Kyle Larson is a structural geologist. That means he climbs mountains, makes maps, collects rocks, and brings them back to the lab where he looks at them on the microscopic level. Larson is gearing up for a major climb to the top of one of the world’s highest mountains where he’ll try to understand how a mountain can exist where the Earth’s plates are mysteriously pulling apart and not smushing together. He chatted with us about what four weeks trekking through the Himalayas can teach us about how the Earth’s plates form its highest peaks.
What do you learn from climbing a mountain?
What don’t you learn by climbing a mountain? When you’re outside and you’re looking at stuff you’re experiencing it firsthand. What i’m looking to do is literally see how the mountains have formed. Why they are where they are and the process behind how they formed.
Why not just look at satellite images?
I’m a structural geologist so I look at how rocks deform. How they fold, fault, and change in response to stresses. The big thing about going out into the field and looking at it, it’s a three dimensional problem. You have to look at it from every angle. The most important stuff is the shape and the orientation in space you have to get in the field to look at it.
What do you learn about the mountain from the shapes of the rocks?
Tons of stuff. In the field itself, you can look at the orientation of the structures in the rocks and you can get an idea of which direction they are moving. Rocks are only static because we live such a short time. But rocks are actually like plastic or silly putty, they deform. We can look at the structures that have formed as a result of that silly putty deformation and get an idea of the forces that are behind that.
In the Himalaya you can get an idea of how India has slammed into Asia -- two continents colliding at the global scale. You can gain meaningful information about how the rocks have been squished to accommodate the plates. When two plates collide there’s a fundamental space problem. Continents that collide have to deform because they can’t occupy the same space otherwise.
Back home in the lab I look at rocks at the microstructural scale. By looking at the orientation of individual crystals in a rock I can extrapolate that data.
It’s a twofold process. One of the biggest things is doing the work in the field. We need to know how these different rocks relate to each other spatially. You have to go out and make geologic maps. That’s the fundamental thing on which all our research is built. Then you add to that information by taking stuff back to the lab.
How do you go about making a map?
A lot of walking. When we work in the Himalayas, we fly into Kathmandu, spend a couple days getting supplies and getting ready for our trek. In Nepal, once you get into the hills there are no roads. You get to a trailhead and then you walk for three or four weeks. All you do is walk and look at rocks. We have compasses and we take a ton of pictures. We have hand lenses and jeweler loops, so we can see what minerals are in the rocks. And we try to map out the distribution of different rocks types and distribution of deformation of rock times. We use an existing topographic map and we try to drape the geology over the topography.
Four weeks walking!? You must be in great shape.
You lose a lot weight. For the most part we don’t do stuff that’s as intense as climbing Everest. But, yeah, it’s better if you keep in shape otherwise it’s a shock to the system. Walking the first week can be kind of hard, but after that your body adjusts quickly. And if you get tired you just stop and look at more rocks!
Eventually you also get acclimatized to the high altitudes. I’m from Canada so I play hockey, obviously. When I come home and play hockey I’m just Superman.
So when you look at the rocks through your jeweler’s loop or back in the lab what do you see?
Some of the other important things we’re looking at are not just rock types. When I’m looking at the minerals, i’m trying to look at the metamorphic grade of the rocks. How hot they’ve gotten in the past and how much pressure they’ve been exposed to. Different minerals are indicators of different levels in the Earth’s crust. You see different minerals that are down 20 or 30 kilometers in the crust. The juxtaposition of deeper and higher rocks starts to tease out a bigger picture of the scale.
If you think about the Himalayas there’s a ton of stress everywhere, but we can never actually see the stress. What we see is strain--evidence of past stress. If we see a rock that used to be deep down, that tells us the rock has moved in response to that stress. If we cross an area where there’s something that’s at the surface to something that was deep in the earth we know we’ve crossed a fault. And looking at the spacial distribution of the faults can give us an idea of how the convergence was accommodated.
Think about it like shoveling snow. When you’re shoveling, well, it sucks first of all, but you put your shovel on the ground and as you move it forward you build up a big wedge of snow. In front of that wedge you create faults. It’ll grow higher in the back and grow longer in front of you. That’s similar to how mountains work.
So you look at rocks to understand faults and how mountains work. What does that teach you about Earth as a whole?
We’re learning how tectonic plates interact and what happens when they collide.
It’s massive scale stuff. We’re learning how tectonic plates interact and what happens when they collide. That has massive implications for what happens deeper in the earth within the mantle. There’s the outer crust which is a hard cell and just below that is a mantle. The upper portion of the mantle has a few percent partial melt, which lets it deform plastically.
When you boil a pot of water, when the bubbles move from the bottom to the top, that’s convection. Moving hot stuff from lower to higher up. As you make something hotter the atoms vibrate and you decrease the density slightly and the atoms float up. At the top they cool and then they move back down.
That happens in the mantle. These convection cells might have something to do with how the plates move on the Earth’s surface. They generally move upward at mid-ocean ridges like in Iceland. They move down at spots where we have crusts being destroyed, like in volcanoes in the Pacific, where cold oceanic crust is going down into the mantle.
So we can get an idea of what’s happening in the mantle and how the space problem gets overcome. Understanding mountains also helps understand global air circulation. The Tibetan plateau is the highest elevation plateau in the world. The latitude that it sits at is just north of the equator. It’s a big flat landmass. When it heats up in the summer, the ground surface heats up, and the air at the ground surface is less dense and it rises. That rising air column needs air to come in underneath and replace it. All this air rushes in from the Indian Ocean to fill that space and that drives the monsoon season.
The plateau is there because of the geology of the collision with Asia. Geology really covers everything--even human and animal migration is affected by mountains.
