Saptarshi Dey , Naveen Chauhan, Pritha Chakravarti, Anushka Vashistha, Vikrant Jain

Understanding the response of glaciated catchments to climate change is crucial for assessing sediment transport from the high-elevation, semi-arid sectors in the Himalaya. The fluvioglacial sediments stored in the semi-arid Padder valley in the Kashmir Himalaya record valley aggradation during ~20 -10 ka. We relate the initial stage of valley aggradation to increased sediment supply from the deglaciated catchment during the glacial-to-interglacial phase transition. Previously-published bedrock-exposure ages in the upper Chenab River valley suggest ~180 km retreat of the valley glacier during ~20 - 15 ka. Increasing roundness of sand-grains and reducing mean grain-size from the bottom to the top of the valley-fill sequence hint about increasing fluvial transport with time and corroborate with the glacial retreat history. The later stages of aggradation can be attributed to strong monsoon during the early Holocene. Especially, the hillslope debris that drapes the fluvioglacial sediment archive may have resulted from the early Holocene monsoon maximum. We observe a net degradation of the valley-fill in the Holocene reflecting the weakening of summer monsoon or reduced input from the glaciers. Our study highlights the coupled effect of deglaciation and monsoon intensification in sediment transfer from the high-elevation sectors of the Himalaya.