The contour-current flow along the southern Iceland—Faeroe Ridge as documented by its bedforms and asymmetrical channel fillings

Abstract

The Iceland—Faeroe Ridge is a natural barrier to the exchange of water masses between the Norwegian—Greenland Sea and the North Atlantic basin. The main overflow of cold and dense water from the Norwegian—Greenland Sea through the Faeroe Channels results in the generation of an intense contour-current flow below 600 m water depth along its southern flank. Side-scan sonar surveys revealed an extensive pattern of various bedforms with current-indicators matching well with contour-flow directions previously inferred from oceanographic measurements. In the shallow ridge-crest area only minor current-induced bedforms were observed, reflecting the relatively weaker intensities of overflow across the ridge. In addition to the observed bedforms, surveys of a nearby ridge-parallel channel system, also located on the southern flank of the Iceland—Faeroe Ridge, document an asymmetrical sedimentation pattern with northern channel flanks displaying condensed sedimentation. This asymmetrical sedimentation pattern is attributed to the influence of the Coriolis force, which is the ultimate driving mechanism for the generation of contour-current systems.