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The Geological Fruit Fly - The Bishop Tuff and Long Valley Caldera Eruption · PlanetGeo: The Geology Podcast

• 0:01
  SPEAKER_01: But that's just an amazing thing to kind of try and visualize a six-day long eruption.
• 0:05
  SPEAKER_01: That's not a super eruption, but it's very close.
• 0:08
  SPEAKER_01: You know, it's in that it's in that conversation of a massive eruption.
• 0:14
  SPEAKER_01: Welcome to Planet Geo, the podcast where we talk about our amazing planet, how it works, and why it matters to you.
• 0:27
  SPEAKER_01: So Chris, this is uh has the great potential for weeds.
• 0:33
  SPEAKER_01: This is an episode about volcanoes with the chance of weeds coming at you a little bit.
• 0:37
  SPEAKER_02: Yeah, we're gonna try what does it the whole Long Valley caldera.
• 0:42
  SPEAKER_02: You know, the whole thing has the potential for weeds.
• 0:46
  SPEAKER_02: It's this has been a slog as you know in some days.
• 0:51
  SPEAKER_01: It's it's uh it's like um I don't know, you know, we need a flat bottom boat because we're going through the reeds here, high w high weeds in the grass, and we just don't know where we're going right now.
• 1:02
  SPEAKER_01: Um this is a good one though.
• 1:06
  SPEAKER_01: This is uh I think this is an interesting.
• 1:08
  SPEAKER_01: I mean, first of all, it's an amazing, it's an interesting geological story, and for me a very interesting scientific story as well.
• 1:15
  SPEAKER_01: Story is not quite the right word, scientific location for reasons that are not necessarily related to the geology, which we'll kind of get into a little bit.
• 1:25
  SPEAKER_01: I mean, it is intimately related to the geology, but it's um it's a geological fruit fly here.
• 1:31
  SPEAKER_01: This is something that gets studied a lot for for reasons that have nothing to do with the geology and everything to do with the fact that other people have studied it a lot, and we'll we'll kind of touch on that, but the geological story is amazing too.
• 1:45
  SPEAKER_01: Yeah, that's right.
• 1:46
  SPEAKER_02: Not till toward the end of the episode.
• 1:48
  SPEAKER_02: We're gonna come back to what you said about this the Bishop Tuff, which is this famous rock layer being the geological fruit fly, is I think it's really an interesting idea, and you know that was really catchy for me when when you first brought that up to me.
• 2:04
  SPEAKER_02: And we're gonna get to that at the end of the episode.
• 2:07
  SPEAKER_02: Why this is the fruit fly yeah, yeah.
• 2:10
  SPEAKER_01: What what what the heck we're talking about with that?
• 2:13
  SPEAKER_01: Uh, and and you know, that this has the potential that that's the part that has potential for infinite amounts of weeds.
• 2:19
  SPEAKER_01: And frankly, we would need to get we would need to interview somebody who's in the weeds about because there are people who spend much of their career studying the Bishop Tuff and getting into really deep geochemistry, developing geochemical tools.
• 2:32
  SPEAKER_01: Anyway, we're not there yet.
• 2:34
  SPEAKER_01: We're gonna talk about how we got to the rocks that we see today.
• 2:37
  SPEAKER_01: Like what we're we're gonna talk about the Bishop Tuff caldera forming eruption is really the geological story here.
• 2:43
  SPEAKER_01: What created the Long Valley Caldera?
• 2:46
  SPEAKER_01: And Chris, we just left off just to just to kind of frame it here.
• 2:49
  SPEAKER_01: We left off with this, what I thought was a great phrase, this transcrustal self-distilling power supply of the basaltic to andesitic volcanism that was like 3.9 to 2.5 you know million years ago.
• 3:02
  SPEAKER_01: That type of volcanism was going on.
• 3:03
  SPEAKER_01: Basalt that was formed in the mantle, transiting the crust, erupting on the surface, bringing in all of this thermal power, all this heat to the crust, and that kind of shuts off around 2.5 billion years ago.
• 3:16
  SPEAKER_01: For a couple hundred thousand years, not much happens.
• 3:18
  SPEAKER_01: There's a period of quiescence, and then around 2.2, things start to happen again.
• 3:23
  SPEAKER_01: And remember, we've got all that heat sitting in the crust.
• 3:25
  SPEAKER_01: So that's kind of where we're picking up.
• 3:27
  SPEAKER_02: That's right.
• 3:28
  SPEAKER_02: And and the the magma that gets erupted is very different during this time period than what we've been talking about.
• 3:35
  SPEAKER_02: You know, the specification.
• 3:36
  SPEAKER_02: During this this new time period, right?
• 3:38
  SPEAKER_02: That's right.
• 3:39
  SPEAKER_02: From 2.2 to you know, 0.8 and a little bit beyond that uh million.
• 3:44
  SPEAKER_01: And this, Chris, hold on, just so real quick on this.
• 3:46
  SPEAKER_01: I I wanna we're gonna you and I are gonna have to be careful with the numbers because we're we're gonna transfer from millions of years to hundreds of thousands of years.
• 3:52
  SPEAKER_01: So 2.2 million years to 800,000 years, that's your 0.8 million years there.
• 3:57
  SPEAKER_01: So I this is where we kind of get a little we got to be careful about the numbers we use here just to make sense of it all.
• 4:03
  SPEAKER_02: But specifically though, Jesse, actually, we're going to 760,000 years ago.
• 4:08
  SPEAKER_01: Yes.
• 4:09
  SPEAKER_02: You know, yes.
• 4:09
  SPEAKER_02: If we're gonna be specific, that's that's the number.
• 4:12
  SPEAKER_02: That's where we left off when you actually cut me off at the last episode.
• 4:15
  SPEAKER_02: You're like, hold on, Chris, you're you're jumping the gun here.
• 4:18
  SPEAKER_01: Um volcanoes, man.
• 4:21
  SPEAKER_02: That's right.
• 4:22
  SPEAKER_02: We're leading up to this cataclysmic eruption of 760,000 years ago.
• 4:27
  SPEAKER_02: So that's really what we want to talk about today's.
• 4:29
  SPEAKER_02: And we want to use the Long Valley Caldera to talk really about how do you end up with magma that is this sticky?
• 4:36
  SPEAKER_02: Because it didn't start this way.
• 4:38
  SPEAKER_02: And that's I think if I'm gonna just say that's what the episode's about, then that's the one-liner right there.
• 4:45
  SPEAKER_02: How did the magma get to be this sticky?
• 4:48
  SPEAKER_01: That's a great question.
