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Ranganath, N.
- Rare Metal-Bearing Pegmatites in Parts of Southern Karnataka, India
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1 Atomic Minerals Division, Begumpet, Hyderabad 500016, IN
1 Atomic Minerals Division, Begumpet, Hyderabad 500016, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 30, No 6 (1987), Pagination: 507-513Abstract
Several pegmatites containing commercially viable sources of columbite-tantalite have been located in the Holenarsipur, Kdshnarajapet and Nagamangala schist belts. The pegmatites in Holenarsipur schist belt near Hassan, contain columbite-tantalite, rich in both niobium and tantalum and carry appreciable amounts of beryl. The Nagamangala schist belt is particularly rich in tantalite-bearing (Ta2O5 50-70%) pegmatites.
Analysis of feldspars from the three different belts indicates that they are potassic in the Nagamangala belt while they are sodic in the case of two other belts. Trace element analysis of muscovite indicates an average of 42, 242, 107, 325 ppm of Be, Nb, Sn and Li in Nagamangala belt as against 55, 114, 127 and 329 ppm respectively in Holenarsipur belt. Presence of considerable amount of bismutite in Mundur pegmatite and traces of spodumene and pollucite in Nagamangala belt have been confirmed.
- Framboidal – Colloform - Recrystallised Pyrite in the Granitoids of Wahkyn Area, West Khasi Hills, Meghalaya
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Authors
Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Central Region, Nagpur - 440 013, IN
2 Atomic Minerals Directorate for Exploration and Research, Western Region, Jaipur - 302 033, IN
3 Atomic Minerals Directorate for Exploration and Research, Southern Region, Bangalore - 560 072, IN
1 Atomic Minerals Directorate for Exploration and Research, Central Region, Nagpur - 440 013, IN
2 Atomic Minerals Directorate for Exploration and Research, Western Region, Jaipur - 302 033, IN
3 Atomic Minerals Directorate for Exploration and Research, Southern Region, Bangalore - 560 072, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 74, No 5 (2009), Pagination: 591-596Abstract
Petrographic studies of Proterozoic pyriteferous granitoids forming basement for upper cretaceous Mahadek sediments from Wahkyn area reveal interesting textural peculiarities of Pyrite. These pyrites also reveal interesting structural peculiarities. The three textural pyrite varieties found in the granitoids are: framboidal, colloform and recrystallised which appear both as composite aggregate as well as independent units. Various textures and variation in reflectivity, microhardness and elemental distribution of the pyrites are described. Average Co/Ni ratio along with the textural manifestation of these pyrites attests their sedimentary origin.Keywords
Ore Mineralogy, Framboidal Pyrite, Radioactive Mineral, Wahkyn, Meghalaya.References
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- Petrography and Geochemistry of Uranium Mineralised Precambrian Granitic-Pegmatitic Rocks of Mawlait, West Khasi Hills District, Meghalaya
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Authors
Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Jamshedpur - 831 002, IN
2 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Nagpur - 440 001, IN
3 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Hyderabad - 500 016, IN
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Jamshedpur - 831 002, IN
2 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Nagpur - 440 001, IN
3 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Hyderabad - 500 016, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 74, No 5 (2009), Pagination: 639-645Abstract
During radiometric investigation at Mawlait, significant uranium mineralisation (0.024-0.22%U3O8) was located mainly within the small pegmatite (garnet bearing quartzofeldspathic rock), which are locally segregated within migmatite at Umiang River section. Pink granite and granite gneisses are the dominant lithounits of the study area showing fertile character and spotty radioactivity at several places. Radioactivity in these rocks is mainly contributed by discrete uraninite grains along with some zircon and xenotime. Granites are peraluminous, low-Ca in nature and their geochemical signatures suggest derivation from a felsic source. Discriminant diagrams using Rb, Nb and Y indicate 'within plate' to 'volcanic arc' nature of the rock. The uraniferous pegmatitic veins within migmatite appear to have formed due to localised metamorphic segregation during late stage of anatexis. Petromineralogical and geochemical studies suggest that the uranium mineralisation in granitic-pegmatitic rocks of the area is mainly syn-magmatic type.Keywords
Pegmatite Veins, Granites, Uranium Mineralisation, Mawlait, Meghalaya.References
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