Dr. Jesse Reimink: ​[00:00:00] What’s up my bald friend?

Chris Bolhuis: Hey, how we doing? Dr. Jesse Reimink. Y'all good?

Dr. Jesse Reimink: Christopher Bolhuis. I'm all good man. All good. We are working our way through the types of hydrothermal features here in Yellowstone. You can't be bad when you're talking about this stuff, right? I don't feel that way at least, and I'm sure you're the same.

Chris Bolhuis: No, you can't. Today we're gonna talk about mud volcanoes, and we're gonna focus on two specific areas here. But [00:00:30] first I, before we go ahead and intro this, I want to turn everybody to image number one. Uh, this is just, this is so cool. This is what mud volcanoes, or mud pots look like, and it's just one of the best examples that you could ever have of what these things, these weird hydrothermal features look like.

Dr. Jesse Reimink: Yeah, I think these are, I mean, we talked last chapter about, mammoth and just watching the terraces, you know, sit there and watch 'em for a while. I find mud pots to be, [00:01:00] sort of hypnotic. You, you can just sit there and stare at them. It's like. a campfire, you know? You just sit there and stare at the thing and it's really kind of fun. And that is one thing about Yellowstone. You can just sit and stare at these features for a long time.

it's a really fun place to just sit And. hang out.

Chris Bolhuis: Not only that, it stinks so bad of rotten eggs. The, the hydrogen sulfide gas is very prevalent.

Dr. Jesse Reimink: Stinks so good for you.

Chris Bolhuis: I love it. I, I do, Listen, I want to, turn you to image number two in your stack. This [00:01:30] shows the locations of the two places that we're focused on. These aren't the only two places where you get mud pots, or mud volcanoes.

Dr. Jesse Reimink: Yeah, that's Right. Chris. I mean they, they're frequently found all over the park, but we're focusing on mud volcano, which is just north of Fishing Bridge there and Artist Paint Pots, which is kind of in between Norris and Madison And Mud Volcano is within the Caldera, Artist Paint Pots just outside. And we're gonna talk about some of the key differences, Chris, but again, maybe, could you frame us here? How are we thinking about hydrothermal features in Yellowstone and why did [00:02:00] we talk about them in the order that we are talking about them?

Chris Bolhuis: Yeah. Good idea. Let's level set here. We went in this order because we wanted to talk about the three types of hydrothermal features in Yellowstone National Park. and so we went away from geography related, you know, going in that kind of order. This is the third hydrothermal feature that you find in Yellowstone. So a bit of review. We talked about the alkaline chloride waters that you get in Old Faithful or the Lower Geyser Basin. In the [00:02:30] last chapter we talked about Mammoth, and these are the calcium carbonate waters that deposit limestone or travertine in this case, which is a type of limestone. And then today what we're gonna talk about are the acid sulfate waters or the very, very acidic hydrothermal features in Yellowstone National Park.

Dr. Jesse Reimink: And yeah. We'll just point to image number three, which we've seen this one before. We'll see it again, but this is talking about the pH of the water. That's really what's controlling the variation in the feature types here. There's kind of two things. The [00:03:00] amount of water available and the chemistry of that water. And if we look at this image, mud volcano in these mud pots, Artist Paint Pots as well. These muddy features are on the left side, low pH. We're thinking about lemon juice or stomach acid. That type of acidity is in these acid sulfate waters that we're talking about. And That's really the, the chemistry of the water controls the features that we see, like why they look the way they do. So, Okay. That's a good level set, Chris. How do we think about this with [00:03:30] regard to geography in the park and like, where's the water coming from? What controls the composition? I, I think we need to get into that a little bit. Like what's driving the chemical change in the water?

Chris Bolhuis: Yeah, good idea. Absolutely. We need to do this. We need to talk about where the water comes from. Well, at depth. The hottest water in the park is above the Caldera. It's 350 degrees Celsius, or 660 degrees Fahrenheit, but it's at, yeah, well above the normal boiling point, right? But it's deep, and so it's under pressure so it's [00:04:00] able to get to those temperatures. This is the same alkaline chloride water that feeds Old Faithful, the upper geyser basin, or it feeds the lower Geyser basin. This water has a lot of gases dissolved in it. Primarily it's got carbon dioxide in it, CO2, and it has that rotten egg, hydrogen sulfide gas. These gases they're there because they got degassed from the magma chamber that feeds the Yellowstone hotspot.