• 4:49
  SPEAKER_01: And Chris, this is such an interesting episode for that reason because I was just talking about this.
• 4:53
  SPEAKER_01: I teach this class, um, kind of really a discussion class where we just read a lot of papers in the class and discuss them.
• 4:59
  SPEAKER_01: But we were talking about the distillation of continental crust and the what's called bimodal volcanism on earth or bimodal rock distribution in the continental crust, where we have a lot of basalts, we have a lot of granites, and the basalts are like 45 to 50 weight percent silica.
• 5:14
  SPEAKER_01: The granites are like 65 to 77 in this case here, percent silica.
• 5:19
  SPEAKER_01: And there's a gap between them.
• 5:20
  SPEAKER_01: If you're a petrologist or you've had some geology training, you'll know that name to be the daily gap.
• 5:25
  SPEAKER_01: And so we have this kind of two peaks in distribution, and there's great big questions about how the continental crust formed, why do we have these two gaps?
• 5:34
  SPEAKER_01: And the Long Valley Caldera is one way to produce two different suites of rocks that have very different compositions in the same tectonic setting.
• 5:42
  SPEAKER_01: And we're going to touch on how that happens right there.
• 5:45
  SPEAKER_01: Like one of the main ways is kind of what we're talking about.
• 5:48
  SPEAKER_01: How do we go from 3.9 billion, 3.9 excuse me, million years ago to 2.5?
• 5:53
  SPEAKER_01: We have lots of basalts, andesites, dacytes, then shut off for a little bit.
• 5:58
  SPEAKER_01: That thermal power is still in the crust.
• 6:01
  SPEAKER_01: Now we pick up, as you said, 2.2 million years ago.
• 6:04
  SPEAKER_01: We start to erupt a very different composition.
• 6:06
  SPEAKER_01: This is silica-rich rhyolite.
• 6:08
  SPEAKER_01: This is 75, 76 weight percent silica, really, really rich, sticky, gooey, very evolved stuff here.
• 6:17
  SPEAKER_01: And this is the glass mountain eruptions that we're talking about here in the world.
• 6:20
  SPEAKER_02: Yeah, and this is on the northeast part of the yeah, northeast portion of the Long Valley Caldera is where the this this volcanism kind of centered, um, if you will.
• 6:30
  SPEAKER_02: So, Jesse, let's just throw some numbers at this before we get into like how this like happened, right?
• 6:36
  SPEAKER_02: Um, 760,000 years ago, this huge eruption, over 600 cubic kilometers of volume was pumped out of this thing, and this was over a six-day period, which I think to be.
• 6:50
  SPEAKER_01: This is such an amazing story.
• 6:52
  SPEAKER_01: This is so this is just really amazing that we we, you know, can can tease out this story.
• 6:56
  SPEAKER_01: But this is the latest, this is the last, this is the biggest in a in a series of eruptions, right?
• 7:02
  SPEAKER_01: There were many eruptions before that that you kind of touched on the glass mountain ones, but this is kind of the culmination.
• 7:06
  SPEAKER_01: So we're kind of you kind of imagine this building up to this big one, this six-day event that you're talking about that produced uh what did you say?
• 7:14
  SPEAKER_01: How how many cubic kilometers is it?
• 7:16
  SPEAKER_02: Six hundred cubic kilometers, which Jesse just like let's put some numbers on this.
• 7:21
  SPEAKER_02: Yeah, um the first of the three Yellowstone eruptions where Yellowstone is right now, that was twenty four hundred and fifty cubic kilometers.
• 7:31
  SPEAKER_02: The third eruption was a thousand cubic kilometers, and that classifies them as super eruptions, not super volcanoes, but super eruptions.
• 7:41
  SPEAKER_02: Anything that's a thousand cubic kilometers or above is that.
• 7:45
  SPEAKER_02: So this doesn't quite meet that bar.
• 7:49
  SPEAKER_02: But it does put it, yeah.
• 7:51
  SPEAKER_02: It puts it though at the third biggest eruption in the last two million years in the US.
• 7:58
  SPEAKER_02: Yellowstone has the first two, Long Valley has number three, and then the second eruption from Yellowstone takes fourth place in terms of volume that was ejected from these beasts.
• 8:11
  SPEAKER_01: So this is bigger than one of than the smallest of the three most recent Yellowstone eruptions.
• 8:16
  SPEAKER_01: So I mean this is it, this is in that category of Yellowstone-like eruptions.
• 8:20
  SPEAKER_01: I mean, huge.
• 8:21
  SPEAKER_01: This is huge.
• 8:22
  SPEAKER_01: This is a monster.
• 8:23
  SPEAKER_02: That's right.
• 8:23
  SPEAKER_02: These kinds of eruptions, Jesse, they these are the ones that can form calderas, and and this is called Long Valley Caldera.
• 8:30
  SPEAKER_02: It's a 17 by 32 kilometer caldera.
• 8:33
  SPEAKER_01: So let me just point out image image number one here is is showing us kind of this caldera.
• 8:39
  SPEAKER_01: It's showing us the scale here, and it's also showing us where the Bishop Tuff, the eruptive products of this eruption, the the rock products, where they're exposed.
• 8:48
  SPEAKER_01: Now, and a lot of this has been eroded, but it this is where it is now, where it kind of flowed out from this caldera.
• 8:53
  SPEAKER_01: So sorry to interrupt, continue on.
• 8:55
  SPEAKER_02: No, no, no worries.
• 8:55
  SPEAKER_02: No worries.
• 8:56
  SPEAKER_02: All I was gonna say is that you know, I had this caldera that's 17 kilometers by 32 kilometers wide.
• 9:01
  SPEAKER_02: So this is you know, that's big, right?
• 9:04
  SPEAKER_02: You and I have stood, you know, uh very close to the Mount St.
• 9:08
  SPEAKER_02: Helens caldera, and we were just in awe.
• 9:11
  SPEAKER_02: You know, we've been there together, and it's uh hard to like put into scale, but that's just a mile across, you know, and it's it just dominates the landscape.
• 9:20
  SPEAKER_02: And so I know you think about this, it's just this is again one of the things I absolutely love about geoscience is is the scale of it all, the potential scale of it all anyway.
• 9:31
  SPEAKER_02: This is truly amazing.
• 9:33
  SPEAKER_02: So and and the caldera, it collapsed, the roof collapsed down about two kilometers.
• 9:41
  SPEAKER_02: So you you talk about deflating the magma chamber beneath Long Valley Caldera, and then it's left unsupported with this partially empty chamber below, and it just collapses down into this series of earthquakes, and it collapsed by two kilometers.
