Bob Holdsworth: The Geology of Assynt
Bob Holdsworth is Professor of Structural Geology at Durham University and Chair of The Scottish Geology Trust. He has been bringing students to Inchnadamph Lodge on geology field trips for over 20 years.
We spoke to him about his passion for geology and why he thinks Inchnadamph is the ideal location to explore the geologist's mecca of Assynt.
Passion for geology
Though born in London, as a child, Bob became interested in pebbles and agates he found on the beach while holidaying in the Scilly Isles, and on trips to Yorkshire with his father, he would visit old mine spoils searching for minerals and fossils.
But it was his first geology field trip while at school that cemented his passion for the subject. "That trip completely changed my life", says Bob. The trip to Cross Fell, near Penrith, lasted five days, and though exhausted, Bob knew what he wanted to do with his life. "What I loved about it was the way you went around looking at lots of nice geological outcrops, and as you went, you looked at the clues in the rocks, and you built up a story."
Bob likens the art of geoscience to that of forensic pathologists in the TV show Silent Witness. "The way they look for forensic clues and reconstruct the story of what happened, that's what geology is all about. It's very similar, only on a much bigger scale!"
Bob went on to study geology as an undergraduate at Liverpool University before completing a PhD at Leeds with fieldwork in Scotland and moving into academia. He has been the Professor of Structural Geology at Durham University since 1989.
Field trips to Inchnadamph
Since taking up his position at Durham, Bob has taken 25 cohorts of students up to Sutherland and has stayed at Inchnadamph Lodge every time since it opened its doors in 1996. The lodge's location is ideal because of its accessibility to the incredible geology in the area.
The lodge itself is also an excellent place for a group of geologists to stay. As Bob says, "It's perfect for us. It's fairly basic, but that's good. We want students to get a feel for what it's like to be a geologist out in the field. It has a nice relaxed atmosphere, and we have the freedom to do what we need to do. There's also great flexibility with the private rooms, bunks and shepherd huts."
The Assynt region of Sutherland, particularly the area around Inchnadamph, is widely known as a geologist's mecca. Bob explains why it's such a remarkable place for geology:
"The geology of Assynt is special. It includes some globally unique and significant geological features discovered at the end of the 19th century by the British Geological Survey, or just the Geological Survey as it was in those days. Back then, they went around on horseback and wore bowler hats, but a group of them did an amazing job mapping out the geology in that area. They discovered one of the world's first recognised examples of an ancient mountain belt."
The Moine Thrust Zone, as it came to be known, was a huge milestone in the history of geology. What it preserves is a piece of geology that was attached to North America until about 425 million years ago.
The incredible range of rocks in the region makes it a fantastic place for students to learn about geology. As Bob explains:
"There's a marvellous range of rocks and structures covering a huge time period. And one of the most important things we want to convey to students is the importance of understanding the enormity of geological time, so it's a brilliant place to do that.
There are fundamental basement rocks that make up the main part of the tectonic plate, revealing some of the oldest rocks in the UK, which are about 3 billion years old. These are beautifully exposed all over the northwestern part of Sutherland. Sitting on top of those, you have various sedimentary sequences laid down by gigantic rivers and the marine waters of Iapetus, the precursor to the Atlantic Ocean. These are all beautifully preserved, almost entirely undeformed.
Then as you trace the rocks eastwards toward Inchnadamph Lodge they become caught up in the Moine Thrust Zone, exposing spectacular geological folds (like those near Calda House) and huge thrust faults (like the Moine Thrust seen at nearby Knockan Crag). This is why these marvellous rocks and landscapes are the centrepiece of the UNESCO NW Highlands Geopark.
Students often work on looking at that succession and reconstructing the geological history. They're doing their own bit of Silent Witness, if you like, only in this case, it covers the time period from 3 billion to 425 million years ago. That's quite a substantial chunk of Earth's history!"
There's also the chance to look at relatively recent features, like the glacial landscapes produced by the last ice age. "Though not immediately obvious, you can see direct evidence that all of northern Scotland has tilted. So it allows students to develop their forensic skills as geoscientists."
Diverse geological landscape
With Inchnadamph surrounded by mountains, lochs and the coastline, students get the chance to work on a real mixture of terrains. And because the geology is so well known, there's a degree of certainty that makes teaching easier. “It is important,” Bob says, “that students understand that there are still things that are not known - a familiarity with uncertainty is a key part of being a geologist. It’s one of the things that makes it such fun.”
Bob is also passionate about the life skills students gain from these trips. Students can quickly do things for themselves, becoming self-sufficient and giving them a sense of identity as geoscientists. Bob recalls that even students who go on to work in the City look back to their fieldwork days as a wonderful experience.
Endless opportunities for discovery
"The other thing I love about geology", says Bob, "is that you never find out everything. You can go back to a set of outcrops that generations and generations of geologists have visited, and you could still find something new."
During one student trip a few years back, the group noticed something was wrong with a block of rock near the village of Clachtoll. Bob and his colleagues suspected that the rotated layers and other curious features of a large area of Lewisian gneiss, might indicate that it was a huge fallen block. Needing more data to make the case, student Zachary Killingback took on the challenge for his master's thesis research. The study was published in the journal Geology in September 2020. "It's a beautiful piece of work", says Bob. The story was even captured in an article by National Geographic.
Working with The Scottish Geology Trust
Bob's passion for geology is infectious, and as Chair of The Scottish Geology Trust, he is eager to encourage more young people into geoscience careers.
"We desperately need geoscientists", he says. "These people are essential to keep modern life going. Everything we use in our daily lives, from mobile phones and personal computers to cars to beauty products, even wind turbines and solar panels, they are all made up of things that have been taken out of the Earth that geologists help find. We need our geoscientists to find the rare minerals, metals and isotopes - everything we need to sustain modern life."
The Scottish Geology Trust aims to inspire people to understand, love and care for Scotland's incredible geological heritage and its role in creating a sustainable future.
Favourite spots in Assynt
The field trips exploring the geology of Assynt mean everything to Bob and his students. The extraordinary diversity and history of the region give students a great insight into what it's like to work as a geologist. "Assynt has everything - the breadth, the depth, the richness and the history", says Bob.
One of Bob’s favourite spots in the region is Achmelvich Beach. “It’s one of the most gorgeous spots in the world” he says, “The whole area around there is stunning with a beautiful sandy beach and fantastic geology. The geology is awesome and there’s so much of it because there’s a huge amount of rock exposed. There’s also wonderful wildlife and the water is so clear you’d be tempted to dive straight in - though it would be very cold!” Other favourites include the north shore of Loch Assynt and Clachtoll.
Bob and his next cohort of students will be back at Inchnadamph Lodge in September this year, ready to unravel the next layer of history of this incredible area of Scotland.