Dr. Jesse Reimink: [00:00:00] Chris, you know we're on chapter nine here. This, is making me want to go to Yellowstone, man. I'm excited to go again and this chapter is one of the greats. I don't know, we say this every time. It's one of the all time great features. It's first ballot, hall of fame, go to Yellowstone. Gotta see this Mammoth hot springs.

Chris Bolhuis: That's right, because it's an anomaly. it's like it doesn't fit. It doesn't belong here,

Dr. Jesse Reimink: [00:00:30] Geologically, crazy cool. We're gonna have an awesome discussion about the Geology of Mammoth. It's also just a beautiful feature like you just said; it's kind of otherworldly there at Mammoth. Image number one shows the location, so we're familiar with this map. The main thing we're gonna take away from this part though, is how far Mammoth Hot Springs is to the north - outside of the Caldera. That's gonna center. The main theme of our discussion is how far we are from the Caldera of Yellowstone and the Caldera outline there is in yellow in image number one. Chris - question [00:01:00] for you. Do you guys still go to Mammoth on summer Science?

Chris Bolhuis: We do, there's been a time in the recent past where we haven't been able to go because of the flooding, but we do. I mean, look, a lot of people will say that Mammoth is their number one thing. I mean, these terraces are undeniably beautiful. Like we said, you're gonna learn about this. They are an anomaly. They don't really belong in a place like this from a geologic standpoint. Well, they do, but they don’t - it's not like intuitive. Right. And[00:01:30] you have these massive terraces and you have these huge, stinky, shallow pools of water. that are beautifully colored travertine, which is a form of limestone. And we're gonna talk all about this and I wanna refer you to image number two then, and you'll kind of get a feel for what we're talking about in this little gif, showing the terraces - the colors. It’s an amazing place.

Dr. Jesse Reimink: So Chris, you know, we've talked about this before. You go there every summer. When I most recently went to Yellowstone, when I was there with [00:02:00] you guys in 2019, I didn't go to the mammoth part. I left earlier before we went to Mammoth with your students. And actually, you know, my memory, my memory's horrible and I don't have any memory of going there. When I was a student on summer science, I had to go all the way back to when I was a kid going along when my dad used to lead this, the trip you lead. Now, as a biology teacher, I would go along as a kid and that's where I like, have Mammoth Hotsprings memories is from when I was a kid. I just, I'm completely blanking on going there as a [00:02:30] high school student with you on the class that you taught. So what do you cover? Like give us the, the one minute, like, what do you cover with your students when you're there at Mammoth? Because I couldn't remember this and I, I kind of wanted to.

Chris Bolhuis: That’s actually a great, segue into the overview of what this chapter is all about, and I'll just hit it one by one, but I do wanna say, I did take you there. And I know this because I remember you and Andrew trucking by me because I brought you down to the Boiling River and we had like a half a mile walk. The Boiling [00:03:00] River is a section where the water from Mammoth Hot Springs trickles into the Gardener River, and so it creates these really nice, awesome, warm or hot pools of water that you can actually soak in. It's one of the very few places in Yellowstone that you could soak. I, I don't think it's available anymore because the floods just totally reshaped this area in the summer of 2022. So, I don't know anymore about that, but it used to be a place where you could reliably [00:03:30] kind of go and soak in. And I remember taking you there because you two were so excited, you sprinted past me and made some comment about how excited you were to go there. So I did, in all fairness, take you to Mammoth Hot Springs and I did teach you the Geology of the Mammath.

Dr. Jesse Reimink: It's just a reflection of my memory more than anything else. But I do love a good soak in a hot spring pool. I love a good soak in a hot spring pool, which is probably part of the reason I have such fond memories as a kid, in Mammoth. So, Chris, the summary here, like, what are you talking about, your students real quick. Hit us with 30 seconds. The [00:04:00] overview of this chapter is kind of probably, basically what you talk about.

Chris Bolhuis: Yeah, so, Jesse, that's a perfect segue to lead into what the overview of this. Chapter is gonna be, so basically we're gonna talk about why Mammoth is so unique. I've said this, you've said it, it doesn't really belong here. Why is that? The bottom line is, it's made up of a unique rock that you don't typically see in Yellowstone National Park. And you know what? We're gonna get into that. We're gonna talk all about that. And you're gonna want to get into [00:04:30] the geochemistry of, I know.

