Latest / PlanetGeo: The Geology Podcast / Are Continents Growing? (Geoshort)

Transcript

Are Continents Growing? (Geoshort) · PlanetGeo: The Geology Podcast

• 0:04
  SPEAKER_00: Welcome to Planet Geo, the podcast where we talk about our amazing planet, how it works, and why it matters to you.
• 0:31
  SPEAKER_02: Hey Jesse, how are you doing today?
• 0:33
  SPEAKER_02: I'm doing well.
• 0:33
  SPEAKER_02: How are you?
• 0:34
  SPEAKER_02: I'm doing great.
• 0:35
  SPEAKER_02: Doing great.
• 0:36
  SPEAKER_02: Um, had some wild weather.
• 0:37
  SPEAKER_02: Did you guys have that?
• 0:38
  SPEAKER_02: Like the weather last night was just absolutely crazy.
• 0:41
  SPEAKER_00: Not that I know of, not that I was awake for at least.
• 0:44
  SPEAKER_00: I don't think so.
• 0:44
  SPEAKER_00: It's probably coming our way though.
• 0:46
  SPEAKER_00: I mean, every weather from you guys good takes a day to get to us.
• 0:48
  SPEAKER_02: Yeah, it was rocking and rolling last night and it's starting up again now, so it's really kind of cool.
• 0:53
  SPEAKER_02: So hey Jesse, let's get uh going today.
• 0:55
  SPEAKER_02: But before we do that, let's do some introductions.
• 0:57
  SPEAKER_02: You are Dr.
• 0:58
  SPEAKER_02: Jesse Rymick, one of my former students, uh high school students, that is.
• 1:01
  SPEAKER_02: Uh, you went on to get your PhD in geoscience, and you are now a professor of geoscience at Penn State University.
• 1:07
  SPEAKER_00: Yeah, that's right.
• 1:08
  SPEAKER_00: And you're Chris Belhois, high school geology teacher, extraordinaire.
• 1:11
  SPEAKER_00: You teach geology, earth science, astronomy, a bunch of field courses.
• 1:15
  SPEAKER_00: I took what three classes from you back in the day, uh, and you taught me the basics.
• 1:19
  SPEAKER_00: Uh, you went to Grand Valley State University and have been teaching at Huttsville Public Schools for a while now, for five to eighty years, somewhere in that range.
• 1:28
  SPEAKER_02: Five to eighty.
• 1:28
  SPEAKER_02: You're right, you got it right in the middle there.
• 1:30
  SPEAKER_02: Yep.
• 1:30
  SPEAKER_00: So, you know, Chris, we we got together recently, and um, you know, I think first of all, it's really fun.
• 1:38
  SPEAKER_00: We got a lot of work done, but also get a lot done.
• 1:41
  SPEAKER_00: Man, sometimes you in the morning, you you look like the 80 end of the spectrum in the morning.
• 1:50
  SPEAKER_01: That is not that is not okay for you to say.
• 1:53
  SPEAKER_00: You brighten up, you you f you freshen up a little bit mid-morning, but man, right away in the morning, it's not a pretty sight.
• 2:00
  SPEAKER_01: That's not a true statement.
• 2:01
  SPEAKER_02: Uh, it does not characterize me at all.
• 2:04
  SPEAKER_02: I wake up and I am ready to go.
• 2:06
  SPEAKER_02: Um you can say a lot of things about me, but you know what I am?
• 2:09
  SPEAKER_02: I am a gamer.
• 2:10
  SPEAKER_00: Yeah, that okay.
• 2:11
  SPEAKER_00: You are that, that's for sure.
• 2:13
  SPEAKER_02: So, anyway, Jesse, let's get going today.
• 2:15
  SPEAKER_02: What this episode is about is kind of an add-on or follow-up to our episode on Bowen's Reaction Series.
• 2:22
  SPEAKER_00: Yeah, the one that came out last week.
• 2:24
  SPEAKER_02: Right.
