How Volcanoes and Fault Lines Shaped Scotland - With Luisa Hendry

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Revisiting Season 4 Highlights: Luisa Hendry aka the Scottish Geologist

Full Episode Link 

Join us for this highlight reel from Season 4 Episode 3 featuring Louisa Hendry, aka the Scottish Geologist, as she takes us on a fascinating journey through Scotland's geological history. From volcanic eruptions to ancient mountain chains, discover how Scotland's dramatic landscapes were formed over millions of years.

Louisa Hendry is a geologist, science communicator, and social media creator known as @thescottishgeologist. Originally from Largs, Scotland, Louisa turned her passion for rocks into a thriving online presence, making geology accessible and entertaining for thousands of followers. She specializes in metamorphic and igneous rocks and is dedicated to inspiring the next generation of geologists.

Key Topics Covered

• How Louisa became a geologist: From collecting rocks on the beach as a child to discovering her passion through geography class
• Scotland's unique geology: Why Scotland is a geological paradise with diverse rock types within just 500 miles
• Why Scotland is a geological paradise with diverse rock types within just 500 miles
• The Highland Boundary Fault & The ancient fault line that separates the Highlands from the Lowlands
• Volcanic history & Scotland's explosive past and evidence of ancient volcanoes
• Plate tectonics & how Scotland was once joined to North America and sat near the South Pole
• Types of rocks & understanding metamorphic, igneous, and sedimentary rocks (and why Louisa has a least favorite!)
• Mountain formation &  How the Scottish Highlands were created through tectonic forces
• Modern volcanism & Understanding different types of volcanic eruptions and how they're monitored
• Granite formation &  The science behind one of Scotland's most iconic rocks
• Science communication & How Louisa uses social media to make geology accessible and exciting

Transcript

 as we prepare for the launch of the Adventure Dairies Podcast, season five, we are revisiting each episode in season four to bring those highlights and call to adventures forward, to give you a reminder and a refresher, and to keep you entertained and inspired until Season five launches in February, 2026.

And now here are some of the short highlights from the episode with Louisa Hendry, AKA, the Scottish geologist. Enjoy and.
 

And honestly, 'cause there's not much editing involved or anything. Yeah. And I'm like, the worst thing about being a geologist is when you see a pretty rock face and you can't even park right next to it. So you're having to park all the way down there and then you see me run to the rocks. Yeah. Like, and I'm actually running with a phone in my hand.

I'm like, I'm now running to the rocks. And then I get to the rocks. I start. Talking about them and people just thought it was funny and people thought it was educational and inspirational and also just really funny.

I'm originally from Largs. I actually probably started in LS when I was away ghetto. I used to go down the beach, collect the rocks, try smashing 'em open and think, you know, I'm gonna find geodes in this. And yeah, I would never find geodes. You know, the geology logs doesn't give you geodes, but. 
  
 But I wasn't smart, like good at English or math or that, like I wasn't smart. Smart. I was just kinda average at school and I was in my fifth year at school and I kind of came across it by accident. Like, 'cause originally I wanted to be a fashion designer or something stupid. Not stupid like, you know, but something like that.

And I thought, oh, I'm good at making clothes in that and I'm good at art, I'll just do that. But I was also really good at geography, like especially the physical side of geography. And that's kind of what got me into the degree and stuff into doing a, yeah, geology degree. So I went to a university of opening day in my fifth year at school, uh, which was the University of Glasgow.  

 forms like all the landscapes that we see today that they're all rocks under it. 

So is there like different niches within geology then? There is whether it's like, I dunno, rocks, fossils, you know? Yeah. 

There, there's different subjects in geology. Yeah. So it's not just geology. You've got all sorts happening.

Obviously you've got your rock types, your three main rock types like metamorphic, geology. So you can go down a route of just studying those kind of rocks, like which have rocks have changed over geological time and Scotland has quite a lot of those rocks in the highlands. 

It's absolutely badness because you can travel 500 miles and come across all these different rock types, but if you were to go elsewhere, you might not come across all these different rock types.

Right. And that's just to do with the geological history of Scotland. But I do like really enjoy it. Like, I mean, I love geology as a whole. But I do really enjoy like that each individual rock can tell you a story about the past environment and stuff like that. And that's what really kind of got me into it.