Dr. Jesse Reimink: I'm already trying to interrupt you. I'm, I'm just like brimming over here trying to interrupt you. Uh, let me

Chris Bolhuis: Go ahead. Say your piece.

Dr. Jesse Reimink: just make one point, Chris, the geochemistry that we're gonna talk about here is super cool and super important. How carbon and CO2 interacts with groundwater is so important in the modern era for all the, the ways that humans are trying to think about drawing CO2 outta the atmosphere are all deeply related to this topic that we're gonna talk about within the context of Mammoth. So that, okay, I'll stop. I'll [00:05:00] shut up now. Rain in the, I can feel the leash pulling on me.

Chris Bolhuis: We are gonna keep it simple. I promise I will rain him in. But it is a very important thing. And so that's really the gist of what we're gonna talk about. You know, why does travertine precipitate so quickly here and why is it here? That's really the gist of this chapter. And, uh, so I think Jesse, let's just jump in. Let's go.

Dr. Jesse Reimink: Let's go and, and let's just reset and draw our attention to the [00:05:30] anomaly part of this. We're really far north. We're on the northern boundary of

Yellowstone National Park here, and we're a really long ways from the Caldera. Probably as far as you can get outside of the park.

Chris Bolhuis: I'm gonna interrupt you because we need to talk a little bit about this. We've, we've hit this before in previous episodes. What is inside the caldera? What is all the rock we've been talking about? Right? It's. All Rhyolite and it's this, really light colored rock and so on. Here we are now on the [00:06:00] northern part of the park. Well outside the Caldera, and again, go back to image number one and look at that. You can see the outline of the Caldera in this, that yellow kind of somewhat circular, you know, line there. You know, We are 20 miles north of that and still in Yellowstone National Park, and that's where Mammoth resides. And that is why this is made up of a unique rock, and it's a unique hydrothermal feature because we don't deal [00:06:30] with Rhyolite when we talk about Mammoth Hot Springs.

Dr. Jesse Reimink: Oh, good one, Chris. I'm gonna go back now to our 30,000 foot view when we're sitting in the hot air balloon up above. Watching geologic time unfold beneath us for four and a half billion years, we talked about this shallow sea. Which was depositing sedimentary rocks all across the interior western part of North America. And that shallow sea was depositing sediments. And one of those [00:07:00] sedimentary rocks was a rock we call limestone. And the makeup of limestone is calcium, carbon, and oxygen. And the formula is CaCO3. And this rock is Chris's favorite rock to eat, right Chris?

Chris Bolhuis: Okay. Um, I guess there's, now look, here's the deal. Here's the deal. Like I learned this when you do Geology in the field and you eat good food in the field, if you're planned properly, right? I don't, I don't like to eat crap when I'm [00:07:30] in the field, so,

Dr. Jesse Reimink: No.

Chris Bolhuis: I like spice, and sometimes then I get heartburn when I'm in the field. I'm prone to that and I don't have my medication for that in me sometimes. And, and so, calcium carbonate, it neutralizes acid. And so if you take limestone, you crush it up, you put it in a water bottle and you drink it or eat it, you do a little bit of both it's like, it's, it's gone right there. So it works. I don't eat it for nourishment. I eat it because it benefits my body. In a good way.

Dr. Jesse Reimink: There we go. [00:08:00] Okay. You're not needing it for the flavor. It's not very flavorful. It is used to raise the pH of water. That's what we're talking about. Antacid. Calcium carbonate is an antacid. Limestone is calcium carbonate dominantly. And so also, it’s what makes water hard? If you think about, I was just Chris at your house recently in Michigan there, and you guys have well water and you have hard water and it's a major constituent of what makes hard water hard is the fact that you, you know, it's hard to get suds going when you have this, basic water, [00:08:30] this water that is a high pH because of the calcium carbonate, because of all the ions and ions and cations in the water. it's a really important.