• 9:56
  SPEAKER_02: Like that's a shocking thing again.
• 9:58
  SPEAKER_01: Yeah, shocking.
• 9:59
  SPEAKER_01: I mean, just just imagine imagine the drama if we were using your analogy of being in the hot air balloon, sitting above this.
• 10:06
  SPEAKER_01: We'd want to be quite far away in our hot air balloon, but imagine doing that and being there and watching this happen.
• 10:13
  SPEAKER_01: I mean, it is just amazing.
• 10:15
  SPEAKER_01: It's astonishing to imagine to really just just picture and imagine this event happening and going off.
• 10:22
  SPEAKER_01: And I want to touch on this, I always like to to Chris point out um places where geochronology is really cool.
• 10:29
  SPEAKER_01: And and one of these is that the age of this eruption, we know I would say quite well.
• 10:36
  SPEAKER_01: Um, the age here that we're getting is 767,100 years, and the uncertainty on that is plus or minus 900 years.
• 10:50
  SPEAKER_01: So that's shocking.
• 10:52
  SPEAKER_01: We know the a so we're going back 767,000 years into the past, and we're under we have the precision to say plus or minus 900 years.
• 11:01
  SPEAKER_01: It's astonishing to me.
• 11:03
  SPEAKER_01: That's just a very cool, uh, the amazing aspects of geochronology here.
• 11:07
  SPEAKER_02: So, Jesse, that is an amazing amount of precision, but let me flip this back to you, which I don't think the answer to this question is not gonna have to deal with geochronology, but it's uh it's other really intriguing research and and just the use of mathematics and physics, I think.
• 11:25
  SPEAKER_02: Really, how do we know it was a six-day period for this cataclysmic eruption?
• 11:30
  SPEAKER_01: Yeah, yeah, it's an interesting one.
• 11:32
  SPEAKER_01: It's it's using the the class sizes, the maximum class size.
• 11:37
  SPEAKER_01: So when this thing erupts, it's bringing all sorts of stuff up on up in the air, including little particles, little little actually lava pieces that get frozen and turn into you know my favorite rock that I could never identify in your class called pumice.
• 11:50
  SPEAKER_01: Pumice.
• 11:51
  SPEAKER_01: A lot of pumice out here.
• 11:52
  SPEAKER_01: I would have not enjoyed this as a high school student because I would have been walking around going, I don't know what the word for this rock is.
• 11:58
  SPEAKER_01: But um the maximum class size, the things that are caught up in this eruption, were compared to other asphalt deposits where the accumulation rates were known.
• 12:10
  SPEAKER_01: So you take that mass maximum class size, go work your way all through the Bishop Tuff layers, and those are mostly continuous and kind of obviously continuous.
• 12:17
  SPEAKER_01: And you can estimate a maximum accumulation time that's somewhere in the ballpark of 90 hours or something.
• 12:23
  SPEAKER_01: So that's the you know the estimate there.
• 12:26
  SPEAKER_01: So the class sizes are also going to diminish predictably as you get further away from the from the vent of the eruption, from the vent and the the amount, you know, basically the the the eruptive power that is you know driving this system and then how the the fall rates and things like that.
• 12:41
  SPEAKER_01: So given that it's a continuous system, you can kind of estimate you know, estimate the accumulation time.
• 12:47
  SPEAKER_01: But that's just an amazing thing to kind of try and visualize a six-day long eruption that's not a super eruption, but it's very close.
• 12:54
  SPEAKER_01: You know, it's in that it's in that conversation of a massive eruption.
• 12:58
  SPEAKER_01: Um, it's sent real quick, Jesse.
• 13:00
  SPEAKER_02: We need to we should distinguish between two things that you said ash flows versus ash falls, right?
• 13:08
  SPEAKER_02: I mean, these ash flows are these pyroclastic flows that flowed more than 70 kilometers down Owens Valley, whereas right now you're talking about ash falls.
• 13:19
  SPEAKER_02: What's the extent of that?
• 13:20
  SPEAKER_02: I mean, this is amazing.
• 13:22
  SPEAKER_01: Yeah, the ash falls go from ne out into the Pacific to Nebraska.
• 13:27
  SPEAKER_01: Uh just a huge range.
• 13:30
  SPEAKER_01: I mean, this is big, you would as you would expect, right?
• 13:32
  SPEAKER_01: This is when we're we're talking about eruptions of this size, this is this is what we're talking about.
• 13:37
  SPEAKER_01: These are big, these are really, really big.
• 13:39
  SPEAKER_01: And Chris, I'm gonna skip ahead to image number two here just to show this little gif that we've animated that shows an example of this.
• 13:46
  SPEAKER_01: This is showing an airfall on the bottom, then we have some surge deposits and an ash fall on top.
• 13:52
  SPEAKER_01: There's this layering to it.
• 13:53
  SPEAKER_01: This is the bishop tuff.
• 13:54
  SPEAKER_01: This is one unit within the bishop tuff, or maybe a couple units here that people go around and map and look at in detail what these rocks actually look like.
• 14:03
  SPEAKER_01: And these are 760,000 years old, 761,000 years old.
• 14:07
  SPEAKER_01: It's it's really cool to imagine this piling up over the six-day period.
• 14:12
  SPEAKER_01: Um, in the in the the drama involved in that.
• 14:15
  SPEAKER_02: Oh, that's a good way of saying it.
• 14:16
  SPEAKER_02: I mean, there's drama like in the detail in the rocks, especially in this bishop tough here.
• 14:22
  SPEAKER_02: You know, there's a there's a thing called fiamme, which are these these pumice clasts.
• 14:26
  SPEAKER_02: This is so cool that that they're they're squished like lens shaped, almost like a football obelisk kind of shaped thing.
• 14:34
  SPEAKER_01: Yeah, yeah, yeah.
• 14:35
  SPEAKER_01: That's a good way to say that.
• 14:36
  SPEAKER_02: Yeah, they were soft and compacted due to the rapid fall of the material on top of it, and it just kind of squished these down.
• 14:47
  SPEAKER_02: And it I don't know why, Jesse.
• 14:49
  SPEAKER_02: I can't I don't remember the derivative of the word fiamme, but the bishop tuff is known for this feature for sure.
• 14:56
  SPEAKER_02: And they're beautiful, beautiful.
• 14:58
  SPEAKER_02: They are, yeah.
• 14:58
  SPEAKER_02: Oh my gosh.
• 14:59
  SPEAKER_01: Really beautiful thing.
