Structural Glaciological Evolution of Rapidly Receding Temperate Piedmont Glaciers: Implications for Debris Entrainment and Landform Development at Svínafellsjökull, Southeast Iceland.

Abstract

Glacier recession in Iceland since the historical Little Ice Age maximum has brought about significant changes in the structure of all glacier snouts, particularly those of the south coast, because of their morphological switch from piedmont lobes to topographically constrained outlets. An exemplar is Svínafellsjökull, because its margin remained relatively stable between c. 1970 and 2000, when overall historical recession was dominated by downwasting. Since that time, it has undergone accelerated recession and pronounced thinning over an overdeepening. Recent research on ice cap piedmont lobes has highlighted variations on ice flow patterns related to the interaction between topographic controls and glacier structure as the glaciers respond to climate change and become more susceptible to recession into overdeepenings. This research provides a detailed understanding of the structural glaciological evolution and the implications for debris entrainment and landform development at Svínafellsjökull, Southeast Iceland. The structure of Svínafellsjökull has been impacted in recent years by a warming climate and this has initiated accelerated retreat of the glacier and pronounced thinning over an overdeepening. A debris transport process model for Svínafellsjökull and neighbouring Falljökull is proposed and incorporates various styles of debris-rich glacial ice formation, debris transfer pathways, and their glaciological controls. Changes in the structural configuration of the lower reaches of Svínafellsjökull, especially the development of radial crevasses, have impacted upon the landform record preserved within the glacier foreland. Geomorphological mapping of the foreland is presented and facilitates the development of more robust understanding of the spatially variable influence of structural glaciological and debris transfer processes on moraine construction since the Little Ice Age maximum.