Geological Society of London
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Fig. S5. Field documentation and genesis of the back-structures from the Garhwal Lesser Himalaya, Uttarakhand, India

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posted on 2018-12-18, 14:14 authored by Narayan Bose, Soumyajit Mukherjee
(a) Nearly isoclinal overturned round hinge parabola-shaped back fold (ductile) verging towards north at Location 14 (30.531917°N, 78.321317°E). The attitudes of the northern limb (L1), southern limb (L2) and axial plane trace (AX) are 96°/70°→186°, 116°/25°→206° and 113°/40°→203°, respectively. The inset diagram shows the stereo-plot of the poles of the two limbs (L1, L2) and the axial plane (AX). As the axial plane is almost parallel to the foliations, no shear sense has been deciphered from the folds. (b) Compressional brittle back shears (top-to-0° up) in Rautgara Formation quartzites and schists at Location 14 (30.531917°N, 78.321317°E). Compressional top-to-0° up brittle shear shown by quartz veins along with their host schists in Rautgara Formation quartzites and schists, at Location 14. (c) North-verging kink back folds, for which the axial traces have been marked in the inset sketch. (d) Compressional ductile back structures (top-to-0° up) in Rautgara Formation quartzose schists at Location 14 (30.531917°N, 78.321317°E). Synthetic shear planes in the sigmoid quartz veins should be noted.