• 15:00
  SPEAKER_01: I mean, this is a this is a beautiful rock.
• 15:02
  SPEAKER_01: I mean, to to see these types of things, these tufts and these pumuses, they're really beautiful.
• 15:08
  SPEAKER_01: Sometimes they have these, um, I think like five percent of the the pumice is this kind of dark and swirly pumice, they call it.
• 15:15
  SPEAKER_01: So there's a lot of variation in it.
• 15:17
  SPEAKER_01: It's not just like a homogenous white powder.
• 15:20
  SPEAKER_01: That's not what this is.
• 15:21
  SPEAKER_01: This is actually a really dynamic, beautiful rock when you get up close looking at it.
• 15:25
  SPEAKER_01: Absolutely.
• 15:26
  SPEAKER_01: Yeah, sorry, go ahead.
• 15:27
  SPEAKER_02: I think just before we dive into this culmination, like how did the magma get to be this way?
• 15:34
  SPEAKER_02: It's just worth noting, I think, that after this, that for over the next hundred thousand years down into the 660-ish, thousand year time frame, there was smaller scale volcanism.
• 15:46
  SPEAKER_02: Some of them were punctuated with bigger eruptions inside the caldera, but this was the big show.
• 15:52
  SPEAKER_02: Kind of like with you and I when we get together, I'm the big show.
• 15:56
  SPEAKER_02: This has the this is the big show.
• 15:58
  SPEAKER_02: Okay, Chris.
• 15:59
  SPEAKER_01: I don't know why you have to frame it.
• 16:00
  SPEAKER_01: It's not just when you and I get together that you're the big show.
• 16:03
  SPEAKER_01: You're the big show all the time.
• 16:05
  SPEAKER_01: You know, it's the Chris Bully.
• 16:07
  SPEAKER_01: Chris Boy is the big show.
• 16:09
  SPEAKER_01: Just ask him.
• 16:09
  SPEAKER_01: That's right.
• 16:10
  SPEAKER_01: Um, that's right.
• 16:10
  SPEAKER_01: Just ask it.
• 16:11
  SPEAKER_01: It's true.
• 16:12
  SPEAKER_01: It's true.
• 16:12
  SPEAKER_01: This is the this is the big one, and we can see the weeds from here.
• 16:16
  SPEAKER_01: Let's put it that way, right?
• 16:18
  SPEAKER_01: We're looking, we're close to the weeds because now we have to talk about the Bishop Tough.
• 16:23
  SPEAKER_01: And this is a famous rock, and I can't emphasize that enough.
• 16:26
  SPEAKER_01: This is a famous rock.
• 16:27
  SPEAKER_01: Actually, let me put some numbers to that, Chris.
• 16:29
  SPEAKER_01: I was kind of curious about this.
• 16:30
  SPEAKER_01: So I did a um, you could go to these different publication databases and just type in keywords and say, how many papers have this keyword or how many papers have this in the title, etc., etc.
• 16:40
  SPEAKER_02: I wish I had your access.
• 16:41
  SPEAKER_02: I, you know, like that bothers me a little bit.
• 16:44
  SPEAKER_02: I don't have all of the access you do, but I know.
• 16:47
  SPEAKER_01: Well, we have to be elitist about it, and we have to restrict access from peons like you, Chris, who just don't know what they're doing.
• 16:53
  SPEAKER_01: There it is.
• 16:54
  SPEAKER_02: Yeah, in one sentence, I'm a big show, and now I'm a peon.
• 16:58
  SPEAKER_02: All right, okay.
• 16:59
  SPEAKER_01: Um, so I typed in the Acosta Nices, which are rocks that I'm deeply familiar with, but I don't think there's anybody who'd question that these are famous rocks.
• 17:08
  SPEAKER_02: And in this particular, can we just compare nicknames a second?
• 17:12
  SPEAKER_02: I'm referred to oftentimes as the big show, and you're often referred to as just Acosta.
• 17:18
  SPEAKER_02: Okay.
• 17:18
  SPEAKER_02: Mine is way better.
• 17:19
  SPEAKER_02: You know, nobody wants to.
• 17:21
  SPEAKER_01: Well, sometimes you're also referred to as smudge fingers.
• 17:23
  SPEAKER_01: And so I, you know, nicknames vary.
• 17:26
  SPEAKER_01: So so Chris, how many papers do you think I would find?
• 17:29
  SPEAKER_01: It's not a fair question.
• 17:30
  SPEAKER_01: What do you think?
• 17:31
  SPEAKER_02: About Acosta?
• 17:33
  SPEAKER_01: Yeah.
• 17:33
  SPEAKER_01: 20.
• 17:34
  SPEAKER_01: 20.
• 17:35
  SPEAKER_01: Okay.
• 17:35
  SPEAKER_01: It depends on which database you're looking at, but this one had 70.
• 17:38
  SPEAKER_01: I just that had the keywords, Acosta Nice complex.
• 17:41
  SPEAKER_01: It doesn't mean that all the papers are on that, but the the papers would be really deeply intimately related to the Acosta Nice complex, even if they're not on those rocks, right?
• 17:51
  SPEAKER_01: Yep.
• 17:51
  SPEAKER_01: The Bishop Tough, so 70.
• 17:53
  SPEAKER_01: 70 of the Acosta Nice complex.
• 17:55
  SPEAKER_01: Okay, so what do you think the Bishop Tough?
• 17:57
  SPEAKER_02: 500.
• 17:58
  SPEAKER_01: Okay, 250, which I thought was a lot.
• 18:02
  SPEAKER_01: Like a lot more than Acosta.
• 18:04
  SPEAKER_01: I was actually shocked that it was I would have guessed it kind of be round about the same.
• 18:08
  SPEAKER_01: There are way more papers published on the Bishop Tough that are keyworded by the Bishop Tough than there are the Acosta Nice complex.
• 18:15
  SPEAKER_01: And you might ask yourself why?
• 18:18
  SPEAKER_01: Like it's a fair question.
• 18:20
  SPEAKER_01: Why is there so much focus on this?
• 18:22
  SPEAKER_01: And it really goes back to the the kind of paradigm model that was started to be built in the 70s by a geologist called Wes Hildreth, who's very famous in the bishop in the um in the Bishop Tuff and has has worked a lot in this region, came up with this model that has become the paradigm or the really the working hypothesis for the the Long Valley caldera in the Bishop Tuff.
• 18:45
  SPEAKER_01: They looked at the layering and the Bishop Tuff looked at stratigraphy from bottom to top, so that's early eruption to late eruption, because we're kind of working over.
• 18:54
  SPEAKER_01: Exactly.
