Impact of tectonics on drainage network evolution of Suru basin, Kargil N/w Himalaya, Jammu and Kashmir, India

Abstract

The main objective of this paper is to work out quantitative measurement of various geomorphic parameters as well as analysis of geomorphic landforms to study the tectonic character of Suru basin. Morphometric analysis, being widely used to assess the drainage characteristics of the river basins, has also been found to be a useful tool to delineate tectonically active zones. A number of parameters including the mountain front sinuosity, asymmetry factor, transverse topography symmetry, hypsometry, longitudinal profile and the shape parameters have been used. The low mountain front sinuosity values < 1.4 indicate that the tectonic forces dominate over erosive activity. Also the asymmetry factor 66.98% suggests that the right side of the basin has experienced uplift with the development of unpaired river terraces. Hypsometric integral 0.96, convex up hypsometric curve and the GPS data of year 2011–2013 indicate that the relief of the basin is high relative to mean, is in youthful stage and actively uplifting at the rate of 2.18 ± 0.99 mm/year. The shape parameters further suggest that the Suru river basin having lower elongation ratio is indicative of elongate shape of basin with tectonic forces outpacing the erosion power. Area-altitude analysis of the Suru river basin indicates that about 72% of the area of the basin is steeply to very steeply sloping and 28% area is moderately to gently sloping. The area-altitude indicates 72% area of basin could slide when there is slight shift in terms of tectonic disturbance. In addition to the geomorphic indices, the field investigations reveal tectonically unstable character, exhibit a complex topography and varied Quaternary sedimentation. The major geomorphic landforms viz., alluvial terraces, alluvial fans, debris cone, scree, and talus cone at the foothills are present throughout the valley with tectonic structures like micro folds, back-tilted beds, deeply incised valleys, faults and tectonic deposits (Ophiolites), indicating that the tectonic activity has affected the basin. The synergized results of geomorphometry, field investigations and GPS data indicate that the Suru basin is tectonically active and uplifting.