08/18/2017

For A Volcanic Prediction, Gaze Into The Crystalline Debris

16:04 minutes

crater lake
Crater Lake is a caldera lake, which is formed after the eruption of a supervolcano. Credit: Shutterstock

When it comes to volcanoes, there isn’t exactly a crystal ball that will tell scientists when the next eruption will take place, but there is crystal debris that is helping researchers see what’s going on below the surface of a volcano.

These crystals, formed in the magma chamber, are ejected along with the lava and volcanic ash during an eruption. Trapped inside these crystals is a bit of magma, preserving all the details of what it was like inside the chamber.

Scientists believe these blebs of magma will tell them about the ideal conditions for producing the increasingly important element lithium, according to Tom Benson, a recent PhD in the Department of Geological Sciences at Stanford University and the lead author of a paper on the subject.

“We all have these little devices in our pockets, called smartphones, and many of us drive Teslas or other hybrid or electric vehicles,” he explains. “All of these modern technologies use lithium ion batteries. … These are very highly efficient and relatively low-cost batteries that are taking the world by storm. Demand is drastically increasing by the day, so it’s really important for us to understand where this lithium comes from in order to meet our future demand.”

[Werner Herzog’s documentary is about the power of volcanoes and the gods they’ve inspired.]

Currently, the world mines most of its lithium in two countries, Australia and Chile. Lithium forms in salt deposits and in an igneous rock known as pegmatite, which is a type of crystalline granite.

One of the fundamental properties of lithium is its volatility, Benson says. When a volcano erupts, it releases a large gas plume into the air. Since lithium is so volatile, it escapes the atmosphere and can’t be measured in the rock that solidifies on the surface of the Earth after an eruption.

So, scientists use a “tricky technique” involving melt inclusions — tiny blebs of magma trapped in the crystals as they grow within the magma chamber of a volcano — to study the levels of lithium in a pre-eruptive volcano, Benson says. “These blebs preserve the pre-eruptive concentration of lithium before all of that degassing occurs.”

Lithium deposits are found mainly in old, dormant volcanic systems, particularly in what are called supervolcanoes or, more scientifically, large caldera systems. Crater Lake in western Oregon is a good example of one of these systems, Benson says, but there are hundreds of them in the western United States.

“The current active one is in Yellowstone in Wyoming, but throughout Oregon, Nevada, Utah and Arizona, these very large systems occur that are tens or hundreds of millions years old,” Benson explains. “The only ones feasible to be mined for lithium are those that preserve caldera lake sediments because that’s where the deposit actually is.”

Benson and his colleagues focused their research on a 16.3 million-year-old supervolcano on the Oregon-Nevada border that has well-preserved caldera lake sediments. It is the largest lithium deposit in the United States, Benson says. A number of other active volcanoes are erupting throughout the world, Benson says, including one in Nicaragua and a particularly “exciting” one, called Bogoslof, north of the Aleutian Arc in Alaska.

While mining the sediment of ancient volcanoes may hold promise for maintaining a domestic supply of lithium, the information scientists glean from active volcanos may also point them toward ways to reverse engineer the process of creating the element, which could lead to the ability to create more superbatteries of the future.

—Julia Franz (originally published on PRI.org)


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Segment Guests

Kari Cooper

Kari Cooper is an associate professor of earth and planetary sciences at the University of California, Davis in Davis, California.

Tom Benson

Tom Benson recently earned his Ph.D. in geological sciences at Stanford University, and will be an adjunct assistant professor at New York University. He’s based in New York, New York.

Segment Transcript

JOHN DANKOSKY: This is Science Friday. I’m John Dankosky. When it comes to volcanoes, there isn’t exactly a crystal ball that will tell us when the next eruption will take place, but there is crystal debris which is helping researchers see what’s going on below the surface of a volcano.

These crystals, formed in the magma chamber, are ejected along with the lava and volcanic ash during an eruption. But trapped inside these crystals is a bit of magma, preserving all the details of what it was like inside the chamber. Scientists are banking on these crystals to tell us a lot of things, including what happens right before a big eruption, sort of like the black box on an airplane.

Maybe it can tell us about the ideal conditions for producing the increasingly important element of lithium. Joining me to share what they found when they gazed into these crystal structures are my guests. Karie Cooper is a Professor of Geochemistry at the University of California at Davis. Kari Cooper, welcome to Science Friday.

KARI COOPER: Thanks very much.

JOHN DANKOSKY: And Tom Benson recently completed his PhD in the Department of Geological Sciences at Stanford University. Welcome, Tom.

