The Barra Fan is a large prograding sedimentary wedge of Pliocene–Pleistocene age that has built out into the deep-water basin of the Rockall Trough west of Britain (Holmes et al. 1998). Together with the Donegal Fan, considered to be part of the same fan complex, it covers an area of about 7000 km2 (Armishaw et al. 2000) and locally approaches 700 m in thickness. The bulk of the sediments are thought to be glacially derived from the British Ice Sheet, with ice flowing from northern Ireland and western Scotland converging to reach the shelf edge between 56° N and 57° N via several cross-shelf troughs, most recently at c. 29–27 ka cal BP (Dunlop et al. 2010).
Description
Located on the western British continental margin between the Hebrides Shelf and the Rockall Trough, a large sedimentary depocentre with outward-bulging contours is found in water depths between c. 200 m at the shelf edge and c. 2500 m in Rockall Trough (Fig. 1a, b). Gradients commonly reach 7.5° on the upper slope, reducing to 1.5° on the …
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