The Worst Year to Be Alive - 536 AD

Jesse Reimink: [00:00:00] Welcome to planet geo the podcast where we talk about our amazing planet, how it works and why it matters to you.

Chris Bolhuis: What are you laughing at?

Jesse Reimink: cause I'm laughing at you, man. It's you got your technology figured out at least. And now we're trying to figure out everything else. I think I get the feeling that you I'm looking at you right now. I can see in your glasses, the reflection of all of the screens you have in front of you.

Chris Bolhuis: I know it's really, I feel important. I feel so

Jesse Reimink: at

Chris Bolhuis: I have, I have three huge monitors in front of right now.

Jesse Reimink: You are glowing.

Chris Bolhuis: My face is lit up.

Jesse Reimink: you are lit up by that computer blue. And to be honest, you look a little like flustered by it all. I think in some way.

Chris Bolhuis: Well, I don't know where to look. Okay. I, I I can't just avert my eyes to, focus in on one screen. I, I have to like turn my whole head.

Jesse Reimink: Yeah, you're cracking me up [00:01:00] right now. looks to be honest, like you're, you're looking at screens, which are not the camera. And so it looks like you're kind of wandering off into space

Chris Bolhuis: I don't, I,

Jesse Reimink: look

Chris Bolhuis: I get that same thing. Like, cause it, I can see myself too. And

Jesse Reimink: Yeah.

Chris Bolhuis: look like you're just drifting off into LA LA land.

Jesse Reimink: man. It's killing me.

Chris Bolhuis: but I

Jesse Reimink: Wow.

Chris Bolhuis: though. I like it.

Jesse Reimink: Yeah. I mean, it's professional. It's professional grade over there. We you're you're crushing it.

Chris Bolhuis: I need to say something. So Jenny and I were listening to , our podcast. Okay. And cuz we do that. And I was talking about Brandon, and how, , I did not have a choice in the matter, and she, oh, did she get mad at me?

Chris Bolhuis: She's like, what are

Jesse Reimink: Jenny got mad

Chris Bolhuis: daughter listens? Oh yeah. She said, you are implying that you don't like Brandon. I'm like, that is not my implication at all. What I'm saying? I love Brandon. I'm saying that my daughter is very strong. So I had no say in the matter at all. And so I [00:02:00] need to, to put a disclaimer out there that I do love my bonus son. , I call him my bonus son and I didn't mean anything derogatory when I said I had no choice in the matter that was more like a rip on my daughter than anything else. So there

Jesse Reimink: If Jenny's listening, nobody took it that way. I mean, Jenny, calm down. Everybody

Chris Bolhuis: Well,

Jesse Reimink: that. I understood it. anyway,

Chris Bolhuis: gonna

Jesse Reimink: That's

Chris Bolhuis: gonna go really well. You telling her to calm down. She's gonna

Jesse Reimink: Yeah. Yeah. Calm down, Jenny.

Chris Bolhuis: It

Jesse Reimink: just calm down. well, today, Chris, We're talking about the worst year to be alive and

Jesse Reimink: shocker spoiler. It's not 2020. I mean, 2020 kind of sucked by most people's accounts. Right? I mean, COVID lots of stuff going on in 2020. That was not a banner year. , at least in the Us.

Chris Bolhuis: No

Jesse Reimink: But the thing is it does not compare to 5 36 Ad, which is the year we are gonna talk about here.

Chris Bolhuis: That's right.

Chris Bolhuis: This [00:03:00] idea actually came from a listener question from Kathy about this mysterious fog or cloud that happened in 5 36 Ad. And I started looking into it and. Talk to you about it because it was really, really intriguing. And that's where this episode's coming from.

