Latest / PlanetGeo: The Geology Podcast / Geology of Puddingstone

Transcript

Geology of Puddingstone · PlanetGeo: The Geology Podcast

• 0:02
  SPEAKER_02: Welcome to Planet Geo, the podcast where we talk about our amazing planet, how it works, and why it matters to you.
• 0:15
  SPEAKER_02: Okay.
• 0:17
  SPEAKER_02: Chris.
• 0:19
  SPEAKER_01: Jesse.
• 0:20
  SPEAKER_02: Mr.
• 0:20
  SPEAKER_02: Mr.
• 0:21
  SPEAKER_02: Belhois.
• 0:22
  SPEAKER_02: Sir.
• 0:22
  SPEAKER_02: Good sir.
• 0:23
  SPEAKER_01: Don't call me that.
• 0:24
  SPEAKER_01: Don't call me that.
• 0:25
  SPEAKER_01: It's not it's not been the day for that, Jesse.
• 0:27
  SPEAKER_01: Hey, hold on.
• 0:28
  SPEAKER_01: Hey, hold on.
• 0:29
  SPEAKER_01: Um, the screen share is I don't like this.
• 0:31
  SPEAKER_01: Can we do this differently?
• 0:32
  SPEAKER_01: Like, you're not big enough.
• 0:34
  SPEAKER_01: How would we like to do it?
• 0:35
  SPEAKER_01: I don't know.
• 0:36
  SPEAKER_01: But you're like, I can't.
• 0:39
  SPEAKER_01: This is not.
• 0:41
  SPEAKER_01: Yeah, it's too small.
• 0:43
  SPEAKER_02: Try pinning it.
• 0:45
  SPEAKER_02: Try pinned to my screen.
• 0:47
  SPEAKER_02: Will that make it bigger for you?
• 0:49
  SPEAKER_01: There you go.
• 0:50
  SPEAKER_01: There we go.
• 0:51
  SPEAKER_01: That's better.
• 0:52
  SPEAKER_01: Good deal.
• 0:52
  SPEAKER_01: All right.
• 0:53
  SPEAKER_01: Okay.
• 0:54
  SPEAKER_02: Now we can proceed.
• 0:55
  SPEAKER_02: We can proceed.
• 0:56
  SPEAKER_02: How are we doing, Jess?
• 0:58
  SPEAKER_02: That was a close one right there, Chris.
• 0:59
  SPEAKER_02: We almost had technical difficulties.
• 1:01
  SPEAKER_02: We got out of it, though.
• 1:02
  SPEAKER_02: We did.
• 1:04
  SPEAKER_02: Okay, well, on this episode of the Chris Bullheis experience, uh, we are gonna talk.
• 1:09
  SPEAKER_02: Oh no, that's not the show name.
• 1:11
  SPEAKER_02: What this is Planet Geo.
• 1:13
  SPEAKER_02: You do get you do get real Chris today, though.
• 1:15
  SPEAKER_02: You know, I do get Chris.
• 1:16
  SPEAKER_02: Yeah.
• 1:17
  SPEAKER_02: I always get real Chris.
• 1:18
  SPEAKER_02: And uh But um I'd rather have real Chris than anybody else out there.
• 1:24
  SPEAKER_02: So that's good.
• 1:26
  SPEAKER_02: Chris, we get to talk well.
• 1:27
  SPEAKER_02: We're talking about a real we're talking about real badass rock today.
• 1:31
  SPEAKER_02: Like this is this is a cool rock, a famous rock, a famous category of rocks.
• 1:36
  SPEAKER_02: If you're a rock collector, you know this word.
• 1:38
  SPEAKER_02: But before we get to that, Chris, you polled your students.
• 1:41
  SPEAKER_02: You had homework, and um I think you've accomplished that, right?
• 1:44
  SPEAKER_02: You're gonna change the name of your course from geology to geoscience, and your homework was to like I forget what it was actually, ask them what they thought about it.
• 1:52
  SPEAKER_01: Yeah, it was yeah, what what were their thoughts?
• 1:54
  SPEAKER_01: You just said poll them.
• 1:55
  SPEAKER_01: I want to know what they think.
• 1:56
  SPEAKER_01: And what okay, um, yeah, what happened?
• 1:57
  SPEAKER_01: What'd you ask them and what'd they say?
• 1:59
  SPEAKER_01: So I changed my class for the last 25 years has been called geology.
• 2:05
  SPEAKER_01: And uh through our discussions with Rachel Phillips, Geogirl, and so on, I decided, and and plus, you know, plus with you and just doing this podcast, we never really refer to this as geology.
• 2:16
  SPEAKER_01: We've always we've we've called this geoscience, and yeah, and so I'm like, you know, I I just put a put a bug in my ear.
• 2:23
  SPEAKER_01: Uh wait, wait a minute, maybe I should change my class to geoscience.
• 2:26
  SPEAKER_01: And so I thought about it, we talked about it, I did it.
• 2:30
  SPEAKER_01: I went and changed it, it was remarkably easy.
• 2:33
  SPEAKER_01: And but I've Okay, that's good.
• 2:35
  SPEAKER_01: You know, so I've gotten questions from people that actually noticed that I my class has now changed from geology to geoscience.
• 2:42
  SPEAKER_01: I'm getting emails from counselors about questions from students and things.
• 2:47
  SPEAKER_01: So I pulled my current geology classes, my beloved, I love them.
• 2:52
  SPEAKER_01: Yeah.
• 2:53
  SPEAKER_02: Um so these are juniors and seniors in high school?
• 2:56
  SPEAKER_01: Mix between the two?
• 2:58
  SPEAKER_02: Okay.
• 2:58
  SPEAKER_01: Yep.
• 2:59
  SPEAKER_01: And uh, and they're so good.
• 3:00
  SPEAKER_01: And and so I said, I want to know what you think.
• 3:03
  SPEAKER_01: And so I wrote on one side of the board, I wrote geology, on the other side of the board, I wrote geoscience, and I said, if you read these, or if you were thinking about course offerings and and these were your choices, how do they hit you?
• 3:17
  SPEAKER_01: You know, do you think about it differently?
• 3:19
  SPEAKER_01: Geology versus geoscience.
• 3:22
  SPEAKER_01: So I just kind of let it sit for a few seconds, and then I'm like, what do you what do you think?
• 3:28
  SPEAKER_01: And I had a couple of camps.
• 3:30
  SPEAKER_02: Oh yeah.
• 3:32
  SPEAKER_01: Some of my students they thought that geoscience seemed to be more difficult in terms of just the rigor of the class.
• 3:43
  SPEAKER_01: Yeah, that caught me by surprise.
• 3:46
  SPEAKER_01: Yeah.
• 3:47
  SPEAKER_01: They thought geology would be just, you know, kind of a rocks for jocks kind of thing, and um, whereas geoscience seemed maybe a little uh more of a reach.
• 3:58
  SPEAKER_01: Interesting.
• 3:58
  SPEAKER_02: Okay, so sort of more quantitative, more difficult, harder class, basically.
• 4:03
  SPEAKER_01: Oh, that's interesting.
• 4:04
  SPEAKER_01: No, okay.
• 4:05
  SPEAKER_01: That was not the majority.
• 4:06
  SPEAKER_01: I would say the majority of my students felt that geoscience was a better term for my course because we do we don't just do geology, we don't just do hard rock geology and and and some soft rock geology and call it that.
• 4:23
  SPEAKER_01: I mean, we talk about resources, we talk about climate and climate change.
• 4:27
  SPEAKER_01: Whenever I can, I bring in planetary because I like to, you know, cross that with my astronomy classes and so on.
• 4:34
  SPEAKER_01: And and so a lot of my students thought that geoscience had a broader umbrella, a bigger, more inclusive umbrella.
• 4:42
  SPEAKER_01: Yeah.
• 4:43
  SPEAKER_02: Well, I mean, that's yeah, okay.
• 4:44
  SPEAKER_02: So they're that's really interesting that they've plugged into that as a junior in high school, having basically no exposure to the field, the discipline, the industry is involved.
