Seabed erosion on the Lomonosov Ridge, central Arctic Ocean: A tale of deep draft icebergs in the Eurasia Basin and the influence of Atlantic water inflow on iceberg motion?

The submarine Lomonosov Ridge, which bisects the Arctic Ocean, is covered by similar to450 m of hemipelagic sediments. High-resolution chirp sonar and side-scan data have documented erosion of a section of the ridge. Here we present multichannel seismic and chirp sonar data which show removal of unconsolidated sediments along the Eurasia Basin side of the Lomonosov Ridge, where the central ridge is shallower than 1000 m. The incomplete erosion of the hemipelagic drape and probable topographic control of ice motion suggest that the deepest draft glacier ice, which reached the central Arctic Ocean from the Eurasia Basin, was in the form of armadas of large icebergs embedded in sea ice rather than a single, continuous floating ice shelf. Massive, rapid discharge of glacier ice was probably required to produce the deepest draft (>800 m) icebergs. Eastward and northward drift trajectories from a likely iceberg source area on the Kara-Barents Sea margin would reflect the relative strength of Atlantic inflow through the Fram Strait. However, only icebergs with drafts exceeding bathymetric thresholds on the Lomonosov Ridge would leave an erosive imprint on the seabed. Advection of Atlantic water may have been relatively strong at times of discharge from the Saalian ice sheet. Icebergs exiting the Arctic Ocean caused massive erosion and redeposition of the hemipelagic sediments on top of Yermak Plateau.