Iceberg scours at almost 1 km water depths on the newly discovered Dana IV Seamount, Greenland Sea, North Atlantic

Iceberg scours are created by drifting icebergs that plough into the seafloor with their keels. These prominent geomorphic features are widespread in the Arctic and provide critical insights into past ice-sheet dynamics and ocean circulation. At local scales, iceberg scours influence benthic ecosystems, pose risks to offshore seafloor infrastructure, and can trigger submarine landslides. Here, we report on multibeam echosounder and subbottom profiler data from the 2025 AOC cruise on R/V Dana that document iceberg scours from the newly discovered Dana IV seamout (71°40’N, 15°W) in more than 975 m of water depth. Semi-automated mapping of 212 iceberg scours shows that they are predominantly oriented in northeast-southwest direction. Iceberg scours occur in two clusters around  810 m and 860 m water depth and are typically  ~20 m deep, 330 m wide, and >2 km long. The longest iceberg scour is more than 10 km long and more than 60 m deep, crossing the entire seamount. Some iceberg scours trend parallel indicating multi-keeled or tabular icebergs. One iceberg scour terminates in a landslide scar, documenting that icebergs can be geohazards hundreds of kilometers away from their source. Sediment core data from the top of the seamount indicate that the timing of scouring is older than the Last Glacial Maximum. Given the large water depths in which we find iceberg scours and evidence for multi-keeled icebergs, we attribute them to giant or tabular paleo-icebergs that were more than 1 km thick. The absence of parallel lineations speak against a grounded iceshelf this far south in the North Atlantic. We conclude that these scours are formed by individual icebergs that probably came from an ice sheet calving front at the Northeast Greenland shelf edge or migrated from the Arctic Ocean southward through the Fram Strait during past glacial maxima.