Chris Bolhuis: Okay, I, I feel like you said something really important there, and I wanna make sure that everybody understands this hard water is called hard water because the calcium carbonate reacts with soap and it prevents it from lathering, which makes it hard to clean. Hence the name Hard Water. It's not because it's got a bunch of metals in it and all that little stuff. It's not. It's because soap [00:09:00] that has that in it, doesn't clean well. It's hard to lather. So anyway, Hey, I don't feel like you finished your thought on the 30,000 foot view, so I'm gonna throw that back to you to wrap that up a second. You got a little sidetracked.

Dr. Jesse Reimink: I got distracted by geochemistry. Sorry. So we're back in the air balloon, right? And we're, the shallow sea is depositing stuff. But the other important thing that did not happen in the northern part of the park here is that the Caldera forming eruptions did not blow apart the crust here. And so we still have those [00:09:30] very important rocks for Mammoth, which is those sedimentary rocks. The limestone was laid down, it's still beneath your feet if you're standing in Mammoth. And that's a really important part about what makes Mammoth unique. So we still have those sedimentary rocks, limestone's the important one beneath your feet. Whereas if you go in the Caldera, it's not there anymore. The volcano blew it apart. And so we're outside of that volcano kind of danger zone, if you will. So, Chris, okay, what's the next step? Why is the limestone so important? Help us [00:10:00] understand this aspect.

Chris Bolhuis: Well first I wanna throw everybody back to if you've ever taken any kind of earth science Geology rudimentary course, you've been introduced to rocks. The one that you remember is identifying limestone because this is the one where you probably got to drop a little bit of hydrochloric acid on it, and it fizzes like crazy. This is the rock. That's the test, right? Everybody does this. So if you drop acid on it, it effervesces or fizzes, kind of like [00:10:30] Alka Seltzer dropped in a little glass of water, fizzes like crazy. It dissolves. Caves are made out of limestone. If you've ever been in a cave, the rock that's involved, the rocks that the caves are in are limestone because groundwater is slightly acidic and it does its work. Just like acid on it. Does. That's what's going on. Mammoth. It looks like an inside out cave. Instead of limestone being dissolved. Limestone's being [00:11:00] precipitated on the surface, and we're gonna get into why is that the case?

Dr. Jesse Reimink: Can I add to that, Chris a little bit? The limestone is being dissolved at depth in being precipitated on the top. So limestone is being transported. It's being dissolved down below and brought to the surface, and there it's being deposited in these beautiful, beautiful formations that we see in for instance, image number two in your stack, or if you're walking around Mammoth, you'll see these things. That's the travertine deposit. So let's get into [00:11:30] the geochemistry of the groundwaters here - that transport - that difference, because it's a really cool story, Chris, and I think

Chris Bolhuis: It is. Jesse, can I do this? Because I feel if I let you do this, you're gonna ramble on forever and we just, we can't do that. We gotta, we gotta keep this tight. So look. Why is the water slightly acidic? I think we have to start with that. We're talking about the water at depth, the water that's flowing through this deeply buried limestone.

Dr. Jesse Reimink: So, Chris, can I interrupt you real quick? And I promise I won't go into the weeds. I just wanna point to image number three [00:12:00] here to talk about

what acidic is and what basic is, cuz we're kind of, kind of use those terms. So in image number three, the x-axis, the bottom axis, there are actually the top plot shows acidic versus basic. And if you don't know what these are, it's, it's relatively simple. Think of battery acid, stomach acid, lemon juice. Those are on the left side. Those are acids. pH of seven is neutral. Stuff on the right -soap, bleach, baking soda. That's basic. Okay, and that's all I wanted to say. I'm stepping back out of the weeds now, Chris. Go. Go for it.

Chris Bolhuis: No [00:12:30] that's a good point. So I want to talk about why the water is acidic to begin with. we're talking about the water that is flowing through the limestone at depth that is deeply buried. So The bottom line is, the water has carbon dioxide, Hydrogen sulfide, H2S, and it has some helium. And we know that these gases came from the magma chamber, the hotspot magma chamber that we've alluded to a hundred times in previous chapters. So those gases are dissolved in it. It makes it [00:13:00] acidic, it goes to work on the limestone. So it dissolves it as it flows through this rock.