Jesse Reimink: Yeah. Yeah, absolutely. And you know, the, the more you looking is this is a very long story and it could be. A long episode, but we're gonna keep it kind of tight. So what we're gonna do here is we're just gonna give an overview of what happened in 5 36 Ad, , in the years that followed, then we're gonna talk about what caused this, which shocker it's geoscience related. It's a volcano spoiler alert, but then we're gonna talk about how volcanoes can drive sort of catastrophes of this scale. And then talk about what sort of data led scientists to that conclusion, how we measure this, that far back in time.

Chris Bolhuis: That's right. You had an idea a long time ago for an episode. I think it was called the [00:04:00] process of scientific discovery, something along that line. And when you look into how they pieced all this together, The data that was used. It reminded me of that. The process of scientific discovery in this story is so awesome.

Jesse Reimink: Yeah. And I like it because.

Chris Bolhuis: Yeah. It's right up your doctory alley. Yeah.

Jesse Reimink: Exactly. And, , it has a lot of technique development built into it. So this is a cool story, but let's set the stage here, Chris. So recently Harvard professor Michael McCormick argued that 5 36 ad was literally the worst year to be alive in. Recent history. And the reason is that earth was cooled to the coldest. It's been in a couple millennia and it started this sort of century of economic ruin that had this plague, a plague of Justinian that hit, uh, , Europe, Eastern Europe, particularly a bubonic plague in 5 41 Ad. And it kind of came about with this 18 month long stretch [00:05:00] of darkness that came across Europe, the Middle East in parts of Asia.

Chris Bolhuis: Yeah, I want to interject something that 5 36 is just the beginning. It was early in 5 36 Ad. And then four years later there was another volcanic eruption, a cataclysmic eruption that, that affected the atmosphere a year after that this plague took off and then seven years and 5 47, there was another volcanic eruption. So within 10 years, The world got just hit again and again, and again, it was unbelievable.

Jesse Reimink: for instance, , we're gonna read a couple quotes here, cuz they're really, really awesome. one of them, Michael Asurian wrote the sun became dark and its darkness lasted for one and a half years. Each day. It shown for about four hours and still this light was only a feeble shadow. Then I love this. The fruits did not ripen and the wine tasted like sour grapes, end quote. I mean

Chris Bolhuis: That's the important part of it.

Chris Bolhuis: the wine didn't taste, right?

Jesse Reimink: ah, [00:06:00] man, life sucks. If the wine doesn't taste good, I mean, come

Jesse Reimink: on.

Chris Bolhuis: Yeah. Um, most of these quotes come from authors and politicians. So that's how we know about what this was like. There was another one that was, written by an author. It goes like this. So we have had a winter without storms spring without mildness and summer without heat. just,

Jesse Reimink: And then it's crazy. I mean, I can't imagine that. And then the last one, a Roman politician wrote the sun had a bluish color. The moon lost its luster and the seasons seemed to be jumbled up together. that's a great description. I mean, it sounds catastrophic. This is not a fun time to be alive, right? And the reason . That this is not a fun time to be alive and what drove all this stuff is that summer temperatures fell during this time period.

Chris Bolhuis: Yeah, 5 36 was really just the beginning when this volcanic eruption happened, because four years later there was another cataclysmic eruption that happened. And then a year later is the bubonic plague that you just talked [00:07:00] about, and then seven years later, and 5 47 ad another. Volcanic eruption.

Chris Bolhuis: So the planet got hit and smacked several times within a 10 year time span. Just absolutely amazing.

Jesse Reimink: So this was a really horrible time in the end. I mean, this was a long period of time with cold, with very little light, poor growing seasons plague and worldwide hunger in. And as we said before, this kick started the coldest decade in the past 2300 years. And the summer temperatures fell on average. Now this is a global average, but the temperatures fell by one and a half to two and a half degrees centigrade. So that's, , you know, four or five

Jesse Reimink: degrees Fahrenheit.

Jesse Reimink: And that doesn't sound like a lot, Chris, but. In the global average, that's a ton.