And especially when it comes to like knowing that at one point in geological time, Scotland used to have like these volcanoes that were erupting, like during several different periods of geological time. And um, you can see the evidence for that and the rocks. Or you can look into the rocks and the S of Scotland and they make up the roots of big mountain chains that once belonged that cross over into America as well, because we used to be joined up to America back in the day


 Boundary fault? So this Highland boundary fault was active 450 million years ago. And what it was doing is it's just our normal fault line. Right. But what it was doing is it separates also the wool ones to the Highland ones. Mm-hmm. So you can see the difference when you're driving up through a lot going and like you can see like, you know, the mountains, like they make up the high ones.

Yeah. And then like the wool ones like of where, you know Glasgow and that's just quite flat. Except from the Camp Sea and stuff. But the Campes are different kind. Hang. They're all lavas so they're a lot harder. So they stick out and they, everything else has been eroded, like in between them eroded away.

But that Highland boundary fault line's a really important fault line. 'cause at one point it was moving, so it was pushing down the way it was moving. 'cause it's a normal fault line. It was, I'm gonna face it this way. So this is like. Glasgow that, and this is what's known as the Midland Valley terrain.

This is moving down the way and this is uplifting up the way, creating all those mountains and the highlands. 

So you're pushing and squeezing them, right? They're getting like beded to depths like of up to 50 kilometers deep. And this mountain chaining, because it's pushing everything altogether, it's changing them. In analogy, it's re crystallizing the rocks over geological time. And usually the first rotta forms like a slate, like this slate that makes a west coaster next to me.

Like if it's a meta sary rock, used to be CEI Elementary, but it's changed over geological time due to heat and pressure. That's 

  
 Right. But they're only moving at the rate of your finger rail. Like growth, like, so you get different plate boundaries. You get ones that collide with each other. Mm-hmm. So two plates will collide and usually that's a continental crust and an oceanic crust. Uhhuh with oceanic crust or abduct under.

Right. And it might drag with that continent. And that's what happened. Obviously here in Scotland, it's like similar to when you look at India. And the Himalayan mountains in Asia. Like the last 65 million years, India has been moving northwards. It's collided with Asia and it's formed the Himalayan Mountains.

 Yeah. And so when you ask a geologist what favorite or his favorite rock is, it is really difficult to like answer that question.

What, what's your least favorite rock? What rocks can you go? Sedimentary 

rocks are my least favorite. So like sandstone and stuff. I mean you get sandstone everywhere in the Midland Valley and around Glasgow, like obviously sandstone buildings that make up the tenements and I have to walk by them sometimes and I'm just like, oh, out there's some cross bed.

And that's only interesting thing about it. Yeah. But you can make it interesting. I'm not saying that they're not interested. Also people study specific subjects in geology and they might enjoy like studying sedimentary rocks over any other rock. But I like. My metamorphic and my IGN rocks. Ign Rocks are volcanic rocks.

Metamorphic rocks are ones that have changed, as I said before. 

So obviously I've spoke about a convergent plate boundary where two plates come together. The other plate boundary that you get. Well, there's two other plate boundaries. The second one is a divergent play boundary where two plates move away from each other. 

And that's happening when you look at the North Atlantic, you know, the Atlantic ocean's splitting apart.

Like, yeah. Like why did you think there's volcanoes in Iceland? You're like, what? I didn't know that. So when you look at a map of earth when you're next on Google map, right? Maps. Or Google Earth look right down the middle. 'cause they've mapped the sea floor and they've put it on that map. Right.

Really? 

Wow. 

And you can see the ridge that's formed like, which is known as a mid oceanic ridge. Right?

Like a fishers opened up. Right. Because the tooth plates move away from each other. It allows, like, you know, there's partial melting of the mantle and the mantle kind of seeps up as a melt. Like it's a crystal mush, like trying to explain this like they, so it's moving up through the crust, it's buoy, it wants to get to the surface and it'll do anything it can to get there, but sometimes it gets stuck in the cross in certain areas.

Sometimes it causes, you know, shakes the ground, causes earthquakes. It's trying to squeeze through all this magma. It's called magma when it's on the ground and then when it erupts at the surface it's lava. Right, right. Okay.

 you get different types of volcanoes associated with different plate boundaries. Yeah. And it does get really complicated and you get different kinds of lavas compositional.

You know, changes in lavas and magmas. And it does it honestly, it's madness like trying to explain it. Sometimes you're just like, oh my god. But basically, yeah, volcanoes just made up of like lots of lava and ash. That's kinda came out probably. Is that actually the 

result of like, yeah, that's it. So when you see a volcano like Mount Mount ve and that, and it's 

like sitting there like, you know.

