Carbon Dating

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

Chris Bolhuis: I really need a new partner. I am not happy with my station in life right now. So

Jesse Reimink: Chris. You're just the luckiest son of a gun out there. You get to hang out with me.

Chris Bolhuis: I know how you doing Jesse Reimink.

Jesse Reimink: I'm doing really well. We have not sat down recorded together for too

Chris Bolhuis: yeah, it's been too long. It's not okay.

Jesse Reimink: I mean, you're coaching track, you know, I'm under this semester. Ah, it's just, we haven't done it in a while.

Chris Bolhuis: It is a busy, busy time of year and we know it's busy. We're no busier than anyone else, but it's, it's a busy time of year, right?

Jesse Reimink: Totally, totally. So what are we talking about today?

Chris Bolhuis: Well, let's do some introductions. It's been a while. Hasn't it?

You are Jesse Reimink. You're one of my former students now, actually. Alright, here we go. You are the former student.

Jesse Reimink: The six foot four, from Hudsonville Michigan.

Chris Bolhuis: That's right. I'm just bumping you right now. Okay. Um, yeah, you're one of my former students and a, you loved, you fell in love with geology as well. Why wouldn't you? And you went to hope college got right. Got a bachelor's degree in geology or geo-science and then went on to the university of Alberta and Canada to get your PhD. And you are now working as a professor of geoscience at the Penn state university.

Jesse Reimink: that's right. Your Chris Bolhuis, my former high school teacher. High school teacher, extraordinary from the great state of Michigan, Hudsonville public schools go Eagles. And, uh, you're a national award-winning earth science teacher. You teach astronomy Summer field courses. You have your track shirt on right now. You can coach Hudsonville track or is that cross country

Chris Bolhuis: No. This is track

Jesse Reimink: let's track.

Chris Bolhuis: the, got the Eagle wings on it.

Jesse Reimink: Yeah, man, and this is planet geo.

Chris Bolhuis: Heck yeah, let's

Jesse Reimink: We get to talk about all things geoscience.

Chris Bolhuis: Yeah, I'm really excited about today. Um, today we're going to talk about carbon dating and which is also called radiocarbon dating. And, uh, this is, this is something that like, I think everybody knows this by now. If we they've listened to our podcast for awhile, they know your into dating rocks. Okay. And,

Jesse Reimink: very much so.

Chris Bolhuis: So it's your, this is your lane. It's your expertise? I have a lot to bring to it from maybe different perspectives and, uh, you know, misconceptions that I come across a lot. I think this is one of the things that is. It's maligned a lot. radiocarbon dating, uh, what it can do, what it can't do, what it's used for. how good is it? think there's a lot of stuff that's just simply wrong about it.

Jesse Reimink: misconceptions about it. Not that method itself is wrong.

Chris Bolhuis: Yeah, you're right. people get a lot wrong about this topic.

Jesse Reimink: Absolutely. So carbon dating, always get this question in class. Why can't we date diamonds, diamonds, most people know diamonds are made of carbon. They know carbon dating is a thing. I mean, people generally kind of know the words carbon dating maybe. And the question is why can't we date diamonds? And we'll touch on that at the end, but basically diamonds are far too old and you, you set up, I like to date rocks, which is very true. I love dating rocks, measuring the ages of rocks, but radiocarbon or carbon dating is not very good for rocks actually. It's actually really good for former organic matter, which is makes it really, really, really useful actually, uh, in the fields of archeology. It's very good for the last 50,000 years. And we're going to go through the details of why that is and why it's not good for dating rocks,

Chris Bolhuis: And it's only good though for dating organic matter, that is younger than 50,000 years old. Some of the misconceptions that I encounter a lot, the misconception is we use radiocarbon dating for dinosaur fossils, things like that. And the bottom line is there's no carbon left. Radioactive carbon anyway, to date in dinosaur fossils. So we can't do radiocarbon dating on things like this. And that is, to me, that's the most prevalent misconception that exists out there is the dating of anything that used to be alive, regardless of how long ago that happens to be

Jesse Reimink: Yeah, no, that's totally right. I mean, I think I was just going through this. We've got a couple undergrads working in our lab doing undergrad thesis projects. And so I was in the lab working with graduate students and the undergrads kind of teaching them the ropes of some of the techniques and basically all these things. You got to learn the tools you don't want to, you know, try and drill in a screw with a hammer, right? Like you got to use the right tool for your task at hand. And so radio, carbon or carbon dating is very different from other types of radiometric dating. And it just depends. Are you dealing with a nail or a screw? Like which one do you use? Are you trying to date a young, burned down tree stump from some archeological find. Then you might turn to carbon dating. If you try to date old rocks, you're getting you turn to uranium lead or something like that. So all these techniques have different niches of where they're useful, where they're really useful in there. There's overlap between them, but