Chris Bolhuis: Yeah, because . We're only talking about an average. We're not talking about the extremes that could come along with something like this, you know, I mean, there were reports of China getting snow in the [00:08:00] summertime. that's

Chris Bolhuis: crazy.

Jesse Reimink: So. We're gonna do this a little bit out of order, or it may seem a little bit out of order. What we're gonna talk about next is how a volcano can actually cool the earth, like how the volcano influences Earth's climate on that scale, or several volcanoes over the course of a decade or two. And then we're gonna talk about. The type of volcano and where it erupted, and then we're gonna come back to the evidence. So we're gonna end with the evidence. Don't worry. We're gonna get there. but we need to start out with how a volcano can cool the earth and you gotta picture a big volcanic eruption. We've all seen images of these. Some of them videos, Mount St. Helens Pinatubo, all of these ones that have erupted while we had video cameras and cameras around, you know, , it sends this huge plume. Ash up into the sky way up into the upper atmosphere. And that is importantly, both dust, rock, dust, and gas, volcanic gases. And those two things get sent really high up into the atmosphere. And that's kind of [00:09:00] what does it,

Chris Bolhuis: So the volcanic dust is, microscopic, , volcanic glass, essentially that is spit up high into the atmosphere. it'll circle the globe, but that stuff is gonna come out relatively fast. It's not gonna stay there long because even though it's microscopic, it still has enough mass where it's gonna settle out rather.

Jesse Reimink: And that's exactly right. And we're gonna come back to that. So remember that dust comes out. We're gonna come back to that. Now, what about the gases?

Chris Bolhuis: Yeah, the gases, there are a lot of gases that are spewed by a volcano. The gas that we're mostly concerned with is it's sulfur dioxide that forms, , these sulfates. And the thing about these gases is that they get higher up into the atmosphere that so we live in a layer of the atmosphere. That's about 20 miles ish thick. That's called the Tropos. the next layer up is called the stratosphere. That's about 20 to 50 miles above the surface. That's the layer. That's super important because it's also the layer that contains ozone and these sulfates [00:10:00] get up into the stratosphere and they're gonna stay there for quite a long time. Why they're important though, is because they have what's called a really high Abido and that means that it's just really reflective. So the incoming solar radiation hits. layer, that kind of blanket that's up there. And then a lot of the radiation is reflected back out into space. And so it's not allowed to do what it normally would do, which is heat the surface of the.

Jesse Reimink: That's exactly right. And, and this is a really important molecule in the end. S so two sulfur dioxide, bonds with water produces sulfuric acid, and those things have exactly, as you said, Chris, this reflective thing. And so it creates this cooling, like that's, that's what it is. It's preventing sunlight and sun energy from making it into earth, which. Therefore cools the earth. If you don't have as much energy from the sun, making it to the surface, then you just don't have as much energy to heat the surface of the earth, right? Like that's actually a lot of heat energy that's coming in through radiation and [00:11:00] sunlight, and that is being trapped in the atmosphere normally. But if you kind of put a layer, a blocking layer in the upper atmosphere, it doesn't make its way in. And therefore it cools the planet.

Chris Bolhuis: the volcanic rocks, this dust, these microscopic grains that are spit up higher up into the troposphere. To me, that's a lot like, , a big forest fire, you know, , this haze that you get and things like that it's really affected by the wind, the direction of the wind and so on. , but it will settle down quickly. This other stuff is not affected by the wind because , the atmosphere is so thin up there anyway, and it's, really just a reflectivity issue that's going on. So it's very different it's really kind of this, this. two pronged punch. If you will, you got the volcanic dust doesn't really last long. And then these aerosols that they last much longer, they stay up in the air.

