Episodes 2022; 45(3): 285-297
Published online September 1, 2022
Copyright © International Union of Geological Sciences.
Neil F. Glasser1*, Adina E. Racoviteanu1, Matthew Peacey1, Stephan Harrison2, Rakesh Kayastha3, Rijan Bhakta Kayastha3
1 Department of Geography and Earth Sciences, Aberystwyth University, UK
2 Department of Geography, Exeter University, UK
3 Department of Environmental Science and Engineering, Kathmandu University, Nepal
Correspondence to:*E-mail: email@example.com
This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/4.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
Understanding the evolution of debris-covered glaciers in High Mountain Asia, the physical processes governing the effect of debris cover on mass balance, and the response of debris-covered glaciers to climatic change are key for assessing water resources, the contribution of glaciers to sea level rise and the potential for glacier related hazards such as glacier lake outburst floods (GLOFs) related to moraine-dammed lakes. Here we illustrate the effects of recent glacier recession on the development of landforms and sediments at Ponkar Glacier, a debris-covered glacier in the Manaslu area of the Nepal Himalaya using a combination of 2019 RapidEye satellite image (5 m spatial resolution), drone imagery (50 cm) and field observations. We describe the key features of the glacier and its ice-surface morphology, including size and extent of flow units and tributary glaciers, supraglacial features of the debris cover and vegetation. Geomorphological mapping is used to describe the moraines, proglacial geomorphology, outwash plains and proglacial streams, the development of new ice-marginal ponds and changes in vegetation. Moraines generally have steep and rapidly degrading inner faces and mature vegetation, including trees, on their outer flanks. They are typically composed of diamicton and silty or sandy boulder gravel. Large outer moraines are separated from the surrounding valley sides by ‘ablation valleys’. We conclude by putting the landforms and sediments developed at Ponkar Glacier into a discussion of the likely future evolution of high-elevation debris-covered glaciers.