Arches National Park

Jesse Reimink: Welcome to planet geo the podcast where we talk about our amazing planet, how it works and why it matters to you.

How's your technology over there today, Chris?

Chris Bolhuis: I am. I'm good, actually. My bonus son, uh, has me set up now. I got a new desk. I've got, uh, two huge monitors in front of me.

Jesse Reimink: Look at you, it consultant, you know, it's a useful skill set. Nice.

Chris Bolhuis: Got it going on. That's

Jesse Reimink: can see why you're bringing him into the bohi family fold. That's a good, uh, good on you, man. Good

Chris Bolhuis: Hold on a. let's be real clear. I have no choice in this matter.

Jesse Reimink: that's true. Yeah, that's true. That's true. Hey, did he ask just out of curiosity, did he ask you before he proposed to Bella or

Chris Bolhuis: he did. He did. Yeah. He asked. Yep. And then he, he knew, I don't know if I told you this. He knew that, or I knew that he was gonna propose at the base of the middle Teton When he did it, then he started to walk away to this rock. That was awesome. just this awesome toothpaste, metamorphic rock and, uh, that's where he wanted to do it. And so he started walking that way. So idiot dad gets his phone out and starts walking around. So Annabelle is looking at me thinking, what the hell is he doing? oh, I, I know what's going on, you know, because I'm an idiot and I gave it away. So

Jesse Reimink: it away. I mean, it wouldn't be unreasonable. for her to think. Oh, dad's just being weird. Looking at rocks, taking videos of rocks again, you know, like dad,

stop being weird out there. You're embarrassing me.

Chris Bolhuis: she's used to that. She doesn't get embarrassed by that stuff anymore.

Jesse Reimink: Oh, she's immune. Okay. That's good.

Chris Bolhuis: she is. Yeah.

Jesse Reimink: Well, how you doing?

Chris Bolhuis: I'm doing great. How are.

Jesse Reimink: Yeah, I'm doing good, man. Before we get started, we should just make a little announcement that we will be at the geological society of America meeting you and I together again in person, very excited for that. But that's in Denver. I think it's early October. So if any of you listening are. Going to GSA, uh, and Denver presenting there, grad students, faculty, undergrads, whatever. Let us know. I don't know. Look us up. Send us an email beforehand. Uh, we can meet up. I think Chris, you've gotta talk. Is that right? You're gonna be talking about planet geo. I believe so.

Chris Bolhuis: I, I do have a talk. I'm not sure exactly what that talk is gonna look like at this point, but yeah, I have a talk

Jesse Reimink: It'll be fun. It'll be great. So, anyway, look us up there.

Chris Bolhuis: Anyway. Welcome to planet geo. We are your host. I'm Chris Heiss and I'm looking across at my little young Sage over there. Dr. Jesse Reimink and. We're gonna be talking all about arches national park, which I think is really appropriate at this point, because we did red river Gorge just a few weeks ago. We talked about natural arches and bridges, and we alluded a little bit in that episode to arches national park and how the arches are formed a little bit differently. So we're gonna get into all of that today. And I can't wait, Jesse, have you been.

Jesse Reimink: I have, yes, we, so let me think through this. I don't believe that the summer science trip that you led went to arches when I was a student. Is that correct?

Chris Bolhuis: Correct. And we don't, I I've never taken students there.

Jesse Reimink: I have been there cuz actually my dad led the summer science trip for five or six years when I was a kid. My dad was a high school biology teacher in the school that you now teach at in the high school I went to and he led that trip when I was growing up. So I have been there maybe two or three times as a kid. And it's so cool.

Chris Bolhuis: Wait a minute. He took students there

Jesse Reimink: Yeah, I ha I have this distinct memory of, I can't remember the river in there, but we were, there was a cliff jump off the river that was like so scary. I was a little kid, it was like terribly terrifying. I'm sure it was

Chris Bolhuis: well, you are afraid of a lot of

Jesse Reimink: yeah. Yeah. I, I am a little bit of a was sometimes, but I remember this in arches and it's just so beautiful there. Yeah, it have, I I've been there. So have you been there, Chris? I'm assuming you.

Chris Bolhuis: I have been there. Uh, I went there with my family a while back and I cannot look like how busy that was. I cannot imagine taking students there. it seems like a logistical

Jesse Reimink: Yeah, well, I think this was a while back, you know, this would've been like the early 20 odds. And so this was, it was maybe a little bit calmer there, it's a very good thing. And in some ways it's a little bit of a bad thing, but the national parks have blown up recently, especially during COVID and you know, that's, that's good and bad, but mostly good. I would say so arches national park. I think Chris, we should start out by reiterating what an arch is. Cuz we talked about this a little bit in the red river Gorge episode. So you can go back to that and listen to it. But I don't know, Chris, what's the lead in here? What's the pitch. What is an arch? I think people kind of know it, but let's define.

