Definition: A blunt-ended, sloping ridge which descends the flank of a valley. Its abrupt termination is normally due to erosion by a glacier which tends to follow a straighter course than the former river.

Grut Fea, Berriedale, Hoy - a fine example of a truncated spur

Ice flowing from N-S down the valley now occupied by the Rackwick Burn has not only deepened the valley, it has widened it too. The cliffs of Grut Fea and Clicknafea truncate preglacial valley spurs and give way downslope to scree. It is noteworthy that these cliffs occur on the outside of a broad bend in the valley where the moving ice would have been forced against the hill slope.

Glacial erosion

Glacial Landscapes

  • The Ice Age in Orkney

    During the periods of maximum cold in the Quaternary, major ice sheets covered Scotland. An ice stream hundreds of metres thick curved out from the Moray Firth to cross the plain of Caithness and flow over Orkney towards ice limits close to the edge of continental shelf.

  • Glacial erosion

    In the gently-dipping sandstone terrain of Orkney, it is often difficult to pick out classic landforms of glacial erosion. Low-lying areas often show a pronounced SW-NE grain to the topography, parallel to the main direction of ice sheet flow. ...

  • Glacial Deposition

    Glacial deposition is largely confined to low-lying areas on Orkney, where thicknesses of till may exceed 10 m. The glacial deposits drape the landscape, smoothing its outlines. Ice-marginal features are largely unrecognised outside Hoy ...

  • Glaciation of Westray

    Westray is the furthest northwest of the Orkney islands. The total area is 47 square kilometres, not huge but the irregular shape gives it a long coastline of almost 80 kilometres, a good place to look for glacial striations. The bedrock of the whole of the island is made up of the cyclical Rousay Flagstone Formation. ...