Have a gneiss day!
Donald's take on North West Sutherland's ancient rocks
I knew practically nothing about rocks before moving to the northwest many years ago but very quickly realised that you cannot ignore rocks here, the landscape IS rocks, outside the front door, through the window or on your drive to work, rocks, rocks and more rocks. After many years I am becoming a bit more familiar with the basic information, a language forged in stone.
Incredibly we live upon some of the oldest rocks in the world. Lewisian gneiss at an amazing three million years [give or take a few], is an unimaginable age by any stretch of imagination.
Lewisian rock originally consisted of both igneous and sedimentary rocks that have been altered from their original composition and structure, metamorphosed, through time by heat, pressure, and the action of solutions of one sort or another. The dominant type is a stripey greyish gneiss that is rich in quartz, feldspar, and iron-rich minerals. The Isle of Lewis is predominantly solid gneiss and is from which this rock type gets its name.
If the weather is reasonable, winter is a good time to go rock sightseeing and rocks have an advantage over birds and mammals; they dinnae run away or wriggle aboot when you try to photograph them, they have endless patience, are clearly visible anywhere plus there are designated rock routes the traveller can follow.
Smoo cave in Durness is an awesome limestone feature, having the largest entrance to a sea cave in the country, harbouring tales of murder, Vikings, archaeology, and ghosts no doubt (perhaps that of Colin the caveman who might well be sitting in a high rocky nook laughing raucously and cursing everyone simultaneously).
Rock doves, starlings, fulmars, wrens, and dippers nest within the cave site, it can be a noisy echoing eerie experience for the unexpecting guest. Elusive eels and brown trout [Fraser the guides, pet “piranhas”] bide in the deep dark peaty water…
…and below them in the murky gravel are tiny ostracods, a rare subterranean species recently discovered by Lee Knight. (See the linked video below where I accompanied Lee to discover these creatures)
Video - Discovering Ostracods - Smoo Cave
Out on a hill walk whilst struggling over a particularly barren massively rock-strewn landscape a young lad asked me “Why did the man put all the rocks here?”, I was nonplussed, I dinnae ken I replied! How to explain the earth’s evolution to a five-year-old? Tectonic plates, thrusts, faults, dikes, cnoc and lochans and we didn’t even know ourselves until about a hundred years ago – and I am not certain that I truely understand it all anyway. However, it is clear to me now why the Northwest has become a UNESCO Geopark, it’s a very special area geologically as well as for its ecology.
Visit the Northwest Geopark website for more fascinating information:
UPDATE! A Gneiss Walk!
Date: January 25th Area: North west Sutherland
Scourie coast, guided walk. A gneiss walk with garnets and dikes.
Time: 10:30 – 12:30
Eventbright booking ref:
A leisurely coastal walk with the ranger around Scourie Bay looking at the ancient gneiss rocks, the oldest in the UK. Taking in the views, breathing the fresh sea air, and looking for the signs of otters. About 2 hours, dress warmly. Meeting place given out on booking.
Donald Mitchell is a High Life Highland Countryside Ranger, a keen observer of nature and wildlife, he dedicates his time to documenting and sharing insights about the natural habitats in North West Sutherland. With a particular interest in marine life, he aims to help others gain a deeper understanding and respect for the delicate balance of our ecosystem.