Dr. Jesse Reimink: That's right. So, Chris, let me just touch on that because we often don't [00:04:30] think of gas in rocks or in magmas, and we've been kind of talking about this, right? But, Magmas will have gas dissolved in them, like magma - liquid rock has gas dissolved in them. Much like water can have gas dissolved in it, like your soda pop or your carbonated water. And as the magmas rise up, they can out gas, and those gases will then go into the groundwater system that we're talking about. The groundwater system circulating above the Yellowstone hotspot will kind of pick up those gases, but they're ultimately coming from the magma chamber [00:05:00] beneath the hydrothermal system, and then they're picked up by the hydrothermal system and That's what's driving the kind of primary composition that you're describing. I just wanted to touch on that.

Chris Bolhuis: Right on. Well, as the water rises, I, I say it like this when I'm talking about this with students, it starts to fizz. The lower pressure causes the gas to come outta solution. And so, you know, if you take a, a soda bottle, and you, it's under pressure and you open it for the first time and it kind of goes like that. All of a sudden bubbles appear. That was carbon dioxide [00:05:30] dissolved in the soda. Well, that's exactly what's happening. We have super heated water below the surface. It's got a lot of gas dissolved in it. Well, as it rises up toward the surface, it starts to boil. And so what you get then is you get carbon dioxide. You get hydrogen sulfide, the rotten egg gas, and you get steam. So it's this combination of water and gases that has separated from the main fluid. Right. And so what happens then is they [00:06:00] often, not always, but they often take divergent paths.

Dr. Jesse Reimink: Well, let me interrupt you real quick, Chris, and just point to image number four, because this is kind of showing the summary as you just beautifully said. All the water, the source of the water is broadly the same, right? It's kind of coming from depth, cold water, recharging down, picking up these magnet chamber gases, and then it's, it's rising to the surface. And as it's degassing, they can take different paths. And so on image number four, we just are basically trying to show that if you hang to the left, And you go through certain rock [00:06:30] types, you get neutral chloride waters. If you go to the right, and you get boiling at depth and the water works its way through different rock types, you can get acid sulfate waters. And remember we talked about Mammoth, where the water flowed through limestone and picked up this very different composition and very different chemistry cuz it's really far away from the ultimate source of the waters around the Yellowstone hotspot. So That's how we get the different chemistry going on here. I just wanted to point that figure - point to that figure.

Chris Bolhuis: Because it shows the separation of the alkaline chloride waters that [00:07:00] goes up and feeds Old Faithful, and then what we're talking about here is very different. This kind of steam, it's got less water, but it's loaded with gases. Well, what happens then? It comes out at the surface and it condenses. Reaches the, you know, the colder air at the surface and so on. And so you have this condensate really that has a lot of carbon dioxide dissolved in it, and that creates carbonic acid. And the other thing that happens is the importance here is the presence of H2S, this rotten egg [00:07:30] smelling gas. Well, there are these thermophiles, these really interesting organisms that use the hydrogen sulfide for energy, and in the process they create sulfuric acid, which is a very potent acid. And that's super important here.

Dr. Jesse Reimink: Yeah, so sulfuric acid is one that we use in the lab to dissolve rocks actually. And so the sulfuric acid, when these microbes, create this sulfuric acid that just helps dissolve rocks. And I, I want to make one [00:08:00] comment here, Chris, because it's really a beautiful thing. You can see Geology happening at all scales in Yellowstone National Park. So we kind of talked about how there's these broad scale differences. Mammoth is very different than Norris because of the types of rocks, the waters flowing through on its path there. But you can also see this at a really smaller scale. Like you walk around any of these basins and there's a bunch of different hydrothermal features, different types of hydrothermal features, and they're. Kind of abundant all over the place, but you can see, you know, mud pots in one place and geyser's [00:08:30] right next door and fumaroles over there. And so we can kind of see the local variation. There's really small scale variation and really large scale variation on average. Right. So I just kind of want to point That out. Like the features or the, the variation we're talking about happens at a small scale too. One walk around the boardwalk and you'll see a ton of variation that's due to the differences in groundwater flow around that boardwalk area.

