Morpho-structural signatures of neotectonic activity along the HFT bound Himalayan mountain front in Kathgodam-Chorgallia sector of NW Himalaya, India

Abstract

Thrusting supports the development of diverse landforms and deformational structures in the Himalayan Frontal Thrust (HFT) region between Kathgodam and the Chorgallia sector, according to this study. The influence of the active tectonic condition in the area was analyzed using seven geomorphic indices, which also underlined the importance of morpho-structural study utilizing remote sensing, geomorphic indices, tectono-geomorphic landforms, field evidence, and luminescence dating. The investigation of sub-basins surrounding the HFT reveals moderate to high tectonic activity, with tectonic activity concentrating in the eastern half and decreasing toward the west. A topographic discontinuity was also observed in the region as indirect active tectonic evidence. Hanging wall rocks have well-preserved features that govern tectonic transport direction, and the HFT in this region is emergent. Shear sense indications point to southerly tectonic migration, with a few modest northward shear senses indicating northward movement, which might be attributable to reverse thrusting along the HFT at some time during the Outer Himalaya's tectonic history. Petrographic investigations reveal sustained frontal deformation at various intervals, with well-preserved thrust-induced deformation fingerprints in deformed rocks throughout the Jam Raula and Sukhi nadi sections. Micro thrust duplexes, or micro-scale asymmetrical drag folds, are shown in thin section investigations as a result of HFT-related brittle-ductile deformation at moderate temperature and pressure. The sandy unit from the Quaternary sediments yields 10 ± 0.8 ka, 11.8 ± 0.7 ka, 17 ± 1 ka, and 56 ± 3 ka quartz OSL dates, demonstrating the migration of hanging wall rocks on footwall post-Siwalik fluvial deposits along the HFT plane and reactivation of the HFT in the study area.