• 4:54
  SPEAKER_02: I mean, it's really interesting that they just kind of because that's the point, right?
• 4:57
  SPEAKER_02: That's the point of everybody rebranding as geoscience or even Earth and Planetary Science as more of a broader envelope, even beyond geoscience.
• 5:06
  SPEAKER_02: So that's right.
• 5:07
  SPEAKER_01: I mean, it was the intent.
• 5:08
  SPEAKER_01: Very impressive.
• 5:09
  SPEAKER_01: Yeah.
• 5:10
  SPEAKER_01: Yeah.
• 5:10
  SPEAKER_01: And some of the questions that the counselors have passed on to me affirm that thought.
• 5:15
  SPEAKER_02: Really?
• 5:15
  SPEAKER_02: Okay.
• 5:16
  SPEAKER_02: Wow.
• 5:17
  SPEAKER_02: So the counselors are getting questions about or asking you questions, sort of how do we advise students about this class, college preparedness, all that kind of all those kind of questions.
• 5:27
  SPEAKER_02: Okay.
• 5:27
  SPEAKER_02: That's so interesting.
• 5:28
  SPEAKER_02: That a little rebranding, slight rebranding change.
• 5:32
  SPEAKER_02: I mean, nothing's gonna change in the course content, it's just a name change.
• 5:35
  SPEAKER_01: And uh Yeah, but we s we so this is really interesting though.
• 5:39
  SPEAKER_01: I mean, you know, we struggle with this right in our field.
• 5:42
  SPEAKER_01: And I had a professor, one of the geoscience professors at Michigan Tech, he emailed me a few weeks ago and said, I want to come down downstate.
• 5:53
  SPEAKER_01: Now, that's no small thing, that's like a nine-hour drive, right?
• 5:56
  SPEAKER_01: It's a long way.
• 5:56
  SPEAKER_01: Yeah.
• 5:57
  SPEAKER_01: And he said, I want to come downstate.
• 5:59
  SPEAKER_01: I want to meet your classes, I want to see your classroom, I want to meet you, I want to talk to your classes about, and this is really cool, careers in geoscience.
• 6:09
  SPEAKER_02: Oh, that's amazing.
• 6:10
  SPEAKER_02: Okay, cool.
• 6:11
  SPEAKER_01: And then he's like, and then also if it would be okay with you, I would like to plug tech, Michigan tech, because we have it going on.
• 6:18
  SPEAKER_01: I'm proud of where I I I this is my alma mater.
• 6:22
  SPEAKER_01: I love this place, we do the best job, and oh, that's your kids need to give us consideration.
• 6:27
  SPEAKER_01: And it was so cool, you know.
• 6:29
  SPEAKER_01: So he came in yesterday actually and talked to my classes.
• 6:33
  SPEAKER_01: And uh really cool, you know, it's like uh I just loved the hustle of it, yeah, to be honest with you.
• 6:40
  SPEAKER_01: You know, like oh yeah, here's a university that's come down and kind of recruit anyway.
• 6:45
  SPEAKER_02: Hey, what am I doing here?
• 6:47
  SPEAKER_02: Come on, I gotta come to Hudsonville and do the exact same thing.
• 6:50
  SPEAKER_01: You you absolutely do.
• 6:52
  SPEAKER_01: I would I would so love that.
• 6:54
  SPEAKER_01: Oh, absolutely.
• 6:55
  SPEAKER_01: So the I thought this guy came down because Michigan Tech had an event last night, and I'm talking to him in between classes because he's stuck around.
• 7:03
  SPEAKER_01: I have you know, my first hour, then I have an off hour, and then I have my third hour.
• 7:06
  SPEAKER_01: So he had like a window of two hours.
• 7:08
  SPEAKER_01: So I'm asking him, like, are you here for that?
• 7:10
  SPEAKER_01: He's like, actually, no, I wasn't even invited to that event.
• 7:13
  SPEAKER_01: I came here to see you, you know, and I'm like, no kidding.
• 7:16
  SPEAKER_01: That's interesting.
• 7:17
  SPEAKER_02: I mean, that really I I think that's such a a good wow, okay.
• 7:22
  SPEAKER_02: He's doing a good job.
• 7:23
  SPEAKER_02: He's doing it right and uh, you know, conveying what the career opportunities are.
• 7:28
  SPEAKER_02: That's very cool.
• 7:28
  SPEAKER_02: And recruiting, too.
• 7:29
  SPEAKER_02: I mean, we're you know, we need to recruit.
• 7:31
  SPEAKER_02: Every university out there needs to recruit at the moment hard.
• 7:35
  SPEAKER_02: And that's a that's a good thing.
• 7:37
  SPEAKER_02: Well, that's super interesting, Chris.
• 7:38
  SPEAKER_02: Um I mean, I want to talk more about this, and I want to come to your class and tell him about the state is all that.
• 7:45
  SPEAKER_02: I'm actually giving a talk at a local college uh in a couple weeks, and one half of the talk will be kind of science.
• 7:51
  SPEAKER_02: It's big, it's one of these big public like talks, alumni supported, so it's an evening lecture.
• 7:57
  SPEAKER_02: Anyone from the public can come.
• 7:58
  SPEAKER_02: So it'll be half science and then half like I firmly believe in a lot of our people we interview have have conveyed this.
• 8:05
  SPEAKER_02: Like, it is a good time to be a geoscientist or even more a geologist.
• 8:09
  SPEAKER_02: Like, it is a good time to be in this space, and I want to kind of convey that in a talk with some data and with some kind of theories about why that is.
• 8:17
  SPEAKER_01: So um, I I know we got to jump into this real quick, but I'm sorry to interrupt.
• 8:22
  SPEAKER_01: But he, as this, as this uh this professor from Michigan Tech was talking to my classes, he pointed at me during this lecture, not lecture, but talk, you know, and he said, and one of your counselors advised one of your students a few years ago to not go into geologic engineering.
• 8:41
  SPEAKER_01: And and he said, I don't know his name, but this other professor, Luke, Dr.
• 8:47
  SPEAKER_01: Luke Bowman will know.
• 8:48
  SPEAKER_01: And and and so he said, You need to tell that counselor that he's now working in Alaska and he's making 150 G.
• 8:55
  SPEAKER_01: So you know, um So there you go.
• 8:58
  SPEAKER_01: Yeah.
• 8:59
  SPEAKER_01: So I found out exactly who the counselor was.
• 9:01
  SPEAKER_01: I know who the student was.
• 9:03
  SPEAKER_01: I figured it all out.
• 9:04
  SPEAKER_01: So yeah, I guess I have to talk.
• 9:06
  SPEAKER_02: Oh, that's super interesting.
• 9:08
  SPEAKER_02: All right.
• 9:08
  SPEAKER_02: Well, 10 minutes into this episode on Pudding Stone, we're finally getting to it.
• 9:12
  SPEAKER_02: But that's all very interesting.
• 9:13
  SPEAKER_02: And and uh the geoscience, yeah, this is a very exciting space.
• 9:16
  SPEAKER_02: Um, and we're gonna have a bunch of interviews kind of conveying this.
• 9:19
  SPEAKER_02: I mean, Richard Alley are about to record I mean, which is the title of his talk, Get Rich and Save the World.
• 9:24
  SPEAKER_02: I mean, that's the title of this talk.
• 9:26
  SPEAKER_02: It's an amazing pitch for exactly what we're talking about here.
• 9:29
  SPEAKER_02: So, anyways.
• 9:30
  SPEAKER_02: All right, can we go?
• 9:32
  SPEAKER_02: This is my idea, so I'm gonna lead it off, okay?
• 9:33
  SPEAKER_02: Yeah, yeah, yeah.
• 9:34
  SPEAKER_02: What's what are we doing?
• 9:35
  SPEAKER_01: All right, we're talking about we're talking about what you call it.
• 9:38
  SPEAKER_01: I mean, I guess it's called pudding stone.
• 9:40
  SPEAKER_01: I like to call it pudding stone.
• 9:42
  SPEAKER_01: Um, it's a little, it's it's a little, yeah, notice it's a merchandise twist on this.