• 18:55
  SPEAKER_01: And you have to visualize this.
• 18:56
  SPEAKER_01: First stuff coming out of the volcano is at the bottom, the last stuff coming out of the volcano is at the top.
• 19:01
  SPEAKER_01: And noticed using a uh really the key thing was iron titanium oxide thermometry, which just means you measure trace elements in magnetite and measure trace elements in ilmenite, and you compare the two.
• 19:16
  SPEAKER_01: And we've talked about this before, Chris, a lot with things like um iron magnesium oxide thermometry in uh garnet and biotite or or titanium thermometry in quartz.
• 19:27
  SPEAKER_01: We talked about that in our geology of quartz episode.
• 19:29
  SPEAKER_01: We've referred to these things before, but the minerals think of the mineral structures, the hotter they are, the more they can accommodate, you know, stuff that doesn't fit super well in there.
• 19:39
  SPEAKER_01: The cooler the structures are, the less happy there are.
• 19:41
  SPEAKER_01: And different minerals have different preferences.
• 19:43
  SPEAKER_01: That's right.
• 19:43
  SPEAKER_01: More exclusive, exactly.
• 19:45
  SPEAKER_01: And so what was noticed was that the temperatures you calculate from this thermometer start cool at the bottom, around 730 degrees centigrade, and then end up throughout the course of the eruption getting hotter up to 800 degrees centigrade.
• 20:03
  SPEAKER_02: Okay, question.
• 20:04
  SPEAKER_02: Let me interrupt you then.
• 20:05
  SPEAKER_02: Um, is that temperature range is that done using the what you just described, what we've talked about in prior episodes, this thermometry thing.
• 20:15
  SPEAKER_01: Yes, it's using iron titanium oxide thermometry specifically.
• 20:18
  SPEAKER_01: That initial work was iron titanium oxide thermometry.
• 20:22
  SPEAKER_02: The second part of the question then is yeah, it does.
• 20:24
  SPEAKER_02: Absolutely.
• 20:25
  SPEAKER_01: I I knew there was something else coming.
• 20:27
  SPEAKER_02: Yeah, this the second part of that question is what does that mean?
• 20:31
  SPEAKER_02: Why is that important?
• 20:33
  SPEAKER_01: Okay.
• 20:34
  SPEAKER_02: This is a great started at the bottom, cool, and got hotter towards the top.
• 20:40
  SPEAKER_02: That's that's what we're saying.
• 20:42
  SPEAKER_01: This Chris is so like this this heating up throughout the course of an eruption from 700 to you know 800.
• 20:49
  SPEAKER_01: So not an insignificant amount, right?
• 20:52
  SPEAKER_01: A hundred, maybe a hundred and twenty even degrees of heating up.
• 20:57
  SPEAKER_01: Why do you think that's why has that that simple idea spawned a massive amount of research and focus on this rock?
• 21:04
  SPEAKER_02: Well, I wonder, okay, here's where my mind goes with this.
• 21:08
  SPEAKER_02: I start to think about well, did it change much compositionally?
• 21:13
  SPEAKER_02: Like, was it becoming less felsic toward the top?
• 21:17
  SPEAKER_01: So it's a great question.
• 21:19
  SPEAKER_01: And the answer is generally yes, very slightly, though.
• 21:23
  SPEAKER_01: So in general, people refer to the okay very slightly.
• 21:26
  SPEAKER_01: So the in general, people say the early bishop tuft is the the early stuff, the hot uh excuse me, the cool stuff at the bottom is um crystal pore, meaning there's not many crystals in it.
• 21:36
  SPEAKER_01: It's a lot of pumice, it's a lot of glass, and it is evolved.
• 21:39
  SPEAKER_01: It has 77 weight percent silica, which is like as much silica as you get in igneous rocks.
• 21:45
  SPEAKER_01: You don't get that much more you it's very rare you get more than that in in igneous rocks.
• 21:50
  SPEAKER_01: The late bishop stuff, the top stuff, the hotter stuff, is less evolved, more like 75 weight percent silica, and it's crystal rich.
• 21:58
  SPEAKER_01: You get more crystals in.
• 22:00
  SPEAKER_01: The thing.
• 22:00
  SPEAKER_01: So you're exactly right.
• 22:01
  SPEAKER_01: I mean, you're really keying in on this.
• 22:03
  SPEAKER_01: That's exactly right.
• 22:04
  SPEAKER_02: Can we talk about that then?
• 22:06
  SPEAKER_02: Like why that might happen?
• 22:09
  SPEAKER_02: Does it have to do with this early stuff that comes out comes from the top of the magma chamber?
• 22:16
  SPEAKER_02: And so there's more going on there in terms of temperature.
• 22:20
  SPEAKER_02: It's touching colder country rock.
• 22:22
  SPEAKER_02: Whereas the stuff that's like further away from all of that, kind of insulated by all of that activity, you actually then have fractional crystallization going on, which is why it's more crystal rich.
• 22:35
  SPEAKER_02: Is that the right track?
• 22:37
  SPEAKER_01: That's exactly the right track.
• 22:38
  SPEAKER_01: That's the stu the the quote unquote standard model.
• 22:41
  SPEAKER_01: Here is really exactly that.
• 22:43
  SPEAKER_01: That we have a magma chamber, a big magma chamber.
• 22:46
  SPEAKER_01: So this massive, nearly super eruption tapped into a magma chamber that was sitting there in the crust.
• 22:53
  SPEAKER_01: The top was cold, did not have many crystals in it, and was very evolved.
• 22:58
  SPEAKER_01: The bottom was hot, had a bunch of crystals in it, it was slightly less evolved.
• 23:02
  SPEAKER_01: Like that's the textbook image of a magma chamber, right?
• 23:06
  SPEAKER_01: Like that's the the intro level.
• 23:08
  SPEAKER_02: If you just what you see.
• 23:10
  SPEAKER_02: Yeah.
• 23:11
  SPEAKER_01: It's what you see, right?
• 23:12
  SPEAKER_01: And and so that this was huge.
• 23:14
  SPEAKER_01: This is like how do super eruptions happen?
• 23:17
  SPEAKER_01: How do massive eruptions what is a magma chamber looking like in the crust?
• 23:20
  SPEAKER_01: This is an answer to the question, right?
• 23:21
  SPEAKER_01: This model, this what I think is a paradigm.
• 23:24
  SPEAKER_01: This is what people I'm not sure if there's if it's consensus, but there's a majority view here.
• 23:30
  SPEAKER_01: And the majority view is that this is correct.