• 2:24
  SPEAKER_02: And this actually came about because you know, we were sitting on my front porch drinking a beer and talking about the episode, and I had a question, and I'm like, well, you know what?
• 2:32
  SPEAKER_02: Let's stop talking about this and let's just do it for a new episode.
• 2:36
  SPEAKER_02: So that's what this is.
• 2:38
  SPEAKER_00: That's right.
• 2:38
  SPEAKER_00: We were just sitting around talking geoscience.
• 2:40
  SPEAKER_00: You had a great question, and uh, I had a probably a long-winded answer or something.
• 2:44
  SPEAKER_00: You're like, hold on, Jesse, shut up.
• 2:46
  SPEAKER_00: Let's just record this because it's maybe potentially interesting.
• 2:49
  SPEAKER_02: Right.
• 2:50
  SPEAKER_02: So let me go ahead and set this up.
• 2:51
  SPEAKER_02: So um, you know, we talked about how Bowen's reaction series explains the formation of continents, right?
• 2:58
  SPEAKER_02: You know, so again, it's this why, if you think about Bones Reaction series as a Y.
• 3:02
  SPEAKER_00: Like the letter Y, not the question Y.
• 3:04
  SPEAKER_02: Yeah, right.
• 3:05
  SPEAKER_02: That's um thanks for saying that.
• 3:07
  SPEAKER_02: The two ends of the Y, or the two sides of the Y, I should say, have a discontinuous side and a continuous side.
• 3:13
  SPEAKER_02: Okay, but the bottom line is that the top of the Y is high temperature.
• 3:18
  SPEAKER_02: Uh so as magma's cooling off, those are the first minerals that crystallize out of magma.
• 3:23
  SPEAKER_02: And then as those minerals form, they take that chemistry out of the magma.
• 3:29
  SPEAKER_02: And so the magma gets increasingly more and more and more felsic, uh, which is richer in the minerals like quartz and feldspar and muscovite mica.
• 3:38
  SPEAKER_02: So to summarize, then we were talking about how continents are formed at subduction zones.
• 3:43
  SPEAKER_02: And what happens then is that plate subducts, you know, some water, water vapor that get in the gas form, can get driven off this plate and it gets injected into super hot rock near the subduction zone.
• 3:57
  SPEAKER_02: And the addition of the water lowers the melting point of these low temperature minerals and it generates then this quite felsic magma.
• 4:06
  SPEAKER_02: And it can generate andesitic and granitic magma.
• 4:09
  SPEAKER_02: That's what continents are made of.
• 4:12
  SPEAKER_02: And so that's how Bowen's reaction series kind of explains this.
• 4:15
  SPEAKER_02: So my question was then well, if that's the case, if that's how continental crust is made, then a continent should grow throughout time.
• 4:27
  SPEAKER_02: Is that a fair statement?
• 4:30
  SPEAKER_00: It's an absolutely perfect question.
• 4:34
  SPEAKER_00: I mean, it is the the obvious question to ask at the end of our Bowen's reaction series discussion, is because if Bowen's reaction series is this distillation mechanism that the continents are being distilled out of the earth, don't they just always keep growing?
• 4:48
  SPEAKER_00: And over time, doesn't it just keep getting bigger and bigger and bigger?
• 4:50
  SPEAKER_02: Right, because subduction continues.
• 4:53
  SPEAKER_02: You know, subduction is going on in the Pacific Ring of Fire all over the place.
• 4:56
  SPEAKER_02: And so if that's what what's going on and that's how chronic magma is formed, then the continent should be getting bigger over geologic time.
• 5:05
  SPEAKER_00: That's right.
• 5:05
  SPEAKER_00: That's exactly right.
• 5:06
  SPEAKER_00: So in the past four and a half billion years of Earth history, if subduction has continued during that time period, then continents maybe have just been getting bigger and bigger and bigger.
• 5:16
  SPEAKER_00: So first let me preface this by saying this is a massive field of research and has is sort of in geology an age-old question in a way.
• 5:25
  SPEAKER_00: As soon as we started to understand the age of the earth and how old it was, the question became when did continents form?
