A COMPLEX SLOPE FAILURE ON BEINN NAN CNAIMHSEAG, ASSYNT, SUTHERLAND

A rare, multi-phased form of slope failure is described from the Assyn t area of NW Scotland. Although possessing some of the characteristics of a rock glacier, detailed analysis of the clastic deposits involved in the slope failure suggest that if is best interpreted as a complex landslide. After the downwastage of the Late Devensian ice sheet, a r ockfall talus sheet developed on the southern slopes of Beinn nan Cnai mhseag. The removal of confining pressure imposed by the ice sheet, to gether with the presence of mylonised facies and fissuring due to tect onic movement along the Ben More thrust plane which cuts across the to p of this hill, led to rock sag and collapse of the central part of th e slope. Holocene rockfall talus cones have subsequently formed, and p artly bury the upper slopes of the blocky apron of debris created by t he landslide. Large boulders found on the upper surface of the blocky debris are due to later toppling processes from the free face below th e summit of the hill.