So, You Think You Know Plate Tectonics? Part 3
Dr. Jesse Reimink: [00:00:00] Welcome to Planet Geo, the podcast where we talk about our amazing planet, how it works, and why it matters to you.
Chris Bolhuis: Are you ready, Jesse? [00:00:15] Reimink? Are you ready to do this now? You seem like you're down in the jib.
Dr. Jesse Reimink: I'm
Chris Bolhuis: pick it up a notch. Okay, here we go. Oh, I don't know about that.
Dr. Jesse Reimink: I am always ready, sir.
Chris Bolhuis: Oh, don't call me, sir. How you doing Dr. Reimink?
Dr. Jesse Reimink: Mr. Bolhuis. What's up man?
Chris Bolhuis: Oh, [00:00:30] yeah. It's been a long, long time since you've ever called me that
Dr. Jesse Reimink: I know it's been, I mean, we might be going on a decade since I've called you Mr. Bolhuis.
Chris Bolhuis: I bet you longer. I bet you longer. Yeah. As soon as you got out, you were like, oh, I can call 'em whatever I want[00:00:45]
Dr. Jesse Reimink: Oh yeah, that's right. It's Chris. It's, Hey, Baldy, all those things. Yeah.
Chris Bolhuis: right. Yeah. All those really original, digs on me. That's right.
Dr. Jesse Reimink: you've probably never heard that before, huh?
Chris Bolhuis: No, never, never been called Mr. Clean Stone Cold, [00:01:00] Baldy. Never, never got any of that stuff at all.
Dr. Jesse Reimink: no, no, no. I'm sure. I'm sure.
Chris Bolhuis: Yeah.
Dr. Jesse Reimink: Hey, today we are continuing on. It's been a while since we talked about our plate tectonic series. Last, I mean, we're going back a couple months now in season [00:01:15] two. Now we're in season three. We're just kind of launching season three here of P Planet Geo, which is really exciting. Uh, but we're revisiting some questions, some plate tectonic questions. Under the sort of moniker, Chris, that you came up with that is, [00:01:30] do you know plate tectonics or so do you know plate tectonics more accurately. What was the origin of this?
Chris Bolhuis: The origin. Just talking to students and they, as soon as I said, we're gonna get into plate tectonics, I got a really unusual reaction and they thought they, oh, [00:01:45] we know this. I, you know, we know everything there is to know about plate tectonics. And so I wrote a bunch of questions and then flipped them back to the students and said, all right, well what do you think about these? you know plate tectonics, do these kinds of questions then make sense? Are you [00:02:00] able to apply what you know about plate tectonics then to our. and the answer was a resounding no. They didn't, they didn't , they had
Dr. Jesse Reimink: they didn't do very well on the questions.
Chris Bolhuis: No, but, but which is totally okay, right? It's, [00:02:15] it's, uh, they had the rudimentary understanding of, the boundaries and, and the features that you get at the boundaries and maybe some of the actions that happen, and that's great, right? Well, we can then take that , and use it to make our world make more sense. Cuz plate tectonics is just this really broad, [00:02:30] overarching,
Dr. Jesse Reimink: Yeah, and I, I wanna interject this, Chris cuz you know, I was initially, as we've talked about, resistant to this idea, but you were right, you turned me around. This is really, really a great idea and it's actually, you know, when we were talking about designing our camp [00:02:45] geo conversational textbook that, uh, people can go to, there's the link in the show notes there. But when we were talking about the sort of structure, the layout of that, what order should we put things in? Where do we put plate tectonics in this, you know, we. Pretty high up. It's not the first thing, but it's near there cuz we kind of [00:03:00] have, you have to understand some of the basic terms before we talk about plate tectonics. But plate tectonics is inextricably linked to every other topic in geoscience, right? It controls how sediment evolves, so there's all these things that feed into plate tectonics. It is sort of [00:03:15] the fabric that ties our understanding of our planet together.
Chris Bolhuis: Yeah. Right. And you, you were talking about order. I think that in an intro geology, like course, one of the first things you have to do is minerals. Then you have to. Go right into rocks. The igneous metamorphic, I [00:03:30] sedimentary rocks. Once you're there, you have the foundation then to dive into plate tectonics. And that's why we kind of put it high up on that, priority list when we started doing this podcast.
Dr. Jesse Reimink: And so that's a great lead in into the last two episodes that we did in this. So you think, you know, plate [00:03:45] tectonics series, we talked about really igneous rocks, a variety of igneous rocks in the first episode, then some sedimentary and metamorphic rocks in the second episode. So if you want to kind of catch up in that theme, go back to those episodes or go to the Camp Geo link and, and learn about the basic minerals and rocks and then [00:04:00] plate tectonics. And then come back to this episode and kind of test your knowledge cuz that's what we're doing right now, Chris. And today we're gonna go into, Planetary tectonics, which is kind of where I exist in my research. So it's kind of near and dear to my heart here of like these [00:04:15] questions about how has plate tectonics evolved over earth history? How does it function or not function on other planets? Like there's some really deep-seated planetary science questions that are built into this that are near and dear to me. So, uh, I'm excited about this one.