Chris Bolhuis: So let's get into Jesse. let's get into some of the basics about w okay. Carbon 12, carbon 13 and carbon 14. what's going on. So these are basically three isotopes of carbon and we need to get into a little bit of this, and we're going to go fast with this because I don't want to lose anybody on this, but basically. Uh, carbon Adam, anything that is called carbon means that it has six protons in the nucleus. And the vast majority of all carbon is carbon 12. That means it has six protons and six neutrons for a mass of 12 atomic mass units. Okay. There are two other common isotopes, carbon 13 and carbon 14. Carbon 13, six protons, but it has seven neutrons. So six plus seven gives it a mass of 13 because protons and neutrons each weigh, one atomic mass unit. And then there's carbon 14. The one that is at the center of our discussion today, because that's radioactive with this half-life that we'll talk about later on. And that has six protons and eight neutrons. So they're all isotopes of carbon, which means they're the same atom, but they have different numbers of neutrons in the nucleus.

Jesse Reimink: That is exactly right. And that extra neutron in carbon 14, where it has eight neutrons and six protons. That extra neutrons, those make it unstable. So this nucleus is not stable, which means it will break apart and it will decay into something different. And what it decays into is nitrogen 14. So it decays through beta decay. So one of those neutrons is unhappy being a neutron and it'll break down, it'll kick out an electron. A neutron is basically a proton plus an electron. So a proton one mass unit and one positive charge, plus an electron one negative charge and basically no mass. So it's a neutral thing with one mass unit.

Chris Bolhuis: Let me back up a second. Okay. So beta decay. This is what happens with carbon 14, that the case into nitrogen 14, if you define beta decay to students, you're like, okay, beta decay is a high energy electron that is ejected or emitted from the nucleus of an atom. some of them will question that like, wait a minute, but there are no electrons in the nucleus of an atom,

Jesse Reimink: Yeah. Aren't those whirring around, outside of it. Aren't isn't there some shell of

Chris Bolhuis: Yeah. And this, Jesse, I got to tell you, this leads to one of my most irritating things regarding chemistry. Like,

Jesse Reimink: I can see the vein coming out of the forehead right now.

Chris Bolhuis: But here's what it is. And when I tell the students this, they actually get a little bit pissed off. Wait a second. This is what beta decay is. So how does an electron, which doesn't exist in the nucleus event? How does it get admitted from it? Well, to me, like, it's such a weird thing, but I didn't learn this til I was maybe a junior in college and it, you know, taking a lot of chemistry classes, what a neutron really is, and you just said it and you glossed right over it, but it's lost on a lot of people. Let's look at first of all, what's a proton. A proton is a positive charge, has a massive one, right? An electron is a negative charge with essentially no mass. It has such a small mass. It is one, 1837th. The massive amount. you're never going to deal with a mass of an electron. So what do you get when you combine that proton with an electron? Well, you take a plus and a minus and you get a neutral charge and it weighs one mass unit. So that's what a neutron is. A neutron is actually a particle that is made up of a proton and electron.

Jesse Reimink: So when that carbon 14 it's too heavy, it has too many neutrons hanging round one neutrons could kick off an electron and turn into a proton. Now it becomes nitrogen, which has seven protons in the nucleus and it still has seven neutrons. So it's nitrogen with mass 14. So it's 14 nitrogen. So 14 carbon, carbon 14 turns to nitrogen 14.

Chris Bolhuis: Really

Jesse Reimink: Chris, Chris, his microphone is falling into his face. What's going on over there. You need to readjust having an earthquake over

Chris Bolhuis: I'm sorry. All right. So it feels like late fall here in Michigan right now and it's cold. And so I have a, I have a hoodie on. Yeah. It's like, it's like 56 degrees right now. It shouldn't be

Jesse Reimink: Just a mess over there. It just interrupted my flow left and right, man, come on. I mean,

Chris Bolhuis: All right. I apologize.

Jesse Reimink: All right. We'll summarize here. The point is, is that 14 carbon. It breaks down, kicks out in electron turns into nitrogen. Okay. That's radiocarbon. That's the radioactive version of carbon. Radiocarbon is radioactive carbon. Carbon 14 is the radioactive version of carbon and this decays over time. And it has a half-life of 5,730 years. And half-life means that this thing's eventually going to decay away. So carbon 14 is going to break down exponentially over time. And Chris, you have an amazing analogy for this. Let's go through that analogy to understand half-life.

