PRE-FLANDRIAN SLOPE DEFORMATION IN THE SCOTTISH HIGHLANDS - EXAMPLES FROM GLEN ROY AND GLEN GLOY

Slope deformation at localities in Glen Roy and Glen Gloy became essen tially inactive prior to the formation of glacial lake shorelines (Par allel Roads) that are related to the maximum of Loch Lomond Readvance glaciers (10 500-10 000 BP). As such it is distinct from, and predates , differential uplift that has been linked with catastrophic lake drai nage, landslip and possible seismic activity. The deformation is tenta tively ascribed, first, to stress relief during glacial unloading and, second, to high cleft water pressures associated with the retreat of the main Late Devensian (Dimlington Stadial) ice across the area short ly after 13 000 BP and with permafrost, particularly during the Loch L omond Stadial (11 000-10 000 BP). Such deformed, but almost featureles s slopes may be present elsewhere where topography and structure are f avourable: their preservation in Glen Gloy suggests that the upper par t of this valley was not glaciated during the Loch Lomond Stadial.