TOM BENSON: Thanks. Thanks for having me.

JOHN DANKOSKY: And if you’ve got questions about volcanoes, 844-724-8255. That’s 844-SCI-TALK. Let me go first to Tom Benson. So, Dr. Benson, you studied volcanic crystals to figure out the right conditions for producing lithium. I guess I’m wondering, why go after this important element?

TOM BENSON: Well, as many of us listening can attest to, we all have these little devices in our pockets called smartphones, and many of us drive Tesla’s or other hybrid or electric vehicles. And in all of these modern technologies, lithium ion batteries, a component of which is lithium, is used. And these are very high efficient and relatively low cost batteries that are taking the world by storm. Demand is drastically increasing by the day, so it’s really important for us to understand where this lithium comes from in order to meet our future demand.

JOHN DANKOSKY: Yeah, and where do we get the lithium from now? I assume we don’t get most of it from volcanoes.

TOM BENSON: No, no. We don’t. Currently, most of the lithium around the world is mined from two main countries, Australia and Chile. They form in different types of deposits in those areas, in pegmatites, which are the very last stages of a granite, like Half Dome in Yosemite. You can find some lithium enrichment there. You can also find them in salt flats in South America, and that’s where the main two current resources are located.

JOHN DANKOSKY: OK, so tell us about what you find, how you use these crystals to find where lithium resides. What are you learning here?

TOM BENSON: Right, so lithium is a really fascinating element, because one of the fundamental properties of lithium is that it’s a very volatile element. So when you think you have a volcanic eruption and it erupts into the atmosphere, people immediately think to places like Mount St. Helens where you have this big gas plume that erupts. And since lithium is a volatile element, it escapes the atmosphere and we can’t measure it on the rock that solidifies on the surface of the Earth.

So we have to use this tricky technique called melt inclusions, and these are tiny little blebs of magma that are trapped in the crystals as it’s growing within the magma chamber. So we get to analyze those little blebs, because they preserve the pre-eruptive concentration of lithium before all of that degassing occurs.

JOHN DANKOSKY: OK, so let me go to Dr. Cooper before I learn too much about lithium, because I want to learn more. It’s such an important element right now, as you were saying, in our smartphones, batteries, and everything else. So Dr. Cooper, let’s go to your study. What were you looking for, and what did you find?

KARI COOPER: So we’re using lithium in a different way. We’re trying to use lithium as a signature to try to understand, what does it look like beneath a volcano, and what happens before volcanic eruptions? And this is important, because pretty much everything about an eruption, including whether a volcano erupts, has sort of set the stage while it’s below the surface. And so we need to understand what’s going on below there if we ever hope to forecast volcanic eruptions.

JOHN DANKOSKY: So tell us more what you’re looking at. I gave my layman’s example in the introduction, but what are you learning inside these crystals that might be trapped beneath?

KARI COOPER: Yeah, so what we in particular are focusing on is trying to understand the temperature where the magma is stored beneath the reservoir. And that’s important, because it really controls the physical properties of the magma. So as it cools down, the cooler it is the more crystals it has in it. And the more crystals it has in it, the more difficult it is to move.

So let me ask you, when you think about a magma chamber, what’s your kind of mental image of a magma chamber?

JOHN DANKOSKY: Like a scene from a movie with a whole bunch of lava broiling underneath, and I don’t want to go anywhere near it. It’s just a bubbling mess altogether.

KARI COOPER: Yeah, exactly. So you think about this big, giant bubbling vat of magma, and you are not alone in that. That’s sort of the common conception of a magma chamber. And it turns out that what we’re learning is that is mostly wrong most of the time. So most of the time, a magma chamber doesn’t look like that. It looks like kind of a slurry or a slush with mostly crystal material and then some liquid in between it.

So the real question, then, becomes, how do you go from that state to the state where it’s mostly liquid and more of the kind of roiling magma that you imagine when you actually see it during an eruption?

JOHN DANKOSKY: OK, so what do we learn from that? That sounds like something that’s new, so what can we glean from this information?

KARI COOPER: Well, there’s two really important implications in terms of, first of all, the kind of surprising result of what we saw was that it’s cold down there. I mean, it’s not arctic cold like we would think of cold for human terms, but by magmatic terms it’s frigid. And so that means it’s really pretty cold most of the time.

And so there’s two important implications, one of which is that when we’re trying to use monitoring signals and look for these giant pools of magma that you envision, we shouldn’t expect to find them most of the time. Most of the time it’s going to be mostly solid. And so when we do see a big pool of magma developing, that’s– it doesn’t say that it’s going to erupt for sure, but that’s an unusual situation. We should keep a very close eye on that particular volcanic system.

