LAUSR

This paper presents evidence of glacier surging in the British landform record. We use new high‐resolution multibeam‐echosounder bathymetry data to map the submarine geomorphology of a former tidewater glacier that drained the Skye Icefield, NW Scotland, during the Younger Dryas Stadial (Greenland Stadial 1) ca. 12.9–11.7 ka. Our onshore and offshore mapping identifies a glacial landform assemblage indicative of surge‐type behaviour, followed by rapid retreat and stagnation. We delimit three separate fjord‐mouth advances of the Ainort Glacier — interpreted as palaeo‐surges — successively decreasing in extent. During the quiescent phase of the final surge cycle, the glacier deposited a suite of cross‐fjord De Geer moraines, interpreted here as annual moraines. Their pattern and spacing suggest that net annual glacier retreat rates increased significantly from around 25–75 ma−1 to 150 ma−1 to >300 ma−1, probably in the presence of seasonal sea ice. On this basis, we find that final post‐surge retreat of the Ainort Glacier, from fjord mouth to marine limit (a distance of 3.5 km), was very rapid — probably taking just 20 years. Once wholly terrestrial, the glacier stagnated and did not experience further frontal oscillations. This work highlights one potential cause of asynchronous ice‐mass responses in the Younger Dryas Stadial of Scotland and reinforces the importance of identifying surge‐type glaciers in palaeoglaciological studies.