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You go north from Ullapool on the road to Lochinver, and turn off left onto a single-track road that winds above Loch Lurgann. The mass of Stac Pollaidh marks the way that takes you across the Coigach peninsula; and then out you come to the sea, with the Summer Isles beyond.
Achiltibuie is one of the small villages lying out along the coast, with houses scattered around the hilly ground and a community hall that must be one of the finest in the north. Everything about the building shows the sign of careful design, from the main hall with its superb acoustics to the comfortable chairs in the lounge where you can sit and enjoy the view. It’s a place where you can feel at home, as well as a facility for many community activities.
Though various buildings are new, the rocks they stand on are very old – some of the oldest in the world, in fact. Professor Brian Windley of Leicester University has shown that some of the rocks in the Coigach peninsula are 3 billion years old. That puts them among the four oldest rocks that have been found on the planet.
Analysis of these ancient rocks shows that they have had a varied history, having been carried down 80 kilometres into the earth and then gradually been brought back up again, all by the slow flows of material in the earth’s mantle, on which the crust and the continents float. So they bear the marks of the huge pressures and temperatures deep below the earth’s surface.
We are on the southern edge of an area of geology so rich and varied that it has been designated as the North West Highlands Geopark. From the Coigach peninsula and the Summer Isles, the terrain runs northwards, including all the west coast of Sutherland, and part of the north coast as well.
This landscape tells a story of events on a planetary scale, including the big crunch about 430 million years ago when two continents began to press up against each other. One of the continents carried Scotland on its edge, while on the other was England and Europe, and the impact formed the British Isles that we see today.
The movement of the continents was so slow that it was almost imperceptible – no more than the rate at which your fingernails grow – but over centuries and millennia the movement continued and immense pressures developed which crumpled zones of land and forced up mountains. One of the crumple zones runs through the geopark from Sleat in Skye to Loch Erriboll in the north – this belt of rocks is called the Moine Thrust. More of the story of the Moine Thust can be learned at Knockan Crag, on the road north from Ullapool.
Much later – around 2.4 million years ago – came the ice, with great glaciers that scoured the rocks, cutting out valleys and sea-lochs. You can see the resulting landscape at Ullapool, at the head of Loch Broom, with the U-shaped valley of Strathmore opening up to the landward beyond.