Morphology and Late Quaternary sedimentation on the North Faeroes slope and abyssal plain, North Atlantic

Whilst the interplay between tectonics, glaciation and oceanography is reas onably well understood on some high-latitude margins, relatively little is known about the nature of Quaternary processes affecting the continental ma rgin north of the Faeroe Islands. We therefore present side-scan sonar (GLO RIA and TOBI) and 3.5 kHz data in combination with a new regional bathymetr y in order to characterise and analyse the margin's physiography and the se dimentary processes that have occurred in the area during the Late Quaterna ry, Seven acoustic facies are identified and interpreted, in combination wi th published core records, The margin is subject to differing sedimentation regimes over glacial/interglacial cycles, relating to the changing importa nce of contouritic, hemipelagic, glacimarine and mass-movement processes. M ass movement is much more extensive than previously thought, with a total s ediment volume of >2000 km(3), similar to that of the Storegga Slide (5500 km(3)) and may occur primarily at glacial terminations. The downslope limit of instabilities is associated with a series of channels, focusing the dep osition of distal, turbiditic sediments into the regional deep beyond. Toge ther with glacigenic debris flows from the western margin of the North Sea Fan, mass-movement processes are identified to have affected 52-70% of the North Faeroes margin area. In contrast, distal glacimarine sedimentation, a lternating with hemipelagic and contouritic development, is found on the re maining 30-48% of the margin during glacials, and hemipelagic and contourit ic sedimentation are active across 90% of the margin in interglacial condit ions. Despite a lack of any local, direct glacial influence, these observat ions on the relative importance of sedimentation processes are comparable w ith other glacially influenced passive margins. (C) 2000 Elsevier Science B .V. All rights reserved.