• 23:32
  SPEAKER_01: You go from low temperature stuff, and as you gradually deplete this massive magma chamber, this caldera forming volume of stuff, you get hotter and hotter and you tap into a different stuff down deeper.
• 23:44
  SPEAKER_01: And so it's a single magma chamber that was stratified thermally and compositionally stratified.
• 23:48
  SPEAKER_01: And at the bottom, you're getting the crystals in there, you're getting the quartzes and the plagioclases and some pyroxines that are trapped up and sucked up into the magma chamber.
• 23:57
  SPEAKER_02: Because those are so, yeah, because those are the early minerals that will crystallize out of a dip of a fractionating magma chamber.
• 24:04
  SPEAKER_02: In other words, um Bowen's reaction series again.
• 24:07
  SPEAKER_02: You know, the the those early minerals are going to be the pyroxines.
• 24:12
  SPEAKER_02: I don't probably not a lot of olivine, though, right?
• 24:14
  SPEAKER_02: You know, you can't blagioclase.
• 24:17
  SPEAKER_01: That's exactly right.
• 24:19
  SPEAKER_01: So you get some you get a little bit uh quote of kind of quote unquote hotter temperature felt spars in those bottom ones.
• 24:26
  SPEAKER_01: So you you get a change in the mineral composition a bit.
• 24:29
  SPEAKER_01: And interestingly, the stuff that's on the top, the late bishop duff, the the hotter to the higher temperature, quote unquote higher temperature stuff, the quartz in there will have a high titanium rim, which as we talked about in our geology of quartz episodes, usually is interpreted as high temperature, because again, titanium is a thermometer, can be used as a thermometer in quartz.
• 24:48
  SPEAKER_01: So there's some kind of hotter pulse maybe hitting the magma chamber at those later stages where you had some injection of hot stuff down low that kind of kicked the whole thing off.
• 24:57
  SPEAKER_01: So there's a lot of models.
• 24:59
  SPEAKER_01: There is debate though.
• 25:01
  SPEAKER_01: There is very clearly debate about this, whether these okay, hold on.
• 25:05
  SPEAKER_02: I think right now, Jesse, you're transitioning into why is the Bishop Tough, this really super important rock in Owens Valley and north of the Long Valley Caldera.
• 25:15
  SPEAKER_02: These ash flows, why is it the fruit fly?
• 25:19
  SPEAKER_01: Okay, right.
• 25:19
  SPEAKER_02: Let's we need to answer that outright.
• 25:22
  SPEAKER_01: That's a good question.
• 25:23
  SPEAKER_01: Um I I pulled a quote from another Long Valley Caldera paper that I really like.
• 25:28
  SPEAKER_01: I think it conveys the reason that this is a geological fruit fly, or at least why it started to become the geological fruit fly.
• 25:34
  SPEAKER_01: The quote is, I'm quoting here, there is scarcely any more important parameter needed for an enlightened understanding of a giant volcanic system than the spatial and temporal variation of temperature in the magma chamber.
• 25:48
  SPEAKER_01: So, what does that mean?
• 25:49
  SPEAKER_01: If we are trying to understand how big volcanoes erupt, why they erupt, when they erupt, we need to know the spatial and time varying temperature in the magma chamber.
• 26:00
  SPEAKER_01: Is it hot on top and cool down low?
• 26:02
  SPEAKER_01: Is it tapping multiple little magma chambers around?
• 26:05
  SPEAKER_01: There's a model for Yellowstone out there that Yellowstone, the latest eruption, tapped multiple little disaggregated magma chambers, and then during the eruption it kind of sucked them all in together.
• 26:14
  SPEAKER_01: Or was it one big magma chamber that was sitting there that could be perturbed and erupt cold stuff first, hot stuff later?
• 26:21
  SPEAKER_01: So this is why it's an important study, and this is why the these sort of Hildreth 1997, 1977, or excuse me, 1977, 1979 papers are classic ones, and why this place receives so much attention.
• 26:35
  SPEAKER_01: But then that doesn't quite answer the fruit fly thing.
• 26:38
  SPEAKER_01: The fruit fly thing really becomes a biologist go study the fruit fly because other people have studied the fruit fly, and we know a lot about the fruit fly.
• 26:47
  SPEAKER_01: And the Bishop Tuff has kind of become that there is so much detailed work, really detailed in the weeds petrology, done on the Bishop Tuff and volcanology and thermochronology and thermometry and all sorts of tools, all sorts of ologies done on this rock.
• 27:02
  SPEAKER_01: That if you want to develop a new tool, if you want to say, I want to know what the oxidation state of magmas are, and I think I have some new tool for it, you're gonna go to the Bishop Tuff because there's so much information on the Bishop Tuff or something.
• 27:15
  SPEAKER_02: There's a lot of work that's already been done, right?
• 27:17
  SPEAKER_01: And it's and it's a great proving ground for any new technique or a great testing ground.
• 27:22
  SPEAKER_01: So when there's discussions about what does titanium in quartz actually mean, is it a good thermometer or a bad thermometer?
• 27:29
  SPEAKER_01: People will go analyze Bishop Tuff samples to help address that because there's so much other information about this rock.
• 27:35
  SPEAKER_01: So it's it becomes valuable because so many people have studied it and it kind of has a snowball effect to it.
• 27:40
  SPEAKER_01: And that's why this is that's where the fruit fly analogy comes from for the the Bishop Tuff.
• 27:45
  SPEAKER_01: Um okay.
• 27:46
  SPEAKER_02: Well, Jesse, I think like we're at the point where we should, as we wrap this episode up, bring it back to just general geoscience and start talking about the evolution of the magma chamber.
• 27:58
  SPEAKER_02: How did we get here?
• 27:59
  SPEAKER_02: And I think maybe maybe we can talk about comparisons of let's say now we know we've established this already, and we want to reiterate it that Long Valley Caldera is not a hotspot.
• 28:11
  SPEAKER_02: But we can think about this magma chamber using Hawaii and Yellowstone as comparisons, or maybe even Iceland.
• 28:18
  SPEAKER_02: We've we know we've done some episodes on Iceland too, where the hotspots themselves are very, very mafic.
• 28:26
  SPEAKER_02: Just the same as the way this all started.
• 28:28
  SPEAKER_02: This was this began with very basaltic magma, and then it changed as time went on, right?
• 28:35
  SPEAKER_01: Yeah, and so let me just Chris, let me just point to this image.
• 28:39
  SPEAKER_01: You're making a really good point here, and I want to just point to this image really quickly and say, and just I think I got we got I got lost in the weeds a little bit.