Jesse Reimink: That's exactly right. And so those dust particles are the key to identifying where.[00:12:00] We can pinpoint, we can fingerprint where those volcanoes come from. And again, spoiler alert, they come from Iceland or they came from Iceland at this time. And so we'll get to how we know that, but it's, it's fingerprinting these little dust particles that rain out after they get chucked up into the stratosphere, they reign out and we can use those to fingerprint where the volcanic eruption came from. But let's have a short little interlude here, Chris. Why volcanoes are on Iceland, just a real brief thing. It's super complicated, but I think we can distill it down. Don't you think

Chris Bolhuis: , well, yeah, I think we're gonna have to The vulcanism on Iceland is unbelievably complicated, so we can't do that justice in this episode at all, but here's, our go at it. here's our run at what what's going on with Iceland you have the Mid-Atlantic Ridge, which is the longest. Divergent boundary [00:13:00] that's on our planet right now. It's it's It looks like a big zipper that goes all the way from the South Pole to the North Pole ish. Right? And so divergent boundaries is where two plates are pulling apart. hot mantle rises up through that crack then leading to the surface of the earth. And so the magma that comes out at mid ocean ridges is what forms the ocean. And that's where Iceland sits right on top of the Mid-Atlantic Ridge, but it's odd, right? Because Iceland is the only spot along the Mid-Atlantic Ridge, where it's actually elevated to an island it's above sea level. So what's going on in addition to just this mid ocean Ridge, Jess, what's going.

Jesse Reimink: Well, it's a really interesting place. And Iceland is unique on the modern earth for having this process. It has a mantle plume sitting underneath of it as well. So it's a mantle plume that's bringing in heat and magma up to the surface of the earth. There's. A mantle plume under Hawaii. There's a mantle plume under [00:14:00] Yellowstone. There's a mantle plume under a bunch of different places.

Chris Bolhuis: Another word for a mantle. Plume is a hotspot. I know you like mantle plumes, and that's like the, the doctory word for it. But just for our listeners, a mantle plume is on a hotspot. They're synonymous. They mean the same thing. So

Jesse Reimink: That's right. Yeah. So there's a hotspot, right underneath of Iceland as well. So. You have, as you described this mid ocean Ridge system, which is producing a lot of magma, it's melting the mantle. There's a lot of heat being added there, but also you have a mantle plume. So you have two sources of heat and two sources of magma, which basically doubles the volume of magma that's produced. When you combine those two things together, you actually have the ability to melt the oceanic crust that you were talking about. Chris. So you talked about this first step, you melt the mantle to form the oceanic crust in Iceland. you're re melting that oceanic crust. So that's why Iceland is sitting above sea level is because it's a little bit thicker.

Jesse Reimink: It's a little bit less dense. It erupts felsic rocks as well as Mafi rocks. So the light colored ones, , [00:15:00] the continental crust, like ones as well as the Mafi the dark ones, the oceanic crustal kind of ones

Chris Bolhuis: Hold on. Hold on. I'm gonna stop you right there. I know you're getting really wordy, but I want you to get a little bit more wordy.

Jesse Reimink: Oh no. You're sending me into the

Jesse Reimink: weeds.

Chris Bolhuis: I am. I am. Why would we have, If the source of the magma is a mantle plum? And divergence. Why does Iceland have this diversity then of extrusive vulcanism why is that going on? Because one third of the vulcanism on our planet, one third of the lava that is Iceland related. So it's a big deal.

Jesse Reimink: Yeah, good question. It's a huge amount. And the reason that you get so much is because you have two sources of heat, two sources of magma, the mid ocean Ridge system and the mantle plume or the hotspot, which produces loads of basaltic volcanism loads of mafic primary melting of the mantle produces the dark color rocks that you see in the photos of Iceland, but you have so much volume [00:16:00] of that. It stacks up on top of each other and it eventually buries those basalt flows. So basalt flows that erupted 20 million years ago, 5 million years ago on Iceland are buried deeper because there's more on top of them. And when they get buried deeper, they get heated up and they start to melt and that produces the felsic rocks, which can produce the big eruptions.

