selective linear glacial erosion
Other landforms of glacial erosion in Scotland
Glacial erosion
The landscape of the Cairngorms is a classic example of selective linear glacial erosion. On large areas of the Cairngorm plateau, ice-moulded glacier bed forms are absent. In sharp contrast, the deep glens testify to incision by glaciers to a depth of several hundred metres. Sugden (1968) recognised the significance of this contrast in form. Ice on the plateau was largely non-erosive, whereas ice in the glens achieved deep erosion. In process terms, the ice on the plateau was not sliding, whilst the ice in the valleys was of sufficient thickness to induce pressure melting at its base and to slide. The absence or presence of sliding ice and basal meltwater is crucial to the main processes of glacial erosion, abrasion and plucking.
The Cairngorms also contain fine examples of many types of glacial landforms:
- glacial troughs and breaches
- truncated spurs
- corries
- roches moutonnées
These landforms are
developed largely in granite, a rock with relatively simple fracture systems
that readily produces blocks of various sizes. This means that the glacial
landforms are unusually simple in form and can be easily related to rock
structure. The preglacial form of the relief can also be reconstructed in detail
and provide insight into patterns and depths of glacial erosion.