• 9:47
  SPEAKER_01: Uh yeah, it's like you like to call it pudding stone.
• 9:49
  SPEAKER_01: I don't say pumpkin, I just like to say pumpkin, you know?
• 9:53
  SPEAKER_01: So yeah, yeah.
• 9:54
  SPEAKER_01: This is this is we're gonna talk about pudding stone today.
• 9:57
  SPEAKER_02: So, Chris, hold on.
• 9:58
  SPEAKER_02: We're just for when I'm writing the title, I need to take the G out and put an apostrophe in.
• 10:03
  SPEAKER_02: Is that what needs to happen here for this one?
• 10:05
  SPEAKER_02: Yes, please, please do, please do.
• 10:07
  SPEAKER_01: So pudding stone is a type of conglomerate, and the term come it's a special kind of conglomerate.
• 10:16
  SPEAKER_01: We're gonna get into that, but it's a term that comes from a conglomerate that resembles like traditional plum pudding or fruit pudding.
• 10:26
  SPEAKER_01: Okay, so in other words, it's this like this kind of cakey material that has fruit globs in it, and that's how Pudding Stone gets its name because it resembles that.
• 10:37
  SPEAKER_01: Exactly, Chris.
• 10:38
  SPEAKER_02: And the the key here, and we're gonna show a bunch of photos.
• 10:41
  SPEAKER_02: We've got some photos showing of a variety of things.
• 10:44
  SPEAKER_02: Throw one up, let's go.
• 10:45
  SPEAKER_02: Well, here we go.
• 10:46
  SPEAKER_02: Okay, so this one there's one, there's three main ones we're gonna highlight that we have pulled some photos from our own collections and from the web here.
• 10:53
  SPEAKER_02: But the key here for most putting stones or put in stones is we we differentiate sediments, especially when they have big classs in them, as either class supported or matrix supported.
• 11:06
  SPEAKER_02: And those terms I think should make sense if you kind of think about it a minute.
• 11:10
  SPEAKER_02: Like what's structurally valuable to this rock?
• 11:13
  SPEAKER_02: Is it the class and then the matrix fills matrix fills in the extra space?
• 11:18
  SPEAKER_02: Or is the matrix fundamentally the structural thing holding it together?
• 11:22
  SPEAKER_02: And in most pudding stones, it's a matrix-supported conglomerate.
• 11:27
  SPEAKER_02: So that the pudding pieces or the the plums in their plum, I don't know, what's the fr plums here?
• 11:34
  SPEAKER_01: It's like a fruit pudding or plum pudding.
• 11:37
  SPEAKER_02: It it's all yeah, the fruit pieces are not touching each other, they're floating around in a sea of matrix.
• 11:45
  SPEAKER_02: And you know, this first photo kind of shows us very few of the grains are actually touching each other here.
• 11:49
  SPEAKER_02: Um, and we can skip ahead even more to see something like this one.
• 11:53
  SPEAKER_02: We'll move down in the end, but uh uh you know, this this famous conglomerate later on in Michigan where the matrix is the is the structure and the plums are just floating in it, I think is that's a that is so that's such a good point, but it's such an interesting take because it's true.
• 12:11
  SPEAKER_01: What you said is true, it's matrix supported, but the beauty of a pudding stone are the clasts, okay?
• 12:18
  SPEAKER_01: Oh yeah.
• 12:19
  SPEAKER_01: Oh, it's the whole game.
• 12:20
  SPEAKER_01: And so yeah, so to in order for it to be a pudding stone, the classes have to be like this is kind of a general unwritten rule, I think, is that the clasts are of of very contrasting color, they are very different from the matrix that supports them.
• 12:37
  SPEAKER_02: That's right.
• 12:38
  SPEAKER_02: So they're usually very rounded as well.
• 12:42
  SPEAKER_02: Most putting put in put putting putting stones.
• 12:45
  SPEAKER_02: No, look, look, it's that's too much.
• 12:47
  SPEAKER_02: Puddin, it's pudding.
• 12:49
  SPEAKER_02: Okay.
• 12:49
  SPEAKER_02: Most puddin stones have very rounded classes as well.
• 12:52
  SPEAKER_02: So these are well-rounded conglomerates.
• 12:55
  SPEAKER_02: This first example here, this photo we're showing here from the Hertfordshire pudding stone in England is very rounded.
• 13:02
  SPEAKER_02: These are these are very rounded, very few sharp edges on the class, right?
• 13:06
  SPEAKER_01: So that's another and and so just from a from a geologic standpoint.
• 13:11
  SPEAKER_01: What that means is uh so first of all, it's conglomerate, the clasts are big.
• 13:15
  SPEAKER_01: These are gravel sized to you know bigger sized pieces, and that is indicative of the depositional environment, then so these were high energy, originally sedimentary, high energy sedimentary deposits, like uh a fluvial deposit that was like a fast-moving mountain stream kind of thing, high energy shoreline, possibly, but the because of the big class high energy.
• 13:39
  SPEAKER_01: And then the rounding is indicative of the degree of transport, the degree of erosion that took place.
• 13:44
  SPEAKER_01: And this was a significant amount of erosion, just simply because as these things are transported downstream, every impact they make it just rounds it off further and further and further.
• 13:56
  SPEAKER_01: And so that's just typical conglomerate stuff.
• 14:00
  SPEAKER_01: But the thing is, like, well, first of all, like Jesse, what are some examples of the classs?
• 14:06
  SPEAKER_01: We touched on a little bit, but let's like let's do that, right?
• 14:09
  SPEAKER_01: There's what are the clasts?
• 14:11
  SPEAKER_02: Yeah, the class can be a wide variety, and the three kind of the three different rocks we'll go through here, three different types of pudding stone will have different classs in them.
• 14:19
  SPEAKER_02: So some of them are are very are chert class, really famous ones that from when we grew up in Michigan.
• 14:24
  SPEAKER_02: Um the famous putting uh this would be you know pure silica jasper uh chemical red, yeah.
• 14:32
  SPEAKER_02: Um, some of the class will be quartzite.
• 14:34
  SPEAKER_02: Out here in eastern Pennsylvania, we have conglomerates, these pudding stones that have basically pure white quartzite as the class material itself, and then other ones will have little volcanic rocks, you know, volcanic or igneous rocks that are the class.
• 14:47
  SPEAKER_02: So the class can be a lot of different compositions, and that's really powerful because if we have a rock that's made up of class of other rocks, and you think of you said a fluvial environment, which is a river environment.
• 14:57
  SPEAKER_02: This is a kind of a river system.
• 14:59
  SPEAKER_02: Think of like a channel bar or a channel cut where there's gravel in the bottom there, and then that gets covered over by sand later on.
• 15:06
  SPEAKER_02: That can be a formation setting for putting stone.
• 15:09
  SPEAKER_02: But by looking at the class, we can tell what was that river eroding?
• 15:13
  SPEAKER_02: What was the the catchment or the river drainage basin?
• 15:16
  SPEAKER_02: What was the geology or the makeup of that drainage basin?
• 15:19
  SPEAKER_02: Was it a huge drainage basin or a really small one?
• 15:22
  SPEAKER_02: So we can study the class and therefore study the actually erosional surface back when this sediment was deposited, when this putting stone.
• 15:29
  SPEAKER_01: In other words, you're talking about like we can sometimes point to the source area.
• 15:32
  SPEAKER_01: Where did these these pieces are distinctive enough oftentimes where they come from a very specific precise location, which I think is a really cool aspect to conglomerate, you know?
• 15:44
  SPEAKER_01: Yeah.
• 15:44
  SPEAKER_02: And and and again, or or you know, that's one example.
• 15:47
  SPEAKER_02: Another example is let's say is you've got uh one class that's uh one age, another one that's a totally different age from a totally different geological province.
• 15:55
  SPEAKER_02: It means that that river, that the basin that was draining into that river system was huge, right?
• 16:00
  SPEAKER_02: So you can both tell like where the sediment was coming from, where these classes were derived from, but also how big was the river's drainage basin, um, which is a really cool feature of these conglomerates.
• 16:12
  SPEAKER_01: So here's a rule All putting stones are conglomerate, not all conglomerate is put in stone.
