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Petrography and Geochemistry of Uranium Mineralised Precambrian Granitic-Pegmatitic Rocks of Mawlait, West Khasi Hills District, Meghalaya


Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Jamshedpur - 831 002, India
2 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Nagpur - 440 001, India
3 Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Hyderabad - 500 016, India
     

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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.
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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

J. Sen
Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Jamshedpur - 831 002, India
N. Ranganath
Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Nagpur - 440 001, India
Y. V. Rathaiah
Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Hyderabad - 500 016, India
D. B. Sen
Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Hyderabad - 500 016, India
S. N. Kak
Atomic Minerals Directorate for Exploration and Research, Department of Atomic Energy, Hyderabad - 500 016, India

Abstract


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