Google Earth image of a glacier in Patagonia with well-developed lateral moraines










Lateral moraine ridges and parallel marginal meltwater channels, SW of the Gairn breach.


Lateral moraine

Definition: Certain moraines are deposited at the side of the glacier as lateral moraines. Where two lateral moraines combine, a central, medial moraine may be formed.

Lateral moraines are a product of rock fall onto the margin of a glacier. Rock fall is a result of frost weathering of the rock wall and of over-steepening of the cliff by glacial erosion, leading to rock slope failure. The rock debris is carried along the glacier edge as it moves towards the snout. Melting of the glacier leaves a ridge or bench made of blocky debris on the flank of the valley. Lateral meltwater channels may also be developed.

Lateral moraines occur widely in the Cairngorms. They tend to be quite small features and are often best seen after light snowfalls, sloping down-valley. Good examples occur in middle Glen Feshie and in the Lairig an Laoigh, by Fords of Avon.