Precambrian deformed granites of possible basement in the Himalayas

Sinha-Roy, S.; Gupta, Saurabh

doi:10.1016/0301-9268(86)90074-4

Cited by 15 publications

(1 citation statement)

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“…The mylonitic gneisses are dated in various sectors of the Himalaya starting from the western sector in the Himachal Himalaya (BMG) to the eastern sector of the Himalaya, Nepal (Ulleri gneisses) and it has yielded Rb-Sr whole rock ages between 1800 and 1000 Ma (Bhanot et al 1976(Bhanot et al , 1978(Bhanot et al , 1982Frank et al 1977;Paul et al 1982;Sinha-Roy and Sengupta 1986;Miller et al 2000).…”

Section: Tectonic Implications and Regional Correlation In The Himalayamentioning

confidence: 97%

Petrography, geochemistry and regional significance of crystalline klippen in the Garhwal Lesser Himalaya, India

et al. 2011

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Uphalda gneisses (UG) is a crystalline klippe located near Srinagar in Garhwal Himalaya. These gneisses are compared with Debguru porphyroids (DP) (≈Ramgarh group) of Garhwal-Kumaun Himalaya and Baragaon mylonitic gneisses (BMG) of Himachal Himalaya. Petrographic study reveals that the deformation of UG was initiated at higher temperature (above 350 • C) and continued till lowering of temperature and deformation led to the mylonitization.Geochemically, these granitic gneisses (UG, DP and BMG) exhibit similar composition. Features such as high molecular A/CNK value (>1), presence of normative corundum and absence of normative diopside, enhanced Rb/Sr, Rb/Zr ratios, enrichment of Th and containing rounded zircons support their crustally-derived S-type granitic nature. The linear plot in major oxides is interpreted in terms of fractional crystallization processes. Mantle normalized multi-element spider diagram of UG illustrates depletion of Ba, Nb, Sr, P and Ti and enrichment of Th and show similarities with DP and BMG.Similarities were observed in lithology, petrographic characters and chemical composition of UG, DP, BMG and Ulleri augen gneisses (Nepal). Comparison with the rocks of Higher Himalayan crystallines (≈Vaikrita), suggests that these rocks (UG) are not transported from Higher Himalaya as understood earlier. This study however proposes that, these gneissic bodies represent an older basement occurring as a tectonic sliver which emplaced within the cover sequence as wedges at different structural levels. This is a regional phenomena observed throughout the Lesser Himalayan region.

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Section: Tectonic Implications and Regional Correlation In The Himalayamentioning

confidence: 97%