Hummocky debris landforms in the Chapursan Valley (Karakoram range, Pakistan): A glacio-geomorphological investigation

This paper contributes to the discussion on the development of hummocky debris landforms by gradual versus catastrophic processes in high mountain areas. It focuses on the upper Chapursan Valley (Karakoram Range, Pakistan), in which the valley floor and adjacent sediment cones are covered with an outstanding hummocky debris landscape over a length of about 10 km and a width of up to 1 km with individual hummocks reaching about 10 m in height. These landforms overlap with the zone of permanent settlement. According to local legends and reports of early travellers in this region, one of the largest settlement concentrations formerly occurred in the upper Chapursan Valley and was destroyed by a natural disaster. In order to study the formation of the debris landforms in more detail geomorphological field investigations, sedimentological studies, a comparison of satellite images, an analysis of historical data and interviews with the local inhabitants have been carried out. The results show that complex geomorphological processes consisting of a glacier advance and followed by glacier lake outbursts and ice avalanches have contributed to the formation of the hummocky debris landforms. The Kit-ke-Jerav and Yishkuk Glaciers seem to have experienced extraordinary fluctuations in historical and recent times.