Podcaster: Dr. Pamela Gay;
Title: Escape Velocity Space News – EVSN: Iceland Has a New Volcanic Fissure Erupting in Fagradalsfjall
Organization: Cosmoquest
Link: http://dailyspace.org/
Description: From March 30, 2021.
After much “will it / won’t it” over the last few weeks in the wake of increased (and then decreased) seismic activity, an eruption in Iceland finally started with a brand new fissure near Fagradalsfjall. No lives are threatened, so Pamela is ecstatic. Plus, arctic methane, a new basalt type, spiders on Mars, Titan’s atmosphere, and an interview with PSI scientists Dr. Nick Castle and Dr. Georgiana Kramer about volcanoes.
Bio: Dr. Pamela Gay is a Senior Scientist at Planetary Science Institute and a Director of CosmoQuest.
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Transcript:
[Dr. Pamela Gay]
Hello, and welcome to the Daily Space. I’m your host, Dr. Pamela Gay. And I am your host, Beth Johnson.
And we are here to put science in your brain. Our news starts us out on the planet Mars and quickly brings us home to a Mars simulation chamber on Earth. I’m doing this story because it involves things called Mars spiders.
That, while not actually spiders, are still able to twig Beth’s arachnophobia. You have been warned. For many years, orbiting space probes have spied strange features on Mars that appear like sponge paintings, but are actually carved into the surface of Mars.
It had been theorized that these features were caused by the sublimation of dry ice that had frozen in the soils over the Martian winter. Essentially, it gets so cold on Mars that, like a scene from The Day After Tomorrow, the air freezes solid. It just does it more slowly than in the movie.
And it can end up in the Martian soil. Unlike water ice, melting dry ice goes straight from solid to gas, leaving behind a dry void where the ice used to be. Well, the theory that these patterns, called Martian spiders, are dry ice voids matches what we’re seeing.
We haven’t been able to visit any with a rover and actually verify our theories, so scientists did the next best thing and recreated the formation of these features in a chamber pumped down to the same low temperature and low pressure of Mars. This work, published in Scientific Reports, was led by Lauren McCowan, who states the experiments show directly that the spider patterns we observe on Mars from orbit can be carved by the direct conversion of dry ice from solid to gas. It is exciting because we are beginning to understand more about how the surface of Mars is changing seasonally today.
Mystery solved. Those spiders, which I really wish were called something else, are nothing more than a sign of the changing seasons.
[Beth Johnson]
I wish they’d call those Mars sponge patterns. I do not like spiders. Nope, not at all.
Here on Earth, we also have cases of gases coming out of the ground, and no spider-like shapes are involved. Beneath the surface of the Earth, methane gas is intermixed with water, forming pockets of methane hydrate. Basically, the surface pressure is high enough that the gas is kept locked in between the water molecules.
It’s what we call thermogenic methane because it’s produced directly by geological processes deep underground. This is opposed to the biogenic methane that we all know from methanogenic archaea in the guts of animals like cows, and some people. Thank you, Mary Roach.
Anyway, methane, of course, is a greenhouse gas, and that is a huge concern these days. The methane that is nicely locked underground can come bursting or seeping out if the pressure on that ground decreases. And the pressure can decrease for several reasons, one of which is the loss of Arctic ice sheets and their tremendous weight.
It’s definitely a negative feedback loop, and scientists are seeking to understand just how big a problem this could be in the near future. So, a team took several sediment core samples off the coast of Svalbard in the Arctic Ocean to see how methane was released at the end of two periods of ice sheet loss. Methane is one carbon atom and four hydrogen atoms, so when it’s released, carbonate-loving critters like Foraminifera thrive and build shells with even more carbon-rich content than usual.
And that carbon content can be tracked over time in the cores to see when the amount of methane changed. They found that as the ice melted, the pressure lessened and methane was released in both violent bursts and slow seeping. Once the ice melted, the release of methane stabilized, but just how much methane was released in each episode is unknown.
Since there are methane-loving critters, the methane is consumed and the calculations are complicated. In fact, the team found massive layers of bivalves—think clams and oysters—in the cores, which confirms modern observations that these animals create massive communities around methane leaks. So, while the methane release isn’t good for us, it is great for some seafloor critters.
