The study of how the Earth formed, and its rocks and minerals, is called Geology. A person who is an expert on Geology is called a Geologist.
Let’s look at how Lochaber itself was formed. We’ll need to go back a thousand million years! Read More
Credit: Pablo Carlos Budassi, CC BY-SA 4.0, via Wikimedia Commons
Over millions of years the continents of Earth have moved and changed, until they formed the shapes we recognise today. Mountain-building is a result of the constant movement of plates on the surface of the Earth, driven by heat from Earth’s core.
The process of mountain-building is called an ‘orogeny’. An ‘orogenic belt’ develops when a compressed plate crumples and is uplifted to form one or more mountain ranges.
There are two different histories of mountain formation in Lochaber; on either side of the Great Glen. The rocks to the north of the Great Glen are called the Moine Supergroup. They began as mud and sand deposits in a shallow sea, on the edge of a supercontinent called Rodinia. Mountains formed between 800 and 400 million years ago. Heat and pressure deep in the mountain range caused the minerals in the rocks to recrystallize, a process called ‘metamorphism’. The most common Moine rock is schist, which contains shiny flakes of mica, a mineral.
To the south of the Great Glen, the mountains are built of rocks called the Dalradian Supergroup. They were formed from ocean sediment between 800 and 600 million years ago on the edge of an ancient continent called Laurentia. The Dalradia rocks include white quartz, marble and slate.
When two adjacent sections of Earth’s crust have different geological histories they are called ‘terranes’. The Great Glen fault is a ‘terrane boundary’ between the Northern Highland Terrane and the Grampian Terrane.
Lochaber boasts some of the best geology in the world, with Scotland’s highest mountains and deepest lochs.
The most famous part of Lochaber’s geology is, of course, Ben Nevis!
Did you know that Ben Nevis used to be a massive active volcano?
Our favourite local mountain is 420 million years old. Like almost all of Scotland’s highest mountains, Ben Nevis has a granite core. Granite is very hard and survives better than many other rocks.
What is unique about Ben Nevis is its pile of surface volcanic rocks. These are not lava flows, but evidence of a mighty, explosive eruption.
What we now see is the remains of a volcano that collapsed in on itself. This is called a ‘caldera’; literally, a cauldron.
Càrn Mòr Dearg model.
Stòran na Talmhainn / The Sources of the Earth by Robin from Bun-Sgoil Ghàidhlig Loch Abar.
Want to find out more?
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Ben Nevis and Glencoe – A Landscape Fashioned by Geology Click here
Room 3 in the West Highland Museum has a collection of local rocks, crystals and minerals, including granite from Ben Nevis.
You can also watch the film ‘The Story of Ben Nevis’ by Lochaber Geopark in this room. Alternatively, you can watch the film at home on YouTube at:
Interesting places to go
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Treasures of the Earth Exhibition in Corpach. This is a fantastic, and beautiful museum of minerals and gemstones from around the world, including our local area. There is also a display on evolution.
Kilmallie Stone Circle – this was created to showcase the geodiversity of Lochaber, and each rock in the circle is a different type. All of these rock types are part of the land of Lochaber.
The Parallel Roads of Glen Roy – these are a series of mysterious parallel lines on the hillside at Glen Roy. They were formed by glacial lakes, and provide early evidence of the existence of glaciers in Scotland.
Activity suggestions
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Start your own collection of Lochaber rock samples. There are wee stones everywhere, if you go for a walk!
Ask your teacher to invite a Geologist to come to your school to give a presentation.
Paleontology is the study of fossilised animals and plants. This important science provides vital evidence for early forms of life in Lochaber and around the world.
‘Fossilisation’ is the name of the process whereby a dead animal, insect, fish or plant becomes stone. Most were formed when creature or plant died and was quickly buried by sediment (such as mud, sand or volcanic ash). More sediment, volcanic ash or lava can build up over the buried organism and eventually all the layers harden into rock.
During the Jurassic age, much of Scotland was a large semi-tropical island. Bivalves (a kind of shellfish) inhabited shallow coastal waters and ammonites were plentiful in the open sea. Near Lochaline and Kilchoan, limestone deposits contain numerous fossils. Fossilised oyster shells, known as Gryphaea or ‘devil’s toenails’ (yuk!), are a common find on Lochaber shores, as well as ammonites. These are around 200 million years old.
If you go looking for fossils, please follow the Scottish Fossil Code. Fossils are ‘finite and irreplaceable’ – that means, once they’re gone, they’re gone. New fossil finds add to our record of past life and environments on our planet, but this precious resource is at risk of abuse and damage, and so must be safeguarded to ensure its survival for future generations.
Paleontology also includes the study of dinosaurs. There has been very little evidence of dinosaurs in Scotland, largely because the rocks are much older than the time when the reptiles ruled the Earth. However, north of Lochaber, on the Isle of Skye, there have been significant finds of dinosaur fossils from the Middle Jurassic – which was between 162 million to 175 million years ago.
Palaeontologists say this was a period of time when there was a massive diversification in dinosaurs.
Our Natural History collection.
Want to find out more?
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NatureScot/NàdarAlba – Scotland’s Nature Agency/Buidheann Nàdair na h’Alba – Fossils in Scotland here
NMS (National Museum of Scotland/ Taigh-tasgaidh Nàiseanta na h-Alba) Review of Fossil Collections in Scotland – a publication listing all the fossils which you can see in Scottish museums here
See in the museum?
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There is a collection of local fossil specimens in the museum, including Gryphaea (see above), Brachiopods and Ammonites, located in room three of the museum.
Interesting places to go
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You can go for a walk at the Fossil Burn on the southern shore of Lochaline, on the Ardtornish Estate. Fossils including Gryphaea can be found in the burn. Again, please follow the Scottish Fossil Code.
The Treasures of the Earth Exhibition in Corpach has fossil collections, as well as interesting exhibits on evolution. Inexpensive small souvenir fossil specimens are for sale in the gift shop.
What did our partner schools do?
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Both schools visited Treasures of the Earth, and the Kilmallie Stone Circle at Corpach.
Lundavra Primary Schools received a visit from geologist Dr. Noel Williams of Lochaber Geopark (here ), who spoke to the pupils about the formation and geology of Lochaber.
Bun-Sgoil Ghàidhlig Loch Abar were visited by Gaidhlig-speaking geologist James Westland of Mull Geology (here ). Mr Westland’s presentation was in two parts. Part one included geology as a subject, the science of the Earth, Earth in space and other planets. He also covered seasons, volcanoes, earthquakes and tectonic plates, and places that volcanoes are found now compared to Lochaber a long time ago. Part two looked at Lochaber – where it is, relative to rest of Scotland, and the Great Glen Fault. Mr Westland also spoke about volcanoes in Glen Coe, Ben Nevis, Ardnamurchan, and the Small Isles. The pupils were told about places to see good geology – those just mentioned, plus other locations such as Clach na Criche in Morvern, Glen Nevis, and the Parallel Roads.
Aimee Ben Nevis
Frankie bhòlcano
Models and pictures of volcanoes and the making of those.
A gallery of models made by pupils from Bun-Sgoil Ghàidhlig Loch Abar.
Aimee Ben Nevis
