Lochaber Geology

The dramatic and varied landscape of Lochaber has a fascinating story to tell of ancient mountain building, fiery volcanic activity and glaciers carving out lochs and glens.

Lochaber Geopark is located in the Highlands of Scotland. It stretches from Rannoch Moor in the south to Glen Garry in the north, and from Loch Laggan in the east to the Small Isles of Eigg, Muck, Rum and Canna in the west. The area displays many geological features of international, national and regional interest and importance. This is a classic area in which to study rocks associated with the Caledonian mountain belt and volcanic activity associated with the opening of the North Atlantic. Before the ocean opened the Caledonian mountain range stretched continuously from Svalbard, through Norway, the British Isles and Greenland to the Appalachian range in North America.

Corran 2A unique geopark

Lochaber is unique among geoparks in having a record that involves both ancient plate collisions and, later, rifting apart of plates. In the east, magmas formed by melting beneath the Caledonian range during the process of subduction, giving rise to the famous caldera volcanoes of Glen Coe and Ben Nevis. In the west, rifting apart of plates, triggered by the up-rise of a hot ‘plume’ from Earth’s mantle, producing the internationally famous volcanic centres of Rum and Ardnamurchan and the lavas of Eigg and Morvern.

The rocks of Lochaber give us a fascinating insight into the past climates that Scotland has experienced on its long journey from the southern hemisphere to its current location.

The final moulding of the local landscape took place during the last Ice Age. There are many fine examples of features relating to glacial action in the area. The Parallel Roads of Glen Roy, the shorelines of a large temporary lake held back by a glacier, are world famous because of a controversy between Charles Darwin and the Swiss geologist, Louis Agassiz.

Find out more about the different geological activity that has shaped Lochaber in the sections below.

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