Chris Bolhuis: Okay. There are 2000 cataloged arches in arches, national park. And the definition that, that. It's a lot. It's a lot, the definition that they have put out there is a little weird. Um, it has to be three feet long, in order to be classified as an arch. Which seems like what a, what an arbitrary number to, put at it. and it can be three feet in any dimension, but as long as it there's a three foot wide or high three feet diameter, arch, whatever. it's classified as an arch.

Jesse Reimink: It is such a weird definition. I mean, totally arbitrary. Right, Chris? I mean this is the way it works, I guess, you know, in order to be an arch, it has to be three feet in some dimension, like a continuous span right across it. You can't have, you know, two and a half feet or you can't have it broken in the middle, but it could be one inch high in three feet wide. And it's an arch. That's kind of what we're looking at.

Chris Bolhuis: The longest arch in arches, national park is 306 feet long, which is a huge arch, but the longest one in the world known anyway is in China. And that's about 400 feet wide.

Jesse Reimink: And to give some perspective, it's hard to picture the scale of this. You just kind of have to Google an image and Google an image and find one that. people in it or something to scale, because that is a massive amount of rock held really high. And the arches here are just beautiful. And what we're talking about is arches national park, which is a relatively small national park by land area in, Eastern Utah. And it's just really, really beautiful. And we're gonna talk about the regional geology of this area a little bit more as we go.

Chris Bolhuis: it is. But we never really defined arches and bridges. It's like, it's a bit squishy. The definition here.

Jesse Reimink: Yeah,

Chris Bolhuis: They,

Jesse Reimink: word for it.

Chris Bolhuis: they get mingled all the time. I guess the best way to define this is that arches do not involve running water, whereas bridges can and do in terms of the way that they formed. They look the same, but in terms of the formation, I guess, I don't know. Do you have a better way to, to define the difference between an arch and a bridge?

Jesse Reimink: No. I mean, we've talked about this before. You're a lumper. You used to lump watermelons, right?

Chris Bolhuis: That's true.

Jesse Reimink: I, I fall into the lumber category too. I, uh, I just don't really care what we call it. An Archer bridge. I just can't get up for either discussion, but there are various definitions. Some people will get. A little bit more nuanced in particular about whether things are an arch or a bridge, but I think it's fairly safe to say in arches national park, they're mostly arches because there's not a lot of running water around, out there. So they're mostly strictly defined arches. So Chris. Should we move into the regional geology. We're gonna kind of cover the regional geology. Then we're gonna talk about how these particular arches form and they're different than the red river Gorge, which we talked about a few weeks ago or even a couple months ago. And then we're gonna talk just a little bit about the particulars of arches national park and some features that you find in deserts more generally, so that if you're walking around arches national park, like go there. It's amazing. If you got an RV, if you got a camper, if you got a tent it's awesome, or there's lodges, you can stay in Airbnbs. That mean it's awesome place. Go there. And you can see all of these features everywhere. It's one of those parks that I'm gonna use a crystal heist ism here. It smacks you in the face, man. It smacks you in the

Chris Bolhuis: It does. It does. It's spectacular. I love arches national park, plain and simple.

Jesse Reimink: Chris. The regional geology. This is kind of the, high level general overview. There's so many details in these rocks that we're not gonna cover. We just don't have time to, but the regional geology, it really starts in the Colorado plateau.

Chris Bolhuis: That's right. The Colorado plateau is this huge uplifted area that's kind of centered on. What's called the four corners. And the four corners is where New Mexico, Northeast, Arizona, Utah, and Southwest Colorado, all kind of meet. you know, you can go there and get a picture taken with your feet. Right at that four corners area, that's where the TTA plateau is kind of center. So huge uplifted area.

Jesse Reimink: And we've talked a lot about things around the Colorado plateau before. For instance, the grand canyon is kind of on the Southwest side of the Colorado plateau. And there's a lot of features in there that are, are really important. It's a really important geological province for the Western United States, really, but the discussion today is centered kind of at near the center of the Colorado plateau, what's called the paradox basin. , this is a basin in the geological sense, meaning that there are sedimentary rocks that were formed in an ancient basin. So , the rocks themselves were formed a long time ago in a basin where sediment was being deposited.

Chris Bolhuis: Question for you? Why is it called the paradox basin? What's the paradox? Do you know? I, I don't know this. I don't know where the derivative of, of this basin is.

Jesse Reimink: That's a great question. Uh, I read this late at night, several nights ago while we were preparing for this episode, I can't remember exactly what it is, but it's something to do with the rivers kind of wander aimlessly. And I don't know if it's the modern rivers or like the paleo rivers, the rivers that are recorded in the rocks, but there's something to do with the random drainage network in the basin that made it a paradox. So I can't remember though. It's a good question.