Chris Bolhuis: That is an excellent point, and here that small Geology that you're talking about, that very specific niche kind of setting[00:09:00] it's all about the acid. It's all about these organisms that create the sulfuric acid. Because what this does, this is a potent enough acid to break down the rock. It breaks down the Rhyolite and it turns it into this clay, and then, combine that with a shortage of water. We're talking about mud volcanoes, or mud pots. We're not talking about hot springs. Hot springs have an abundance of water. That would just wash away the mud. That doesn't happen here because of the shortage of water that's [00:09:30] involved, and it allows this acid then to get very, very concentrated.

Dr. Jesse Reimink: Just think about the name here to make mud. What do you need? Well, you need some sediment, and you need a little bit of water. Too much water, and you're gonna be making a liquid, a soup. But really what you want is a sticky mud, right. So you need a shortage of water. To create these mud pots and the acid that can dissolve the rock, basically. So That's what this mud pot stuff is, and these images, we go back to image number one. You can kind of get a sense for this. This is like what we call viscous. This [00:10:00] is not easily flowing stuff. This is thick, soupy stuff. Mud pots, mud pot material is thick and soupy because limited water and dissolved rock in there.

Chris Bolhuis: So I wanna also mention something about the heat here. Mud pots, and particularly fumaroles. Fumaroles, even have less water where the water boils away and it doesn't condense until it comes out at the surface. These are the hottest hydrothermal features in the park, and there's a reason for this, and I don't want to get [00:10:30] into complicated chemistry. We don't need to. If you think about a tea kettle on your stove, The steam coming out of the tea kettle is hotter than the water that's inside of the tea kettle. Very, very easy to burn yourself on that kind of stuff. There is a reason for it. We don't need to get into that, but I think it's cool to understand too, that these are the hottest hydrothermal features - mud pots and fumaroles.

Dr. Jesse Reimink: That’s exactly right. That, I mean, it's a super cool thing and so this, this super hot, when we talk about chemistry, the [00:11:00] hotter something is the more a reaction will progress. So if you just crank up the heat, you're gonna drive a reaction to happen more frequently or more quickly. And so this acid water, this sulfuric acid breaking down rhyolite into clay, that's happening really, really quickly because it's so hot. If these waters were like mammoth and a lot cooler, this process would happen much, much slower. And heat, the temperature is sort of an exponential control, so if you increase the temperature 10 degrees, it gets a lot faster. [00:11:30] If you increase another 10 degrees, it gets exponentially faster. So it, it just, it's not like a linear scale, which is hard to kind of understand, but the hotter it gets. The more and more and more and more tt, it progresses. It drives this reaction. Yeah, Exactly. Exactly. Exactly.

Chris Bolhuis: All right. So let me point everybody to image number five in your stack. This is a great gif showing a typical mud pot or mud volcano at Mud Volcano, just north of Fishing Bridge. Here, the mud pots tend to be a, [00:12:00] light to dark gray. Um, you can clearly see that in this example.

Dr. Jesse Reimink: Another thing I wanna point out in this example, Chris, and maybe you're getting there, so sorry for interrupting you, but I just love this gift because it zooms in and it kind of shows the erosion or the, the steam eating away at the rock above it, like it shows this kind of cavern that the steam has clearly eaten away in the, the rhyolite presumably above this thing, which is helping to feed the mud in the mud pot here. I, I just love this [00:12:30] example. It's such a great one for just showing how this process works.

Chris Bolhuis: And this one is even for a mud pot. This is super runny. This is a lot of water for a mud pot. And you can see that in this gif and you compare it to image number one. Where we first started off that was a little bit thicker, and that leads us beautifully, Jesse, into Artist Paint Pots. This is in between Norris and Madison, and you can see that in image number two, exactly where this is located. Go down to image number six in your stack [00:13:00] a second. I love this stuff.

