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Episodes 2020; 43(1): 369-380

Published online March 1, 2020

https://doi.org/10.18814/epiiugs/2020/020023

Copyright © International Union of Geological Sciences.

A Re-look at the Himalayan metamorphism

Naresh Chandra Pant1*, Preeti Singh1 and A.K. Jain2

1Department of Geology, University of Delhi, Delhi-11007; *E-mail: pantnc@gmail.com
2CSIR-Central Building Research Institute, Roorkee-247667

Correspondence to:E-mail: pantnc@gmail.com

Received: April 15, 2019; Revised: August 7, 2019; Accepted: August 7, 2019

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

Regional metamorphic rocks preserve records of geodynamic evolution of orogenic belts. The Himalaya represents an evolving mountain belt with a complex geological history and is considered here as a composite of Trans–Himalaya and the Himalaya per se and the intervening Indus–Tsangpo Suture Zone. Each of these three tectonic domains is evaluated in the context of their metamorphic evolution. An episodic evolution is inferred and described. The beginning of the Himalayan orogeny is ascribed to the Cretaceous initiation of the suturing of the ‘island arc’ rocks with the Asian block, followed by underthrusting of the Indian block ~57Ma ago. Differences in metamorphism of underthrust and overthrust blocks are reflected in their P-T-t evolution. The exhumation along the strike length was unequal with significantly higher exhumation rates along the syntaxes. The anatectic melt produced at the time of the Tertiary age Himalayan metamorphism got emplaced within the Himalaya as well as within the Trans–Himalaya, possibly through crustal-scale faults such as the Karakoram fault.