• 16:19
  SPEAKER_02: Yeah, right.
• 16:20
  SPEAKER_02: Nicely said, nicely said.
• 16:22
  SPEAKER_01: It's a just this general thing, and what we're looking for is these classed, the matrix-supported classes that are have really contrasting colors to that matrix, and it makes it resemble and it does.
• 16:37
  SPEAKER_01: I mean, if you Google image fruit pudding, you know, you you get these, it it looks just like it, and it's so cool.
• 16:44
  SPEAKER_01: So special kind of conglomerate.
• 16:47
  SPEAKER_02: Yeah, the other rule is they have to be kind of beautiful, and most conglomerates are pretty beautiful, but these ones are like spectacularly pretty with the contrasting colors as you're describing them, right?
• 16:56
  SPEAKER_02: So we can do a lot scientifically with these pudding stones, and they have they have served many different purposes, and it depends which pudding stone we're talking about, and we'll work through three of them here, but we can do things like reconstruct past river systems.
• 17:11
  SPEAKER_02: We've talked about that climate conditions.
• 17:12
  SPEAKER_02: We're gonna touch on that with the last pudding stone, the one that's exposed in around the Michigan area, um, talk about ancient climate conditions.
• 17:20
  SPEAKER_02: We can use these rocks because they're deposited in like a river setting, a riverine setting.
• 17:25
  SPEAKER_02: And so that is very intimately connected to climate at that time.
• 17:30
  SPEAKER_01: Something else to think about.
• 17:31
  SPEAKER_01: I'm just gonna pose it as a question, then we'll we'll talk about this, right?
• 17:34
  SPEAKER_01: But how maybe would puddin stone or pudding stone?
• 17:37
  SPEAKER_01: Because I can see it bothers you when I say it every time this is cringy.
• 17:43
  SPEAKER_02: No, it's just uh it's like positive.
• 17:45
  SPEAKER_02: I never I'm not confident I'm gonna say it right, so I don't want to butcher it.
• 17:48
  SPEAKER_02: So I'll stick with what I know.
• 17:49
  SPEAKER_01: It's not positive, you know, like a dog's paw.
• 17:53
  SPEAKER_02: Case in point, Chris, case in point.
• 17:55
  SPEAKER_02: I'm just gonna botch it.
• 17:56
  SPEAKER_02: So I'll stick with what I know.
• 17:57
  SPEAKER_02: Thank you very much.
• 17:59
  SPEAKER_01: How might pudding stone be related to plate tectonics, to to tectonic activity and and tectonic uplift?
• 18:08
  SPEAKER_01: That's one of the geologic significances of pudding stone is that it is tied to that because it it may indicate this like extensive mountain building event that provided ample sediment then to get carried away and then later deposited.
• 18:24
  SPEAKER_01: And and we can tie those classes back to that mountain building event.
• 18:28
  SPEAKER_01: So you know it's important from that standpoint.
• 18:31
  SPEAKER_02: Let's think about this because a pudding stone just has a kind of um it's a little bit counterintuitive.
• 18:37
  SPEAKER_02: Um, and here's the reason you have large cobbles or large classes, which those are heavy, so those are not easy to transport, right?
• 18:45
  SPEAKER_02: Those those require high energy, you know, river to transport those things, but they're also very well rounded, which means they had to be transported kind of far.
• 18:54
  SPEAKER_02: And so you need to have high energy and far transport to get big cobbles that are well rounded, and that means something pretty peculiar or pretty, let's say, unique about the debuff settings.
• 19:07
  SPEAKER_02: So high mountain ranges, you know, where there's a lot of the river is cascading down thousands of feet of mountains, is a good way to do that.
• 19:15
  SPEAKER_02: So that's right.
• 19:16
  SPEAKER_02: Anyway, scientifically, that's what we can do.
• 19:18
  SPEAKER_02: And then we already touched on the provenance.
• 19:20
  SPEAKER_02: We can look at the class so we can study the individual.
• 19:23
  SPEAKER_01: Let's explain what you mean by so provenance means the the source, right?
• 19:28
  SPEAKER_01: That's your fancy term for you know, where did they come from?
• 19:32
  SPEAKER_01: That's how I stick my finger up in the air while we're talking about what's going on.
• 19:34
  SPEAKER_01: Yeah, you do provenance.
• 19:36
  SPEAKER_01: Yeah.
• 19:37
  SPEAKER_01: Well, uh Jesse, let's just get into then some really exceptional examples of pudding stone.
• 19:45
  SPEAKER_01: And we'll end with my favorite, of course, because it comes from my beloved state of Michigan.
• 19:49
  SPEAKER_02: No, my favorite too, because you and I we grew up, uh we went, we've we've spent ample time looking in gravel pits in Michigan for pudding stone.
• 19:57
  SPEAKER_02: Um, all right, we're gonna start with one called the Hertfordshire Pudding Stone from England from the UK.
• 20:03
  SPEAKER_02: This is a silicified conglomerate, so it has had silica enriched.
• 20:10
  SPEAKER_02: So it's had silica flushed through this rock.
• 20:13
  SPEAKER_02: And silica, which makes up quartz, is is easily dissolved in fluids.
• 20:18
  SPEAKER_02: And so if you can dissolve it in fluids, you can flush it through rocks that have porosity permeability, and you can pass fluids through them.
• 20:25
  SPEAKER_02: So sediments, you can flush it through with silica.
• 20:28
  SPEAKER_01: Let's talk about that a second, though, because silica actually is not easily dissolved.
• 20:32
  SPEAKER_01: Not at least in terms of a common cementing agent or you know that kind of thing that binds it together.
• 20:38
  SPEAKER_01: This might be indicative of something special, right, Jesse?
• 20:42
  SPEAKER_01: Yeah.
• 20:42
  SPEAKER_01: Well, you need to have pretty high temperatures, high temperature fluid.
• 20:46
  SPEAKER_02: I mean, we're not talking about like ocean water, at least modern ocean water.
• 20:49
  SPEAKER_02: We're talking about relatively high temperature fluids that you will get sort of in the crust, not uh surface waters, really.
• 20:56
  SPEAKER_02: So, yeah, that's a really good point.
• 20:58
  SPEAKER_01: Uh again, points back to the geologic significance of what you have in this rock, you know.
• 21:02
  SPEAKER_01: Right.
• 21:02
  SPEAKER_01: Um, yeah, water is a powerful solvent, but hot water is even more powerful as a solvent, especially if it's hot and salty.
• 21:09
  SPEAKER_02: Exactly.
• 21:09
  SPEAKER_02: And in this rock, this image we're looking at here, um, you can go again to our Camp Geo app and see the visual podcast version of this.
• 21:16
  SPEAKER_02: Um, also on YouTube, you can see this as well.
• 21:18
  SPEAKER_02: But basically, these all all these uh cobbles or all these classes, many of them at least, have this dark rim on them, this dark rind, which is silicification kind of front.
• 21:27
  SPEAKER_02: So this is the silica flowing through the matrix.
• 21:29
  SPEAKER_02: It's easier to flow through the matrix, and it it has a hard time getting into the cobbles, so it makes these beautiful concentric rings around these cobbles, and you know, it's driving different reactions in different cobbles, but but it it's all just for reference to when when you're referring to the matrix, you're referring to the finer grained, basically the cement that is supporting these big clasts, right?
• 21:51
  SPEAKER_02: Yeah, thanks.
• 21:52
  SPEAKER_02: Yeah, that's exactly right.
• 21:54
  SPEAKER_02: That's exactly right.
• 21:55
  SPEAKER_01: And here this wait this hurt hurt Hertfordshire has mystical powers.
• 22:00
  SPEAKER_01: Jesse?
• 22:01
  SPEAKER_02: Well, rumor has it.
• 22:03
  SPEAKER_02: Rumor has it.
• 22:03
  SPEAKER_02: It's mystical power.
• 22:05
  SPEAKER_02: Actually, we've referred to this in an old podcast episode.
• 22:07
  SPEAKER_02: I don't actually remember.
