A Snow-Push Mechanism for Ridge Formation in the Cairngorm Mountains, Scotland

Abstract

Observations are presented of a newly deposited snow-push ridge superimposed on a Holocene moraine in Coire an Lochain in the Cairngorm Mountains. The ridge formed when a sliding snow slab was thrust up the proximal slope of the moraine, entraining till gravel and redepositing it on the moraine crest. The process was a late-stage event during the complex wastage of a large snowfield resting on a rock slab, involving basal sliding, avalanching and melting. Snow-push landforms appear to be rare in Scotland. Nevertheless, these observations suggest that fresh material may be added to relict moraine crests in the present-day climate, with implications for exposure-age dating of moraines. However, in this case the addition of debris by snow push to a late Holocene moraine crest does not affect the interpretation of moraine age.