Chris Bolhuis: Yeah. Two things that I wanna [00:04:30] mention here real quick before we jump in. One is, I, I bet you, I wonder, I'm gonna, I'm gonna ask you a question actually, Jesse, when you started your research in the Northwest Territories, did you ever consider that this is where your interest would go, the direction that you would go? I mean, [00:04:45] you were just doing research on super old rocks. At the point, you didn't really know why you were doing what you're doing. Is that right?
Dr. Jesse Reimink: No, I mean that, that's exactly right. When I started your masters, I think this is probably a a similar, similar for most people. When you start a masters, you don't really know like why you're [00:05:00] doing the things you're doing. You kind of trust your supervisor to sort of have the big picture questions in mind. I was excited to go fly around to float planes and go way up in the remote north and look at old rocks. I mean, that sounded cool to me, right? So you're right. I had really no idea. Of what the big picture [00:05:15] questions were and now that's the motivating factor. It's still fun to go fly around in float planes. Not as fun as it used to be, but the big motivator is like answering these questions about Earth. So great question.
Chris Bolhuis: right. You know, which I think is, is an important thing for us to come to [00:05:30] understand. Right. But you and I had some deep conversations about this very thing because it's important to you and, and it's always been important to you to do important things. , you know, like, and, and we had this discussion about, you know, you said Chris, what the [00:05:45] hell? Who, who cares when play tectonics began on this planet? And we, you know, we sat on my front porch and had a few beers and, and talked about this many times. and it's just really cool to see like the direction that it's taken you and, and now [00:06:00] you've fully vested in it and comfortable with the Yeah, you know what, we need to know this, this is important. Um, just kind of it, it's come full.
Dr. Jesse Reimink: It's an interesting, you know, space. I, I, I would say that I still, on a sort of very deeply personal level, [00:06:15] I still struggle with some of the relevance of this. Like, it, it is not the most immediately concerning to society of when plate tectonics started on Earth, for instance. Right. It's extremely interesting to me personally. I, I, I love the question. I like all the, [00:06:30] the, the sort of unknowns in the question that are built into the question, but it's still, you know, part. What motivates me in research is I also have to have something else that's more societally relevant, a research direction that is not just this question about when did plate tectonics start, [00:06:45] right? So it's always a balance. Like everything and, frankly, I sometimes still struggle with that. Uh, but, but having it be sort of one direction of a research portfolio is, is where I've landed to sort of make me happy and stay fulfilled in that. So [00:07:00] anyways, it, it's a really, really interesting, important question as far as understanding our earth and just a totally cool, like sort of like mind blowing thing to think, wait, we might not have had plate tectonics at some point in earth history. And, and how did that develop? Like it's [00:07:15] totally.
Chris Bolhuis: That's right. I think so too. And I think it's important, but we can talk about that later on, But before we begin with the questions, I want to just maybe. Mention that maybe it's a good idea when we ask the question to push pause and think about how you would answer it. [00:07:30] You know, we have a lot of different listeners with a lot of different backgrounds and we have gotten a ton of feedback from this email questions and responses to this kind of series that we're doing. So I'm curious about that. If you hear us ask the question, push, pause, [00:07:45] think about how you would answer it, and then resume listening of course, and see how we go about it. Not that
Dr. Jesse Reimink: Yeah, right, because cuz there's very few answers here that are exclusively right. You know, there's a lot of potential good answers here and some potential sort of less [00:08:00] good answers. But yeah, push pause and reach out to us. You can find us on all the social medias at Planet Geo Cast. You can send us an email, planet geo cast gmail.com or go to our website, planet geo cast.com. There you can kind of find out more information about us, listen to all the past episodes, [00:08:15] subscribe and, uh, support us as well. And also the last thing, if you. Kind of are struggling with some of the terms that we're covering here in this podcast or in this series. Our Camp Geo is, is sort of designed for that. So you can go there, you can listen to what it's, what we're calling conversational textbook. We [00:08:30] have images of the rocks, the minerals, the processes we're uploading really cool new schematics to that all the time. We're getting some really cool graphics made. Um, and so you can go to that. It's the first link in the show notes and there you can kind of. Bolster your background knowledge before diving into some of these pretty [00:08:45] complicated questions about plate tectonics, Chris. So with that, let's get started here with the first question that I think you wrote this one initially is, what would Earth look like if plate tectonics was not an active process? So what would the earth look like if plate tectonics [00:09:00] was not active? And this is a really cool question. So where did your mind go when you were writing this, and maybe what did some of your students say to this answer? I'd be curious.