This work is published in the journal Geology with lead author Pierre-Antoine Dessandier.
[Dr. Pamela Gay]
As an astronomer, I’m used to seeing our universe as hydrogen, helium, and everything else. Where I’m absolutely willing to refer to that everything else as a metal. Today’s news is challenging this way of seeing things and forcing me to consider the chemistry behind all the different ices and rocks that make up our world and others.
Here on Earth, as we’ll be discussing more in the context of Iceland later in the show, here on Earth we can learn about our world’s history and internal structure from what we can find around volcanoes and coming out of their fissures and calderas. One of the most fascinating places to explore is the ocean floor. In new research in the Pacific Ocean, a team from Leeds Institute of Geophysics and Tectonics has obtained new samples by sinking their drilling equipment 6 kilometers to the floor of the ocean and then drilling a further 1.5 kilometers. The site of their drilling was along the Pacific Ring of Fire, a region that has been geologically active for at least 50 million years. This particular drill site was off the coast of Japan and according to researcher Ivan Savov, this was one of the deepest waters ever to be considered for drilling using a research vessel specifically designed for such challenging deep sea environments. When lava cools into a solid, that solid is called basalt.
And Savov goes on to say, Basalt is among the most common types of rock on Earth. We were looking for basalt that was formed during the Ring of Fire volcanic eruptions. And they found the basalts.
And they found it was like nothing ever before seen with a unique chemical and mineral makeup that indicates early eruptions were both more powerful and more voluminous than previously thought. Savov adds, Now that we know where and how this rock type is formed, we anticipate that many other rocks that we know were originally formed by ocean floor eruptions will be re-examined and potentially alter our wider understanding of the basalt formation. There are two places humans are only beginning to explore, the bottom of the ocean and outer space.
Let’s face it, planets like to hide their secrets. And our Earth is counted among that secretive group.
[Beth Johnson]
We don’t talk about Titan all that much around here, but that is going to change in the next few years. NASA has chosen the Dragonfly as the next New Frontiers mission and the little rotorcraft is currently expected to launch in 2027, which seems like a long time from now and definitely feels like a long time since the end of the Cassini mission in 2017. I’m still sad about the end of Cassini, I won’t lie, but that mission is the gift that keeps on giving.
A team of scientists led by Rajani Dhingra continues to analyze Cassini data with regards to Titan and they’ve published a new paper in Geophysical Research Letters that provides more evidence for rainfall on Titan. That’s right, rainfall. You see, Titan may be a moon of Saturn, but it’s also the most Earth-like body in the solar system that isn’t actually Earth.
It has a mostly nitrogen atmosphere, there are clouds, seas, rivers, lakes, and even rain. Now, the lakes are made of hydrocarbons like methane and ethane instead of water, and the surface pressure is about 50% higher than Earth’s. But still, those lakes and seas might harbor life.
It would be life that uses different chemistry from most life here on Earth, though. Hence, the continuing interest in Titan. And back in 2019, this research group published a paper, also in Geophysical Research Letters, that outlined the observational evidence for rainfall at the north pole of Titan.
Due to its axial tilt, Titan also has four seasons, which last about 7.5 years each, and these observations were conducted by Cassini during Titan’s summer. Now, Cassini had already observed precipitation at the south pole of the moon, but surprisingly, not in the northern hemisphere, where the majority of lakes and seas are located. So, this team finds a bright ephemeral feature that appears to be the result of sunlight reflecting off a puddle, like sunlight would off of wet pavement here on Earth.
The rainfall that caused this potential puddle should also have affected the temperature, but the event was so short-lived that Cassini’s observations weren’t precise enough to detect any change. The new study, however, details another bright ephemeral feature that came from the next pass of Cassini later the same year, and that detection was solid enough to resolve a temperature drop of 1.2 Kelvin around the bright ephemeral feature compared to the area surrounding it. By the next flyby, the bright ephemeral feature was gone.
Dhingra sums up the research. We were fortunate enough to have that number of spectra to see a perceptible temperature difference in a single flyby in a single day on Titan, so we have, for the first time, probably looked at the weather on Titan. We don’t know the fate of the rainfall.