Behind Pompe, like I'm gonna erupt and get used. Yeah. I mean I might not, it's just kind of sitting there like, but that's associated with, you've got like in Italy and stuff like that, you've got a lot of volcanism related to, because there's two plates collided with each other that have created the ALP.

Mountains, like Alps and stuff have been created from.

  
 boundaries that are coming together. But plate boundaries that are moving away from each other are more like Hawaiian eruptions we call 'em in geology where it's just.

Very gentle at the lab is, I mean, it might look like it's dangerous, but it's not gonna, 

and can these all be predicted through technology and stuff like that? Some extent. To a certain extent, yeah. Yeah. So they 

can monitor and put seismic things into the ground and they can like roughly guesstimate, right?

Or like, okay, we've got more activity here, there's more earthquakes. We've had like a thousand a day of small earthquakes, so it must indicate that something's moving through the crust. Yeah, like I think it's harder with the volcanoes that are four minute, like convergent plate boundaries, like, but they probably have a similar set up, but when they go boom, they go boom, they'll go like crack toa or Mount Zu.

They're completely different eruptions just because of the magma that feeds those volcanoes is a different composition.

  

 

 basically granite forms as a magma in the crust, but it forms from partial melting of the crust. Okay. So when you have the association of like, you know, for instance you've got two plates Co that have collided with each other and caused all of this heat.

And also there's pressure in there too that's, that's making all the other rocks turn and make more foot rocks. What that does to the crust, the surrounding crust, is it'll melt it a wee bit, 

right? 

When you melt the crust, it usually forms because the crust is very silica rich. It'll form and granite is a silica rich rock.

It'll form a granite, but you get different types of granites and it gets dead complicated, right?  I mean, you probably wanna start 500 million years ago, even though the Earth is 4.6 billion years old. We're not gonna go that far back in time because. Far back in time it was like a little bit too much Anyway.

Yeah. So I, or even because like 

part of North America or I mean Panga, I think it was like there was one big mass continent, weren't they? There was Panga. Yeah. 

So Pangea was the last super continent before, and it was like around 250 million years ago and we were part of North America. Well join up to North America and Norway and all that.

Basically that's split apart. Mm-hmm. Like obviously due to the North Atlantic Ocean split and open. 

Yeah. 

You had shallow kinda season that like during the Triassic and Jurassic periods. In the Cretaceous periods as well. But right at the end of the Cretaceous period there was a lot of volcanism that you can see, which is 65 million years ago.

There's a lot of volcanism associated with the split above Pania, like that you can see on like the west coast of Scotland. But if you were to go right back in time, we sat like south of the equator, like probably a thousand million South South. Wow. But near the South Pole. So we were at like close to the South Pole maybe a thousand million years ago.

 many clips, many documentaries speaking about the geology of Scotland and when I started it, I always wanted to do it even when I was at uni. Yeah. I kinda, I always wanted to like make documentaries about, or geology, you know, 'cause I felt like there wasn't enough out there.

Mm-hmm. And I noticed as well there was a decline in the number of people that were coming to study at university. Okay. And I was like how do we get the subject to geology out there? Social media is one. Why don't I start making all these videos about rocks and see how it goes? And when I first came up with a name, like, you know, I was like, well, I'm a geologist and I'm Scottish, so why not?

Like, I am proud to be Scottish, you know, like, and it was dead funny. I, I started it up like a year and a half, maybe 20 months ago now, more than a year and a half. On March, 2023, I basically, I was in the Northwest Islands with my mom and I gave her my phone. And she started recording me next to the rock face and I just winged it.

 So I hope we enjoyed that. These short, snappy highlights

and if you haven't listened to the full episode, then please go back and do that. You can find a link to that full interview within the show notes. I'm sure you'll find that highly entertaining, compelling, and informative.

And as we wrap up here, if you do enjoy the show, then please do consider leaving a rating and a review. 'cause it really helps the show tremendously. Those ratings and reviews help get this out to a wider audience. Piece.

So I hope you enjoyed that. These short, snappy highlights from the episode with Louisa Hendry, AKA, the Scottish geologist. And if you haven't listened to the full episode, then I do recommend that you go back and do that. And I'll put the link to that within initial notes. And as we wrap up here, if you do enjoy the show, then please do consider leaving a rating and a review. 'cause it really helps the show tremendously. Those ratings and reviews help surface the episodes and the show to a wider audience and help keep this adventure going, and look out for the next set of highlights that are coming up next from Chaz Powell and his wildest journeys Peace.