• 5:32
  SPEAKER_00: So this has been a hot topic in the scientific literature and hotly debated amongst researchers for probably 60 or 70 years by this point.
• 5:41
  SPEAKER_02: Alright.
• 5:41
  SPEAKER_02: So you're getting rambly already, okay?
• 5:46
  SPEAKER_00: Let's cut to the chase here.
• 5:48
  SPEAKER_00: Let's what's going on?
• 5:49
  SPEAKER_00: I'm qualifying because what I say is going to be my personal sort of scientific opinion, which there will be people who disagree with that.
• 5:57
  SPEAKER_02: Come on, now answer the question.
• 6:00
  SPEAKER_00: Okay.
• 6:00
  SPEAKER_00: The question, I'm gonna flip it around because the question is not have continents been growing?
• 6:04
  SPEAKER_00: They have been growing.
• 6:05
  SPEAKER_00: The question is, are continents being destroyed as well?
• 6:08
  SPEAKER_00: So that's really the question because continents have been growing, subduction has been going on for the last, well, depends who you ask, but probably two and a half billion years at least, if not more than that.
• 6:19
  SPEAKER_00: And so subduction has been going on, continents have been growing.
• 6:22
  SPEAKER_00: What, if any, continental crust has been destroyed is the question.
• 6:27
  SPEAKER_02: Now that's a that's a huge question because, like in any traditional beginning geology class, you learn that nothing really happens to continental crust.
• 6:36
  SPEAKER_02: It is too buoyant to undergo subduction.
• 6:39
  SPEAKER_02: So once it's created, it doesn't get destroyed.
• 6:42
  SPEAKER_00: Yep.
• 6:43
  SPEAKER_00: So the question, it's a hot topic of whether there's continental crust being destroyed currently in the modern earth, and how much of that destruction occurred back in time.
• 6:52
  SPEAKER_00: And by destruction, I mean taking continental crust and putting it into the mantle and kind of mixing it back into the mantle.
• 6:58
  SPEAKER_00: The mantle is huge.
• 6:59
  SPEAKER_00: Continental crust is the skin of the apple, and it's taking some skin of the apple and putting it back into the mantle and mixing it apart there.
• 7:06
  SPEAKER_02: But what's the mechanism for doing that?
• 7:08
  SPEAKER_02: Since it's too buoyant to subduct, well, how does it get recycled back into the mantle?
• 7:13
  SPEAKER_02: Then how would that happen?
• 7:14
  SPEAKER_00: Yeah, so that we know that there is some recycling that has happened, and that's the term we use is continental recycling.
• 7:20
  SPEAKER_00: So taking it, putting it back in the mantle.
• 7:22
  SPEAKER_00: There's two ways to do that.
• 7:23
  SPEAKER_00: First of all, take the bottom part of the crust and just have it sink into the mantle.
• 7:28
  SPEAKER_00: The bottom part of the crust is typically thought of as being relatively dense.
• 7:33
  SPEAKER_00: It's sort of the anchor at the bottom of the boat, or actually it's it's the ballast at the bottom of the boat.
• 7:38
  SPEAKER_00: And so think of your sailboat.
• 7:40
  SPEAKER_00: You know, most sailboats have this big ballast thing at the bottom that kind of prevents the boat from capsizing over.
• 7:46
  SPEAKER_00: That could break off and sink down into the mantle.
• 7:49
  SPEAKER_00: So that's one way.
• 7:50
  SPEAKER_02: Okay, I don't understand though, and I'm I'm not like I don't understand what you're saying, because even though the bottom of the crust is denser than the top of the crust, it's not denser than the mantle below.
• 8:03
  SPEAKER_02: So how would it sink down in?
• 8:05
  SPEAKER_00: So certain types of crust can be denser than the mantle, and it this is eclogite.
• 8:11
  SPEAKER_00: So basically, if you take the the continental crust is thought to be not granitic on average, but sort of intermediate composition or andesitic on average, and it's usually thought to be stratified chemically with depth, meaning the top is very felsic, very light colored, very granitic.
