Quantification of short‐term transformations of proglacial landforms in a temperate, debris‐charged glacial landsystem, Kvíárjökull, Iceland

Abstract

AbstractProglacial areas are dynamic landscapes and important indicators of geomorphic changes related to climate warming. Systematic and repeat surveys of landforms presently evolving on glacier forelands facilitate the quantification of rates of change and an improved understanding of the processes generating those changes. We report short‐term (2014–2022) transformations of the proglacial landscape in front of Kvíárjökull, SE Iceland, and place them in a longer‐term context of glacial landsystem evolution using aerial image archives since 1945. Short‐term quantification uses a time series of uncrewed aerial vehicle (UAV) surveys, processed utilizing a structure‐from‐motion (SfM) workflow, to produce digital elevation models (DEMs) and orthophoto mosaics. The land elements surveyed include a kame terrace staircase, an outwash plain, an ice‐cored hummocky moraine complex and ice‐cored hummocky terrain with discontinuous sinuous ridges, for which elevation and volumetric changes are quantified. The kame terraces between 2014 and 2022 and the outwash plain between 2016 and 2022 were mainly stable with, respectively, 87% and 85% of their surfaces showing no change. The ice‐cored hummocky terrain with discontinuous sinuous ridges underwent a volume loss of 64,632 m3 in 2016–2022, with a maximum surface lowering of ≤9 m. The most dynamic land element was the ice‐cored hummocky moraine complex, with transformations recorded for more than 87% of its area in 2014–2022; the surface was lowered by ≤23 m in some places, with a total volume loss of 365,773 m3. Our results confirm the ongoing degradation of ice‐cored moraine and outwash complexes at variable rates related to buried ice volume and age of deglaciation. The evolution of chaotic hummocky terrain from debris‐covered glacier ice, glacitectonic thrust masses, outwash fans/heads and complex englacial esker networks is an important modern analogue for informing palaeoglaciological reconstructions.