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Ghosh, A. K.
- On the Nature and Petrogenesis of Dhanjori Lava Near Rakha Mines, Singhbhum, Bihar
Abstract Views :188 |
PDF Views:134
Authors
A. K. Ghosh
1,
A. K. Banerji
2
Affiliations
1 Department of Geology, University of Calcutta, IN
2 Department of Geology, Presidency College, Calcutta, IN
1 Department of Geology, University of Calcutta, IN
2 Department of Geology, Presidency College, Calcutta, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 11, No 1 (1970), Pagination: 77-81Abstract
No Abstract.Full Text
- Abundance of Co, Ni, Cd, Ag and Hg in the Polymetallic Sulphide Deposit of Rangpo, Sikkim
Abstract Views :185 |
PDF Views:144
Authors
Affiliations
1 Department of Geology, Calcutta University, IN
1 Department of Geology, Calcutta University, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 16, No 1 (1975), Pagination: 99-102Abstract
No Abstract.Full Text
- Deformational and Metamorphic Imprint upon Lesser Himalayan Sulphide Ores: Examples from the Nepal-Sikkim Belt
Abstract Views :225 |
PDF Views:2
Authors
Affiliations
1 Department of Geology, University of Calcutta, 35, B.C. Road, Calcutta-700 019, IN
1 Department of Geology, University of Calcutta, 35, B.C. Road, Calcutta-700 019, IN
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 48, No 1 (1996), Pagination: 3-13Abstract
Ore textures in the stratabound Zn-Pb deposit of Ganesh Himal (Nepal) and the Cu-Zn deposit of Dikchu (Sikkim, India) from amphibolite-facies environment of the Lesser Himalaya arc described and discussed in relation to deformation and metamorphism. Primary are depositional fabric is almost completely obliterated in the ores, except for the rare presence of some framboids and polyframboids at Ganesh Himal. Both deposits show features characteristic of intense deformation and high-grade metamorphism. A variety of fracture, overgrowth and rotational fabric followed by recrystallization textures are recorded. The majority of the fabric characteristics are syn- to post tectonic with respect to the strongest deformational episode and associated metamorphism related to the Tertiary Himalayan orogeny. However, the meta-carbonate hosted Zn-Pb ore of Ganesh Himal is strongly recrystallized, whereas the metapelite hosted Cu-Zn ore of Dikchu is characterised by a more noticeable deformational imprint. The textural characteristics of ores in the two deposits, with respect to the contrasting host lithologies, indicate that the variations in are compositions and in host rock rheologies in different tectonic settings of the deposits might have influenced the resultant ore textures.Keywords
Economic Geology, Sulphide Ore Textures, Lesser Himalaya.
- Interpretation of Pb and S Isotope Data for the Ganesh Himal Metamorphosed Stratiform Zn-Pb Deposit, Central Nepal Himalaya
Abstract Views :175 |
PDF Views:2
Authors
Affiliations
1 Department of Geology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata - 700 019, IN
2 Natural Resources Canada, Geol. Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, CA
3 Nepal Metal Company Limited, Gyantole, Gyaneshwor, Post Box 468, Kathmandu, NP
1 Department of Geology, University of Calcutta, 35 Ballygunge Circular Road, Kolkata - 700 019, IN
2 Natural Resources Canada, Geol. Survey of Canada, 601 Booth Street, Ottawa, Ontario K1A 0E8, CA
3 Nepal Metal Company Limited, Gyantole, Gyaneshwor, Post Box 468, Kathmandu, NP
Source
Journal of Geological Society of India (Online archive from Vol 1 to Vol 78), Vol 65, No 6 (2005), Pagination: 725-737Abstract
The Ganesh Himal Zn-Pb deposit in central Nepal has been highly deformed and metamorphosed together with its host rocks. Pb isotope data for the deposit are interpreted to define an age of about 875 to 785 Ma, which is permissive of age equivalence to the upper Vindhyan Supergroup of the North-Central and northwestern Indian Shield. The slightly positive to slightly negative sulphur isotope values for the Ganesh Himal deposit are in accord with coeval seawater sulphate δ34S values in the range +15 to +20 %, and thus with an age greater than about 650 Ma. Apparent equilibrium sulphur isotope fractionation temperatures for sulphide pairs are generally 500°C to 750°C, a range that agrees with Kyanite-Staurolite and Biotite-Staurolite assemblages.The 875 to 785 Ma age for Ganesh Himal has been calculated on the basis of Pb isotope ratios and age data for other Neoproterozoic and Cambrian Sediment-Hosted deposits. These Ganesh Himal results and those for the Genekha deposit, Bhutan, help confirm the previously postulated widespread distribution of Vindhyan rocks in Himalayan metasedimentary belts. The available Pb isotope and age data for the Amjhor deposit, in Upper Vindhyan rocks in Bihar State, India, are suggestive but not confirmatory of a tentative condusion that the Ganesh Himal deposit is its age equivalent.