• 8:27
  SPEAKER_00: The bottom is more dense, more mafic, and more basaltic.
• 8:32
  SPEAKER_00: And when that stuff forms garnet and pyroxine, two minerals that are very dense, that stuff can break off and sink down into the mantle in the same way that a subduction system works.
• 8:44
  SPEAKER_00: So that's one way that this could possibly happen.
• 8:47
  SPEAKER_00: And we know that this happens a little bit.
• 8:50
  SPEAKER_02: Alright, hold on.
• 8:51
  SPEAKER_02: So, you know, I get it how at when crust is formed, when cottonal crust is formed, it's gonna differentiate.
• 8:57
  SPEAKER_02: And while that means the lighter stuff floats up to the top, and I still don't see how the bottom of the crust is denser than the mantle below it, even if that mechanism happens.
• 9:09
  SPEAKER_00: So in that differentiation thing, that distillation process you're talking about, the first minerals to form in a subduction zone underneath of a volcanic arc, underneath the cascades, could be amphibole and garnet, and garnet's really dense.
• 9:24
  SPEAKER_00: And so a rock that is pure garnet is more dense than the mantle.
• 9:27
  SPEAKER_00: So if you have enough of that happening, that could disengage and sink down into the mantle.
• 9:33
  SPEAKER_00: So that's whether you define that as continental crust, it was part of the continental crust as a physical mass, but chemically it's not really the average, but it goes into the average of what the continental crust is.
• 9:44
  SPEAKER_00: So there's the bottom part of the continental crust can can sort of break off and sink down in the mantle.
• 9:48
  SPEAKER_00: We call that delamination.
• 9:50
  SPEAKER_00: The other main mechanism for recycling continental crust and putting it into the mantle is erosion and sedimentation.
• 9:57
  SPEAKER_00: So this is mountains being eroded down, the sediments being deposited in the ocean basin, and those sediments being attached to an oceanic plate that then subducts beneath the continent, and the sediment gets carried down into the mantle as part of the oceanic plate.
• 10:12
  SPEAKER_00: We know that that happens at least a little bit.
• 10:15
  SPEAKER_00: We can detect some of that material that has gone down, comes back up in volcanism in other parts of the world, and we can tell it's oh it's previous sediment that's been brought down in the mantle.
• 10:26
  SPEAKER_00: We just don't know how much of that has occurred.
• 10:28
  SPEAKER_02: Okay.
• 10:29
  SPEAKER_02: So uh just to paint a picture of what you're describing, I think.
• 10:33
  SPEAKER_02: You're talking about at a subduction zone, you have this basaltic crust, this oceanic crust, but on top of that is a skin of sedimentary rocks.
• 10:42
  SPEAKER_02: Okay, now that that skin of sedimentary rocks in the subduction zone, some of it gets scraped off and plastered to the overriding plate, and some of it gets thrust down in the subduction zone.
• 10:56
  SPEAKER_02: And it's this it's this sedimentary skin covering the basalt that manages to get down into the subduction zone.
• 11:04
  SPEAKER_02: That's what you're talking about.
• 11:05
  SPEAKER_00: That is exactly right.
• 11:06
  SPEAKER_00: Yep.
• 11:07
  SPEAKER_00: It's this little layer of sediments, and it's actually kind of a lot.
• 11:10
  SPEAKER_00: If you do this over a long period of time, a small amount recycled in the mantle over long periods of time can actually end up being a lot of continental crust.
• 11:18
  SPEAKER_00: So there those are the two ways that it's possible to recycle continental crust and and sort of return it to the mantle.
• 11:25
  SPEAKER_00: And that's one part of the question.
• 11:27
  SPEAKER_00: One part of the question is are continents continuing to grow?
• 11:30
  SPEAKER_00: And yes, they are continuing to grow, but there's potentially this counterbalance of destruction that is also occurring that we have to account for if we're thinking about how much volume of continental crust was there on Earth back in time.