Dr. Jesse Reimink: So, Chris acidic at the bottom. Right. But we talked about how it's basic. And then image number three, you can see that mammoth hot springs is not very far to the left. It's actually slightly above a pH of seven. So it's slightly basic. How does it get to be basic is the question, because at the surface it's basic. And we talked about how acids dissolve this calcium [00:13:30] carbonate. And that's what's happening at depth. We'll come to that, hold that thought in your head cuz we're gonna come back to why that's happening at depth. But at the surface we said we're precipitating this stuff. We're precipitating travertine. Why is that happening? Well, at the surface, the water is not boiling. Importantly, it's steaming, but it's not boiling off. And so the water at depth doesn't get above boiling really either. Contrary to a lot of the sort of geyser features that we've seen elsewhere in Yellowstone here.

Chris Bolhuis: Let me interrupt you, Jesse. [00:14:00] So the water is not boiling. It looks like it's boiling though. If you're standing there, gonna say, that water's boiling. No. What's happening is the carbon dioxide, the hydrogen sulfide, those gases that we talked about that are dissolved - they're becoming undissolved. It's like opening a can of pop as soon as you open it and it goes. Like that. You crack the pressure, you lower it, and it starts to fizz. The water is rising to the surface, and we'll talk about the mechanism for this in a little bit. It's [00:14:30] rising to the surface. Lower pressure and the gases that were dissolved are now fizzing out of the water. So it's not boiling, it's just bubbling because of escaping gases. Sorry to interrupt you. Go ahead and continue.

Dr. Jesse Reimink: No, that's right. And that escaping gases really changes the chemistry of the water and makes it more basic, which means that this calcium carbonate, if we have acidic water, then it dissolves the calcium carbonate. And that calcium carbonate is what we call soluble in the [00:15:00] water, means it can be floating around in the ions and it's dissolved by the water. If we change the pH and make that water basic, all of a sudden that calcium carbonate is not stable in the water. It precipitates out. So that's what's happening. We're kind of dissolving the calcium carbonate at depth. When the water's acidic, rises to the surface, degases. It goes from acidic to basic. All of a sudden, calcium carbonates not stable anymore. This travertine gets dumped outta solution and precipitates and forms these amazing hydrothermal features at Mammoth Hot Springs. And [00:15:30] that's why on figure three, mammoth Hot Springs is labeled between a seven and H a pH of a seven and H. That's the surface water. If we go at depth, it's gonna be a lot more acidic than that. If we drill down into Mammoth. And looked at the chemistry of the water at depth.

Chris Bolhuis: If you look at image four in your stack, you'll see a picture of beautiful limestone. This is, actually a famous layer called the Madison Limestone, but this picture is taken from the Black Hills of South Dakota.

Dr. Jesse Reimink: Uh, one of our favorite places and I [00:16:00] know it's a special place to you as

Chris Bolhuis: Special place in my heart. That's right. So that's just a picture of limestone. It's, it's maybe 4 to 500 feet thick. That deposit of limestone we're looking at, it's the Madison Local, it's called the Pahasapa in the Black Hills. Um,

Dr. Jesse Reimink: Chris, real quick, we're gonna talk about where that limestone is that Madison limestone with regard to Yellowstone. But it's an interesting point in this picture, is that out west in the western US where there's not a lot of precipitation, not a lot of acid rain, limestone is a cliff [00:16:30] forming unit. So limestone's often a cliff former. Out here in Pennsylvania, we have a lot of slightly more acidic rain and a lot more rain. And so limestone is actually a valley forming rock. It gets dissolved really quickly around here in Pennsylvania. So the - a lot of the valleys where I live are limestone and the ridges are gonna be like sandstones and things that are more chemically resistant. So it's just kind of an interesting point when you have acidic rainwater - and a lot of it - versus out west where you don't have a lot of rainwater and not a lot of acidic rainwater. The limestone's a cliff former, [00:17:00] it's not dissolved. So image.

Chris Bolhuis: interesting point.

