Geomorphic and structural evidences of neotectonic activity in the Sub-Himalayan belt of Nahan Salient, NW India

Abstract

Neotectonism in the Sub-Himalayan belt is not new. Moreover, the word ‘Sub-Himalaya’ is almost synonymous with ‘neotectonic activity’. In the present paper, we report some of the most convincing geomorphic and structural evidences of neotectonic activity from the Sub-Himalayan belt in the Nahan Salient. The geomorphic evidences mainly include the four geomorphic surfaces identified from the transverse topographic profiles drawn parallel to the Himalayan front. These surfaces are commonly covered with terrace deposits that are tilted as well as faulted at a number of places. A number of faults, directly observable in the field, are normal in nature and they are oriented at high angles to the Himalayan Frontal Thrust (HFT). These faults are similar to the E-W extension in southern Tibet in response to the oblique convergence of India at ∼N20°E in the NW Himalaya. They are attributable to the kinematics of neotectonic compression along the HFT, the frontal ramp-oblique ramp-frontal ramp geometry of the thrust fault and related adjustments.