Chris Bolhuis: Interesting. Anyway, the paradox basin is the reason why arches is where it is , so this is really an important thing. The basin itself was caused by the collision of two super continents. And those super continents are called Gondwana. And Laurasia, we talked a little bit about. Earlier in our episodes. Where was that? Jesse? Where did we talk about the super continents? A little bit with red river, I think. And I think with, um, also the smokey mountains that we alluded to these super continents, then,

Jesse Reimink: Absolutely. Yep.

Chris Bolhuis: So anyway, when these super continents Gowan and Laia collided, they created this basin, this kind of trough, and this trough was surrounded by mountains all around, but mainly the one that we're concerned with are the mountains that we're to the east of this basin, when these two continents collided, they form this trough. So this trough, imagine this, kind of rumpled carpeting, ? go to one end of a room where the carpeting is all torn up and just kind of push it. And it forms these kind of like folds in the carpeting. That's what the paradox basin looked like. It was in this trough, surrounded by mountains, all around it

Jesse Reimink: That's a great analogy, Chris, I might steal that one from you because I, here, I want your insight being the, the Sage educator, cuz the analogy I always use for this kind of thing in class is I like, okay. Super continents. That's kind of cool. I also really like, I mean I used to read these Janes battleship books growing up when I was a kid, like I love like battleships old battleships and stuff. So

Chris Bolhuis: I did not know that about you.

Jesse Reimink: I know weird. Right? Uh, major deviation here, but I, I love world war II, Naval history. So like Pearl Harbor, I was there this summer. I was in heaven. It was amazing. Anyway, I think of like two super battleships or Supercars. And if you collide like two. Big ships. If you imagine, like the flight decks of an aircraft carrier and you run two of them into each other, the front end's gonna be completely smashed, but the back end will kind of get rumpled, right? This sort of rumpling pattern. That's kind of what you're referring to here. The same kind of process. we're not in the, collision zone, but we're near enough to it that the crust is rumbling because of the collision. Is that an accurate assessment?

Chris Bolhuis: absolutely. So I always use this in class, the rumpled carpeting, or I don't know if my kids know what I'm talking about, actually, when I think about now saying this, but in accordion,

Jesse Reimink: Oh, okay. Yep.

Chris Bolhuis: you know, it's, it's kind of, kind of ripples where you have the, up and the down and the up and the down and the up and the down. And that's what this looked like. But in the paradox basin, , a shallow sea invaded the area. Okay. And, Jesse, I mean, we know this, what, like, what do you tell your students what happens in any basin for that matter? What happens in any basin?

Jesse Reimink: Well, all the water's gonna run into the center of the basin, which means you're bringing sediment, you're bringing dissolved ions, you're bringing material to the center of that basin. And then that water's going to either. Evaporate or it's gonna be connected to the ocean, but rocks are going to be deposited basically, almost as soon as you're below sea level in general, you're going to be kind of depositing rocks. So we start to get sediments deposited and this is

Chris Bolhuis: Hold on. I just want to go back and, and reiterate that that any basin has deposition in it, especially when it's surrounded by mountains. And that's what we have going on here. Collision of two super continents creates this trough, surrounded by mountains deposition. Now in this trough, a shallow sea invades, but this was. A little different from the standpoint of it was kind of a restricted basin. And so it was super warm. It got very, very salty. And what happens when the water gets super, super, super salty?

Jesse Reimink: Oh, man. I mean, we talked about this several times, including, lithium talking about lithium just recently, but when you have water that's eroding and is very salty, it flows into a basin. It just evaporates. It's got nowhere to go. It's called a restricted basin, like you just said, and it just deposits salt. And this is really the key here. This is one of the main keys to why arches are in where arches national park now is, is that salt. So the salts deposited, we also have some other really important sedimentary layers on top of this.

Chris Bolhuis: we do, but it's important to emphasize how thick these salt deposits were. I mean, this is. This is impressive. We're talking about over a thousand feet of salts and I think we need to do a better job of what does a salt mean? We're not just talking about rock salt, particularly like the mineral Haylight. I mean, that certainly was involved in this, but we're talking about potassium salts to like potassium chloride. So we have sodium chloride, potassium, chloride. We have gyps. That's being deposited, which is also assault. And then on Top of that. what happens?

Jesse Reimink: Oh, on top of that. We get these really amazing rocks that you can kind of find all over the Western United States. We talked about this in the grand canyon, too. We. Big huge packages of sandstone. And there's a few important ones here, the Navajo, the caramel or caramel, depending on how you pronounce that and the Entrada sandstones. And these are the important ones that we're gonna talk about here. And there's slight differences, which we'll come to, uh, briefly here, but big thick sandstone layers, the Navajo sandstone. Basically you envision a massive desert with Windlow sand. It's called an erg ERG. Like the rowing machines are sometimes called RGS. This is called an erg but wind blown sand is depositing this big sandstone layer. So a desert-like environment.

