Temporal and spatial variations in Late Quaternary slope sedimentation along the undersupplied margins of the Rockall Trough, offshore west Ireland

A total of 63 gravity cores, together with high-resolution bathymetry data and sidescan sonar imagery, were studied along both eastern and western margins of the Rockall Trough, offshore west Ireland. The datasets are used to establish the response of the slopes to high-frequency glacial forcing and they help constrain the shallow stratigraphy left on undersupplied current-swept slopes. During full glacial conditions, multiple episodes of mass wasting took place against a backdrop of weak bottom current activity and ice-rafting. During interstadials and interglacials, the eastern trough margin was characterised by more stable slopes and strong bottom currents resulting in periods of erosion and winnowing and the deposition of sandy biogenic (interglacial) and mixed clastic-biogenic (interstadial) contourites. On the western margin, the currents remained weak resulting in mud-prone deposits. Spatial variations in current flow reflect variations in slope gradient and the impact of local topographic highs or depressions that deflected and enhanced or forced deceleration of the currents, explaining the distribution of sands and muds.