Fair Isle glacial erratics

Significance: Fair Isle occupies a critical position between the Atlantic and the North Sea for establishing patterns of ice sheet flow. Glacial erratics provide a way of discriminating between the possible sources for the ice sheets that crossed the island during the Pleistocene

Erratics at South Harbour    Erratics at North Harbour                                                                                                 

Glacial erratics of Sanday, Orkney    Glacial erratics of Stronsay, Orkney

Glacial deposits are both patchy and thin on Fair Isle so it is not easy do conventional stone counts. Where glacial till occurs at the coast, however, it is rapidly eroded by storm waves, releasing cobbles and boulders to the storm beaches. The storm beaches thus provide a clean sample of the population of stones contained with the till, although there is always the possibility that foreign stones have been added through shipwreck and dumping of ballast and other anthropogenic means. These images show that the beaches of Fair Isle retain a remarkable array of rock types, some of which can be traced with confidence back to sources in Shetland and Scotland.