Chris Bolhuis: I find that term to be hilarious because in, in Erg, this sea of sand, erg, is also a unit of energy measurement. Okay. And I use this in astronomy and I is about the same amount of energy as a fly, doing a pushup. That's an, I. When I, when I read I'm reading this, I'm like RG fly, push up.

Jesse Reimink: Oh, that's great. That that's an awesome one. I like that. Okay. A fly doing a pushup or a rowing machine or a massive desert of Windlow sand. There you go. I mean, you know, you're gonna be so popular at dinner parties. If you just have those three definitions for rG, like, I mean, bust this out at the next party, and everybody's gonna be following you round for the rest of the night, seeking you for information.

Chris Bolhuis: everybody follows me around. Anyway, what do you like, come on, you know

that.

Come on. All. All right. Let's

get back to

it. Okay. Salt. Okay. Salt. That's what we have in this shallow restricted sea in the paradox basin. Is this salty water as water evaporates. The water gets saltier and saltier and saltier. When it gets saturated with those salts, it can't like, hold it in solution anymore. As evaporation continues, now it begins to deposit or lay down these salts, just like a beaker that you fill with salty water, and then you just set it on your counter and you let it sit when all the water's evaporated, you're gonna have a crust on the bottom of that beaker of just salt. That's what we have going on here in the paradox basin. there isn't much room for fresh water to come in and to kind of dilute it where you would get then deposition of other rocks like Shas and sandstones. Not yet. All we primarily have been deposited here are just these various salts from this super salty, shallow basin.

Jesse Reimink: And these sandstones now the Navajo, the caramel and the Entrada sandstones are sitting on top of the salt, which is going to. Important in our next phase, when we're talking about how arches formed, but we have to finish up the differences here. The Navajo is this ER, environment, ERG, , desert Windlow, sand, the caramel and, and Trada sandstones are also Windlow sand, but we also have stream deposits in there too. So they're kind of more like a braided stream environment with lots of sand deposited and we get these beautiful cross beds in here. Where we have these stacking of kind of dune or stream environments. You can see these in the grand canyon. You can see these in arches, these beautiful, big cross beds that are stacked into rocks.

Chris Bolhuis: And I just wanna point out too that in terms, just so you can see it. You have , these salt beds, and then you have deposition on top of that, like many thousands of feet of deposition on top of it, higher up closer to the surface. You have the Navajo sandstone, the caramel sandstone, and then the Entrada on top of that. So just in terms of ages that we're referring to here, The salts in the paradox basin are the oldest, and then you have a bunch of other rocks on top of that, but then we're, kind of skipping ahead. And you alluded to this at the beginning of the episode, we're keeping it general here. So we're not bogging you down with all kinds of different formations. There are other formations in between, but then you have the Navajo. And then younger yet is the caramel and then younger yet is the Entrada. And the Entrada is the one where the vast majority of all the arches in arches national park are preserved. So that's why we're honing in on those layers.

Jesse Reimink: right, Chris, we're gonna talk about why that's with the really important one. It's a really cool story there, but I just wanna make a comment here about this, and this is common amongst all of our national bark episodes and the ones we've talked about, a geological story. We always kind of paint this picture, right? Chris, we tell the story and then we say, and this happened, therefore the rocks are there. Especially like regions where the Colorado plateau, where there's a lot of uplift and sea level change. And those two things are going on. The rocks change in composition. Like we're talking about, we move from salt to sandstones and different types of sandstones. I always kind of get a little bit confused in these sequences and we paint this really nice, clear story, and we say then the Rock's formed, but actually that's not the way this story is figured out. We're not just like, given this story as scientists, the story is actually made from geologists, looking at those rocks. So geologists work through the Navajo sandstone, the Entrada sandstone, the salt that's in there and they say, oh, this is what happened. The salt is there. So therefore this was a restricted basin back in time. And there's this big package of sediments here in the center. It's a thinner sequence of sediments over there. And on the opposite side, if I turn to the left, it's thinner over there as well. So I'm standing in the center of an ancient basin. is how geologists use the rocks to paint a picture of the ancient earth or a planet that does not exist anymore. Really in Marty Gilmore used that phrase. That's a great phrase. I'm stealing it from her though, but go,

Chris Bolhuis: That is, a really good point. My young Sage well done, but I want you to do one thing real quick. Just say what you wanna say here about this in a sentence, boil it down. What are you trying to say?