Dr. Jesse Reimink: It's so good.

Chris Bolhuis: So these are different for a couple of reasons, right? And you can see in this image that it is much, much thicker. This is viscous, sticky, kind of like fried eggs, and it's often described that way in the literature. So Artist Paint Pots is different because it tends to involve thicker mud and it also has iron oxides that are present in the different mud pots, which gives them different [00:13:30] colors. these mud pots can be brown. Uh, kind of this reddish or reddish orange and even shades of yellow here. So, It's just kind of this cool, cool thing. And it's also a photographic challenge. If you wanna like get a mud bubble that's in the process of popping. It's a very cool thing. But be prepared to take about a thousand pictures.

Dr. Jesse Reimink: It is a very cool thing. I love, I know you love these things too. The little like burps, they, they kinda go [00:14:00] bloop and they chuck up, and you can see this in image number six. It chucks up like a little tiny piece of mud and then it. plops back down. It's just so fun to watch. I think. The iron oxide thing is really, really cool. We talked about this with regard to the Grand Canyon of the Yellowstone as well, like the color variation on the sides. It's all variations on iron and oxygen and hydrogen. So different minerals with different proportions of those elements will change the color of the iron the rock itself, right. And the same thing is going on here [00:14:30] in these mud pots, in in Artist Paint Pots.

Chris Bolhuis: The other thing that I wanna point out about Artist Paint Pots that I think is just this beautiful example of something that you alluded to before, this small Geology, and here we go. Let's get into a little bit of the weeds here. This area is located near the edge of a lava flow. And so you have these hillsides that kind of surround this basin. It's a perfect example to see the availability of water and what you get

Dr. Jesse Reimink: I mean, it, it's a great example of this control on how [00:15:00] much water, the local scale as you've described it, controls exactly what you see. Like there's, there's a reason why we see what we see, where we see it. I go, I'm sorry I'm interrupting. I'm just so excited. It’s a cool phenomenon.

Chris Bolhuis: Nah, that's okay. It is. If you walk around this area, you can go one direction or you can go the other. You can go clockwise or counterclockwise, but it's just basically this loop. It's this boardwalk and then slash like, you know, dirt trail, and then it goes back to boardwalk again, but higher up on the hillside. Further away from the water, you get fumaroles a little bit [00:15:30] lower down. This is where the paint pots are, and then further down at the edge of the lava flows in the basin itself. That's where you get hot springs and it's all about then availability of water. Fumaroles have the least water, then mud pots, and then obviously hot springs have an abundance of water.

Dr. Jesse Reimink: Yeah, and we had a great image of this in chapter four, I believe it was, where we talked about the overview of all of the hydrothermal features, where we have this sort of hill slope diagram that is based on Artist Paint Pots, that image, that [00:16:00] schematic is based on the Geology here that we're talking about. Another interesting thing about Artist Paint Pots is we've talked about seasonal change. And seasonal change is really a function of how much water is in the ground. The groundwater, amount. And this changes throughout the season here. The mud gets thicker. And I think this makes intuitive sense. The mud gets thicker as it dries out. Late summer, late fall, less water around, things get thicker. The snow melt has passed through the groundwater system and has drained away, and things are drying out a little bit. So the mud is typically a lot [00:16:30] thicker if you go there in July and August and September than if you went there in May or June.

Chris Bolhuis: You can actually even see this at Mud Volcano and Sulfur Cauldron, just north of Fishing Bridge. If you go back to image number five. That in the late part of the season that really, really soupy mud pot there will turn thicker even there. So it is, that's a cool thing. The seasonal variations, it's all driven by the amount of water.

Dr. Jesse Reimink: Let me ask you a question. I know you've gone there. I mean, your summer science trip, it usually goes roughly the same time of year, but we went later when I did it, when I [00:17:00] was on the a student on the trip, we went later. We went in July to early August. Now you go sort of June to early July, I think. What is your favorite mud Pot and your favorite time to see that mud pot? Tough question. I know, but I, I wanna pin you down to an answer here. Like, cuz I know, I know what you love. You love stepping off the bus saying, ah, I'm home dude. I'm home kids. You know the sulfur smell you love standing there and watching it go. Bloop, splat, bloop, splat. You love the thick ones, so I'm guessing it's [00:17:30] gonna be like Artist Paint Pots in August, but I I don't know if that's the answer.