Chris Bolhuis: Okay. First half-life the half-life like the textbook definition of it is the time it takes for one half of the atoms that are present to decay. So we've talked about this before in previous episodes, it's a shoe box analogy. If you take a, an empty shoe box and you put a hundred pennies in it and you close the lid and you shake it up, however many shakes you give it, right. You shake it up a bunch and you open up the. I have to remove, let's say all of the tails. If I put in a hundred, how am I? How many statistically should I remove?

Jesse Reimink: roundabout 50

Chris Bolhuis: Yeah. Right. I'm going to remove 50 of them. So that's one half-life I remove 50. So now I have 50 that are head side up in my shoe box. I close the lid and I shake it up again. I open it up again. And now how many statistically should I remove?

Jesse Reimink: roundabout 25.

Chris Bolhuis: Twenty-five that's how half-life works. It is half of the half of the half. So if each time I do this, where I close the lid and I shake it up and I open it up and I remove the tails. You know, whatever time span you want to pick it, does that represent one day? Does it represent 10 days? Does it represent in the case of carbon 14, 5,730 years? That's the half-life the time it takes for one half of those atoms to decay. So the first time I did it. I removed 50 in, in like rookie students want to say, well, okay, the next time you're going to remove the other 50. No, I don't have a hundred it's half of the half and that's the way atoms decay as well.

Jesse Reimink: and this is the beauty of this analogy. Chris's cause that coin flip scenario, anytime a coin has flipped, it's 50, 50 chance. It's a probabilistic thing. Like you might get 10 heads in all in a row, right? You might have that one coin left for many, many half lives because it's, you know, randomly getting lucky and it staying in there. But every flip it's 50% chance. That's the same thing as radioactive decay. Every atom has a fixed probability of decaying in a year. And that probability just equates up to a half-life. We can scale that up and it becomes a half-life when you have billions and billions of atoms sitting there. So it's a perfect analogy for radioactive decay, Chris, it really, really works well.

Chris Bolhuis: there's a point to make here, I think is that every radioactive element and only certain atoms are radioactive only certain isotopes already active they're radioactive because they have an unstable nucleus. there's nothing that changes that isotopes rate of decay. No temperature changes, no pressure changes. The half-life is what the half-life is. The time it takes doesn't change. And each isotope though has its own identity for half-life. You know, we go to like long extremes, right?

Jesse Reimink: Yeah. And so if you're sitting there listening, you should be raising red flags in your head right now about radiocarbon, because your shoe box analogy, Chris, you're thinking, okay, we've got a bunch of carbon, 14 items. Let's say we've got a billion of them. And a half-life 5,730 years. We opened up the shoe box and we take out half. And then we do that again in 5,730 years later, we do it again and we do it again and again and again and again, and pretty soon, like there's no more carbon 14 kicking around, like where's the carbon 14, right? We're going to run out. So why is this a useful system? Why is there carbon 14 around on earth ever? And the answer is that it's different from other isotope systems that we have talked about on this podcast. We talked about in our ancient nuclear reactors and in a couple of different episodes, we've talked about uranium.

Chris Bolhuis: episodes by the way,

Jesse Reimink: It was a great one.

Chris Bolhuis: go back and listen to ancient nukes. That was a great episode. I think I'm proud of that one. That was.

Jesse Reimink: I agree that that was a really fun one to do, but uranium 238, there's a uranium, 238 isotope. It has a uranium, 235 isotope. They're both decaying way. They're decaying at different rates. Uranium 235. We're almost six. Half-lifes into the decay of uranium, 235 from the start of the solar system. So there's not much 235 uranium around on earth anymore.

Chris Bolhuis: we're only one half-life into uranium, 238.

Jesse Reimink: so, there's a bunch of that around still. Carbon 14, if it has this really short half-life like, why is it still around? And the answer is that it's constantly being produced. So carbon 14 breaks down to nitrogen 14. Actually in the upper atmosphere, nitrogen 14 is interacting with cosmic rays and being turned into carbon 14. So carbon 14 is being actively produced in Earth's upper atmosphere. And this means that your shoe box analogy, Chris, I think we need to modify just slightly. And so every time we're going to take this analogy and every time you open up that shoe box, I'm going to dump some more coins in. So you're going to take out all the tails and I'm just going to Chuck some more coins in there. How do you feel about that?