Jesse Reimink: Okay. I'm trying to say that the rocks tell the story, even though we're telling the story. And then pointing to the rocks, the rocks, tell us the story. And also it's complicated. The rocks are complicated. It's not always crystal clear exactly what the interpretations are. So if the story's a little bit squishy and unclear, it's because the rocks are a little bit squishy and unclear sometimes too. Right? Like we don't know everything. We're missing pieces of information and geology's just totally cool. So I went longer than you gave me the allotted time, but in summary

Chris Bolhuis: that's okay. No, that's all right. No, it's a really good point. I mean, in geology, we only get the last, we get to see the last page of a book. We get to see the end. All right. Here's what it looks like. Now we have to then use that last page to put in all the other chapters. From the beginning of the book to that last page, we have to interpret what happened. I think like that's what you're

Jesse Reimink: that's really well put that's exactly what I'm saying. So, you know, Chris, give me my 10 seconds back and I will say, oh, you know what? It's like, it's like the end of a book. We're leading the last page of a book and we have to infer everything before it well, put

Chris Bolhuis: being serious or, or, uh, you're ripping on

Jesse Reimink: I'm stealing that. I just, I just gave this lecture.

Chris Bolhuis: simplistic

Jesse Reimink: No, I just gave this lecture, uh, on Thursday to my big intro level, class of 200 students. And I gave my version of it, which was clearly not as intriguing as yours because they looked at me blankly. So maybe on Tuesday, I'll try your style. see

Chris Bolhuis: you know, this is the hard part of geology though is doing this. This is why it's so difficult for beginning geology students to look at this and then try to make sense of how did we get to this point? That is, it's a different way of looking at the. Most people don't do this. geologists are a little odd. We look at the world, we only ever get the last, you know, well, we're, more than a little odd, but we only get the last page and we have to then think about things differently. I love the way geologists think because it's it's difficult. it's not an easy way of looking at the world.

Jesse Reimink: No, it's it's super great though. Okay, Chris, let's get into how the arches formed and why they are, where they are.

Chris Bolhuis: Okay. Before we get into the arches, I want to talk a little bit about the transition from when we go from salt to the other rocks on top, something happened, geologically. The salt was this restricted basin. It got super salty, saturated, and began to lay down these various kinds of salts. Then conditions changed. , this restricted basin got connected to a larger sea, which allowed then this influx of fresher water. It was still salt water, but it wasn't salty enough to lay down salts. So it started to deposit other kinds of rocks from the Highlands around it, things like Shas and sandstones and limestones and things of this order. So it changed. From the bottom of the paradox basin to the top of it, in that it went from salty to fresher water. So the rocks changed and reflected that.

Jesse Reimink: Exactly and yeah, absolutely. And, and thank you for pointing that out because. Belabored the salt point, because it's so important, like salt is key. And the reason that salt is key to this story is that salt is not very dense compared to the rocks above it. It's light. You can think of it as light and the rocks are heavier. So if you take a salt layer, a really thick salt layer, a up to a thousand feet, and you bury it with really heavy rock on top, that salt is under a lot of pressure and it begins to migrate upward. Due to the massive pressure of the rocks on top of it. And this is really important for the hydrocarbon industry. They're always looking for salt, domes, what we call salt domes, where salt is moving up through the rocks, , that overly it, that are heavier than it because it's less dense.

Chris Bolhuis: That's right. I want to interrupt and say one thing though, that the reason why it migrates is salt behaves differently when it has a lot of pressure on it, salt becomes kind of toothpaste, like with that kind of pressure or think about a lump of silly putty. Let's say if you have like silly putty laying on the floor, a ball of it and you step on it, it's gonna behave in this kind of toothpaste way and it's gonna begin to flow. And that's what salt does when it gets a lot of this overburden on top of it, it becomes. Somewhat liquified in flows. And then when it finds these avenues leading to the surface, because it's, less dense than the rocks on top of it. It's gonna begin to migrate up to the surface, forming these domes that you were

Jesse Reimink: Exactly. And these domes, like I said, are really important for trapping hydrocarbons oil, natural gas reservoirs, actually Chris Jackson, who we interviewed in season one, who is an amazing, amazing geoscientist he focuses a lot on the salt domes and is an expert in sort of analyzing this. There's a lot of focus on understanding how salt moves through rocks, because it creates these little traps and seals for hydrocarbons to move around for fluids, to move throughout the sedimentary package layer. And this really brings us as well into the arches. So why is salt important for arches, Chris?