Chris Bolhuis: um, I did not get a good reaction from them on this question. In other words, [00:09:15] they, they really, this is something that they hadn't even thought of, you know? And so that makes it difficult just from the onset. Like this was never on their radar. So that was a difficult one, but, we live on an amazing planet. I mean, it is just [00:09:30] exceedingly beautiful. And you know, that's one of the reasons why you and I are in geology, let's be honest, right? This gives us a, one of the best excuses on the planet to go and see cool geology, right? And we
Dr. Jesse Reimink: And on that note, we can go, we, we get to experience [00:09:45] those beautiful places in a whole new way cuz we get to look at the rocks and sort of understand what's going on. Even at a basic level, even with just a basic geology understanding, you get to appreciate beautiful areas in a completely different way than other people do anyway.
Chris Bolhuis: That's right. You can't think about words you don't know. Right? [00:10:00] And so the more you know about geology, the more you're able to like, think about the world that's around us. And that's really what you and I get excited about. So if we're gonna go to see really cool geology, almost always, not always, but almost. It [00:10:15] involves some sort of mountains, right? Mountains are almost always formed due to some sort of plate tectonic activity. And so if I'm gonna summarize it in a really [00:10:30] simplistic way, where does my mind go? Our planet is gorgeous because of plate tectonics. We have the mountains, we have these, you know, rivers and valleys and everything in between, largely because of plate [00:10:45] tectonic.
Dr. Jesse Reimink: so I guess the inverse of that would be that if, if, to answer the question directly, if there was no plate tectonics, the, the earth would not be beautiful in your kind of answer to this question or where your mind goes. Is that the idea?
Chris Bolhuis: yeah, I, I don't wanna [00:11:00] make any enemies here, but if you take a
Dr. Jesse Reimink: Mars people and Venus people cover your ears,
Chris Bolhuis: No, but like if you think of a place that is a long ways away from any kind of tectonic activity, , [00:11:15] um, and is relatively quite flat. And to me, geologically kind of boring. I think of places like Nebraska or you know, sometimes like Florida and Florida's got the weather and so on. I didn't mean to offend anybody like that, but, [00:11:30] um, they're not. To me the most geologically exciting areas, and it's because they are so far removed from any plate tectonics. They haven't been glaciated. Um, and so you just end up with just, I [00:11:45] don't know, bland, flat, topography. You know,
Dr. Jesse Reimink: Yeah. Yeah, that's right. , always phrase this Chris, as like, there's two forces, the forces that push things up, which is, uh, plate tectonics and the forces that knock things down, which is erosion on our planet. And [00:12:00] if you stopped plate tectonics, sort of, this is kind of the, a little bit, the way my mind goes when we discuss this question of removing plate tectonics from earth is that if you just stop, play tectonic, stop pushing things up, then the only process you have is pulling things down and you're [00:12:15] gonna knock things down. You're gonna erode everything to just at or right around C level. is sort of where erosion is trying to get the land surfaces to get it under the water or right near there. And so, you know, once that happens and you don't have anything built up anymore, we have a very different [00:12:30] planet and it will evolve in a very different manner, um, from that point forward as well too.
Chris Bolhuis: And then the only kind of tectonic activity or, or resembling tectonic activity that I can think of without the traditional mechanisms of tectonics would be, is [00:12:45] adjustment. Right. You know, if you take these mountains and you remove the, the mass. That's on them. Then, the mantle below is gonna respond by uplifting them at least until they've lost enough mass where you don't get asy anymore. And you get the same thing with [00:13:00] deposition, right? We have this going on with the Mississippi River, for instance. When it empties into the Gulf of Mexico, the weight of that sediment causes that delta to sink, and then that allows for more deposition, which causes it to sink and so on. So you get [00:13:15] this kind of issy, which can be episo. you can have earthquakes and seismicity associated with that, but it's not really plate tectonics. But I think like that's what we would be reduced to eventually.