Chris Bolhuis: So partial, melting of the basalt. Produces then, And the reason this is important, it produces a more felsic. Um, magma, the reason this is important is because felsic, magma is stickier. It's more viscous and therefore it tends to be more violent and explosive. It's less frequent, but it's more explosive. And so that's how you get this diversity of magma that. Comes out of a place where the source shouldn't be, that the source should be more mafic and that's important because mafic magma is more runny, less viscosity, and it [00:17:00] tends to be then less violent when it does erupt it, it tends to produce more just lava flows, kinda like what

Jesse Reimink: Yeah. That's exactly. Absolutely. Chris and Iceland. I people probably remember from a couple years ago when there's a big volcanic eruption that was disrupting air travel between europe and North America. And I'm not gonna try, I'm not gonna embarrass myself by trying to pronounce the name of it. But Iceland is a, a key place where there's a lot of vulcanism and there's some pretty violent vulcanism that can throw stuff up into the upper atmosphere. This is not like stuff oozing out into the surface and running around. That happens in Iceland too, but you also get the big ones. The big boys are there.

Chris Bolhuis: Yeah, I'm not gonna try to pronounce it either, but there's a volcano that is, , has recently come to life again and gotten very active. And they think that this might be the beginning then of decades, long volcanism from this particular volcano. So this is. These aren't singular events and same thing with the 5 36 thing that started this whole thing.[00:18:00] That was not one singular eruption. This went on for a period of time. It went on during the course of that year.

Jesse Reimink: that leads us nicely into how do we measure this stuff? How do we know that the story we've just told you, how do we know this? Right. Let's get to the data. And it really comes down to ice core records. next week we're gonna have a conversation with Dr. Richard Ali who's at Penn state and works a lot on ice core data and has done a lot for the modern climate perspective. Um, and, and sort of looking at this type of data. So., Stay tuned to that for next week. But what is an ice core? I mean, people don't know what an ice core is. Chris, can you describe what's going on here?

Chris Bolhuis: Think of an apple corer, if you will, you know,, these things that you put on top of an apple and you clunk it down and it, slices the apple into nice, neat little things, but it leaves this cylindrical core of an apple left behind. That's what an ice core looks like. So if you take a hollow drill and you drill down through the ice and you remove the casing and the casing still has the ice.[00:19:00] you get this perfectly cylindrical? You know, what are they Jesse? A couple of inches in diameter, two to four inches in diameter, probably. ,

Jesse Reimink: Yeah. That's exactly right.

Chris Bolhuis: they use these cores to study what was blocked up in the ice at the time that it was formed, right? Because I think of these,, ice sheets, these glaciers they're time machine. , if you think about it, the Greenland ice sheet is really a two mile thick time machine, because if you can drill down all the way through that locked up in the ice can be all kinds of things, little tiny bubbles of air, but those bubbles of air represent atmosphere composition at the time that that fell as. And so we're going back in time and man, we can learn a ton. This is really, really cool stuff. This gets me excited.

Jesse Reimink: Let me interrupt there, Chris, and say that we gotta picture this a little bit more because we think of a glacier. As you know, we see these pictures of glaciers [00:20:00] coming down the mountain side, and , we see the end of the glacier where the glacier is actually melting out, but up where the glacier's forming up, where the ice is forming,, that is actually adding ice to the system.

Jesse Reimink: And these style glaciers, the ones in Greenland and Antarctica are huge. And you have a zone where glacier is actually forming ice, where as you described, snow is falling. Snow is interacting with the air there's air stuff there. If there's dust around hint, hint, hint. If there's dust around, it'll fall on top of the snow, then next season, or, you know,, the next month there'll be more snow, which burs it. And as you bury it, you form ice as it gets deeper and deeper and deeper,, it forms ice. So those little dust particles. The gas particles from the atmosphere are trapped in the ice. And so think of it as like you're just layering more ice on top of each other. It's like a tree ring growing except turned on its side. That's how ice is forming. And so we just drill down into it and we get this nice record. This sort of,, we could see the bands in the record.

