The Callander (Auchenlaich) moraine: A new site report for the Western Highland Boundary block of the Quaternary of Scotland Geological Conservation Review (GCR)

Abstract The Callander Moraine (also known locally as the Auchenlaich Moraine) is an exceptionally well-preserved glacial landform on the outskirts of the town of Callander, in the council district of Stirling. It is part of an assemblage of neighbouring glacial landforms and sedimentary sequences which include eskers, kame terraces and kettle holes. When viewed both individually and together these features provide evidence for the interpretation of the nature, timing and extent of an ice margin at one of the south-eastern limits of the main icefield that occupied the Western Highlands during the Loch Lomond Readvance (Lowe, 1993), the last episode of glacial expansion to affect Scotland. This site description forms a new inclusion of the site into the Quaternary of Scotland Geological Conservation Review (GCR). The Callander Moraine is a key feature because it one of the best constrained of the ice limits dating to this glacial episode: sedimentary sequences within kettle hole basins closely located on both the up-valley (GCR site at Mollands) and down-valley (GCR site at Tynaspirit) sides of the moraine provide stratigraphic and independent dating evidence for the age of the feature, although recent advances in dating methods should allow significant refinement of the current age estimate. Although much remains to be clarified about the origin and age of the Callander Moraine, this very close association between a terminal moraine of Loch Lomond Readvance age and datable deposits that bracket its age makes it unique in the UK, and a key target for future research. Finally, there is presently an emerging debate over the pattern and timing of disintegration of the Loch Lomond Readvance ice masses, the last to occupy the Highlands of Scotland, an important topic in which the evidence from the nationally important site of the Callander Moraine, together with the assemblage of surrounding glacial landforms and sediments, can continue to play a pivotal role.