Dr. Jesse Reimink: me just build on that, Chris. Cause that was, that's a great point and a great [00:13:30] description of this ISO adjustment kind of thing because I think it's important when we're talking about this plate tectonic process, especially in the context of other planets and other options, It's good to really think about what are the other options. So plate tectonics is, [00:13:45] the Earth's surface is broken up into discreet plates. So we have tectonic plates, they migrate around. We've got the North America plate, we've got the Pacific plate, the Wanda Fuka plates almost gone. You know, we have all these different tectonic plates that are interacting with each other. They're moving [00:14:00] horizontally. So most of the movement is horizontal in these plates. Now, if you remove that, if you say there is no plate tectonics, the question is, what else could there be? And really what we're talking about is what we call a stagnant lid. Planet is one sort of other [00:14:15] category of non plate tectonic planets, which Mars is one of them, the moon is one of them, and this is just, you have a single Lithospheric plate that covers the whole planet. And so what you're describing is this lithospheric or Lithos static [00:14:30] adjustment. It's basically all vertical motion and, and that's the only thing that's going on. There's very little like horizontal. Motion going on, and there could be a little bit, but not a ton. And so you get these sort of, um, these bulges maybe that are forming, but it's all kind of vertical up and [00:14:45] down movement, not horizontal, where plates are sinking down and diving down underneath of other plates that subduction zones. So I, I just want to kind of level set on sort of what the other alternatives are for a non plate tectonic planet Basical.
Chris Bolhuis: And you bring up [00:15:00] a good point. I mean, really the only thing that we can look to are the other planets that we are close enough for us to study kind of in detail. Right. And that leads us to the next question or a sub-question of this really is. [00:15:15] about Mars. Mars has all, all of our solar system's, largest volcanoes, the biggest one being Olympus Mons, and it is unbelievably hard to imagine. Huge. Right? . I mean, [00:15:30] so That's the biggest volcano in the solar system. And the question is, well, why does a planet that doesn't have plate tectonics, which we tend to think of as the mechanism for generating magma, right? Why does it then have these [00:15:45] absolutely enormous volcano? So push pause on that a second and think about it, right? Like if it doesn't have plate tectonics, we do, you'd think we have the biggest volcanoes, but actually the answer lies in that [00:16:00] because we have plate tectonics, our volcanoes never get to be that magnitude.
Dr. Jesse Reimink: I mean, it's a great question. This is in a really kind of fundamentally interesting one is why are they there, right? So I'm gonna start, maybe I could, Chris, take the first half of this answer and, and then you can, I think, [00:16:15] build on it. And I think I know where you might go with this, this question. so first of all, we have to think of why is there vulcanism, why is there melting going on in Mars, right? Like if it's a stagnant lid planet, it's got one lid, the lithosphere is all one piece [00:16:30] covering the whole planet, there's actually something really important that we have to consider. And that's heat. Heat has to get out. Heat is trying to escape this planet, right? And basically what we've done is we've taken a heat blanket, the lithosphere being a heat blanket, and we've just covered the whole planet in a single heat [00:16:45] blanket.
Chris Bolhuis: I want to interject something a second, Jesse, cause I want you to explain for everybody why there is this heat source. You said why it can't get out, but why is there a heat source there?
Dr. Jesse Reimink: Yeah, so there's sort of three ways, or there's three sources of heat in a [00:17:00] planet, in a planet like Mars at least. First is just a creary heat, so this is heat left over from when the planet formed. A lot of that gravitational energy of things colliding together is stored as heat in the planet and, and so it's hot inside of it. The second one is [00:17:15] radioactive decay, so there is uranium, thorium, and potassium in Mars in the interior of Mars. And as those elements decay. They release energy, which becomes heat, and so that heat has to escape as well or is trying to escape. And the third one is, um, we don't [00:17:30] quite have a great idea of the interior picture of Mars, but at least on earth, the crystallization of the core is releasing heat. So the liquid outer core, when crystals form, they release heat, latent heat of crystallization. They actually are pushing heat and there's heat coming out [00:17:45] of Earth's core into the mantle as the intercourse is crystallizing. So that probably is going on to some degree at Mars as well, or it did in the past, at least.
Chris Bolhuis: Maybe I can interject something with that. The, you know, \ the heat from crystallization. It's, it's like this, evaporation is a cooling process, right? [00:18:00] So when liquid molecules evaporate. The result is that it's a cooling process, and we feel this when we, you know, our, our bodies get wet from sweat or, you know, just got out of a pool or something like that. Evaporation happens and , we feel that almost immediately. [00:18:15] The cooling process of that, well, crystallization is the opposite of evaporation. So condensation is a warming process then it's the opposite of what we feel when we get out of a pool. So it's a warming process and that's the heat that you're talking.
Dr. Jesse Reimink: Exactly. [00:18:30] That's a great, great analogy, Chris. Absolutely. Great analogy. So the, you know, why is the planet melting? Why is there vulcanism? Well, the interior of the planet's solid but it's, it's heating up because there's all this heat and it's got this heat blanket over it that can't escape. The lithosphere, the single lid, the stagnant [00:18:45] lid is, Not allowing heat out. So that heat builds up and eventually will start melting and it'll do this partial melting. We've talked about this, uh, you know, ad nauseum on Camp Geo cuz it's such an important thing. But, it starts this partial melting, which produces magma and that stuff [00:19:00] wants to escape too. And so it'll eventually puncture through this stagnant lid. It'll build up and kind of create a volcano that breaks through the single lithospheric plate. and then what happens from there? Chris, why does it get so?