Dr. Jesse Reimink: Yeah. Uh, it's kind of a curious thing, and in this Madison limestone, that image from the Black Hills, the Pahasapa limestone, that's really the source of all of this calcium carbonate, all this travertine in Mammoth Hot Springs. And image number five is a gif that shows in general the path of the water flow here. I kind of think about this, Chris, like if you're on a beach, And you're making a sandcastle. You take both [00:17:30] hands and you scoop it into the sand, and then you lift up in the center like you're trying to take a big arm full of sand. You dig down from the sides, and then you run your hands underneath. Then you kind of scoop up in the middle. That's kind of what I'm envisioning here. The water's going down around Norris, the water's going down around Gardner to the north. That's the north and south of Mammoth, and then they're flowing. Because of faults. They're getting down at depth because of faults. They're acidic. They're flowing horizontally through limestone. And then [00:18:00] again, because of faults near Mammoth, the water is coming up there. And this leads to to some really interesting features of the water. For instance, you said it's quite cool. It has all of this calcium carbonate dissolved in it because it flowed through limestone all the way through there.

Chris Bolhuis: So it's interesting, you know, it sinks along faults, and then it slides horizontally through the limestone. Through this porous and permeable and fractured limestone, gets to mammoth, where now ascends through faults, and that's what you just left off with, is [00:18:30] as it ascends towards the surface, pressure lowers, it starts to degas. Well, those gases -that's what made it acidic. So a couple of things are happening, right? As it comes to the surface, it's losing those gases. So the water is becoming less acidic, and in fact, it's becoming basic. Now it's going beyond neutral seven, to higher numbers. Well, acid dissolves limestone. Well, the opposite of that then is if the water is [00:19:00] not acidic anymore, instead it's the opposite - it’s basic. Now it's gonna precipitate limestone. So the fact that it's Degassing and becoming basic. At the surface, it's bubbling. We can see it that's causing it to start to precipitate calcium carbonate. And the other thing that's happening is the water's cooling off and both of those help it precipitate this calcium carbonate. Now the thing is, limestone the kind that everyone is familiar with. This is precipitated by warm shallow [00:19:30] salt water oceans, right? Well, travertine. Is the same as that, except it's precipitated not by oceans and salt water and so on. It's precipitated by really hot water reaching the surface, degassing, and laying down calcium carbonate. That's the only difference. It's just how the calcium carbonate is formed, and that's what travertine is and that's what Mammoth Hot Springs is made

Dr. Jesse Reimink: And I think that's a really cool thing to think about when you're standing there looking at Mammoth, cuz you described it [00:20:00] as, it looks like it's boiling. Chris, you're gonna see steam rising. You're gonna think about this like, oh, it's boiling water coming out. But that's not what's happening. It's actually a lot cooler water. It's a lot different water, a lot different chemistry and composition. It had a lot different life underneath of the subsurface than any of the other hydrothermal features in Yellowstone National Park, which makes it really, really cool. Mammoth also has an incredibly high rate of deposition - something like up to three millimeters per day, which Chris, I, that is a massive rate in Geology. That's so [00:20:30] fast in Geology that not much happens that fast in Geology. So that,

Chris Bolhuis: No.

Dr. Jesse Reimink: kind of impressive, uh, fact.

Chris Bolhuis: yeah, Why is it so fast? Well, I think of a couple things when I think about why this is so rapid. One, the water gets super saturated with calcium carbonate because of this rapid degassing of carbon dioxide mostly. Now also, I wanna say this; it is very apparent that it's degassing a lot of H2S as well, because hydrogen [00:21:00] sulfide, that H2S is that rotten egg smell. And when you're at Mammoth, I'm telling you right now, be ready. It flat out stinks. I think it's a wonderful smell, but a lot of people don’t agree with me.

Dr. Jesse Reimink: You, you, Chris. I could just picture Chris Bolhuis on the bus driving down. You got the CB radio going. You're lecturing about how the groundwater's flowing through limestone. You get out the bus. Chris parks in the parking lot, gets out and he goes, I'm home kids. I can just picture. You do that

Chris Bolhuis: almost verbatim what I [00:21:30] say I do. Yeah. That's one reason why it's so rapid. The other reason is something that we've already talked about are these thermophiles. These heat loving or, and heat thriving organisms. That break down the hydrogen sulfide, you certainly smell it, as we just said. And they help precipitate calcium carbonate in the process of breaking down that hydrogen sulfide gas. So those are the two things that result in that really, really rapid deposition of travertine terraces. Now I want to [00:22:00] switch gears here, Jesse, because this is your chance right now. Now just, we gotta keep this kind of tight. Okay. Just don't go off, you know, too bad. But I want to ask you though, about travertine and this geologic clock idea. Okay? So you got two minutes to kind of lay the foundation for what this is and how this is done. What's the geologic clock with travertine?