• 11:41
  SPEAKER_00: And let me come back to prefacing this because this is uh the main thrust of my research, as well as many, many other people out there, academic researchers and and industry researchers, who are thinking about this kind of problem.
• 11:54
  SPEAKER_00: So there's a lot of people who have been trying to tackle this problem for a long period of time for many decades, using a lot a wide variety of techniques, and we don't really we haven't come to a sort of unified answer yet.
• 12:07
  SPEAKER_00: So Okay.
• 12:08
  SPEAKER_02: So hold on, and I'm not I'm not trying to be sarcastic, okay, here, but But you that has that's never stopped you before.
• 12:15
  SPEAKER_02: It's not gonna stop me.
• 12:16
  SPEAKER_02: I still don't what's the second mechanism of destroying continental crust?
• 12:22
  SPEAKER_02: I don't know if you ever you clearly laid that out.
• 12:25
  SPEAKER_02: I think you started to with the subduction zone, but I don't know if that got finished off.
• 12:28
  SPEAKER_00: Yeah, so let me come back to it.
• 12:29
  SPEAKER_00: So it's a mountain belt that's being eroded, those sediments are being carried down rivers, they're big eventually ending up in the ocean basin.
• 12:37
  SPEAKER_00: Those sediments in the ocean basin, whether they're chemical sediments or they're uh detrital sediments, meaning whether they're mineral grains and they're detrital sediments, or they're actually chemical deposition of sediments like carbonates and things, those sediments in the bottom of the oceans are brought down into the mantle with the subduction zone, and they make it down into the deep, deep mantle.
• 12:56
  SPEAKER_00: So we know this happens.
• 12:57
  SPEAKER_00: We know this happens by several ways.
• 12:59
  SPEAKER_00: In modern volcanoes, we can see evidence of ancient recycling going on, ancient sediments going down in some of the really deep diamonds that people have found.
• 13:08
  SPEAKER_00: We can see evidence of recycling of ancient continental crust.
• 13:12
  SPEAKER_00: So we know it happens a little bit, we don't know how much of that has happened.
• 13:17
  SPEAKER_02: Okay.
• 13:18
  SPEAKER_02: So which mechanism is the most likely?
• 13:21
  SPEAKER_00: Great question.
• 13:22
  SPEAKER_00: We know that the subduction mechanism is going on currently.
• 13:28
  SPEAKER_00: We know that that's occurring for sure.
• 13:30
  SPEAKER_00: We don't know how long ago subduction initiated.
• 13:36
  SPEAKER_00: I have my own opinions on this, but subduction, meaning we don't know how long subduction has been going on in on Earth.
• 13:42
  SPEAKER_00: Has it been going on for half of Earth's life?
• 13:45
  SPEAKER_00: Has it been going on since Earth was born?
• 13:48
  SPEAKER_00: We don't really know that, and that's a major, again, a major question in the geosciences, especially in my field, is when did these big processes that really define our planet, when did they begin?
• 13:59
  SPEAKER_00: Because we don't really have a firm grasp of that.
• 14:01
  SPEAKER_00: All of this really plays into, I mean, Chris, I could ramble for many, many hours about this.
• 14:06
  SPEAKER_02: I know, I know.
• 14:07
  SPEAKER_02: I'm getting a handle on this.
• 14:09
  SPEAKER_00: You're doing a good job of reining me in right now, actually.
• 14:12
  SPEAKER_02: Well, hold on a second.
• 14:13
  SPEAKER_02: Now I I want to follow this up though, okay?
• 14:15
  SPEAKER_02: Basically, do you feel comfortable saying that the continents are not going to be much larger, if any, a billion years from now?
• 14:26
  SPEAKER_00: Ooh, that's a good question.
• 14:29
  SPEAKER_00: No, I am not comfortable saying that, in part because my opinion on this, which many people will disagree with, my opinion is that continents have been growing throughout Earth history, um, and that recycling has been limited.
• 14:48
  SPEAKER_00: So that's my opinion.
• 14:49
  SPEAKER_00: Based on some evidence.