Chris Bolhuis: Well, when salt moves up through the denser rocks above it, it encountered these more brittle sandstones that we talked about before the Navajo, the caramel and the Entrada. It began to bulge them up, but sandstone that's close to the surface is quite brittle. And so as it bulged them up, it cracked those sandstones. And it's kind of like sometimes during the wintertime, I get dry skin on my hands, particularly I kind of look like a reptile. You it's really gross. And your knuckles get drier than everything else. Right? And so when you have this dry skin and you make a, tight fist, you stretch the skin and your skin splits over the knuckles So you get these like ridges and valleys where your skin splits. It's a gross analogy. I know, but I

Jesse Reimink: I mean, no, it's great. It's a great one. I mean, you are the analogy master today. I mean, it's unbelievable. That is a great one. It's perfect. It's these little like cracky fins you get in your knuckles. I mean, I totally know what you're talking about. Easy to visualize nicely done. Chris. Nicely done.

Chris Bolhuis: Can I do one more

Jesse Reimink: Yeah. Yeah. I mean, you're on a

Chris Bolhuis: if you, okay. All right. Alright.

Well, so this, the sandstone cracks into these parallel fin, like I'm saying fin F I N you know what it's like? It's like taking a book. And putting it with the binding edge down on a table. And so you have the pages standing vertical and you just kind of, quit holding it together and let the pages spread out a little bit. That's what these fins and valleys look like.

Jesse Reimink: Oh,

Chris Bolhuis: Does that, does that

Jesse Reimink: A absolutely. Yeah, you kind of get some space in there and this brings. Nicely into exactly why the arches are where they are. And so I'm gonna try and keep this as clear as possible, Chris, but so keep me on track here a little bit. Okay. But

Chris Bolhuis: do my best. I'll try it.

Jesse Reimink: Okay. I wanna just give the sequence of rocks again. Remember there's salt. That salt is doming, it's kind of moving up through these sandstones. It's cracking the sandstones, but let's remember the order here. We have Navajo at the bottom. We have caramel right on top of that. And then we have Entrada on top of that. And we said before that the Entrada sandstone is the one where all the arches are in that's the sedimentary layer, where the arches exist in. And the reason for that is because. The caramel is slightly different than the Entrada. The Entrada is basically all sand water can work its way really easily through the Entrada and these cracks give the water avenues to get deeper down as well. But water can't go as easily through the caramel or the caramel. So water percolates through the intra. And then it hits the caramel and the caramel has a bit more clay in that unit. It was a slightly different depositional environment. Chris, you talked about the sea, this ancient sea in the paradox basin. sea level was rising and falling. And we were changing the environment of deposition. So a slight change will put more clay into this Sandy environment. And so the Entrada is clean. Water goes through it very easily. The caramel, the caramel has clay in it. So water doesn't go through there as easily. So what happens while this water? Percolates through the Entrada and then hits the caramel and can't move. So it just sits there. And we've talked about how water is the universal solvent. It likes to dissolve stuff. And so what does it dissolve? It dissolves the cement that holds the sand grains together. The cement that makes a sand pile, a sandstone. if you have a loose pile of sand and you want to turn that into a sandstone, you need to cement those grains together. So the Navajo sandstone, the Entrada sandstone, those are cemented together, sand grains, and this water dissolves the cement that holds them together.

Chris Bolhuis: Not like, ah, I have another analogy.

Jesse Reimink: go, go for it. Yeah. back in my, uh, basketball playing days here, when somebody was on fire, the phrase was feed the dog, man, you gotta feed the dog. So you're on fire right. now. Chris, I'm gonna feed you. Go for it.

Chris Bolhuis: While you're talking about the process of lithification, you're talking about the process of converting sediment into rock loose sediment into rock. You need compaction and you need cementation. What's the cement. What's the glue. All right. Take a Dixie cup, little plastic cup, fill it with sand and squish it. Okay. If you take a pin and put little holes in the bottom of the cup, the sand stays in the cup, but not the holes. Aren't big enough to let the sand drain out. And then you take bottled water and you pour it through the sand filled Dixie cup and the water begins to drip out. Okay. And you take that cup and you let it sit on a window sill. Just let it sit, take another cup, do the same thing. Fill it. Poke little holes in the bottom of it. And now pour salty water through the Dixie cup. The water will drip out. You just let it sit in the window. So come back in a week, everything is dried up. You take cup number one, where I poured bottled water through you, tear the cup away. And what do you have in your hand? You have a lump full of. Okay, nothing. Right. You take cup number two, that you pour the salt water through and you tear the cup away. And the sand doesn't fall apart. It's bound together by the salt that's, what's holding, it's sticking all the grains of sand together in the poor space, the little air pockets, where the water was circulating through. That's, what happens to sandstones.

