Isle Of Skye Geology

It would be difficult to wander Skye's strange landscapes without becoming interested in their geology. The rocks of Skye are fascinating for both experts and amateurs wanting to make sense of the landscape they are walking on. The oldest rocks are found in the Sleat peninsula and the south east of the island. These are more than 450 million years old – amongst the oldest in the world - and include Lewisian gneiss, Torridonian sandstone, shales, schists, quartzites and limestones. The hills above Kylerhea are Torridonian sandstone formed from the deposition of sand, gravel and mud in rivers.

The remains of ancient volcanic systems on Skye can be seen in the Cuillin and Red Hills. This was formed during an intense period of volcanic activity in the area during the time when north west Europe was splitting from North America and the North Atlantic was formed. The Black Cuillin is mainly made up from gabbro and peridotite and the Red Hills from red-coloured granite. These rocks were formed about 55 million years ago, relatively recent in geology terms.

Geo at Rubha Hunish

The ice and frost of the Ice Age (between 26,000 and 13,000 years ago) took its toll on this landscape forming dramatic corries, aretes and the superb glacial trough and basin in which Loch Coruisk sits. Frost has shattered rocks from the cliffs and pinnacles of the Cuillin forming many scree slopes. The largest is the Great Stone Shute, over 450 metres high and a necessary climb from Coire Lagan for walkers wanting to ascend Sgurr Alasdair. The melting of the glaciers at the end of the ice age caused the land to slowly rise once the weight of the ice was removed. This produced the many classic raised beaches which can be seen around the coast of Skye including at Staffin where the slipway road has been built on this landform.

In Trotternish spectacular landslides caused by Paleogene age lava falling away from weaker sediments underneath have produced a unique landscape. The whole of the Trotternish ridge is just such an escarpment with the dramatic Quiraing and the Old Man of Storr forming the most well known landslip features. Where the landslip is still slowly moving into the sea fossils can be found, including the 170 million year old footprints of the Hadrosaur dinosaur on the beach at Staffin. More fossils and information about local finds are displayed in the excellent Staffin museum.