Chris Bolhuis: Yeah, that's the whole thing. You did a really [00:19:15] good job, by the way of explaining how the heat goes and it, it creates its own plumbing network. Right. It, it just, for whatever reason, you get this center where there's melting that's taken place below the lid, and it finds a way to the surface. Well, because there's no tectonics, the [00:19:30] plates, then there it's one rigid lid that has a plumbing system leading to the surface because the plates aren't moving. The mag just keeps erupting out of that one eruptive center, whereas on earth. It creates an [00:19:45] avenue, but then the plates move and it creates a new avenue and the plates move and you just keep getting this. So you get vulcanism on Mars that just piles up and piles up and piles up and over time. Then you get [00:20:00] these just absolutely massive volcanoes because they're not gonna be strung out in a chain like you would get here on, Earth.
Dr. Jesse Reimink: Right, and you use this great analogy in cla Chris, which I've stolen shamelessly, is that you hold the lighter, you have a little hand [00:20:15] lighter, you light it and you hold a piece of paper over it. And on earth that piece of paper is the tectonic plate and it's moving. And so think of Hawaii, there's a hotspot, which is the lighter. And a piece of paper, which is moving over that hotspot, which creates a linear scar in that piece of paper. And [00:20:30] also, on top of that, it would be, in our analogy here, we'd be piling up lava on top. And in Hawaii we have this chain of volcanoes, Olympus Mons, you're just holding the lighter underneath a piece of paper and that paper's not moving. So you just burn a single big hole in the piece of paper, right? And it [00:20:45] piles up and all that lava piles up and creates a huge volcano. So that's a, a really great explanation, Chris, of how. This, or I guess of why Mars has the solar system's largest volcanoes and earth does [00:21:00] not, which is an interesting juxtaposition there.
Chris Bolhuis: So let's move on to the next question, which I gotta, I'm a little worried about you in this because this is your thing. The next question is, you know, [00:21:15] Jesse, I'm looking at you over your shoulder and you have these Harvard classics there, which I gave you a long time ago. I'm, I'm starting to think that you need to start reading more of those and less of your science papers because every time we get together now you come up with these weird things like, oh [00:21:30] yeah, read a paper on this. And I don't know. I think you need to become a little bit more well-rounded, Jesse. So you, you start read,
Dr. Jesse Reimink: too in the weeds. Huh?
Chris Bolhuis: and All right, so here we go. Is there granite on other [00:21:45] planets? That's the next question.
Dr. Jesse Reimink: That's the question.
Chris Bolhuis: so push, pause, think about that.
Dr. Jesse Reimink: And, if you haven't listened to sort of part one in this series, you know, we talked about how plate tectonics helps explain the formation of granite on earth. And so in that episode, [00:22:00] we kind of alluded to the fact that plate tectonics might be intimately related with granite production. So the question then is, is there grant on other planets? Chris, what did you think about, well, I think I wrote this question. So what did you think about, where did your mind go with.
Chris Bolhuis: [00:22:15] well, We don't know of granite on any of the other planets in our solar system. You know, Mars on down to, to mercury. So there's no granite. There's a ton of assault, but no granite. Okay. And I, my [00:22:30] question went to silicates right away. the silicate minerals, you know, the sheet silicates and the framework scates, the most abundant mineral group on the crust, on the continental crust, I should say, of the Earth. And so that's where my mind went. [00:22:45] And, and it interesting when I saw that you wrote this question, yours went a different direction, you. Right away went to water, you know, which I want to talk about cuz I want to hear your answer because I have some thoughts on this about water. So you have this, this [00:23:00] punchy kind of title up there. I think it comes from a paper that you read. It's called No Water, no Granites, no Oceans, and No Continents. So why don't you talk about this a little bit and why water is important in the formation of.
