Papa Stour (HU 165613). Boulder-strewn terminal moraine ridges with lateral meltwater channel. Ice contact slope to left. Photo by Hamish Ross.
Moraines
Moraines are landforms created at the margins of glaciers by the melt-out of debris from the glacier and by the bulldozing action of the ice. Moraines are classified according to their position relative to the former glacier.
On Shetland and the nearby shelf, moraines relate to two periods of former glaciation:
- Loch Lomond Stadial,
- Late Devensian deglaciation, when large glaciers flowing out of the created major moraine complexes.
Moraines were observed by Peach and Horne (1879) at the heads of Dales Voe, Colla Firth, and Swinings Voe and near Voe, Voxter and Brae. These were attributed to a late flow of locally-derived ice from central Shetland. Small retreat moraines probably exist in many valleys on Shetland but patterns are obscured by the depth of peat and by the ubiquity of rock knobs.