Cosmogenic nuclide exposure ages from the 'Parallel Roads' of Glen Roy, Scotland

The 'Parallel Roads' of Glen Roy, Scotland, are the shorelines of former ice-dammed lakes created by the last glaciers to occupy the area. We use surface exposure dating with cosmic ray-produced 1 Be in quartz to provide the first numerical age control on the timing of formation of one of one of these shorelines and depositional features in Glen Roy. Four bedrock samples from the surface of the 325 m 'Parallel Road' yielded a mean formation age of ca. 11.5-11.9 ka. This age range confirms the long-held view that the 'Parallel Roads' are Loch Lomond Stadial (ca. 12.9-11.5 ka) features. The age range reflects variation in currently available cosmogenic nuclide scaling schemes and the related 1 Be production rates. Two samples from the surface of the Turret fan indicate that the 260 m lake drained before ca. 10.7-11.0 ka, while two samples from the Brunachan fan suggest that subaerial sedimentation occurred after ca. 9.7-9.9 ka. Copyright (C) 2009 John Wiley & Sons, Ltd.