Dr. Jesse Reimink: Yeah, [00:23:15] so that title, no Water, no Granites, no Oceans, no Continents, kind of flows together. I mean, it says if there's no water, then there's no granites. Therefore, if there's no oceans on Earth, then there's no continents on Earth, and it's mostly pretty accurate. So [00:23:30] why is water tied to the formation of granites is the first question here. Well, the way that melting happens, we've talked about minerals and rocks that have water in them, and we don't mean like a water molecule, like in a poor space in the rock. We mean a mineral group in the [00:23:45] rock that has an oh group hanging on the end of it, or an oh group. That's part of the crystal structure. So that's for our intents and purposes. Water in the rock is hydrus minerals, minerals that are hydrated, and rocks that have hydrated minerals in them melt [00:24:00] at much lower temperatures than rocks that do not have hydrated minerals in them. So if you try and melt the mantle, which has very little water in it, as default. You try and melt the mantle, it's really hard. You gotta get to high temperatures at any given pressure to melt the [00:24:15] mantle. If you add water to that system, you can melt it at much lower temperatures, in much lower pressures at the same sort of conditions, right? So adding water to the mix makes things melt quicker. It also kind of changes the composition of melts that are produced. So [00:24:30] the partial melt. Happens at different pressures and temperatures, but also the melt composition that is produced changes dramatically as well. So true granites, like real granites on earth, which has a specific definition, it [00:24:45] has potassium
Chris Bolhuis: You're getting into the weeds there, doc. Hey, you're getting into
Dr. Jesse Reimink: up.
Chris Bolhuis: here, doc. Let's
Dr. Jesse Reimink: Alright. Alright. Come back. Come back to reality. Alright.
Dr. Jesse Reimink: The main point here is that.
Chris Bolhuis: all right, go ahead.
Dr. Jesse Reimink: Well, let me, let me just try and make the connection here to the end of this statement. So if [00:25:00] so, water helps, is really instrumental to producing granite and therefore, oceans on Earth are where all this hydration happens where a lot of water is mixing with rocks, it's interacting with rocks. So the idea there at the, the later part is if you didn't have oceans, we wouldn't [00:25:15] have continents. Which kind of ties that, uh, comes full circle there.
Chris Bolhuis: Okay. Two things I want to say, Jesse. One is that when water is involved in melting, you called it partial melting, and the general rule is, is like this [00:25:30] so ultra. Which means ultra-rich in iron and magnesium, the composition of the mantle, if you partially melt that you generate a magma that is less meic than what you started with. So now you go from ultra meic to meic. If you partially melt that, you go [00:25:45] to intermediate and composition, and if you partially melt that, you go to a fsic end member composition, which is granite. Okay. So that's the general rule of, of what you were just describing there, in a detailed kind of way. The second thing that I want to say is though, [00:26:00] Both Mars and Venus, we are exceedingly confident that both of them had water at one point, yet there's no granite. So do you have a thought about that?[00:26:15]
Dr. Jesse Reimink: It's a great question. I would kind of wiggle out of it and say that we don't know that we don't have granite, like we haven't found a ton of granite on either planet. Now on Mars. It kind of goes back to this resurfacing question or this vulcanism [00:26:30] question. Like there could be an argument, especially on Venus, we need to have a look at the interior of the planet. We need to drill down and evaluate. Is the middle part of the crust? Does it have granite in there or not? Because you can envision a scenario where there were some sort of [00:26:45] continent, pseudo continents around, and then the planet sort of died from a plate tectonic standpoint, became a stagnant lit planet. And then, It got resurfaced. The surface is all the salt because of this sort of heat pipe vulcanism that's pumping stuff out like Olympus Mons and just resurfaced the planet. [00:27:00] So it's an open question, I would say, particularly for Venus, about how much granite, now I, I wanna say one thing. There are andesites on these other planets. There's little tiny fragments of andesite that have been found on Mars, and actually there's one that's been found.[00:27:15] An extinct protoplanet, like what's called a condic protoplanet, and it is 4.56 billion years old, and it's a little andesite clasped fragment, inter meteorite, and it has an andesite composition, which on earth we [00:27:30] think that's a subduction zone. Volcano, . But on other planets, it has some chemical differences that say, okay, it's not a, it's, it's not an endocyte like we think it forms, but it is an endocytic com.
Chris Bolhuis: Interesting. So maybe the water wasn't [00:27:45] around long enough to distill it all the way, maybe. Is that, is that a thought that's out
Dr. Jesse Reimink: Th that's, that's, yes. E either the water's not around long enough or we have, uh, this process that we've talked about on Camio is fractional crystallization. [00:28:00] We talked about Bowen's reaction series previously in Planet Geo. Here we have an episode on Bone's Reaction series where if you take a magma, early form, minerals start to crystallize out, which changes the composition of the magma and it gets more evolved so you can actually produce andesite. If you [00:28:15] crystallize something like 80% of a basalt, what you're left with is endocyt. So you can produce small volumes of endocyte on any planter body really, if you have a big basaltic mag chamber just by this Bowen's reaction series, fractional crystallization process. [00:28:30] But it does not produce huge continents like we think of on Earth. So there, there is a difference here, I guess, in the volumes that we're speaking about.