• 22:08
  SPEAKER_02: I was trying to remember where we referred to this, but this was a rock that was thought to procreate.
• 22:15
  SPEAKER_02: Um, because you can imagine why, right?
• 22:17
  SPEAKER_02: You've got this conglomerate.
• 22:19
  SPEAKER_02: Wasn't that Devil's Tower?
• 22:20
  SPEAKER_01: Uh, was it Devil's Tower episode?
• 22:22
  SPEAKER_01: We refer to the Tower grew.
• 22:24
  SPEAKER_02: I mean, well, no, we referred to this particular pudding stone.
• 22:27
  SPEAKER_02: Oh, did we?
• 22:28
  SPEAKER_02: Okay.
• 22:28
  SPEAKER_02: And we referred to the the ancient lore um that you know, this would come up in fields, like seasonally, these these putting stones would kind of come up in fields.
• 22:37
  SPEAKER_02: If you look at this rock, it looks like you have a bunch of baby rocks inside the rock.
• 22:41
  SPEAKER_02: And then this rock is kind of being birthed from the ground.
• 22:43
  SPEAKER_02: So you can imagine how this lore starts that like this rock is procreating down in the earth and forming more of itself, and it's coming to the surface, and every year we have to freaking get it out of our fields so we can grow potatoes or whatever the heck is grown in Hertfordshire.
• 22:57
  SPEAKER_02: Sorry if anybody's from there and I'm getting the crop wrong.
• 23:00
  SPEAKER_01: But it's such big the no, don't worry, it is such a pretty rock.
• 23:04
  SPEAKER_01: Like, I I love this rock is is a pretty amazing rock.
• 23:08
  SPEAKER_02: And there's a lot of varieties of it.
• 23:09
  SPEAKER_02: Uh for me personally, this one on the right here.
• 23:11
  SPEAKER_02: You know, we're talking this is gray cobbles with these dark rims and this kind of gray matrix.
• 23:17
  SPEAKER_02: Stunningly beautiful.
• 23:18
  SPEAKER_02: This is a exceptionally beautiful rock.
• 23:21
  SPEAKER_02: I I love this rock.
• 23:22
  SPEAKER_02: Yeah.
• 23:22
  SPEAKER_02: So I don't know.
• 23:24
  SPEAKER_02: That's that's kind of the Hertfordshire one that silicified.
• 23:27
  SPEAKER_02: And I've seen countertop material, Chris.
• 23:30
  SPEAKER_02: Um, actually, one of my collaborators who works in the Northwest Territories has this countertop material.
• 23:34
  SPEAKER_02: It's not this rock, it's a similar one, a silicified conglomerate that has, I think it came from Brazil, maybe.
• 23:42
  SPEAKER_02: I I don't remember the name of it, but when you cut and polish this stuff, man, is it spectacularly beautiful.
• 23:48
  SPEAKER_01: It reminds me so much of the Terrazzo floors in my hallways at school.
• 23:53
  SPEAKER_02: Oh, yeah.
• 23:54
  SPEAKER_02: Like the the um yeah, the the the sort of fake concrete with the little flu uh flecks in it and stuff.
• 23:59
  SPEAKER_02: Yeah.
• 24:00
  SPEAKER_01: It looks a lot like that.
• 24:01
  SPEAKER_02: It's really good.
• 24:02
  SPEAKER_02: Yeah, totally, totally.
• 24:04
  SPEAKER_02: Okay, Chris, number two.
• 24:06
  SPEAKER_01: The Roxbury conglomerate, Massachusetts.
• 24:08
  SPEAKER_01: You know, we've been here.
• 24:10
  SPEAKER_01: We've we've collected here.
• 24:11
  SPEAKER_01: We have.
• 24:12
  SPEAKER_01: That's right.
• 24:13
  SPEAKER_02: Not here in this photo, but uh this is this is a photo from Gettysburg.
• 24:16
  SPEAKER_02: We have not collected at Gettysburg.
• 24:18
  SPEAKER_01: This is just sacred.
• 24:21
  SPEAKER_02: We've both been to Gettysburg uh separately.
• 24:23
  SPEAKER_02: And actually, we've been working on putting together a geology of the Battle of Gettysburg episode, which will be very exciting.
• 24:29
  SPEAKER_02: It's just taking a long time to kind of wrap our heads around exactly what we want to say about it.
• 24:33
  SPEAKER_02: But this is a photo, this is an image of a big monument, a big this is a huge block of conglomerate that was shipped down from Massachusetts in honor of the the 20th Massachusetts Infantry and is on the field at at Gettysburg there.
• 24:46
  SPEAKER_01: Um Yeah, I'm trying to remember like where is so it's July 3rd.
• 24:51
  SPEAKER_01: Is it Pickett's charge?
• 24:52
  SPEAKER_01: Like I I don't know where this is.
• 24:54
  SPEAKER_01: Honestly, I'm not familiar with with the battlefield of Gettysburg.
• 24:59
  SPEAKER_01: I've been there so many times, uh but I've I don't recall this monument, and and I have to fix that.
• 25:05
  SPEAKER_01: That's a shame.
• 25:06
  SPEAKER_02: Well, look it up and report back.
• 25:07
  SPEAKER_02: I will absolutely yeah.
• 25:09
  SPEAKER_01: Um this is the official rock of Massachusetts.
• 25:14
  SPEAKER_02: Yes, interesting, right?
• 25:16
  SPEAKER_02: Uh uh a pudding's a puddin stone is the official rock of Massachusetts.
• 25:20
  SPEAKER_02: I'm not sure how the the New Englandites would appreciate it being pronounced puddin stone, but you know, whatever.
• 25:27
  SPEAKER_02: Chris, this this rock what is the state rock of Michigan?
• 25:31
  SPEAKER_02: I don't actually know that.
• 25:32
  SPEAKER_02: Do you know?
• 25:32
  SPEAKER_02: Potaski.
• 25:34
  SPEAKER_02: Of course.
• 25:34
  SPEAKER_02: Oh, that's obvious.
• 25:35
  SPEAKER_02: Yeah, duh.
• 25:36
  SPEAKER_02: Okay.
• 25:36
  SPEAKER_01: Yeah.
• 25:37
  SPEAKER_01: Right.
• 25:37
  SPEAKER_01: Yeah, which is uh Potaski is a type of coral organism.
• 25:42
  SPEAKER_01: It's really pretty.
• 25:43
  SPEAKER_01: It's known for this kind of honeycomb look to it.
• 25:46
  SPEAKER_01: It's pretty amazing.
• 25:48
  SPEAKER_02: Very beautiful.
• 25:49
  SPEAKER_02: Um, and uh I you know, I just had to look this up a minute, but Pennsylvania does not have a state stone, apparently.
• 25:56
  SPEAKER_02: Interesting.
• 25:56
  SPEAKER_02: Oh, good.
• 25:57
  SPEAKER_02: No state stone.
• 25:58
  SPEAKER_02: We might have to go by changing that.
• 26:00
  SPEAKER_02: That needs to be fixed, Dr.
• 26:02
  SPEAKER_02: No State Stone, no state mineral.
• 26:04
  SPEAKER_02: What the heck?
• 26:05
  SPEAKER_02: Oh no.
• 26:06
  SPEAKER_01: And you guys have great rocks.
• 26:08
  SPEAKER_02: You have great and great rocks, and we have a great and long history of geology.
• 26:12
  SPEAKER_02: Uh it's crazy.
• 26:13
  SPEAKER_02: What do we what are we doing over here?
• 26:14
  SPEAKER_02: We've got to get it together.
• 26:15
  SPEAKER_02: It needs to be taken care of.
• 26:16
  SPEAKER_01: So coming out of state college in the near future, state rock.
• 26:21
  SPEAKER_02: Uh maybe this will be my platform for running for office in Pennsylvania.
• 26:25
  SPEAKER_01: Please don't ever do that.
• 26:27
  SPEAKER_01: Please don't.
• 26:28
  SPEAKER_01: That's not good.
• 26:28
  SPEAKER_01: I cherish you as a friend, and we might have to part ways if you become a politician.
• 26:32
  SPEAKER_02: So no no no no.