JOHN DANKOSKY: Is it something–

KARI COOPER: And the–

JOHN DANKOSKY: Please go ahead.

KARI COOPER: The other important thing is that we’re finding that it transforms from this mostly crystalline state to this mostly liquid state where it gets erupted. That happens very quickly on geologic times. That’s years to decades. And so that means that we really need to have monitoring in place on these volcanoes so we can catch the early signals of something really starting to get going.

JOHN DANKOSKY: Yeah, that’s what I was going to ask. I mean, this is important information, but it doesn’t replace the real time monitoring of active volcanoes certainly.

KARI COOPER: Absolutely. So what it does is it gives us a way to interpret these active monitoring signals and understand what they mean in terms of volcanic hazards.

JOHN DANKOSKY: If you’ve got questions about volcanoes for our volcano experts, Kari Cooper and Tom Benson, 844-724-8255. That’s 844-SCI-TALK.

Turning back to you, Tom Benson. We were talking about what you’ve learned about lithium in active volcanoes. You’re not talking about finding volcanoes and going in there and mining for lithium in the same way that you would in some other part of the world, I assume. You’re talking about maybe reverse engineering the process of creating lithium? Tell me more what you’re learning and how it might help us create more super batteries that we need.

TOM BENSON: Right. So with lithium deposits, we’re really looking at really old dormant systems. And in particular, what we call– in the public, we call them super volcanoes or large caldera systems. And what happens in a– I like to think of it as sort of like a recipe to create a lithium deposit.

The first one is you have to be within thick continental crust, so within the, say, Western United States where the crust is very thick, kind of like a granite in composition. The second component of the recipe is that you have to have this big caldera forming eruption or super volcano. And that forms a giant hole in the ground because all of the magma that was once there is current– is then evacuated out to the side, and you have this big depression kind of like at Yellowstone, which is the most famous example. And then in that hole in the ground, the next component is you have to have a caldera lake that forms. Think of like Crater Lake in Western Oregon.

And then the final component is that you have to have some sort of hydrothermal system where geyser or fumarole activity that creates the exact right temperature and pH conditions in which clays that are enriched in lithium can form. So it’s like this four component recipe that leads to the ideal lithium deposit.

JOHN DANKOSKY: And so these are found in the types of caldera systems that you described. How many of those are in the United States, roughly?

TOM BENSON: So there are hundreds of them in the Western United States, and we’re talking over millions upon millions of years. The current active one is in Yellowstone in Wyoming, but throughout Oregon, Nevada, Utah, Arizona, there are these very large systems, tens, hundreds of millions years old, that occur.

However, the only ones that would be feasible to be mined for lithium potentially are ones that preserve these caldera lake sediments, because that’s where the deposit actually is. And the research that I published with my co-authors– Gail Mahood, who is a professor at Stanford, Matt Coble is a researcher at Stanford, and Jim Rytuba of the US Geological Survey– we really focused on a 16.3 million year old super volcano on the Oregon-Nevada border. And these have well-preserved caldera lake sediments, and it’s actually the largest lithium deposit in the whole United States.

JOHN DANKOSKY: So that’s pretty important. It’s so interesting, Dr. Cooper, because we don’t really think about volcanoes unless we’re in some sort of direct threat, right? We worry about them exploding and devastating a city, but a lot of this research seems to suggest that we should be paying much closer attention to them all the time because they might help us out.

KARI COOPER: Yeah. Well, that too, but even from the hazards perspective– I mean, it really is an important question to think about why should somebody in the mid-continent care about volcanic eruptions when there’s no volcanoes near them? But I think that one of the important messages to get out is that volcanic eruptions can have very widespread effects. The volcanic ash can be distributed hundreds of miles away from the volcano.

And we saw in the 2010 eruption in Iceland how disruptive this ash can be. I mean, that was a very small eruption, and yet it shut down air traffic across Europe for days and caused billions of dollars of economic disruption. So if something like that were to happen in the west coast of the United States, it would certainly have some significant economic effects, even if you weren’t living right next to it.

JOHN DANKOSKY: The information we’ve been talking about that you’re finding in some of this preserved magma, is this something that you can apply relatively quickly to help the monitoring system that obviously already is well in place around the world?