Jesse Reimink: So let me jump in there, Chris. That's a great analogy in what's going on here is a reverse of that process. You had your little Dixie cup, you put some salt water through it. You cemented those sand grains together. You turn it upside down, you dump it on the kitchen table and you pull the cup away and you have this cup shaped sand. Brick that's shaped like the Dixie cup. Right. But it's cemented together what we're doing here at the base of the Entrada on top of the caramel cuz water, can't go through the caramel. So water percolates down through the Entrada, it sits there, it ponds at the base of the caramel and what happens that water dissolves that salt. So we take that cemented cup shaped block of sand. We put it on a plate and we put more water in there and we just let it sit and it dissolves it. Reolves the salt. We put this really clean water. It's very reactive. It dissolves that salt. And then the sand just kind of is loose. It's not in a cement. It's sand now it's not a sandstone. And that is key because now. The arch. You remember these big fins that you talked about, the salt domed up created these big fins. Now wind and water can get in there and can hit the base of the Entrada, which is much, much weaker because all of the cement has been dissolved. That's where the arches are forming. And so. There's a great picture. There's a great drive in arches national park, where you could look and you see this singular unit on the horizon. It's one big sandstone block, and there's a whole bunch of arches, right at the base of that. That is the base of the Entrada sandstone. And the Carmel is just beneath it and all the arches form at the base of the Entrada, because that's where the water sat. That's where it dissolved the cement, which made it weaker, which made it easier for wind and water to create the arch.

Chris Bolhuis: That was a great explanation, actually, Jesse. Well done.

Jesse Reimink: Thank you. Well, that was a team effort. I

Chris Bolhuis: good.

Um,

Jesse Reimink: would say that was a team effort. You're still on fire. I'm gonna keep feeding you the ball, man. I'm gonna keep feeding it to you the whole rest of this episode. so I think we just wanna, I just wanna wrap this part up and then we're gonna finish up with some desert features that you can see in arches, national park, as well as other deserts. But I just wanna point out that the arches are actually formed. By wind and water action beating down these sandstones. And they're just beating down the weak areas at the base of the Entrada faster. And so that's why arches are there, but arches are not a permanent feature and there's a really famous one. The wall rock arch that collapsed in 2008. And so if you go to arches national park, I think actually nowhere, there might be one you can walk on, but basically you can't walk on any of these because they're really, really fragile things actually. And they're not permanent features. They're ephemeral like weathering and erosion is still going on in arches and it's still breaking down these things and arches will collapse and then you'll just have a column of rock. And then new arches are also being created as well. So this is a very active environment on the human time scale.

Chris Bolhuis: This arch, that collapsed wall rock in 2008 happened during the summertime. So it's during the busy season and it was heard by people that were camping in devil's garden, campground in the middle of the night, just this mass. They didn't know what it was, it's it startled a bunch of people. , and then of course, the next morning people went and looked at what happened and the center of the arch was gone.

Jesse Reimink: Oh man. Yeah, it just collapsed underneath it. Yeah, it would be

Chris Bolhuis: is amazing. It really is.

Jesse Reimink: really powerful stuff. Um, alright, Chris, let's just wrap up here real quickly with

Chris Bolhuis: Okay.

Jesse Reimink: other desert features.

Chris Bolhuis: Okay, Jesse, we're gonna talk about desert varnish and another feature, less commonly known feature called Toon.

So let's start with desert Jesse. What's going on.

Jesse Reimink: Yeah, it's a really cool process. It, creates beautiful features that you can see on the surfaces of rocks. It's a surface feature and what it is is these black, red, and white streaks and all shades in between there that. Occur on the rocks. And you could see this as coatings on rocks on the ground as well. So if you, you see some rocks that are kind of Blackish on the ground, turn 'em over and you'll see that's a very different color on the underside that's desert varnish. And what's going on here is it's basically clay minerals. Oxides hydroxides they're weathering minerals that are formed from Dustin rock, covering the surface of these rocks over a long time period. So in the desert, the little water that you do get, sits there. It creates these clay minerals, then evaporates pretty quickly.

Chris Bolhuis: This is a kind of weathering called chemical weathering. it's, now this is not a mechanical weathering process and it is so common in the Western United States. I saw tons of this in the Tetons, in the Rocky mountains. It doesn't have to be just this really, really dry arid climate. This is a common feature in the Western United States period.

Jesse Reimink: Yeah. And it's really nice because there's none of that GD biology all over the place. I mean, I was just up in the Arctic and there's lichen everywhere. Lichen is always covering the rocks. If it's not some shrub it's lichen. And going down to the Southwestern us is beautiful because there's no biology on top of it. You could just see the rocks, but basically this stuff is forming there because there's no biology. So most of these minerals are rich in iron and manganese and manganese. Rich regions are typically black where the iron rich ones are as we've talked about before reddish, right. They mostly make red. If you have iron, you're getting a red color. Most of the.

Chris Bolhuis: And you can also see this quite easily because You can see the direction the water's streaking down the rock. It looks kind of like, um, somebody that wears a lot of makeup goes out for a run sweat and the makeup kind of streaks down the face. That's what desert varnish looks like to me.

