Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

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Mylonitic Microfabrics from the Rocks of MCT Zone in Alakhnanda Valley, Garhwal Himalaya


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1 Department of Geology, Banaras Hindu University, Varanasi-221 005, India
     

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MCT Zone of Alakhnanda valley is a major ductile shear zone in Garhwal Himalaya, which is characterised by different types of mylonite rocks. On the basis of grain size and the percentage of matrix in the rock, zones comprising protomylonite, augen mylonite, mylonite and ultramylonite have been identified. The study of microstructures, grain size and crystallographic preferred orientation of quartz c-axis fabric reveals that the rocks of the MCT zone were deformed by a combination of intracrystalline creep (power law creep) and grain boundary migration (sliding super plasticity).

Keywords

Microfabrics, Mylonite, MCT, Garhwal Himalaya.
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  • Mylonitic Microfabrics from the Rocks of MCT Zone in Alakhnanda Valley, Garhwal Himalaya

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Authors

H. B. Srivastava
Department of Geology, Banaras Hindu University, Varanasi-221 005, India
Vaibhava Srivastava
Department of Geology, Banaras Hindu University, Varanasi-221 005, India

Abstract


MCT Zone of Alakhnanda valley is a major ductile shear zone in Garhwal Himalaya, which is characterised by different types of mylonite rocks. On the basis of grain size and the percentage of matrix in the rock, zones comprising protomylonite, augen mylonite, mylonite and ultramylonite have been identified. The study of microstructures, grain size and crystallographic preferred orientation of quartz c-axis fabric reveals that the rocks of the MCT zone were deformed by a combination of intracrystalline creep (power law creep) and grain boundary migration (sliding super plasticity).

Keywords


Microfabrics, Mylonite, MCT, Garhwal Himalaya.

References