• 14:52
  SPEAKER_00: Uh there are people who would disagree.
• 14:54
  SPEAKER_02: So Do you see this problem getting solved?
• 14:56
  SPEAKER_00: So let me finish that.
• 14:57
  SPEAKER_00: I would say that given my opinion uh where we are today, I would say that in a billion years we will have more continental crust.
• 15:04
  SPEAKER_00: We'll have larger continents than we do today.
• 15:08
  SPEAKER_00: So do I see this being solved?
• 15:11
  SPEAKER_00: Um I would like to think so.
• 15:14
  SPEAKER_00: You know, I'm working on this problem.
• 15:16
  SPEAKER_00: Other people are other really bright people are working on this problem.
• 15:20
  SPEAKER_02: I don't very bright.
• 15:21
  SPEAKER_02: So I know.
• 15:22
  SPEAKER_00: I'm kind of the dummy in the room, and everybody else is really bright, and they don't agree with me, so I'm probably the one that's wrong.
• 15:30
  SPEAKER_02: Well, I would like to think what's the breakdown on this?
• 15:33
  SPEAKER_02: Like, is it half and half with this the research scientists that you know believe continents are growing, and then the other half say no they're not?
• 15:41
  SPEAKER_00: That's a great question.
• 15:42
  SPEAKER_00: I don't really know.
• 15:43
  SPEAKER_00: I I would say that a majority or a plurality, I suppose, of people think that continents started to grow a lot around 3 billion years ago or 2.5 billion years ago, is we sort of had a big uptick in continental growth or in continental preservation, I guess.
• 16:03
  SPEAKER_00: And I think a lot of people would say that in the ancient earth, prior to three billion years ago, between three billion and four point five billion years ago, that there was a lot of continental recycling going on, that continents were formed and then destroyed really quickly.
• 16:16
  SPEAKER_02: Okay.
• 16:17
  SPEAKER_00: I don't necessarily agree with that, but I think that might be where 30 or 40 percent of people might fall, and then you know, everybody else has their own opinions on uh on different sides of that discussion.
• 16:29
  SPEAKER_02: Okay, so here I go.
• 16:30
  SPEAKER_02: Then, you know, I'm I'm not an over-educated PhD like you are, so I see the subduction thing where sediment that gets weathered off from erosion and so on gets deposited in the oceans and then gets destroyed in a subduction zone.
• 16:45
  SPEAKER_02: I see that as a much more, well, it's easy, it's easier to understand that mechanism than the other one where deep crustal material sinks into the mantle.
• 16:56
  SPEAKER_00: I mean, you bring up a great point because the deep continental material that sinks into the mantle, it begs the question, is that continental crust?
• 17:03
  SPEAKER_00: Because it's not chemically necessarily the same.
• 17:06
  SPEAKER_00: And so maybe it's part of the Bowen's reaction series progression.
• 17:11
  SPEAKER_00: It's part of the distillation of the crust.
• 17:13
  SPEAKER_00: And so even though it was physically part of the continental crust, it's not chemically what we think of as continental crust.
• 17:18
  SPEAKER_00: So I completely agree with your point.
• 17:20
  SPEAKER_00: You know what, Chris?
• 17:20
  SPEAKER_00: Maybe what we should do is when we go to AGU, this meeting in the in December, we should sit in a session together about you know continental crust growth.
• 17:27
  SPEAKER_00: I would love to try to do that.
• 17:28
  SPEAKER_00: And uh, and I'd love to get your opinion about it afterwards, about you know, hearing some of these arguments.
• 17:32
  SPEAKER_02: You mean you don't want me to pipe up and ask any questions?
• 17:35
  SPEAKER_00: No, I would love it if you asked questions.
• 17:37
  SPEAKER_00: I would like that's gonna happen.
• 17:39
  SPEAKER_00: I would love to hear your opinion, like coming at it from fresh eyes, not coming at it with any preconceived notions about people who are giving talks that they've talked about before, things like that.
• 17:48
  SPEAKER_00: So all right.