Jesse Reimink: Chris, you went with makeup. That's the funny one. I would've gone to like sunscreen or something like that, but makeup's a good analogy. Okay. I

Chris Bolhuis: Well,

Jesse Reimink: one. That that's funny.

Chris Bolhuis: sunscreen, isn't really colorful, like, you

Jesse Reimink: It's true. Yeah.

Chris Bolhuis: and stuff, just running down and you

Jesse Reimink: I, I I

Chris Bolhuis: yeah. I don't know.

Jesse Reimink: the ball from you a little bit from now on, I don't know if your hot streak's still

continuing

here, but it. It's a pretty good one. It's a pretty good one. All you can keep it. All right. Alright. You convinced me. So let's wrap up desert varnish by just saying that some of these things, especially the manganese varnish can take a thousand years to actually make. So, that means that this stuff has been going on for a thousand years, but also don't damage it. Like don't scrape it. Don't carve over it. This is a beautiful feature that takes a long time to form. So, you know, if you go to arches, don't scrape the rock, don't try and carve your name into it. That stuff drives me crazy. Um, just just leave it as, as natural. So chris, the next one T what do we got? What's

Chris Bolhuis: Teon

this is a lot lesser known and not nearly as common, but it is kind of common in arches. I, I think of Teon as these mini arches, these kind of mini caves or a honeycomb. Kind of weathering or Swiss cheese rock. That's what Teon kind of looks like to me. so this is found in our rocks, the rocks that are super important in terms of the arches themselves. So it's found in the Navajo sandstone it's found in the Entrada. Why would that be what's going on? Why are they in those rocks?

Jesse Reimink: it's the exact same reason why the arches are there. It's the exact same process, just on a smaller scale. And you can see this on. walls near the arches, you can kind of see these mini honeycomb thing, mini arches, mini caves, honeycomb weather, and you can see it on the rocks themselves. You can also see it on rocks that laying on the ground too. It's all over the place. If you just keep your eye open and look carefully for it. And it's the exact same process cement in one area is getting a little bit more weathered because for whatever reason, water is ponding there. And this is a positive feedback loop phenomenon. So if you have one region. A little bit more water ponds. It's gonna dissolve the cement there more because there's more water there. Then the next time water comes in the next batch of rainfall that brings water in more. Water's gonna pond there and it's gonna dissolve quicker because there's less cement there. So it's more porous, more. Water's gonna go in there. It's going to dissolve the cement faster. And so. You can see how a little bit of dissolution makes more dissolution the next time and more and more and more until there's none left. And so those little honeycomb weathering, there's sort of an immature arch, right? It's going to be an arch someday because it's making the rock weaker. It just hasn't yet. So you can kind of think of those as future arches in a way.

Chris Bolhuis: This cementing agent for a lot of these sandstones, the Navajo and the Entrada is a calcium carbonate, which is a Cal site cement, which is very soluble. So it dissolves much easier than other kinds of cement and that kind of aids in the process of making

Jesse Reimink: that's kind of a wrap on this episode, you know, we talked about the regional geology, the paradox basin in the center of that, the value and the importance of salt for forming these fins and as it migrates up and then how the Navajo caramel and Entrada sandstones are the ones there and why we have. All the arches are in the Entrada sandstone because of water, precipitating and percolating through that unit. So, ah, man, this is a great place, Chris go there, go check it out. We're I don't know. Maybe we're end of the travel season. No, probably not. Southwest us. You can probably still make it in the fall or the winter. And if you can't do it this year, make a plan for 20, 23 to go there. It's an amazing place.

Chris Bolhuis: And canyon lands is right next to arches. It's very big, more remote, just as awesome. I love canyon lens. That is gonna be coming up next week in our geo short and yeah. Do both at the same time.

Jesse Reimink: yeah. And you could do so much down there. I mean, Utah is just like the playground state. There's so much good stuff there. It's awesome. All right. Hey, follow us on all the social medias. We are at planet geo cast. We have a new social media intern. Ingrid's gonna be joining us here soon and helping us out with that. Visit our website, planet geo cast.com. You can donate to us and help us keep, you know, keep running this thing and not burning as much money, uh, running this podcast. But most importantly, Chris, what do people do most important?

Chris Bolhuis: you need to share planet geo with somebody that cares about our planet.

Jesse Reimink: Or somebody that doesn't. And should you know that? I think we're, we're trying to convey that, you know, um, and send us a review. We've gotten a lot of good questions, a lot of great suggestions for future episodes. Keep those coming our way, leave us a review in a rating on your podcast platform that really helps the algorithm.

Chris Bolhuis: it does.

Jesse Reimink: to see those

Chris Bolhuis: Yeah. Cheers.