Field documentation and genesis of the back-structures from the Garhwal Lesser Himalaya, Uttarakhand, India

Published on 2018-12-18T14:14:43Z (GMT) by
Collisional fold-and-thrust belts are characterized by foreland-verging thrusts. Conversely, structures with hinterland-ward vergence, known as back-thrusts, also exist. Strain intensification, critical taper deformation and presence of thrust ramps generate back-thrusts. This study focuses on the exposure-scale brittle and ductile structures showing hinterland-ward vergence (back-structures) from a part of the Garhwal Lesser Himalaya, NW India, mainly along the Bhagirathi river section. In our field-traverse, back-structures were found at 31 locations. Towards the north, in the Outer Lesser Himalaya, the back-structures locate (Group 1) on the inverted limb of the Mussoorie Syncline. The Tons Thrust is a south-dipping thrust, i.e. back-thrust. Hence, the Tons Thrust and the nearby parts (Group 2) show intense back-structures. In the Inner Lesser Himalaya, back-structures (Group 3) generated by shearing related to the folded Berinag Thrust. The back-structures at and near the Main Central Thrust zone (Group 4) can be correlated with the presence of the Delhi–Haridwar Ridge. In this way this study establishes the back-structures to be an integral part of the Garhwal Lesser Himalaya and provides the genesis of those structures by correlating them with the (local) tectonic settings.

Cite this collection

Bose, Narayan; Mukherjee, Soumyajit (2018): Field documentation and genesis of the back-structures from the Garhwal Lesser Himalaya, Uttarakhand, India. Geological Society of London. Collection.