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Kate Humble: It is just the most spectacular landscape this, isn’t it, it’s just so craggy and rugged.
Hermione Cockburn: Well we’re basically walking through a classic glaciated landscape.
Hermione: All the mountains, the shape of the mountains and the valleys that you see around us are a result of ice sheets and glaciers scouring the landscape over the past two to three million years. But it’s not just the ice that determines what you see, it’s also the underlying rocks.
Hermione: Because the ice responds to the hardness of the underlying material that it’s trying to work its way through.
Kate: So would this area have been mountainous and formed mountains before the ice was here because of tectonic plates shifting, bashing together and that, you know, you getting that uplift, if you like?
Hermione: No, we’re in a slightly different setting here. The reason why the whole area was uplifted was actually a lot of volcanic activity.
Hermione: What’s really exciting is that we’re actually in what’s known as a volcanic province that records some of the most explosive and catastrophic volcanic activity that ever occurred on our planet.
Kate: Really? I mean when would have this happened?
Hermione: This was all happening about 30 million years ago.
Hermione: There were some really, really massively exploding volcanoes.
Kate: So it would have been like those sort of things that you see sometimes on programmes of just hundreds of volcanoes exploding into the air. Look, geologists always do that, I think it’s quite rude!
Hermione: Sorry! Can you just, I just want to show you something.
Hermione: Just to prove to you that ...
Kate: So this whole area would have been basically just fire and sparks and molten stuff flying about everywhere.
Hermione: And almost double the height it is today. That’s what we think.
Kate: And the ice has just eroded it down.
Hermione: And all the erosion since that time has created the mountains that we see around us.
Kate: And because it was volcanic, look at you with your rock, does it mean that you, there are certain sorts of rocks that you expect?
Hermione: What I’m looking for and what I suspect Mount Kendall’s completely made of, volcanic rocks.
Hermione: And just walking up here, all of this stuff,
Hermione: this, you can see crystals in here. This is an intrusive volcanic rock, which means it’s cooled underground,
Hermione: that’s given time for these crystals to grow.
Kate: Oh yeah, the little sort of glittery things that almost look like it’s covered in little grains of sugar.
Hermione: Hmm. This is a fine grained granite.
Hermione: Still, you can get much larger crystals,
Hermione: but I know that we’re kind of in the right area, as it were.
Kate: So are you going to take this and work out its density, and will this sort of form part of the equation, if you like, to work out the mass of the mountain?
Hermione: Well interesting as this rock is, I don’t think it’s actually representative of Mount Kendall as a whole,
Hermione: because of what we saw from the other side of the valley looking at it.
Kate: That very cone-shaped.
Hermione: The shape, and just the way it was weathering at the top, the way it was sort of falling apart. It didn’t look like granite to me.
Kate: Yeah. Right.
Hermione: And given the history of this area, I’m actually expecting more explosive volcanic rocks.
Hermione: Or rocks that have formed from explosive volcanism.
Kate: Okay, so you’re going to abandon this one, are you?
Hermione: Yes, don’t want that one.
Kate: I can’t believe you just threw it away. I mean surely if you’re going to work out the weight of a mountain you need to take into account all this stuff, all these pebbles and bits of rock lying around.
Hermione: Good point. But at the scale that we’re dealing with I’m going to ignore the trees, the soil, the rocks that only cover a tiny bit of the mountain.
Kate: So it’s a little bit like, you know, if you go to the doctor and they want to weigh you and they say, “Can you take all your clothes off and your shoes off”, and you’re, I mean is that?
Hermione: Yeah, weird analogy but correct, yes.
Kate: So basically all these pebbles and things are like the clothes, and the trees and everything else.
Hermione: Stripping away all the detail,
Kate: Oh okay.
Hermione: and I just want the key rocks that make up the real heart of the mountain.
Kate: Well come on then, let’s go and find these key rocks.