Do you learn anything about earthquakes?
There are earthquakes in Tibet--there are some big ones. But the time scale that I’m looking at, earthquakes occur at the human timescale but they’re difficult to see in the geology. My research does get at the sentimental issue of understanding what happens after millions of years of earthquakes and why they occur but nothing too specific.
So why aren’t there mountains at every fault line?
There are different types of faults at different plates. There are places where plates are being pulled apart, so there’s a negative space problem. Magma comes ups from the mantle to fill that space. In California there’s the San Andreas fault where the plates are moving side by side, but there aren’t any space problems, they’re just slipping side by side. You see mountains forming where the plates converge: New Zealand, Japan, and the Himalayas.
What made you want to study these space problems created by faults?
I’ve kind of fallen into it. I never said: “this was what I want to do.” I’ve always liked being outside and walking around. When I grew up from our back window I could see Mount Baker, one of the cascade volcanoes like Mount Rainier.
I took a geography course in high school, but somebody told me there are no jobs in geography, because a lot of people like it. It’s like biology, there are jobs but it’s more competitive. Once I kind of started down the path and started looking at stuff it made a lot of sense to go into geology because everything in the world is controlled by Earth’s processes. The world starts to make a lot of sense when you can think of it in those terms.
What’s the difference between geography and geology?
The main difference is that geology is looking at surface processes. What is happening to physical features on the surface of the Earth? How do landscapes develop? How did the bedrock get into the position it’s in? Geographers don’t really care about that unless it’s happening right now.
For your next big trip, you’ll be climbing the world’s sixth highest mountain in conjunction with a cerebrovascular physiologist and cognitive neuroscientist who will be studying the alittude’s effects on the human body. Is it common to share logistics like that?
This will be the first time we’ve done it. But it’s so expensive to go up to those altitudes in a safe controlled way and you need to have a minimum number of people.
From a scientific point of view, there have been a couple studies that have looked at things higher up on mountains. From the cognitive side it will give me an idea of how much I can trust the information that comes out of these high altitude studies.
Walking at those altitudes is one thing, but it’s also minus thirty degrees and you’re trying to write stuff down.
There have been some geologists that have gone to higher altitudes, but a lot of it has been from samples collected by sherpas. It’s expensive and it’s tough to get up there. When you’re not doing a big commercial expedition you actually have to do the work. We have to lug our own gear up. It’s very difficult. Walking at those altitudes is one thing, but it’s also minus thirty degrees and you’re trying to write stuff down.
There aren’t not that many mountains that are that high and those that are in places you don’t necessarily want to go.
The mountain we’ll be climbing is Cho Oyu, which means turquoise goddess. It’s an 8,000 meter peak just to the west of Everest. One of the reasons we’re going there is because it’s not Everest, so it will be less busy and it’s cheaper to climb. It’s the easiest 8,000 meter peak to climb. There are no technical bits, so it’s just a nice walk up to the top of the hill.
We need to get to those altitudes to do tests. And I’m not a trained climber. So we need to have something that can get us up there easy. Geologically the same stuff we see on Everest comes through Cho Oyu. There’s an interesting geologic feature that comes through the mountain. Near the peaks of some of the high mountains in the himalayas is a fault that accommodates extension (the plates there are pulling apart). For the last 15 years we’ve been looking at it and the more we look at it the more interesting it becomes.
In these convergent boundaries you expect to see faults that accommodate convergence. So this is the opposite than what you’d expect to see there. That tells us there was something not quite right about the way we thought mountains formed. Now that we know it’s there it’s a paradigm shift, a total rethink of models for the Himalaya.
We haven’t nailed down yet exactly what’s happening in plate tectonics, but we know it’s not what we thought it was.
It hasn’t been that long that we’ve been looking at the Himalayas. Because of political instability it’s been sporadic and spotty. It’s an unknown place scientifically in a lot of ways. The idea of plate tectonics only came into popular view in the 1970s. It wasn’t until 2001 that our view of the Himalayas started to change. We haven’t nailed down yet exactly what’s happening, but we know it’s not what we thought it was. We’re moving closer to something that makes sense.
Of course by the time we get there something else will be discovered.
Where have you done research?
I’ve been seven times to Nepal, twice to Tibet, and once to India. Here in Canada I’ve done work up in Yukon.
For me that’s the payoff of doing all the office work--being able to go back and chill out and disconnect for three weeks. There’s no internet, there’s no phones, and no real means of good communication. It’s really nice to be disconnected. Nepal is kind of like what the old west must have been like. You cruise into town, wander into somebody's house and they have booze, you have a meal, sleep the night, and you’re off to the next town.
How do you organize a trip like that?
I use local people. I have a friend at a trekking agency there. He takes care of the details. If you’re going to go for three weeks you have to carry food, which means you have to have people, and they need food. Two Westerners on trek for three weeks is about nine support people. I sometimes feel very much like I have a massive footprint. When you’re there enough times you can get to know the guys, but the first couple times you really stick out like a sore thumb.
Do you have another trip planned before you head off to Cho Oyu?
There’s going to be a warm-up climb where we’ll go and test the methods on a smaller mountain so we can make sure everything is going to work. Hopefully that will be this upcoming spring. But I was in Nepal twice this last year so now I need to sit down and look at all the data.
Not all science is done in a lab by guys in white coats staring into microscopes. Lots of discoveries require brave men and women to put their boots on the ground and get down and dirty in dangerous environments. Every month we’ll profile one of these field scientists, tell you how they do their job, and explain the science behind what they do. If there’s a scientist or field of science you’re dying to hear more about shoot us an email or a tweet: erin at erinbiba dot com, @erinbiba