Dr. Jesse Reimink: Yeah, so travertine is a really important thing. For instance, in caves, travertine is [00:22:30] precipitated in caves. So, stalactites and stalagmites have travertine deposited on them. Actually, there's a lot of caves where there's, um, petroglyphs or, you know, prehistoric human cave art that has calcium carbonate travertine coatings on it. So a lot of the ways we date that artwork is by dating the travertine layers. The way this works is a little bit complicated, but it's called, what's called disequilibrium dating. And the way to think about this is part of the uranium lead decay system. So uranium decays to lead, but [00:23:00] there's a bunch of intermediate steps along the way. Uranium actually decays to thorium, and then it decays, to a bunch of different elements. There's 13 steps along this path. It hits radon somewhere in there, um, then it ends up being lead, and then it, it, it is stable at lead. So there's this, what we call intermediate products between uranium - the parent and lead - the product. And over geologic time scales, over hundreds of thousands of years. Those are in equilibrium. Uranium has decayed to thorium, and that's decaying down and it's kind of an equilibrium process. Water [00:23:30] changes that. Water likes uranium - hates thorium. So anytime water precipitates something, there's uranium in there and no thorium. So we can go and measure the buildup of thorium and the sort of disequilibrium between the two. That's kind of a clock or that is a clock.

Chris Bolhuis: Oh, I get it. Hold on. So the way I interpret what you just said is that any thorium then that's present is straight up because of the decay of uranium.

Dr. Jesse Reimink: That's right. But then we also have to factor in the fact that the thorium is also decaying away as [00:24:00] well. It doesn't build up infinitely, right? It's

like having a sand dial pouring into another sand dial of a different size like, there is some equilibrium between that. But when you just start the system, you can measure how long it takes to reach equilibrium. So uh, it's a good clock for short time scales. It's really hard to make the measurement. People do it really well and really reliably, but it is one of the more difficult measurements to make. But it's a really cool process for this sort of younger stuff. Thousands to tens of thousands of years old stuff.

Chris Bolhuis: Very cool. Very cool. [00:24:30] I did not know that actually. And so I learned just with everybody else right there. Thanks, Jesse. That was awesome.

Dr. Jesse Reimink: Well, thanks. Uh, th this was your, uh, you know, one trip into the weeds.

Chris Bolhuis: Yeah,

Dr. Jesse Reimink: uh, per chapter.

Chris Bolhuis: I threw a lob on that one, I'm gonna tell you right now. So, another interesting aspect that I wanna touch on here with Mammoth as we wrap this up is that more than any other feature that I consistently see in Yellowstone National Park, which is a lot - is change. Mammoth hot springs change all the time. Pools [00:25:00] will flow. Then they won't flow. And then they'll turn back on. Or they'll turn back on somewhere else. And that is something that you can count on when you visit Mammoth, is they will not look the same as the last time you were there, even if it was a week ago. I mean, these things change on that kind of time scale, and I want to talk about why.

Dr. Jesse Reimink: Let me, before you do that, let's just talk. The colors are spectacular. Just wanna point. Two image number six, which shows the colors really well. And these colors change as well. The color variations are changing. And I just [00:25:30] wanna draw our attention to three millimeters per day. Uh, that's a fast rate, so no wonder they're changing week to week. Right? Really cool. All right. Why the change? Why are things shutting off, turning on all the time here?

Chris Bolhuis: A lot of people I think, look at this and say, well, that's because maybe what the water's flowing through is getting clogged with precipitated minerals. But

that's actually not what's going on. Because if you think about this, again, back to what we already talked about. The water at depth is acidic, and so it's actually [00:26:00] dissolving the limestone, not precipitating limestone in its cracks. So what's going on is it's kind of like, uh, the weight of the terraces. This rapid deposition and the mass that's accumulated there causes it to sink and collapse and pinch cracks off at depth. So instead of precipitation, the cracks are just getting squished. And it forms then - it has to find new paths to the surface and so a pool will shut off and then a new pool [00:26:30] opens up. And it just keeps doing this back and forth, back and forth thing. And so that's something that you can absolutely count on with Mammoth is change. They will not look the same.

