Landslide morphology of the Batote area, Jammu & Kashmir, NW Himalaya: Implications for the age of prehistoric debris slides

Identification of morphological elements is pre-requisite to understand the landslide behavior and composition. The relative age determination of the identified prehistoric debris slides depends on the subtle preservation intensity of surficial geomorphological features, topographic elements, and drainage evolution. The land use land cover along the western slope of Chakwa and Mogu Nalas show predominance of cultivation and forest area over a thick overburden material. The field-based mapping of intrinsic factors revealed the presence of prehistoric debris slide features such as thick debris material, water escape structures in debris material, large slabs (4-6 m) of bedded shale-mud sequence of Murree Formation, subtle rolling topography, slope-top benches, smoothened steep crest slopes with elliptical to amphitheater shape, and reversal of contours. Such features were used to determine the relative age of six identified prehistoric debris slides along the western slope of Chakwa and Mogu Nalas . Three prehistoric debris slides along the Mogu Nala are much smaller but have preserved comparably better morphological features and, therefore, are younger. In contrast, the prehistoric debris slides along the Chakwa Nala show tell-tale signs of steep smoothened scrap, dense vegetation, and rolling topography with streams flowing off the main slide body. The smoother nature of these features along with drainage deflection and dense vegetation indicates prehistoric debris slides activity along the western slope of Chakwa Nala to be very old of Early Holocene in age or older about 5000-10000 years.