• 17:49
  SPEAKER_02: So let me summarize this up, okay?
• 17:51
  SPEAKER_02: So basically, we don't really know if continents are growing throughout time.
• 17:56
  SPEAKER_02: The research still needs to bear this out and and answer the question and figure out what the mechanisms are and and so on.
• 18:03
  SPEAKER_02: The other thing is I would like to apologize because this was a heavy Jesse Rhymanck episode, and I apologize to the listeners for that.
• 18:12
  SPEAKER_02: Um I did my best.
• 18:15
  SPEAKER_02: Okay, I tried.
• 18:16
  SPEAKER_02: I tried to contain you, but you're like a caged cat right now.
• 18:20
  SPEAKER_02: I mean, you're pacing back and forth, and you it's just uh I'm ready to pounce.
• 18:25
  SPEAKER_00: You are you are I'm ready, I'm getting ready to lecture.
• 18:28
  SPEAKER_00: I've got a big lecture building up inside of me.
• 18:30
  SPEAKER_00: No, I I I'll just end with just a little personal note here because the only the reason I am interested in studying what I study is this was an astonishing fact to me that we didn't really know when continents formed on Earth.
• 18:43
  SPEAKER_00: It seems like such a basic thing that we should have figured out by now that I was kind of blown away that we didn't understand this.
• 18:49
  SPEAKER_00: And it was early in graduate school when I kind of came to this realization, which was probably fairly late in my academic journey that I realized this.
• 18:57
  SPEAKER_00: But I I was just blown away.
• 18:59
  SPEAKER_00: I felt like this is why don't we know this?
• 19:01
  SPEAKER_00: This is so cool.
• 19:01
  SPEAKER_00: What a cool topic.
• 19:03
  SPEAKER_00: And uh the more I dive into it, the more I understand why we don't understand when continents grew, because it's very complicated, as we're sort of highlighting here.
• 19:11
  SPEAKER_00: But um anyway.
• 19:12
  SPEAKER_02: There's a lot more that we don't know than what we do know.
• 19:14
  SPEAKER_02: I think that's pretty common in science in general, no matter whether it's chemistry or biology and and so on.
• 19:20
  SPEAKER_02: I mean, you know, we still haven't really figured out this whole cancer thing, you know, and that seems like it's it's kind of the same realm in terms of how you'd think that we would have figured this out by now, but we will.
• 19:32
  SPEAKER_02: It's just gonna it's just gonna take time.
• 19:34
  SPEAKER_00: Yes.
• 19:35
  SPEAKER_00: And whenever we figure something out, we figure out ten more things that we don't know.
• 19:39
  SPEAKER_02: So and I and I enjoyed this because I one, I learned a lot.
• 19:42
  SPEAKER_02: Two, this was just more of a really an unscripted, open-ended episode because you know, we didn't talk about this.
• 19:50
  SPEAKER_02: We started to and we stopped.
• 19:52
  SPEAKER_02: No, let's not do this.
• 19:53
  SPEAKER_02: Let's let's just let's just do this live.
• 19:55
  SPEAKER_02: And that's what this is.
• 19:56
  SPEAKER_00: All right, well, this is Planet Geo.
• 19:59
  SPEAKER_00: You can visit us on all our social medias at Planet Geocast.
• 20:02
  SPEAKER_00: We have a new website, planetgeocast.com, and send us an email, planetgeocast at gmail.com.
• 20:08
  SPEAKER_00: We love all the feedback we've been getting.
• 20:11
  SPEAKER_02: You know what?
• 20:12
  SPEAKER_02: Can I just simplify this?
• 20:13
  SPEAKER_02: Just please tell somebody if you get something out of this that might enjoy learning about our awesome planet.
• 20:20
  SPEAKER_02: Just share it so that more and more people get exposed to how this planet works.
• 20:26
  SPEAKER_00: Amen to that.
• 20:27
  SPEAKER_00: All right.
• 20:28
  SPEAKER_00: Peace.
• 20:29
  SPEAKER_00: That's a wrap.