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: terminal, medial and lateral.

On Orkney the final phase of mountain glaciation was confined to the corries of Hoy. Here a series of small end and retreat moraines mark the outer limits of former corrie glaciers during the Loch Lomond Stadial. The distribution of moraine ridges at Rackwick appears to relate to the parting of the last ice masses on western Hoy, with ponding of water bodies and the retreat of ice masses into the two main valleys. No major terminal moraines relating to deglaciation have been recognised elsewhere on Orkney but the widespread hummocky moraine probably relates to the final disintegration of the last ice sheet.

Lateral moraine at Rackwick deposited by a final push of ice into the bay from the Pentland Firth

Glacial Deposition

Glacial Landscapes

  • 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. ...

  • 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 ...

  • 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. ...

  • 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.