• 26:34
  SPEAKER_02: I could you come stump for me.
• 26:35
  SPEAKER_02: That's what you'd have to do.
• 26:37
  SPEAKER_02: That's true.
• 26:37
  SPEAKER_02: That's true.
• 26:38
  SPEAKER_02: So back to the Roxbury conglomerate.
• 26:40
  SPEAKER_02: So this is a this is a 580, 590 million year, somewhere in that ballpark.
• 26:45
  SPEAKER_02: The breakup of a supercontinent is really what's happening here on the eastern seaboard pre-appalaisions, the breakup of the supercontinent, big rift basins forming, big river systems, ancient river deposits dumped in this Roxbury conglomerate.
• 26:59
  SPEAKER_02: And this, if you can see a photo, there's uh science museums in Boston, uh at universities in in Massachusetts and in New England who have slabs of this.
• 27:08
  SPEAKER_02: It's a very common building stone in the Boston area.
• 27:11
  SPEAKER_02: It's spectacular.
• 27:12
  SPEAKER_02: Bright red cobbles, green cobbles, set in a kind of a greenish matrix.
• 27:17
  SPEAKER_02: It's really, really beautiful.
• 27:18
  SPEAKER_02: And Chris, I'm going to skip ahead here a photo.
• 27:21
  SPEAKER_02: This is these ages of rocks, these conglomerates like this occur all up and down the eastern seaboard.
• 27:28
  SPEAKER_02: There are different basins that formed in this 530 to 580 million year interval that are in the what's called Piedmont area, and is sort of you get east of the Appalachians.
• 27:38
  SPEAKER_02: There's a whole bunch of these old basins that dumped around that time, 530, 580 million years ago, formed conglomerates.
• 27:45
  SPEAKER_02: And this is a photo of a conglomerate that I collected in York, Pennsylvania, um, where we used to live.
• 27:50
  SPEAKER_02: And this is a big bookend.
• 27:52
  SPEAKER_02: I mean, it doesn't really look like it, but it's like a foot and a half tall.
• 27:54
  SPEAKER_02: It does big pure, pure quartzite cobbles in there, bright white cobbles in a really green chloride-rich matrix.
• 28:02
  SPEAKER_02: So it's been metamorphosed to get that green color.
• 28:06
  SPEAKER_02: I was gonna ask you about that.
• 28:07
  SPEAKER_01: And and also, too, Jesse, these quartzite clasts are not very well rounded.
• 28:13
  SPEAKER_01: At least some of them, you know.
• 28:15
  SPEAKER_02: And and it's it's actually class supported, so it's not technically a pudding stone, but this is just to show that like these kind of extensional environments create a lot of rocks like this, and it all up and down the eastern seaboard, you can find out crops of this stuff.
• 28:29
  SPEAKER_02: So the Roxbury conglomerate is one of them, and that the Roxbury Pudding Stone, another name for it.
• 28:34
  SPEAKER_02: Very famous pudding stone.
• 28:36
  SPEAKER_01: Okay.
• 28:36
  SPEAKER_01: So Chris.
• 28:37
  SPEAKER_01: Well, Jesse, can we get to the big show now?
• 28:39
  SPEAKER_01: Let's get to the show.
• 28:41
  SPEAKER_01: I'm not talking about me, I'm not, I'm talking about the the the rock.
• 28:44
  SPEAKER_01: Okay.
• 28:45
  SPEAKER_01: The rock.
• 28:46
  SPEAKER_02: I I did I do see that the the guns are out today with the short sleeve shirt on, despite it being freezing cold in Michigan, I'm sure, right now.
• 28:52
  SPEAKER_01: Yeah, but I'm warm and toasty in my house.
• 28:54
  SPEAKER_01: So yeah, let's let's go to the Lorraine quartzite pudding stone or pudding stone.
• 29:00
  SPEAKER_01: Oh man.
• 29:01
  SPEAKER_01: Which I I think is the Michigan, it's the you know, it's the Ontario, Canada, but it's the it's the Michigan pudding stone, if I'm gonna be for quite honest with you.
• 29:10
  SPEAKER_02: Well, in here um here's here's why, Chris.
• 29:12
  SPEAKER_02: Let me just say why that is.
• 29:14
  SPEAKER_02: This rock is exposed in the bedrock in Ontario, so right across Lake Huron from Lake Michigan, it's kind of the northeast side of Lake Huron.
• 29:24
  SPEAKER_02: There's exposures of it.
• 29:25
  SPEAKER_02: And what that means for Michigan is that this rock is everywhere in Michigan because as the glaciers scraped down, they were kind of coming into Michigan area, kind of straight down to the south or down to the southwest, scraping across that direction.
• 29:39
  SPEAKER_02: So this conglomerate, this rock, has been broken up by the glaciers and deposited all over Michigan.
• 29:45
  SPEAKER_02: You can usually, if you find a cobbly beach on the on the Michigan side of Lake Michigan, on the east side of Lake Michigan, you can usually find a piece of this, of this conglomerate, because it's that common in the glacial till and the glacial kitty litter that that is all over Michigan.
• 30:03
  SPEAKER_01: And it's common too in gravel pits.
• 30:06
  SPEAKER_01: Um I mean, it's like super common.
• 30:09
  SPEAKER_01: You can find well, I mean, super common.
• 30:11
  SPEAKER_01: Uh you know, you can find it in gravel pits, and you can find like fist-sized pieces up to really, really big size.
• 30:19
  SPEAKER_01: House size, spectacular, yes.
• 30:21
  SPEAKER_02: If the owners and operators of the gravel pit have half a brain in their head and you drive past one, the gravel pit, you'll usually see a big piece of this like sitting out like gateposts because they've recognized this is a really cool rock, we got to go put that out front of our building or of our you know, parking lot, or of the entrance to the gravel pit.
• 30:40
  SPEAKER_02: So it's uh you and I, Chris, have have we've we've gone fishing in a lot of gravel pits for rocks for this rock, exactly.
• 30:47
  SPEAKER_02: And we've gotten some some I've got a beautiful monster piece that I've dragged all over everywhere I've moved.
• 30:52
  SPEAKER_02: It's um sitting in my yard right now from those gravel pits.
• 30:55
  SPEAKER_01: So I call it the big show because to me it's the prettiest.
• 30:59
  SPEAKER_01: I love this picture that you have up there right now.
• 31:01
  SPEAKER_02: I mean, there's no doubt, and let's zoom in the next one here, Chris.
• 31:04
  SPEAKER_02: Let's let's zoom in on this.
• 31:05
  SPEAKER_02: There's no doubt, this is a stunningly beautiful rock.
• 31:07
  SPEAKER_01: And what makes it so stunning is the contrast.
• 31:10
  SPEAKER_01: You have this really light-colored white to light gray quartzite matrix.
• 31:17
  SPEAKER_01: So it's a this is a meta conglomerate.
• 31:19
  SPEAKER_01: It was a sandstone that was the matrix supporting these what are the Jasper clasts, these red, beautiful red clasts in it.
• 31:28
  SPEAKER_01: And then it got metamorphosed.
• 31:29
  SPEAKER_01: We'll talk about that in a second.
• 31:30
  SPEAKER_01: But so I call it the big show because it is to me the most beautiful, and also it's 2.3 billion years old.
• 31:38
  SPEAKER_01: I mean, this is a very I don't know.
• 31:41
  SPEAKER_01: Like that's just that's impressive.
• 31:43
  SPEAKER_01: It's it's such a beautiful rock.
• 31:48
  SPEAKER_01: So it is the big show of the pudding stones to me.
• 31:53
  SPEAKER_02: Chris, there is a big scientific story that these this rock tells too.
• 31:57
  SPEAKER_02: First of all, I want to touch on a couple things.
• 31:59
  SPEAKER_02: The red class, beautiful Jasper kind of uh Jasper nodules in here, very red.
• 32:05
  SPEAKER_02: This this photo, we're zooming in a little bit here, so you can see a couple big red class, a lot of big white class, and then this white sandy matrix, this ultra clean sandy matrix.