Chris Bolhuis: Well, okay, so Mud Volcano has the stronger stench. And why do I love this? I wanna, I have to level set with everybody here on why I love the hydrogen sulfide smell. Okay.

Dr. Jesse Reimink: cuz you're a weirdo, that's all. You're just weird.

Chris Bolhuis: That's, well, that's true. It's, it's a true statement, but it's just this reminder that, oh yeah, hydrogen sulfide is a volcanic gas. So it's this constant reminder that we are [00:18:00] inside of one of the biggest volcanoes on the planet, and I love that. Okay. I love just knowing that. And so that's, that's kind of why I like it. But you're right, I do love the thick ones of Artist Paint Pots and how they splat. So I, I don't know. You can't nail me down. I like Mod Volcano because of this very, very strong stench. And I love Artist Paint Pots. Here's the thing though, that is a good thing to set aside for everybody. The parking lot at Artist Paint pots is small and almost always [00:18:30] very crowded, so parking can be difficult there. Be prepared maybe to, uh, park on the road at a pull off and do a little bit of walking to get there. It's just a,

Dr. Jesse Reimink: gotcha. Do you go there with the students with, with the big bus and you, you, you find parking for the big bus in that, uh,

Chris Bolhuis: no,

Dr. Jesse Reimink: or do you avoid it with students?

Chris Bolhuis: I do now. I avoid it because they stopped allowing RVs and buses to park in the parking lot, and we don't go to Artist Paint Pots anymore. It's been a couple of years now since I've been there with students anyway.

Dr. Jesse Reimink: That's a bummer. [00:19:00] Well, I mean, cuz you just, just look at image number six. I could watch this all day long. Just watch this little bloop, the little mud bod blooping up and splatting down. It's just so fun. Alright Chris, well, I, I think that's a wrap on, on mud, volcano and Artist Paint Pots here. We need to end with an FAQ. So our frequently asked question of the day of the chapter here is, are mud volcanoes, real volcanoes? This is a common one that we get, and I'm sure you get this every year from students and probably every year from random people. who kind of glom onto [00:19:30] your trip as you're walking along with all the students along the boardwalk.

Chris Bolhuis: That's right. Um, the answer is no. They are not actually these should be called mud pots. Not mud volcanoes, but it is named Mud Volcano. The specific location just north of Fishing Bridge, so should be called Mud Pots. A true volcano involves magma, magma from below, and magma can be generated in many different settings and so on, and it erupts out at the surface and becomes lava. And so, Short answer, no, [00:20:00] they're not real volcanoes.

Dr. Jesse Reimink: And there's not often a lot of pressure built up in these things, right? they're not super explosive. The gas bubbling up through is what's causing this, bloop up and then splat down. That's just gas bubbles migrating through this thick soup. They're not building up pressure at depth. There are things that are much more like quote unquote volcanoes, mud volcanoes that occur in the world that actually erupt explosively mud out. But that's not this. This is a different thing. This is more like you described it as, mud [00:20:30] pots, which are kind of like hot springs with mud, you know, you can kind of think of it that way. So, man, mud pots, they're just such an interesting phenomenon. They're so fun to watch. You kind of look at them and you think these should not exist. You know, it's like they're so weird.

Chris Bolhuis: That's,

Dr. Jesse Reimink: so goofy looking. They're so fun to watch.

Chris Bolhuis: But I love what you said earlier. It's small Geology. it's just this getting into the detail and, and why is this here? Because it, you're right. It looks out of place. It's like, what the heck is going

on here? yeah. Now it makes sense.

Dr. Jesse Reimink: That's right. [00:21:00] Hey, that's a wrap. Go check it out. Get out

Chris Bolhuis: That's right. Cheers.

Dr. Jesse Reimink: Peace.