Chris Bolhuis: Yeah. [00:21:00] Hey, I just had a thought, , , this is right up your alley. Can you really fast you know,, don't be too wordy this time. Okay. But can you tell us how we're able to analyze composition of little gas bubbles? How are we able to measure the chemical composition of a gas ?

Jesse Reimink: Yeah, this is really cool. And it's using the same techniques that I use in my lab. If we made just a slight modification, we could do these types of measurements, but basically in this case, you take that core. You kind of cut it in half. And so you're looking at all of these layers, you got the layers and you got this long core with tons of layers in them. All you really need to do is blast that ice with a laser. Most of that material is water. Great. , that's just gonna go into your machine and not really do anything, but the stuff trapped in the gas will give you spikes in composition. So we can measure things like lead. We can measure things like calcium. We can measure things like carbon and CO2. And so you can get this trajectory through this, [00:22:00] where you're measuring the chemical composition of the stuff, all the. Down the core back in time, and you can do just a straight line. So you get a continuous record all the way across. Now you can do more complicated things. You can drill out little parts of the ice. If you wanna make more precise measurements, that's a, in some ways, a better way to do it for certain types of analyses. The point is you put little drills or you use a laser and you just get a nice clean chemical line down. It.

Chris Bolhuis: Cool. That was, that was decent explanation. J

Chris Bolhuis: Jesse, well done my Young sage . Nice, nice

Jesse Reimink: , not,

Jesse Reimink: not too long.

Chris Bolhuis: here's how it went though. In 2015. Researchers had a core, uh,, from Greenland and Antarctic. So ice cores from both ice sheets. Okay. And what they found is very high levels of sulfate. And that's that reflective aerosol that got very high into the atmosphere and they combined those findings. With tree ring analysis to find that over the last 2,500 years every single cold summer was tied to a volcanic [00:23:00] erupt.

Jesse Reimink: It's so cool.

Chris Bolhuis: That's amazing geology can't get away from it.

Jesse Reimink: Because we can get temperature out of the ice core. And we're gonna come back to that next week with Richard Ali kind of more detail about how we get temperature out of it.

Chris Bolhuis: And they can get temperature out of tree rings too, because the, of the slow growth because of the colder summers.

Jesse Reimink: So now we have this story where we've got ice core data. We've got tree ring data. We can get globally, average temperatures , and we can link those with chemical records. Now. , it comes back to how did we fingerprint this stuff? And it's the dust particles, cuz you can find little shards of glass. That's the volcanic dust that is preserved in the ice core. So that dust came out of volcano, moved around the atmosphere, fell down on ice cores in the Alps.

Chris Bolhuis: In 2013 researchers they took a 72 meter long core of a glacier in the Swiss Alps. That 72 meter spans back the last 2000 years. they found fallout from this volcano little [00:24:00] microscopic. Volcanic glass beads. And you know, what else they found in certain layers of this 2000 year old time machine. They found Sahara dust storms. They, found lead pollution from human activities, like the mining of silver. They, So they found spikes of these chemicals that really tell such a cool story. that all happened in this research , that involved the glacier in the Swiss Alps.

Jesse Reimink: It's exactly right. And we can put that chemical record. So you take , the little tiny dust fragments, you know, that that's probably a volcanic eruption. And so you can look at the chemistry of that dust particle and link it to volcanic eruptions that we know from the. Record or know. Oh, that volcano has a kind of a chemical fingerprint to it. And so it's probably that volcano that produced that Ash that ended up in the Swiss Alps in the ice, locked in this time machine in the Swiss Alps. And then link it with all these other chemical tracers. and those dust particles low and behold are at the 5 36 [00:25:00] ad mark, which led to this year and a half of darkness and then sort of decline of civilization in the decade after that with plagues. And, you know, you can imagine a scenario where if there's no food, if your wine is bad and there's no food, then, you know, life gets pretty hard and actually plagues can come out and, you know, it's terrible, right? It's led to sort of a decline of the Eastern Roman empire and.