Roger Clark, a senior scientist at the Planetary Science Institute who was not involved in the research, notes that a wet surface, ice, or even clouds can all cause the kind of spectral reflections that have been detected on Titan. So, while this research seems solid, we won’t know for certain until Dragonfly gets to Titan in 2035 and can make its own observations. As always, we’ll keep you up to date with all the Dragonfly mission news and science as it happens.
[Dr. Pamela Gay]
Several weeks ago, we shared with you news that increased tremors on the Reykjanes Peninsula seemed to indicate magma was on the move and that a volcanic eruption was possible. Well, last Friday night, that eruption finally occurred. For the first time in 900-some-odd years, the Fargrika Falls volcano began to erupt.
This is a fissure volcano, which, to my astronomer’s eye, basically means it appears that the Earth has cracked open, allowing magma from deep below to ooze and fountain out, building up a small cone in a lava field as it does. This volcano is considered safe, with the exception of periodic clouds of poisonous gas. It is neither expelling ash high into the air nor threatening homes or life with lava.
The only real concern so far has been for possible archaeological sites. According to the Icelandic news site Möblis, archaeologist Odger Arksson raced to the site by helicopter after the eruption started, but didn’t find any burial sites, stating, I did not see the valley in its entirety before it went under the lava, so I do not dare swear that nothing went under. But judging by aerial photographs, it is unlikely.
For now, this volcano is calmly filling the valley it is located in, and if the eruption continues for tens of days, it may overfill it and spill into neighboring regions. Volcanologists from the Iceland Met Office have already taken and processed samples of the lava emerging onto the surface, and it appears to come directly from the Earth’s mantle at a depth of 17 to 20 kilometers. This kind of a direct connection below the Earth’s crust is rare, and I look forward to more footage of volcanologists getting crazy close, cooking sausages over the lava, which is a thing they do, and collecting more samples to science upon their return to their labs.
Joining me now is fellow PSI researcher Dr. Nick Castle. Nick works with the Mars Ops team, but as a petrologist, which is something I’m going to have him explain in just a moment, he’s pretty much interested in what goes on on any world that has a solid surface. Welcome, Nick.
Tell us more about what you do.
[Dr. Nick Castle]
Okay, so I’m a petrologist with Mars Science Laboratory. I work with what’s called the Chemistry and Mineralogy, or CheMin, instrument, which is an X-ray diffractometer. What that means is that we look at what are the minerals on the Martian surface, and looking at that compared to something like ChemCam with its libs that can give you elemental compositions is a little bit like looking at a recipe.
They can tell you whether or not the recipe contains eggs, but we’ll let you know if it’s a sandwich or a cake.
[Dr. Pamela Gay]
That is cool. Now, while you’ve been studying Mars, you kind of have checked out rocks from many different worlds. Can you tell us just what makes Iceland such a special place for geologists and petrologists?
[Dr. Nick Castle]
Iceland’s a fascinating field place for anyone who studies igneous petrology. So let’s break down that word for a second here. Petrology is the study of how rocks form, and igneous means we’re talking about rocks that form from molten rocks, or in other words, lava or magma, the difference being whether it’s above the surface or below.
Magma is something we have to calculate. Lava is something we can actually grab, which is why we care about the distinction. It’s not about being pedantic about above or below the ground.
Iceland sits on a combination of a hot spot and the Mid-Atlantic Ridge, which is where the oceanic plate that is underneath the Atlantic Ocean splits apart and is making new ground all the time. Because it’s a hot spot, we get to see this Mid-Atlantic Ridge come all the way up to the surface of the ocean because of the extra volcanological activity related to the hot spot.
[Dr. Pamela Gay]
That is amazing. What does that all mean for this growing nation?
[Dr. Nick Castle]
Quite literally, actually. There’s kind of three different settings on the Earth for where volcanoes are common. One of them is where plates are splitting apart, and so you get this breaking open.
Those are what we call mid-ocean ridges, the Mid-Atlantic Ridge being one of the more famous ones. There are also hot spots, which are for one reason or another, heat is welling up from the mantle, possibly from as far down as the core mantle boundary, and that creates volcanoes as well. Yellowstone being a very famous example of that.
