Analysis of 'hummocky moraine' using Structure-from-Motion photogrammetry

Abstract

This study presents results of a high-resolution topographic survey of the proglacial area of Austre Lovénbreen, Svalbard. Structure-from-Motion (SfM) was used to generate a digital elevation model (DEM) of the proglacial zone from aerial imagery. This DEM is used to explore the topography of a zone of hummocky moraine within the glacier’s Neoglacial limit. The origin of hummocky moraine has proven controversial, but detailed morphological studies can contribute to a better understanding of how these features form, and the extent to which they may be preserved in the palaeo-glaciological record, including within northwest Britain. In cross-profile, hummocky moraine is characterised by a sequence of asymmetrical ridges, with longer, low angle up-glacier faces, and shorter, steeper down-glacier faces. This profile is interpreted to represent a sequence of ridges stacked-up against a bedrock riegel and reverse bedslope. Whilst the origin of these features is uncertain, the enhanced compression associated with glacier flow against a bedrock riegel, possibly during a glacier surge, may have been sufficient to have generated debris-rich englacial thrusts that subsequently melted-out to form the observed hummocky moraine. The significance of this research highlights ongoing studies aimed at understanding the origin and palaeo-glaciological significance of hummocky moraine in northwest Britain