Chris Bolhuis: I just wanna jump back because I, I would think that you would find this to be really interesting how they did this with the glacier, that 72 meter, long ice core from the Swiss Alps. They carved 120 micron sliver of. So a micron is a millionth of a. meter. So they were using 120 micron, little tiny S slivers. And each of those microns, Jesse represented just a few days and sometimes weeks of snowfall along the length of the entire [00:26:00] core. So each meter of this core had 50,000 different samples, 50,000 different, little tiny slices from each meter that. Painstaking research. And what they did is they ran these cores. They analyzed them for about 12 key elements. , and they used this to pinpoint all this other stuff that was going on, like the sandstorms, volcanoes, and other chemicals that would've been put into the atmosphere from human activities, like the mining of silver.

Jesse Reimink: , that's a great description, Chris. We're very well done. And you can find these glass shards. It's a field called tephro chronology. Tephra is what the little glass shards are, but you can find these shards all over the place. And you find them in bogs, in lakes, people do this all up in down the Canadian Arctic, you can find. Shards from Iceland eruptions shards from ancient volcanoes all over the earth that kind of make it everywhere. So this dust getting blasted all over the place is actually a really powerful [00:27:00] tool for reconstructing the chemical history in the, the volcanic eruption history of the planet. Really.

Chris Bolhuis: Jesse. they found in the Swiss Alps, they found some glass shards that are embedded in the snow that fell out. Okay.. Where else did they find this stuff then? How, like, how did this lead to iceland?

Jesse Reimink: Well, this led to Iceland because you can match the chemistry of volcanic shards in the ice core to volcanic shards. That you found elsewhere. So things like lakes and peat, bogs in Europe or Greenland ice cores, and you can look at the chemical fingerprint of a particular eruption and match it to volcanoes in Iceland. Volcanoes on Iceland. Produce magma in Ash of a very different chemical composition to the Andes or to the cascades or to volcanoes basically anywhere else on the earth. It's pretty diagnostic. It's a pretty unique place that produces magma in Ash. That's pretty unique from a chemical standpoint. So you could kind of do this fingerprinting by matching the tephra, [00:28:00] the dust particles in the ice core, in the Swiss Alps to other locations, and really pin down where, and when that volcano erupted.

Chris Bolhuis: That's amazing that they found the same chemical fingerprint in, you said Pete bogs in Europe and lakes in Europe. , the same fingerprint as the shards that were in a Swiss Alps glacier, the shards that were in Greenland and Antarctic ice sheets that's unbelievably

Jesse Reimink: cool

Chris Bolhuis: I mean, that had to be really exciting to,, to do that.

Chris Bolhuis: Now what's next right.. Is to find the volcano, right? , that's gotta be the next progression , in this research. I mean, they're not done

Jesse Reimink: Right. No, for sure. We could kind of say, oh, it looks like Iceland, but we need to find exactly which volcano.

Jesse Reimink: So

Chris Bolhuis: Well, they haven't found the exact volcano yet. They don't know. Okay.

Chris Bolhuis: And. now they have to go back to Iceland, find more of these shards that are preserved in whether that be lakes or what I, I don't know where they're gonna look, but from what [00:29:00] I read that's what's next is they want to actually find the exact volcano that this came from, because then they can study that and why it was so devastating.

Jesse Reimink: And this leads really nicely into how the story kind of wraps up because around 6 0 5 Ad. 5 36 was the first eruption in this dark period. this 18 months of darkness, 540 and 5 47 Ad had more volcanic eruptions and around 6 0 5. So, uh, you know, 70 years later there starts to be a kick up in. You said it before Chris, the lead signal. So. Atmospheric lead. That is again, kind of raining down on the glaciers. We can measure a kick up in lead in the ice core. Which the inference is that this is civilization rebuilding itself. And this is led produced during silver mining. So society and civilization started to mine, silver and other metals, which can produce lead and [00:30:00] put lead into the atmosphere.