• 28:46
  SPEAKER_01: So I want to just reframe it.
• 28:47
  SPEAKER_01: Remember here that the magma chamber was formed by crustal melting.
• 28:51
  SPEAKER_01: So we had basalt intruding.
• 28:53
  SPEAKER_02: That's funny.
• 28:54
  SPEAKER_01: Yeah, yeah.
• 28:55
  SPEAKER_01: Well, at least I'm honest.
• 28:57
  SPEAKER_01: We're poking our head up, you know.
• 28:59
  SPEAKER_01: Oh, looking around.
• 29:00
  SPEAKER_01: All right.
• 29:00
  SPEAKER_01: Um, all right, Windy Jesse, let's go.
• 29:03
  SPEAKER_01: Well, what we just we had this early basalt and describing this this image we have, uh is a cool gift.
• 29:08
  SPEAKER_01: A bunch of basalt's intruding.
• 29:10
  SPEAKER_01: That basalt does the crustal melting, forms this magma chamber.
• 29:13
  SPEAKER_01: The traditional model is that magma chamber gets thermally stratified such that when the big eruption happens, the early stuff to leave is colder, it's more evolved, and then we start to progressively tap the lower parts of the magma chamber.
• 29:26
  SPEAKER_01: And when that thing gets 50 or 70 percent depleted, then we have this calderic collapse over a six-day period.
• 29:32
  SPEAKER_01: And then there's you know, there's more eruptions after that.
• 29:34
  SPEAKER_01: But but then we have an empty magma chamber that's still down there that we'll talk about in the next episode as well.
• 29:39
  SPEAKER_01: So back to your analogy here.
• 29:40
  SPEAKER_01: You said comparisons to Yellowstone and uh Hawaii.
• 29:44
  SPEAKER_01: Did you say Hawaii?
• 29:45
  SPEAKER_01: Yeah, okay.
• 29:46
  SPEAKER_02: I did, yeah.
• 29:46
  SPEAKER_02: We can talk about other ones.
• 29:47
  SPEAKER_02: It just those are easy, everybody knows about them.
• 29:50
  SPEAKER_01: Yeah, for sure.
• 29:51
  SPEAKER_02: You know, the the difference is uh, you know, when you talk about volcanism in general, anyway, the more um infrequent the volcano is in terms of eruptions, the more violent it is.
• 30:01
  SPEAKER_02: And so Hawaii erupts all the time, and so it's it doesn't tend to be very violent and explosive and so on.
• 30:08
  SPEAKER_02: Well, you have this hot spot that is emplaced below and then shallower magma chambers that are within oceanic crust.
• 30:16
  SPEAKER_02: So what are we assimilating here?
• 30:18
  SPEAKER_02: What are we blending into the ultra maficness of the hotspot itself?
• 30:24
  SPEAKER_02: You're blending ultramafic plus mafic, and the result is then a really runny, soupy mafic material that gets ejected out, and that so you you know you have Hawaii and this it's all black rock, you know, it's all basalt versions of it.
• 30:40
  SPEAKER_01: You know, there's very limited amounts of inner even intermediate, even like andesitic, very little day site.
• 30:46
  SPEAKER_01: There's some really small layers of of kind of evolved stuff, but it's really rare.
• 30:51
  SPEAKER_01: It's mostly basalt with olivine or without olivine in it, you know, or with plagioclaser with olivine or with nothing.
• 30:58
  SPEAKER_01: It's basalt and it's shades of basalt.
• 31:01
  SPEAKER_01: Compare that to yellow.
• 31:03
  SPEAKER_01: I mean exactly.
• 31:04
  SPEAKER_01: You made the great point.
• 31:04
  SPEAKER_01: Like it's sitting, what is it?
• 31:06
  SPEAKER_01: It's a it's first of all, when you have a hot spot coming up like Hawaii, it's huge amounts of melting.
• 31:11
  SPEAKER_01: So you're producing loads of basaltic melt and even more ultramafic uh melt down deep, really voluminous melting in a mantle plume.
• 31:21
  SPEAKER_01: In this little transtentional setting that we have in Long Valley, we talked about this in the tectonics episode.
• 31:27
  SPEAKER_01: In this transtentional thing, we're not doing nearly as voluminous of melting of the mantle beneath us.
• 31:32
  SPEAKER_01: So, first of all, we're not starting out with as much basalt, we're just not just gonna swamp the system with basalt.
• 31:37
  SPEAKER_01: And then, Chris, uh, compare that to Yellowstone.
• 31:40
  SPEAKER_02: Yeah, let's talk about Yellowstone.
• 31:42
  SPEAKER_02: Yellowstone, you have the same kind of material, it comes from you know the liquid outer core mantle boundary, ultra mafic, really, really deep, comes up and and it these shallower chambers are injecting into this really felsic, high up into this continental crust, which is much more felsic.
• 31:59
  SPEAKER_02: So one felsic crust is much easier to melt because the minerals are lower temperature.
• 32:04
  SPEAKER_02: Uh it just sits there and it assimilates these the wall rock, this country rock around it, which changes the composition of this melt.
• 32:13
  SPEAKER_02: So you really kind of have this if we were I'm I'm surprised.
• 32:16
  SPEAKER_02: You know, you talk about the bishop tuff as the fruit fly.
• 32:19
  SPEAKER_02: Why hasn't Yellowstone been studied in the same kind of way?
• 32:22
  SPEAKER_02: Because you would have to have the same kind of thing.
• 32:25
  SPEAKER_01: It's a great question, Chris.
• 32:27
  SPEAKER_01: It's a it's a really excellent question.
• 32:29
  SPEAKER_01: Why is this the fruit fly?
• 32:30
  SPEAKER_01: And I I was kind of thinking about that too.
• 32:32
  SPEAKER_01: And I think I don't know if this is the right answer, but it's an answer, probably.
• 32:37
  SPEAKER_01: Is that first of all, Yellowstone is a huge system.
• 32:42
  SPEAKER_01: I mean, Yellowstone is so Yellowstone's had three eruptions in the last couple million years that are of the scale of the Long Valley Caldera.
• 32:49
  SPEAKER_01: And there's no basalt in Yellowstone, or at least not very much basalt in the Yellowstone area.
• 32:53
  SPEAKER_01: There's a little basalt, yeah.
• 32:55
  SPEAKER_01: There's a little bit, you know, it's a little bit around.
• 32:57
  SPEAKER_01: Yellowstone, the hotspot track, has blown a path, a swath through the mountains in the last 17 million years.