KARI COOPER: Yeah, I mean there are certainly techniques that are similar to what we’re doing that could be applied in real time. The particular technique that we’re using takes a little bit more lead time to kind of prepare the samples and get the analyzes done, so it’s not something that we could do on the timescale of days and provide information that feeds back into the hazards assessment. So it’s really more like we’re trying to reconstruct the events leading up to the eruption so that people can then look at the events that are leading up potentially to an eruption or not, and sort of compare that and see, are we headed towards an eruption, or are we headed away from interruption. Or how do we interpret these signals that we’re getting.

JOHN DANKOSKY: We have a call from Francisco, who’s calling from Miami. Go ahead, Francisco. You’re on Science Friday.

FRANCISCO: Hi. Yeah, I just want to share with you guys that in Nicaragua this morning at 2:30 in the morning, volcano San Cristobal, which is one of the largest active volcanoes in Nicaragua, started a phase of spewing ashes. And it’s– I just thought it was interesting for you guys to know. And those enthusiasts with volcanoes can always visit, and it’s a tremendous show. And it’s only two hours away on a flight from Miami or Fort Lauderdale.

So I just wanted to share with you guys that. It’s in the community– it’s in the [INAUDIBLE] city of [INAUDIBLE], and also volcano Messiah, which has a nice viewing area for– you can see the magma really from the top of the volcano almost looking down. So it’s very interesting.

JOHN DANKOSKY: It does sound– and Francisco, it does sound interesting, and I actually want to ask our guests to talk about it in just a moment. I do want to say that this is Science Friday from PRI, Public Radio International. Tom, have you been following this Nicaraguan volcano that Francisco was talking about?

TOM BENSON: Sorry, can you repeat that?

JOHN DANKOSKY: Oh, I’m wondering if you’ve been following the Nicaraguan volcano that our caller Francisco has been following.

TOM BENSON: Due to technical difficulties, I couldn’t really hear what was– we were talking about, but I have not been following that eruption specifically. However, there are a bunch of active volcanoes that are erupting throughout the world, and I think that one of the most exciting ones that’s happening right now is north of the Aleutian Arc in Alaska.

And Kari and I are currently in Portland right now. There’s an international conference on volcanology, so it’s the largest gathering of volcanologists ever that’s currently occurring in Portland, Oregon. So we’re looking into places like Nicaragua, Bogoslof, and all these other volcanoes, both dormant and active, throughout the world that are really– we’re all looking at them from different perspectives, looking at the seismic activity, the crystals like we’ve been talking about on this program, and also just geologic mapping and a bunch of different angles. So it’s an exciting time to be involved in volcanology when we’re all here together this week in Portland.

JOHN DANKOSKY: Yeah. I’m wondering, Dr. Cooper, can you tell us more about that? Because it does sound like an exciting time for a bunch of people who study volcanoes all to be in one big room together. What are the things that you’re most excited about happening in your world?

KARI COOPER: Yeah. Well, one of the things that I’m most excited about in terms of– it’s a really– I would say broadly speaking, this is a great time in volcanology, because we’re at a point where different approaches to understanding volcanoes are all sort of coming together in a way that they haven’t really been able to before. So the intersections between, for example, looking at the chemistry of volcanic rocks and looking at seismic signatures and looking at computer simulations, they’re now actually at the point where they can start to directly influence and interact with each other at the same space scales and time scales. And so we’re sort of poised to make some really big advances. And one of the things I’m seeing is that in the volcano science community, there’s a lot of excitement about this recently.

JOHN DANKOSKY: Before we go, Dr. Cooper, and Tom had suggested this a moment ago, but there are a lot of active volcanoes happening all around the world. How many are you and your colleagues monitoring? I mean, how big a task is this?

KARI COOPER: It’s a huge task. And so as I said, I personally am not involved directly in the monitoring effects, but the US Geological Survey is tasked with that in the United States. And talking to my colleagues at the USGS just, for example, in the Cascades– out of the Cascades volcanoes, only maybe one or possibly two of them are what we would consider to be adequately instrumented in the sense that we could see the earliest signs of an eruption.

And that’s certainly not for any lack of will or effort. It’s simply a matter of resources. So we as a society have to decide where we’re going to put our resources, and we could do a lot better in terms of that.

JOHN DANKOSKY: Kari Cooper is Professor of Geochemistry at the University of California at Davis. Tom Benson recently completed his PhD in the Department of Geological Sciences at Stanford University. Enjoy the rest of your time at this volcano conference. I hope you find out some more really cool stuff. I appreciate you joining us here on Science Friday.

KARI COOPER: Thank you very much. Thanks for having us.

TOM BENSON: Thanks for having us.

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