Chris Bolhuis: This is something I don't know. So I'm gonna put you on the spot because you're the smartest guy in the room right now. Um,,

Jesse Reimink: pretty small

Chris Bolhuis: it is a small room, but , I don't know, this. Why is the mining of silver responsible for putting lead into the atmosphere? Do you know how that works? I don't, I don't get it. I

Jesse Reimink: Lead is it's kind of the silver oars that you have. Like You rarely find pure silver. Silver's often encased in another metal. Sometimes it's in, , Galena lead sulfide. We have collected Galena together. Chris, I

Jesse Reimink: think, you know, the big people have probably seen this. Like it's the big, beautiful blocky silver. Silver crystals. They grow in perfect cubes. And when you break 'em, they break in perfect cubes and it's very shiny and that's a good silver ore there's trace amounts of silver in that. So as soon as you start to crush that up to get silver out, lead is an element that is extremely what we call volatile.

Jesse Reimink: It [00:31:00] can be a gas pretty quickly. so it could get pulled into the atmosphere. If you crush anything with lead in it, it could get in the atmosphere. , and so that's how this kind of works.

Chris Bolhuis: Okay. Interesting. So lead is a common marker then for studying what's going on in human civilizations?

Jesse Reimink: Yeah, yeah, that's right. That's right. And there can be, you know, changes if, if people were originally sort of mining copper and then they start mining. silver, there can be an increase in lead. So it's sort of a civilization shift. And for instance, There's a huge lead spike and then a big lead decline in modern civilization record because we started to use leaded gasoline.

Jesse Reimink: We put lead into gasoline in like the 1930s to prevent engine knocking. And so there's lead all over the place in the record, but then we, we went to unleaded, gasoline in like the seventies. And so there's been a drop off.

Chris Bolhuis: Do you remember that or not? You, are you too young? Did you ever go to a gas station and get asked? Do you want leaded or unleaded? Is that something that ever happened to you?

Jesse Reimink: Not that I remember. No,

Chris Bolhuis: Uh, us [00:32:00] old people. We remember that. I, I remember, I think I was probably with my parents. I don't think that it was still around when I started driving. but I remember Yeah. Led or unleaded. That was

Chris Bolhuis: a common thing that you got at

Chris Bolhuis: full serve gas station. So

Jesse Reimink: Yeah. So there's some complexities in the lead uh,, record, especially in the modern earth, but it's this great indicator of civilization recovering at 6 0 5 Ad in the ice record. So that kind of wraps up the story here. And it's just a really cool example of how geoscience volcanoes can dramatically influence civilization and affect civilization in various ways.

Jesse Reimink: And in this case, a fairly negative way.

Chris Bolhuis: this is just more proof that geology, you just can't get away from it. There's no escaping it.

Jesse Reimink: I mean, it's just the best, like, I don't know why we don't all know this. This should be like, This is basic. Geology's the best, like end of story. We don't really need to worry about anything else.

Chris Bolhuis: That's why we do this podcast

Jesse Reimink: right.

Chris Bolhuis: enlighten everybody to bring 'em around geology is where it's

Chris Bolhuis: at

Jesse Reimink: Oh, it's just so fun. So, Hey, if you like planet geo, this kind of [00:33:00] ends at a wrap up. If you like planet geo, if you like this episode, give us a review and a rating that really helps the algorithm share with your friends and you can follow us on all the social medias.

Chris Bolhuis: and

Chris Bolhuis: keep the questions coming. This episode came from listener question, Kathy. Thank you again. That was.

Jesse Reimink: Absolutely keep 'em coming. We love that stuff. , follow us all the social medias at planet geo cast and send us an email planet. Geo cast, gmail.com. We are happy to hear from you.