium Group, Uranium Mineralization.

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Santu Patra ¹, U. P. Sharma ², Kamlesh Kumar ³, D. K. Sinha ⁴

Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Hyderabad 500 016, India, IN
2 Atomic Minerals Directorate for Exploration and Research, Nagpur 400 001, India, IN
3 House No. 171, Swami Colony, Phase 1, Akar Nagar, Katol Road, Nagpur 440 013, India, IN
4 Flat 511, Block Garnet (E), Rainbow Vista@Rock Garden, Moosapet, Hyderabad 500 018, India, IN

Abstract

Here we report anomalous uranium concentration in tourmaline-bearing leucogranite occurring at Nuranang, Tawang district, Arunachal Pradesh, North East India. The leucogranite occurs as concordant layers parallel to gneissic foliation, similar to the gneisses of the Palaeopro­terozoic Se La Group. It is medium to coarse-grained, and is composed of quartz, potash feldspar and plagioclase as dominant minerals with variable proportions of muscovite, biotite, tourmaline and garnet. Apatite, zircon and pyrite are accessory minerals. Geochemically, the leucogranite is alkali-rich, peraluminous and highly differentiated. It is emplaced in a syn to late orogenic collision tectonic setting. Analyses of 10 granite samples collected at 500 m intervals show relatively high radioelemental concentration (U: 5–96 ppm, Th: 5–23 ppm, K: 2.23–7.72% and Th/U; 0.07–1.00, n = 10) compared to normal granite. Anomalous uranium concentration in the leucogranite is observed in a 200 m ´ 50 m area at Nuranang. Samples from this area have assayed 0.016–0.029% U3O8 and <0.005% ThO2. Leachable U3O8 content determined in five samples varies from 81.25% to 87.50%. Preliminary studies indicate that uranium is in the adsorbed state associated with iron oxide and alte­red feldspar/clay. The findings of anomalous uranium concentration in tourmaline-bearing leucogranite likely open up a new target area for uranium search in the Higher Himalaya of Arunachal Pradesh

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