Glacial geomorphology - Breiðamerkurjökull, southeast Iceland

A new landform type was identified, hummocky meltwater tracts, which potentially provide evidence for high meltwater supply to subglacial bed.Changes were quantified between all four datasets, enabling the identification of dominant processes and six distinct change zones (e.g. stable areas, buried ice terrain). The short time period between datasets allowed for seasonal signatures, such as glaciofluvial deposition, to be detected.

Ground penetrating radar (GPR) surveys provided additional contextual information related to subglacial topography. The results captured different modes of ice loss (i.e. thinning and retreat) and provided insights into the transient nature of landforms in ice-marginal environments. The outputs also indicate this section of the glacier is undergoing passive retreat and downwasting.

Buried ice underlying pitted sandar areas is undergoing secondary deglaciation and may take decades to stabilise.Two detailed case studies were undertaken allowing the development and refinement of process-form and landsystem models. The first case study focused on englacial eskers. Repeated surveying and GPR data suggest these features have poor preservation potential, which has implications for reconstructing palaeo-ice sheets using preserved landforms alone.

The second case study captured a shift in landform assemblage across the eastern study site since 2017, which was attributed to a local ice-flow switch and topographic variations. Developed process-form and landsystem models were applied to a palaeo-example - the Pakowki Lake region, southeast Alberta which was once covered by the Laurentide Ice Sheet. Geomorphic and topographic comparisons enabled existing reconstructions of palaeo-ice dynamics in the region to be corroborated.This research highlights the valuable role of UAVs and repeated surveying in enhancing our understanding of rapidly changing environments, refining process-form regimes and landsystem models.

The increasing availability of high-resolution imagery across ancient landscapes coupled with refined process-form regimes will enable improved palaeo-ice sheet reconstructions. Future work could adopt a similar workflow to examine landscape evolution at other deglaciating margins.<br>