• 32:14
  SPEAKER_02: There's a really cool story in this rock, and in this kind of the the outcrop or the series of rocks that these conglomerates are exposed in.
• 32:23
  SPEAKER_02: First, I want to point go back to this photo where we we're showing this is really a conglomerate lens in a sandstone, right?
• 32:30
  SPEAKER_02: It's not hundreds of meters of conglomerate with jasper in it, it's little lenses that are conglomerate rich with quartzite and you know more around it.
• 32:38
  SPEAKER_02: Sandstone is much more common in this Lorraine group or Lorraine formation.
• 32:42
  SPEAKER_02: But the store the scientific story here is really cool.
• 32:45
  SPEAKER_02: This is part of a package of rocks that's a really famous package of rocks called the Huronian supergroup.
• 32:51
  SPEAKER_02: And these things are like 2.4 to 2.3, 2.2 billion years old.
• 32:55
  SPEAKER_02: And they contain a record of a really interesting geological history of probably snowball Earth events, like global ice age events, and really a climate that was oscillating wildly between an ice planet and a greenhouse planet, an ice house planet and a greenhouse planet.
• 33:13
  SPEAKER_02: Like our, you know, right now we have this, we've talked about you know the greenhouse effect and climate dynamics, and and we have a climate that oscillates back and forth, and there's some thermostat regulator on that.
• 33:24
  SPEAKER_02: And back in time, that might have that regulation might have been way off, and so it's going glaciers everywhere, no glaciers anywhere, glaciers everywhere, no glaciers anywhere, something like that.
• 33:34
  SPEAKER_02: And this particular rock, from the base of that Heronian supergroup sequence to the top where this Lorraine quartzite sits, shows a record of no oxygen in the atmosphere at the base, to these rocks contain a record of oxygen in the atmosphere.
• 33:52
  SPEAKER_02: So the first time that Earth got oxygen, free oxygen, O2 in the atmosphere, called the great oxygenation event, was around this time, 2.2, 2.3 billion years ago.
• 34:02
  SPEAKER_02: And the evidence, some of the evidence, comes from this rock where we have quartz crystals, the little quartz crystals in the sandstone, have little hematite coatings around them, little red hematite coatings.
• 34:13
  SPEAKER_02: You could kind of see it in this photo, just a little bit hints of it.
• 34:16
  SPEAKER_01: Um now can I interrupt, Jesse?
• 34:18
  SPEAKER_01: Is that because the hematite can't precipitate unless there's oxygen present?
• 34:26
  SPEAKER_01: Beautiful because absolutely dissolved in water all you want.
• 34:33
  SPEAKER_01: You can saturate it with iron, but it stays in that form unless there's oxygen present, then it can precipitate, which that forms the iron oxide, the mineral hematite, which is one of my favorite minerals, by the way.
• 34:45
  SPEAKER_02: Yeah, you know, it's I mean, and and hematite is is a really oxidized form of iron.
• 34:50
  SPEAKER_02: You know, there's there's more oxygen in that mineral than there is um, you know, magnetite, for instance, which is iron and oxygen, but a different proportion of that.
• 34:57
  SPEAKER_02: And at the bottom of this sequence, so at the bottom of the Herodian supergroup, you have rocks with detrital pyrite in it and detrital uraninite, which we'll talk about these in later episodes where we talk about this great oxygen event.
• 35:10
  SPEAKER_02: Um, but basically, those minerals cannot survive if there's oxygen free oxygen in the atmosphere.
• 35:16
  SPEAKER_02: They'll create sulfuric acid, they'll create acid mine drainage, what we call acid mine drainage.
• 35:21
  SPEAKER_02: If you take pyrite and expose it to the modern atmosphere with loads of oxygen, it creates sulfuric acid and mass acid mine drainage right now.
• 35:28
  SPEAKER_02: Um, it's a really interesting story.
• 35:30
  SPEAKER_02: It's an absolutely beautiful rock.
• 35:33
  SPEAKER_02: I I mean I love this rock.
• 35:34
  SPEAKER_01: I I want to maybe this is a a prelude to another episode, then, because that was super interesting.
• 35:40
  SPEAKER_01: Um, you got really doctory on me there because all I was gonna say is this is a conglomerate that got metamorphosed, you know, it got buried really deep.
• 35:49
  SPEAKER_01: But I have a story about this that to me that is relatable, I think, because I think a lot of our listeners do a fair amount of traveling and and exploring in the western United States, for instance.
• 36:00
  SPEAKER_01: So this conglomerate with all of the jasper and these rounded jasper clasts surrounded in a matrix of quartzite because of metamorphism, this kind of low grade but confining pressure metamorphism.
• 36:13
  SPEAKER_01: So you don't get foliation, you don't get this alignment is very similar to what we find in Glacier National Park, which in our in the surrounding areas, which is this mud chip brecia rock.
• 36:25
  SPEAKER_01: Oh, yeah, it's identical to this.
• 36:28
  SPEAKER_01: Yeah, so what you have are these red oxidized iron-rich mud chips that during storm events the mud chips would get ripped up and carried in this sand and deposited then, and the only sorting you get is just really rapid deposition, and then it got buried and metamorphosed into this kind of mud chip breccia, it's a meta brecha rock.
• 36:53
  SPEAKER_01: It's spectacular, it's such a cool story, but it looks identical to our conglomerate here, minus the rounded class, their own angular, okay, yeah, yeah, yeah.
• 37:04
  SPEAKER_02: It's such a cool thing, you know.
• 37:06
  SPEAKER_02: I mean, the stories I I I just love these rocks.
• 37:10
  SPEAKER_01: The stories that these rocks are stories of rocks are amazing, you know.
• 37:14
  SPEAKER_01: It's amazing.
• 37:14
  SPEAKER_02: And I I, you know, I I study you and I love the hard rocks.
• 37:18
  SPEAKER_02: We love the igneous and metamorphic rocks, right?
• 37:21
  SPEAKER_02: The story in those rocks is amazing.
• 37:24
  SPEAKER_02: It's a little harder to look at and extract the story out of those types of rocks.
• 37:29
  SPEAKER_02: You look at something like this, this pudding stone here, and you say, Oh, there used to be jasper exposed on the surface of the earth, and that got eroded and deposited in this ancient stream bed.
• 37:40
  SPEAKER_02: You can stand on the outcrop, explain that story, and it just hits you in the face.
• 37:43
  SPEAKER_02: It just says, Oh, okay, I get it.
• 37:45
  SPEAKER_02: That's amazing.
• 37:46
  SPEAKER_02: So sediments have this beautiful they are very good at at exposing this very descriptive storytelling that rocks contain.
• 37:54
  SPEAKER_02: Uh I so I love sediments for that, for that fact.
• 37:57
  SPEAKER_01: Well, I wanna I want to wrap up this maybe this segment here by just saying that these rocks were brought to Michigan from Canada about 24,000 years ago from the Laurentide ice sheet.
• 38:10
  SPEAKER_01: But I I wanna without like can we just mean to make this quick, Jesse?
• 38:14
  SPEAKER_01: So I'm gonna limit you on this.
• 38:15
  SPEAKER_01: You get a short leash, but how how can we say that the original rock was 2.3 billion years old?
• 38:24
  SPEAKER_01: Do you have a like can you do that in a quick way?
• 38:27
  SPEAKER_02: So there's a couple different ways.
• 38:30
  SPEAKER_02: The most reliable way is to date ash fall deposits that are in with the sediments.
• 38:37
  SPEAKER_02: So in this huge sequence of the Heronian supergroup, there are ash deposits that are embedded in the sequence.
• 38:45
  SPEAKER_02: Um, if you don't have ash in the sequence, so if there's ash fall, we can extract zircons from that and date those zircons and say, okay, we know when that volcano erupted, you know, plus or minus 50,000 years, which is plenty of age resolution for this time.
• 38:59
  SPEAKER_02: If we don't have that, you have to go back to some really basic first principle geology.
• 39:03
  SPEAKER_02: What's the rock that the lowest sediment is?
• 39:06
  SPEAKER_01: Cross-cutting relations and things like that.
• 39:08
  SPEAKER_01: Cross-cutting relations.