• 33:04
  SPEAKER_01: There's Snake River Plain, there's all these caldera complexes from McDermott all the way to Yellowstone.
• 33:10
  SPEAKER_01: That's a huge, massive, complicated system with tons of eruptions going on.
• 33:14
  SPEAKER_01: The Long Valley Caldera is kind of simple.
• 33:16
  SPEAKER_01: It's mafic melting, going through, injecting stuff in, and then you produce this felsic magma chamber by melting the crust and assimilating the crust, and then that thing pops off.
• 33:28
  SPEAKER_01: And then uh we don't really know what's next.
• 33:30
  SPEAKER_01: We'll touch on that in two episodes, talking about kind of is there magma still down in the crust, or is it all just hydrothermal?
• 33:37
  SPEAKER_01: Is this like a dyeing system, or is this still kind of active and has the potential to erupt more?
• 33:42
  SPEAKER_01: Is a little bit of debate about that, but it's certainly not the scale of Yellowstone.
• 33:46
  SPEAKER_01: Like we know at some point, like Yellowstone's still very active.
• 33:49
  SPEAKER_01: So I think the sim the relative simplicity here actually makes it a little bit easier to become the geological fruit fly, whereas Yellowstone has a bunch of different eruptions and is kind of a more complicated system.
• 34:00
  SPEAKER_01: So I don't know if that's a good answer or not, but it it might be part of the story.
• 34:04
  SPEAKER_02: Well, my only thing is I would take issue with this being a simple system because man, it sure was complicated for you.
• 34:11
  SPEAKER_01: No, that's right.
• 34:11
  SPEAKER_01: But yeah, that's right.
• 34:12
  SPEAKER_01: Yeah.
• 34:13
  SPEAKER_02: But you know, the other thing that I want to say too is what else helped this evolve so much from its original early eruptive mafic material to what it culminated in 767,000 years ago is also fractionation.
• 34:27
  SPEAKER_02: You know, this fractional crystallization, which is removing whatever mafic component is there, it's gonna the crystals are gonna form and they're gonna then settle down toward the bottom of the chamber, further away from what the you know, the eruption starts at the top and works its way down, you know.
• 34:44
  SPEAKER_02: And so fractional crystallization is also gonna help the system evolve.
• 34:47
  SPEAKER_02: And that's a part of Hildreth's quote that you uh that you cited a lot in the last episode.
• 34:52
  SPEAKER_02: Yeah, because you love it.
• 34:53
  SPEAKER_02: Yeah, yeah.
• 34:54
  SPEAKER_01: That's right.
• 34:55
  SPEAKER_01: It was a I really enjoyed that quote.
• 34:57
  SPEAKER_01: I and I think it's it's also we're talking about a single magma chamber.
• 35:01
  SPEAKER_01: I think the the evolving paradigm in Yellowstone is that the Yellowstone eruptions tap multiple magma chambers.
• 35:08
  SPEAKER_01: That imposes a bunch of complexity on any given eruption, where the model here is one single eruption.
• 35:14
  SPEAKER_01: Now, not everybody agrees with that.
• 35:16
  SPEAKER_01: There is a a bunch of debate in this kind of geological fruit fly thing about whether it's two magma chambers side by side, whether the iron titanium oxide thermometry or any other kind of thermometry people have applied is actually good.
• 35:28
  SPEAKER_01: And you can imagine why, like you might think, why is that in debate?
• 35:32
  SPEAKER_01: But if you have a rock that is pulling up phenocris, really, it's pulling up other crystals from the magma chamber, you have to ask the question, were they in equal chemical equilibrium?
• 35:43
  SPEAKER_01: Were they close enough together to be chemically communicating with each other such that it is a good thermometer?
• 35:49
  SPEAKER_01: Or were they so were they just kind of in different parts of the magma that were unrelated and we can't relate their chemistry to each other or to the mineralogy around them?
• 35:57
  SPEAKER_01: So that's kind of where the debate sort of centers around a little bit is which of these tools is reliable as a tracer of the the chemistry in the magma chamber, not the chemistry on the way up through the throat of the volcano, and not the chemistry of two different parts of two different magma chambers.
• 36:14
  SPEAKER_01: So I don't know.
• 36:15
  SPEAKER_01: It's it's a cool story.
• 36:17
  SPEAKER_01: It's a very, very cool place with a very, very cool story.
• 36:19
  SPEAKER_01: The fact that we can tell it's a six roughly six-day eruption, and we can date the thing with the amazing precision we can date it with, and it tells this story of potentially an emptying magma chamber that was cool on top and hot on the bottom is is really kind of amazing.
• 36:34
  SPEAKER_01: I I think it's just a totally cool place.
• 36:36
  SPEAKER_02: And I think it's also just a really important case study in the episode of magma.
• 36:42
  SPEAKER_01: Yeah.
• 36:43
  SPEAKER_01: For sure.
• 36:43
  SPEAKER_02: Which is it's a good instructional tool for basic principles in geoscience.
• 36:48
  SPEAKER_01: And a very famous rock now.
• 36:50
  SPEAKER_02: That's right.
• 36:51
  SPEAKER_02: It's great.
• 36:52
  SPEAKER_01: It's great.
• 36:53
  SPEAKER_01: Um, what do you think, Chris?
• 36:54
  SPEAKER_01: Is that uh do we do it justice here?
• 36:58
  SPEAKER_02: I think so.
• 36:58
  SPEAKER_02: I think so.
• 36:59
  SPEAKER_02: Yeah, I think so.
• 36:59
  SPEAKER_01: Yeah.
• 37:00
  SPEAKER_02: Well, coming up next, we're gonna talk about all things hydrothermal then.
• 37:04
  SPEAKER_02: Because it's it's got it's got some of that.
• 37:05
  SPEAKER_02: It's got some hot spur.
• 37:06
  SPEAKER_01: Got some hydrothermal stuff there.
• 37:08
  SPEAKER_01: Super interesting hydrothermal stuff.
• 37:09
  SPEAKER_01: We got hydrothermal stuff coming up, and then we're gonna talk about you know what's going on now.
• 37:13
  SPEAKER_01: What is there a future to this place from an igneous perspective or not?
• 37:16
  SPEAKER_01: Is it all hydrothermal stuff?
• 37:18
  SPEAKER_01: So um, that's coming up.
• 37:19
  SPEAKER_01: Hey, if you enjoy what we're seeing here, you can get more content, more stuff on our Camp Geo Mobile app.
• 37:24
  SPEAKER_01: It's the first link in your show notes.
• 37:25
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• 37:29
  SPEAKER_01: We have planned geocach.