Dr. Jesse Reimink: And another thing that you can absolutely count on, and I think you should definitely spend some time just kind of watching, is the terrace formation. These are really cool to just sit and like watch for five, 10 minutes and just ponder, like watch a pool or a terrace. Each terrace is a broad flat pool, roundabout, a foot deep, and image number seven in our stack here [00:27:00] shows this terrace feature. And so it's a broad flat pool, maybe around a foot deep with a rim on the edge, and then this lip that kind of impounds it. And the lip is actually quite a cool feature. So the reason that there's this lip, and the reason that all of these terraces have broadly this same structure is because as the water kind of spills over the edge of the, the terrace over the lip here, the agitation in the water releases CO2. It's like shaking up a can of pop or shaking up your carbonated water and then opening it. It releases [00:27:30] CO2, which as we talked about changes, the chemistry of the water and forces this precipitation. It also cools it down like the water is getting colder more quickly as it goes over the lip there as well. So the combination of those things that you described so well, Chris, means that you get more rapid travertine buildup. Along the edges of the thing, which builds up these nice little lips. And then, as you said, they're always changing, so the weight of them will kind of collapse on themselves. The water will break through the edge, et cetera, et cetera. So, in image number seven just really shows that. And if you're going to Mammoth, spend some [00:28:00] time just watching that process for a little bit. It's really cool.

Chris Bolhuis: Well, Jesse, that is pretty much a wrap of everything we wanted to cover. I think it's time to do one frequently asked question that surrounds Mammoth. You ready? Okay. Well, this one is about how much water is coming out of Mammoth. Now, again, we talked about how it changes a lot, but the amount of water coming out of Mammoth doesn't, it's just where the water comes out. That's what changes.

Dr. Jesse Reimink: Yeah. [00:28:30] Right. Oh, I see what you mean. So you mean it comes out at the same rate, but at different points in the system? That Okay, gotcha. Yeah, for sure. So it's kind of, I don't know, I, I thought this was maybe less than I thought it was gonna be. You look at this thing and you think there's a lot of water cascading, it's 590 liters per second. So that's 155 gallons per second. And so that converts to 9,300 gallons per minute, which is a [00:29:00] lot like, there's no doubt that's a lot of water, but you kinda look at Mammoth. I don't know, Chris, do you feel this way? Like you, you look, you look at it and you feel like this is so much water coming out of this thing, but I don't know. That number feels a little smaller than I would've guessed it at, I suppose.

Chris Bolhuis: But let me interrupt a second, because, you know, you talked about these lips on the edge of the terraces, right? Those lips impound the pools behind it. They create these pools, but those pools are rarely deeper than a foot.

Dr. Jesse Reimink: Yeah, that's a good point. That's a really good point cuz the tear, you look at [00:29:30] this thing and it looks monstrous. Right? And you're right, they're not that deep. The other thing is that, Of that amount of water, that 590 liters per second we just talked about, 10% of it comes out of the terraces. There's another 90% that flows into the Gardner River. So there's a lot of water kind of coming out of this broader system that you don't necessarily obviously see, uh, when you're standing there looking at it.

Chris Bolhuis: That water coming out into the Gardner River is what we alluded to before with the Boiling River, where in years past anyway, people have been able to soak in that, you know, because as we [00:30:00] said, the water is not exceedingly hot, and it is certainly not acidic. So it's somewhat safe to soak in. It's rather disgusting, to be honest with you. It's like a cesspool, but I think in my older age, I'll pass on that, but, OK.

Dr. Jesse Reimink: Yeah,

Chris Bolhuis: So anyway,

Dr. Jesse Reimink: Well, despite the cesspool, go to Mammoth, ponder it. It is one of the more unique places in Yellowstone and you know, it is in the first ballot Hall of Fame features of Yellowstone in my category. Gotta go check it out. It's amazing. [00:30:30] So,

Chris Bolhuis: Yep. It's a must see.

Dr. Jesse Reimink: Hey, I think that's a wrap, Chris.

Chris Bolhuis: Cheers.

Dr. Jesse Reimink: Peace.