Chris Bolhuis: Okay. Interesting, interesting. All right, well, anything else that you want to add to this discussion then about water, granites, [00:28:45] oceans? Like, What about, what I originally said to my question where my mind went to the silicates themselves? Like, is Earth unique And you know, like I think about this, that maybe we should do an episode, Jesse, on the condensation sequence in planet form. [00:29:00] Just, just that one topic, you know, I think that be, especially with your deep background in geochemistry, I think you would have a ton to add to this, and I can just kinda sit in the background and direct you and keep you outta the weeds. Too bad, you know, too much. But I think that'd be a really cool topic that would, [00:29:15] that kind of follows with what makes Earth so unique. But what do you think the, the, silicates, um, what's your.
Dr. Jesse Reimink: I think you're, you're, exactly right and
Chris Bolhuis: First of all, tell us what a silicate is a second.
Dr. Jesse Reimink: Silicate is a mineral that has a, silica si as a [00:29:30] primary constituent phase. So it, you know, that is a building block for silicate minerals. Usually it's an SIO for bond, silica, tetrahedron bond. And then you, you add some other cations to it to make a mineral. Calcium, magnesium, iron, something like that. so that's the bulk of planet [00:29:45] Earth. we have. Core part, which is metal, and then we have the silicate part, which is the mantle and the crust and the, the lithosphere. Most of our planets in our solar system have that same sort of breakdown. We have cores and we have silicate parts of the planets. Now, that's [00:30:00] because our solar system. Has generally the same composition. And so if you form rock from our solar system, it's going to be like a silicate based rock. There is some pretty active research in the exoplanets, people looking, mainly astronomers who look [00:30:15] at other stars and look at other planets around other stars, and they see that the star. Has a different, what's called metallic city, a different ratio of silica and an iron and magnesium in, in those different proportions. And the idea is that you would generate planets around [00:30:30] those stars that have different proportions of iron, magnesium, silica, calcium, to what our solar system has. So for our intents and purposes, most people who study silicates in the, so our solar system kind of use earth. A good [00:30:45] analogy for the rest of the planets, but that does not necessarily mean that other planets in other solar systems exoplanets have the same process. So I think, Chris, your question is is great. Yeah. Too many variables, but I think your question's a great one. When we start to consider exoplanets [00:31:00] that are orbiting other stars, we really have to consider, are silicates the main mineral group or are they a little bit more of a, a smaller. A less important mineral group than they are on our planet, for instance.
Chris Bolhuis: Interesting. Okay.[00:31:15]
Dr. Jesse Reimink: Yeah, great question.
Chris Bolhuis: think I get it.
Dr. Jesse Reimink: I mean, it gets pretty, it gets pretty armory. It gets kind of like this plate tectonics discussion where like if we don't, uh, think about what we know on earth, then how do we think about it? Like, there's so [00:31:30] many other options out there. You know, you can make a soup, uh, you can make a recipe using the periodic table and generate some random compositions. How relevant are they to other planets like and other sy solar systems? It's kind of, it gets really complicated, really quick and there's very few constraints, [00:31:45] so it kind of gets, um, difficult to understand for sure.
Chris Bolhuis: Well, that leads us into our last question, which is a good way to wrap up this episode, I think, which is, why does plate tectonics make Earth a beautiful planet? And I think, you know, I think we've already kind of covered it, but it's a good summary, [00:32:00] right, to me, it's undeniable that. Plate Tectonics makes earth beautiful because I love the mountains and so do you and it, it obviously then we have mountains on this planet because of plate tectonics, but we [00:32:15] also have these massive, deep, impressive valleys because of plate tectonics too. It's because we have this really, Well, first of all, because we have an atmosphere, you have to have that to have the weather and an erosion part of it, you have to have an atmosphere. [00:32:30] Okay. The uplift, which accelerates weather and erosion and the, like One of the things that makes mountains so beautiful is how caught up they are, how jagged and carved they are, right? And that's because of water. Whether [00:32:45] that be. Water or running water. This is what makes mountains truly beautiful, in my opinion. Glaciated Mountains are, you know, they're just amazing, right? and so all of this is intertwined with, you know, you get [00:33:00] accelerated weather and erosion if you have plate tectonics rapidly uplifting mountains, you can't separate.
Dr. Jesse Reimink: Absolutely. And Chris, that really sort of points right in the direction that I was thinking with this, it answer to this question of why does plate tectonics [00:33:15] make earth a beautiful planet Is that plate tectonics makes earth a habitable planet. plate tectonics is instrumental in keeping our oceans and keeping an atmosphere intact and has all these really important feedback loops that maintain a, a moderate climate. The only reason we're here is. [00:33:30] in large part plate tectonics has been operative on our planet for a long time. So that's kind of where I went is like we wouldn't even be able to see it's a beautiful planet unless we had plate tectonics going on, you know? So,
Chris Bolhuis: Can you give me, I want to, I want to, I want to take that a [00:33:45] little bit further. Jesse, can you provide an example of why that's the case? Okay. That's a really interesting thought and it's one that I had not, I had, and it didn't occur to me.
