Late quaternary geomorphology palaeoclimate and active tectonics of the Indus valley between Leh and Batalik Ladakh Himalaya

Abstract

The uplift of Himalaya has profoundly influenced the regional and global climate by newlineintensification of monsoon and splitting the surface westerly winds. Situated in a newlineclimatically and tectonically sensitive domain, a key area of Himalaya orogen, Ladakh newlineprovides a unique set up to study Earth s surface morphology defined by interaction of newlineclimate, tectonics and surface processes. The present research is focused at integration of newlinefield work, morphometric analysis, sediment grain size analysis, Loss on ignition, newlineenvironmental magnetism and dating methods (AMS 14C and OSL) along the Indus river newlinevalley, Ladakh, Trans-Himalaya to address the past climatic changes, tectonic activities newlineand their role in the evolution of the landscape during the late Quaternary. newlineUpper Indus river catchment from Leh to Batalik, approximately 225 km in newlinelength, is studied to address landscape development in terms of Quaternary sedimentation newlineand active tectonics along the Indus Suture Zone. Geomorphic indices of active tectonics newlinesuch as gradient index, steepness index, asymmetry factor, hypsometric integral, newlineelongation ratio and valley width valley height ratio is used to quantify the recent newlinetectonic activity. Based on morphometric attributes the region is divided into three newlinemorphotectonic segments separated by transverse faults that are marked by two newlineprominent knick points along the river profile. Segment 1 indicates erosion dominated newlineasymmetric basins in the Leh region, while distribution of land at higher elevations in the newlinelower reaches of the Indus valley in Segments 2 and 3 suggests a still continuing newlineupliftment. Occurrence of two major palaeolakes namely Spituk-Gupuk, (occupying ~40- newline50 km of valley length) and Saspol-Khalsi (~55 km) by blockage of the River Indus in newlinethe vicinity of the knick points suggest prominent role of tectonics in addition to climate newlinevariability in their formation and sustenance. Distribution of seismites at Spituk (Segment newline1), Khalsi (Segment 2) and Bhima (Segment 3) ~ 130 km apart in similar geological and newlinehydrological setting suggest a major tectonic activity concentrated at ~10 ka.