The third setting is what we call an island arc setting, and this is where two oceanic plates run into each other and one goes underneath, and you get volcanoes on the overriding plate. So the Aleutian Islands would be a good example of that one, which is that island chain that connects Alaska to, well, Russia.
[Dr. Pamela Gay]
And so it’s the fact that we have both these things coming together in one place that allows this specific point to have this massive island despite the lack of islands most of the way along the rest of the mid-ocean rift.
[Dr. Nick Castle]
Yeah, it’s unusual to get that mid-ocean mountain chain or rift coming all the way up to the surface. In fact, to my knowledge, Iceland is pretty much one good example of that.
[Dr. Pamela Gay]
And what is kind of amazing about this island to me is the volcanoes have distinctive personalities that have gotten wrapped up into human mythology and lore. There’s one of my favorites is Katla, which hasn’t gone off in a long time, but has been known to kind of ash over Scotland, which is a bit far away. We saw a few years ago that back in 2010, there was an utterly unpronounceable volcano that disrupted air traffic.
And since then, there’s been other volcanoes that simply melted ice. What are the different factors that go into making all these volcanoes so very different?
[Dr. Nick Castle]
So there are a lot of different factors in how a volcano erupts, just like there’s a lot of different personalities of people. I mean, some people are easily perturbed and very easy to annoy. Some volcanoes are very explosive and blow up all the time.
And the big controlling factors are what’s the composition of the magma? That is, if it comes straight out of the mantle, it tends to be low in silica. And so it tends to be a very fluid sort of magma.
We would say it has a low viscosity. And this makes it tend to be runny. On the other hand, if it has time to sit and dwell, it tends to drop out a lot of minerals that increase the silica content.
It becomes much more viscous. It’s like the difference between boiling a pot of water on your stove and boiling a pot of honey. I’d rather stand near the water because it’s going to boil happily.
The honey is going to pop, and I don’t want to be anywhere near the hot sugar flying everywhere. The other thing is what we call magmatic volatiles. And this is how much, well, for lack of a better term, gas is going along with the magma.
Now this can be stuff that’s coming out of the mantle too, where you’ve got, for whatever reason, there’s a lot of carbon dioxide or water or hydrogen sulfide or a number of other things coming along with it. Or even when it hits the surface, it can hit an ice cap. And if it hits an ice cap and your lava is sitting around 1,000 Celsius, well, that’s 10 times as hot as it takes water to boil.
So your glacier very suddenly became a steam bath. And that tends to make a nice explosive eruption as well.
[Dr. Pamela Gay]
Now, with this one, there’s been some confusion about what the essentially plumbing beneath it is. And now we’re seeing today with the announcement that this is coming from 17 to 20 kilometers, a lot of excitement. Can you help put all these pieces together?
[Dr. Nick Castle]
Yeah. What we call a primary magma is the holy grail for petrologists. A primary magma is something that the mantle melted, and then we saw it on the surface.
Nothing else happened in between. And so if it’s coming from 17 kilometers or deeper down, that’s the mantle. That’s definitely the mantle.
And so if the melt happened there and came up over the course of even a year or so, that’s really fast. So that’s definitely a primary magma we’re looking at. And that tells us a lot about the composition of the mantle underneath.
You see, petrologists are always trying to figure out what’s the middle of the planet looking like. The stuff that we don’t normally see on the surface. So when we get these direct samples, it’s a free sample return from a place we can’t go.
That’s why we get so excited.
[Dr. Pamela Gay]
This is amazing. And I love the fact that because this is such a gentle eruption, we frequently see pictures of volcanologists just walking right up to the lava and grabbing a sample. And I can’t wait to hear more about analysis of these samples.
But as much as I could talk to you all day, our show must come to an end. This has been The Daily Space.
[Speaker 5]
Today’s episode was written by Dr. Pamela Gay and Beth Johnson. Engineering is provided by Allie Pelfrey and web content is produced by Beth Johnson. You can get a complete transcript, show notes, and see images related to each of our stories at our website, dailyspace.org.
The Daily Space is a product of the Planetary Science Institute, a 501c3 nonprofit dedicated to exploring our solar system and beyond. We are here thanks to the generous contributions of people like you. The best way you can support us is through patreon.com slash CosmoQuestX. Like us? Please share us. You never know whose life you can change by adding a daily dose of science.
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