Dr. Jesse Reimink: So, The main thing, there's, there's feedback loops. [00:34:00] Like the main thing that controls climate is the, the sort of CO2 content of our atmosphere with our kind of gas makeup of our solar system. And so CO2 content controls the, the temperature of the planetary surface. And when you push mountains up, [00:34:15] What happens is CO2 is drawn down. We've talked about this before the carbon cycle. We've talked about, how we get salty water and stuff like that. Chemical erosion pulls CO2 out of the atmosphere by making rocks and, and, and dissolving rocks and putting them in the ocean basin. [00:34:30] Now if carbon's going down that way, what's putting it up into the atmosphere? Well, carbon is going up in most volcano chains. So volcanoes are outgassing CO2 in this active feedback loop. So we have this, this sort of modulating effect, and you can think of it this way, what happens if I just increase a [00:34:45] bunch of volcanic activity and I put a bunch of CO2 into the atmosphere? Well, if we do that, weathering is gonna happen faster. So more weathering means that we're gonna start drawing down CO2 more rapidly and it's gonna go into the ocean. So we have to have oceans, we have to have [00:35:00] uplift plate tectonics to regulate CO2 in this manner. And it's a feedback
Chris Bolhuis: but why? Why will weathering? Why will weathering accelerate if there's more CO2 into the atmosphere?
Dr. Jesse Reimink: Because the reactions will go. So if you just, [00:35:15] if you think of it like a basic chemicals, chemical reaction, if you put more product in, or more reacting in, it'll drive the reaction faster in the other direction. So if you have a bunch of rust forming on your truck, um, and you know, [00:35:30] let's say you suddenly clean off a bunch of rust, well that reaction will happen faster because you, you cleaned it off and so there's new surface that can be rusted. Right? Or if you. Put a bunch of oxygen, you put it in an oxygen chamber, that rusting is gonna happen really fast. So as soon [00:35:45] as you add more reactant or product, it drives the reaction in the other way, the speed of it. Does that
Chris Bolhuis: Okay. Yeah, that, yeah, you did that. That really drove it home. I just have another idea. I think this is a really good idea, and I don't want any pushback on this. I think that we need to [00:36:00] do a series
Dr. Jesse Reimink: a yes man. Now, Chris, I'm just a sick of fan who just goes with whatever you say.
Chris Bolhuis: I think that you and I need to do a series on the carbon.
Dr. Jesse Reimink: Oh yeah,
Chris Bolhuis: It's so big. It's, it's [00:36:15] too big of a topic. We can't do this in one or two episodes, but we could do a little mini series on the carbon cycle. do you think? That's a good idea, isn't
Dr. Jesse Reimink: I think it sounds great. I think it sounds great. And you know what we're gonna, we're probably gonna tie it up with our carbon cycle chapter on Camp Geo that we're putting together [00:36:30] pretty soon on the guessing. So, um, yeah, I think it sounds great.
Chris Bolhuis: true. Okay. Good deal.
Dr. Jesse Reimink: All right, man. Well, we're gonna pick up. with, uh, some more questions and, and you're gonna have your work cut out for your next episode. Talking about when Plate tectonics started on earth,
Chris Bolhuis: That's right. Cause [00:36:45] that's, that's right. Episode four in this series is gonna start with the question about when did plate tectonics start on earth and why is this an important question to answer? This is Jesse's research. It's Ben's research. It's gonna, it's, you know, it's, it's consumed massive parts of his [00:37:00] life, so he has a lot to say.
Dr. Jesse Reimink: far too much
Chris Bolhuis: I'm, I'm good at it. Yeah. So
Dr. Jesse Reimink: All right, man. Hey, that's a wrap. You can follow us on all the social medias at Planet Geo Cast. Send us an email, planet geo cast gmail.com and go to our website, planet geo cast.com where you can subscribe, you can follow us, [00:37:15] you can support us. We always appreciate that and, um, . Yeah. Leave us a review in a rating. We really appreciate those. Still helps the algorithm. And gosh, check out Camp Geo. We, we love hearing feedback on that. A couple you have gone there, have found some sort [00:37:30] of minor errors in our labeling and we really appreciate that, uh, sort of feedback. So go check it out and let us know what you think.
Chris Bolhuis: Also share Planet Geo with somebody else. That really helps us out too. And that's, yeah, we love that.
Dr. Jesse Reimink: love that. All right.
Chris Bolhuis: Cheers.[00:37:45]
