Abstract
Abstract Rapidly deposited Neogene sands and Pleistocene glacigenic sediments originating from NW Britain were transported across the shelf and downslope to the Barra Fan depocentre. In contrast, the Holocene interglacial shelf environment is typified by sediment winnowing, sea-floor polishing and transport of relatively small volumes of sediment along the shelf to the northwest. Interpretation of swath bathymetry, 32 kHz side-scan sonar, 3.5 kHz pinger, sea-bed photography and near-bottom current survey data on the shelf edge and slope provides good morphological evidence for both downslope and alongslope sedimentary processes on this composite slope-front fan. On the northern fan a corrugated shelf edge gives rise to a network of channels on the upper slope, which incise into Pleistocene and older sediments and funnel sediment to middle and lower fan. An underpinning variable topography on the fan bulge originates from major and minor slide masses, sediment creep and debris flows. These are reworked by spatially and secularly variable strong-to-weak bottom currents and redistribute material across and down fan forming transverse and linear bedforms, draped sandy contourite sheets and moulded drifts.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call