• 39:08
  SPEAKER_02: Yep.
• 39:09
  SPEAKER_02: And exactly that's where we get the 2.2 number.
• 39:11
  SPEAKER_02: So the top of this sequence, you know, that 2.3, 2.2 number is a little bit well, it depends which sequence we're talking about here, but there are some cross-cutting dikes that are dated around 2.15.
• 39:24
  SPEAKER_02: So that provides a minute, you know, a minimum.
• 39:26
  SPEAKER_01: That's so cool.
• 39:27
  SPEAKER_01: So even here we have multiple tools in our box that we're using to date the big show of putting stone conglomerates, metal.
• 39:37
  SPEAKER_01: That's exactly right.
• 39:38
  SPEAKER_01: So that's that's pretty awesome.
• 39:40
  SPEAKER_02: Well, we're looking at a rock like this, we can provide a maximum depositional age on it too.
• 39:45
  SPEAKER_02: We could say what is the oldest this rock could be, and that's by looking at the the class in there and looking at any minerals in that rock, because any minerals in that rock had to form before the rock itself.
• 39:56
  SPEAKER_02: It's you know, principle of inclusions is what we call that.
• 39:58
  SPEAKER_02: Uh, so if I date zircons in the conglomerate, the youngest zircon has to be older than the age of the rock.
• 40:07
  SPEAKER_02: So the youngest zircon is the maximum depositional age, it provides an upper bound on the age of this conglomerate by you know doing that kind of basic geograchronology.
• 40:15
  SPEAKER_02: So you're right, it's it's we have loads of tools to tell these stories with or tease apart the story.
• 40:20
  SPEAKER_01: And and also just to reiterate, uh we've covered this before, but it doesn't, it never hurts to cover this ground again.
• 40:26
  SPEAKER_01: Is that dating sedimentary rocks, which I know this is metamorphic, but the original rock was sedimentary, is exceedingly difficult because you're dealing with clasts that got eroded, weathered and eroded out of another rock that formed at a different time.
• 40:42
  SPEAKER_01: So it doesn't give you the time of deposition, it gives you the time of formation from the parent rock that kind of gave birth to the clasts that became this rock.
• 40:53
  SPEAKER_01: So it's uh it's tough.
• 40:55
  SPEAKER_01: And uh, you know, we've covered this in detail before, but it never, like I said, it never hurts to cover ground again, I think.
• 41:01
  SPEAKER_02: I mean, it never gets old too, talking about geochronology in in beautiful rocks.
• 41:05
  SPEAKER_02: Um the last the last thing, Chris, I'll note here about putting stone.
• 41:08
  SPEAKER_02: This is a very this is a a photo of a pudding stone rock that I have cut.
• 41:13
  SPEAKER_02: I mean, I mentioned this before on the podcast, but we have this little Etsy store that we cut rocks and and I haven't haven't done much recently with it because we've been moving and my rock saws have been defunct button.
• 41:22
  SPEAKER_02: Decommissioned, yeah.
• 41:23
  SPEAKER_02: Decommissioned for a little bit until I get the correct, you know, power out to the garage or whatever.
• 41:27
  SPEAKER_02: Um, but but this just go to like Etsy or go to some rock collectors website and type in Pudding Stone because there's a lot of the rocks that we've talked about, the three that we've talked about are pretty common in that in those search results.
• 41:40
  SPEAKER_02: And it's a it's a it's a very, very, very common rock.
• 41:44
  SPEAKER_02: You could spend a lot of money buying yourself a pudding stone piece um on rock collector websites.
• 41:49
  SPEAKER_02: It was surprising to me how popular these things are in the in the kind of you know rock selling markets, these pudding stones, because they're they're really beautiful, really popular.
• 42:00
  SPEAKER_02: Um and this isn't is not a spectacular photo of of the pudding stone.
• 42:04
  SPEAKER_01: Well, yeah, so that brings up an interesting point, Jesse, is that I sent you like three pictures today.
• 42:09
  SPEAKER_01: Not one uh listen, everybody, not one of my pictures made the cut.
• 42:14
  SPEAKER_01: Okay, I sent Jesse pictures of Chris Bullheis pudding stone, and none of them made the cut here today.
• 42:21
  SPEAKER_01: So I'm Chris.
• 42:22
  SPEAKER_02: If you'd send me photos of rocks bigger than your thumbnail, it'd be nice.
• 42:26
  SPEAKER_02: You know, then they might get you out here.
• 42:28
  SPEAKER_01: Please.
• 42:29
  SPEAKER_01: Oh my gosh.
• 42:30
  SPEAKER_01: Send me here's what I want.
• 42:32
  SPEAKER_01: Send me a photo of that.
• 42:33
  SPEAKER_02: I know you have that big giant one sitting in your backyard, probably.
• 42:37
  SPEAKER_01: It's covered in snow right now.
• 42:38
  SPEAKER_01: It's two feet of snow outside right now, Jesse.
• 42:40
  SPEAKER_01: I'm not gonna go and uh pour water over it to uncover it.
• 42:44
  SPEAKER_01: Sorry.
• 42:46
  SPEAKER_02: I'm just your commitment level, Chris.
• 42:47
  SPEAKER_02: I'm I'm constantly disappointed by your lack of commitment to good you know images for this podcast.
• 42:52
  SPEAKER_01: What the heck?
• 42:54
  SPEAKER_01: That's unfortunate.
• 42:55
  SPEAKER_01: I sent you good pictures, and you just you you're you're getting a little too arrogant, Jesse.
• 42:59
  SPEAKER_01: You know, you tone it down a little bit.
• 43:01
  SPEAKER_01: That's not news.
• 43:02
  SPEAKER_01: That's not news.
• 43:03
  SPEAKER_01: Yeah.
• 43:03
  SPEAKER_01: That's not true.
• 43:04
  SPEAKER_02: Um true stuff.
• 43:05
  SPEAKER_02: All right.
• 43:06
  SPEAKER_02: All right, well, let's summarize here for us, like real quick here, right?
• 43:10
  SPEAKER_02: Pudding stone, beautiful rocks, put in stone, if you want to pronounce it that way.
• 43:15
  SPEAKER_02: Lots of different varieties.
• 43:16
  SPEAKER_02: We touched on three Hertford Shire Pudding Stone from the UK, the Roxbury conglomerate from Massachusetts, and the Lorraine quartzite pudding stone.
• 43:25
  SPEAKER_02: And you know, these rocks, they're just spectacular.
• 43:26
  SPEAKER_02: They're we're these are one of the cooler rocks that's out there.
• 43:29
  SPEAKER_02: If you're gonna study sediments, it might as well be a conglomerate, is kind of the way I think about it.
• 43:34
  SPEAKER_02: And if you're gonna go spend your time collecting sedimentary rocks, it might as well be a pudding stone because they're beautiful.
• 43:40
  SPEAKER_02: That's a good point.
• 43:41
  SPEAKER_02: They are, yeah, absolutely.
• 43:43
  SPEAKER_02: Hey, that's a wrap.
• 43:43
  SPEAKER_02: You can follow us on all the social medias at Planet GeoCast.
• 43:46
  SPEAKER_02: You can follow us on YouTube now.
• 43:47
  SPEAKER_02: We have a YouTube channel.
• 43:48
  SPEAKER_02: You can find that on our website, the Planet GeoPodcast.
• 43:51
  SPEAKER_02: And uh head to our Camp Geo Mobile app.
• 43:53
  SPEAKER_02: First link in your show notes.
• 43:54
  SPEAKER_02: There we have visual podcast series about a whole bunch of things.
• 43:57
  SPEAKER_02: Yellowstone National Park, Grand Tetons, Grand Canyon, Earth's climate, Earth's oldest rocks, a lot of series that we've been building in the background.
• 44:04
  SPEAKER_02: Got a lot of download that, lots of fun stuff there, and we're just continuing to put more.
• 44:08
  SPEAKER_02: This episode will be there as well.
• 44:10
  SPEAKER_02: So you can see the images under the Planet Geo tag there in the visual podcast series.
• 44:15
  SPEAKER_02: So check that out and let us know what you think.