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Pandey, Subhajit
- Garnetiferous Metamorphic Rocks in Jaspa Granite, Himachal Pradesh, India:Implication of Tethyan Himalayan Metamorphism and Tectonics
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Authors
Affiliations
1 Wadia Institute of Himalayan Geology, 33 GMS Road, Dehradun 248 001, IN
1 Wadia Institute of Himalayan Geology, 33 GMS Road, Dehradun 248 001, IN
Source
Current Science, Vol 115, No 8 (2018), Pagination: 1576-1583Abstract
Studies on the magmatic enclaves, pelitic xenoliths and host Jaspa granite pluton outcropped in the Lahaul area, NW Himalaya, India illustrate that the rocks have undergone garnet-grade metamorphism. The P -T pseudosection modelling shows that the metamorphic mineral assemblage is stable in the P -T range ~4.5-7.3 kbar and ~440-500°C, matching quite well with the results obtained from the conventional geothermobarometers (5.7-8.6 kbar and 409-531°C). The observed garnet-grade metamorphism in and around the Jaspa pluton is proposed to be due to localized perturbation of high-temperature isotherms in the Tethys Himalaya, as a consequence of the Cenozoic tectono-thermal event during Himalayan orogeny. Further, the Haimanta group of Tethys Himalayan rocks in the Lahaul area has been interpreted to have attained right-way-up metamorphic field gradient.Keywords
Garnet-Grade Metamorphism, Granite Pluton, Magmatic Enclaves, Pelitic Xenoliths.Full Text
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- Characterization of Radioactive Organic Matter from Kaimur Group, Vindhyan Supergroup, India
Abstract Views :72 |
Authors
Affiliations
1 Atomic Minerals Directorate for Exploration and Research, Hyderabad 500 016, IN
1 Atomic Minerals Directorate for Exploration and Research, Hyderabad 500 016, IN
Source
Current Science, Vol 127, No 7 (2024), Pagination: 862-866Abstract
The Vindhyan sediments overlying the Bundelkhand granite complex have conducive attributes for hosting unconformity-type uranium mineralization. In the Kaimur sandstones of the Vindhyan Supergroup overlying the basement Bundelkhand granites, uranium mineralization hosted by subfeldspathic arenite intercalated with shale has been observed. Uranium minerals are associated with organic matter and pyrite present in arenite. Globular organic matter disseminated in the sediments shows moderate reflectance under reflected light. The average total organic carbon content in organic matter-rich rock samples is 1.1%. It has undergone excessive thermal maturation and high dehydrogenation reflected from a low H/C ratio. Raman spectral analysis indicates that the organic matter contains amorphous carbon.Keywords
Amorphous carbon, organic matter, radioactivity, sediments, uranium minerals.Full Text