Chris Bolhuis: Well, like that conjures up a funny mental image of like me doing my little shoe box analogy and, you know, very regimented, very focused. And then I got the little devil over there. Jesse just dumping in random carbon fourteens. When I opened it up, like.

Jesse Reimink: I've got this vision of you up in front of your class, try to, you know, explain it, you know, radioactive Decatur students in your opening up your shoe box that I'm sneaking in behind you chucking them in over your shoulder. And Chris is like, what the hell? Why are these things not decaying away? What's going on here? So

Chris Bolhuis: first of all, you're a piece of work. Okay. But second of all, um, I really, I don't know where you're going with this two things you're right. Carbon 14 is regenerated in a way that most radioactive isotopes are not, but I don't see why it matters. I don't see why you have to be dumping in carbon 14 into my shoe box. So explain that.

Jesse Reimink: sure.

Chris Bolhuis: Does that make sense?

Jesse Reimink: yeah, absolutely. So it's a, I mean, it's a great question. Leads right into I think the key point is we need a way to stop me from dumping in new coins, into the shoe box. Right. And

Chris Bolhuis: isn't that just death

Jesse Reimink: Exactly. That's what it is. So if your shoe box is the atmosphere, then carbon is always being produced. Carbon is always decaying and you know, carbon is turning into nitrogen. Nitrogen is turning back into carbon, et cetera. We need a way to stop me from dumping in those extra coins. We need to, you know, you need to lock me in your little back office of your classrooms. So I can't dump coins there anymore. And then that is death. We are living right now. We are respirating. We're breathing in oxygen. We're eating carbohydrates. We're taking carbon out of the atmosphere eventually through our food and putting into our bodies when we die, that process stops and that carbon is no longer exchanging with the atmosphere. And now it's just you and your shoe.

Chris Bolhuis: So the ratio of carbon 14 to carbon 12 in our bodies, when we die. Is representative of the ratio of carbon 14 to carbon 12 in the air at the time we die.

Jesse Reimink: Basically. Yes, exactly. Yes, it's very close to the air ratio. So you are, if I, if you died tomorrow or if I died tomorrow, we would stop exchanging carbon with the atmosphere and with the food and with the water, through our bodies. All that carbon 14 would be locked in our cellular structures and it would decay away to nitrogen 14. And so basically we don't actually need to measure nitrogen at all in this system. So when we talked about uranium Lead, dating uranium lead chronology, we need to measure uranium, the parent and lead the daughter or the product isotope for this system. We only need to know how much carbon 14 is there in the thing. Chris, if you have a lot of carbon 14 in your body and your, you know, laying down the street, I can say, oh yeah, actually you died pretty recently. If there's no carbon 14 in you, you died a long time ago because all that radiocarbon decayed away,

Chris Bolhuis: And I know the limit probably isn't quite 10 half lives. Is that right? It's not 10 half lives. Is it?

Jesse Reimink: it's a little bit more than that for radiocarbon. People are pushing it up to 80 to a hundred thousand years. So we're

Chris Bolhuis: That's amazing

Jesse Reimink: times incredible.

Chris Bolhuis: because I want everybody to understand when you go through 10 half lives, you have a 10th of a percent of the carbon 14 left. No matter what you started with it's one 10th of a percent left after 10 half lives, virtually nothing is left at that point. That's my point. Okay.

Jesse Reimink: Very very, very little,

Chris Bolhuis: Very little and it's amazing to me that they're pushing that even like further, and that's a lot further too, by the way,

Jesse Reimink: Yeah.

Chris Bolhuis: awesome. Wow.

Jesse Reimink: it. It's crazy.

Chris Bolhuis: Okay. So basically what I can say is if we started with, a hundred thousand .Atoms of carbon 14 in something after 10 half lives, we have a hundred Adams left, you know, there's very little left, right?

Jesse Reimink: Yeah. So Chris, I think at this stage we should just step back. Re-summarize the shoe box analogy with me adding coins and make sure we're all on board with where we're at right now. Cause we're going to add another layer of complexity.

Chris Bolhuis: So basically, something that was alive dies. And it had a hundred thousand atoms of carbon 14, but it died 57,300 years ago. That means it went through 10 full half-lives. So at that point, I went from a hundred thousand parent isotopes atoms to a hundred that's all that's left. Okay. That's 0.1% of a hundred thousand. So there's virtually nothing left. That's pushing the limit what we're able to tap. Oh, you know, and you said that actually we can go further than that, which is absolutely amazing because there's so little left at that point. So that's just a summary of the shoe box analogy

Jesse Reimink: Beautiful Chris. So the shoe box analogy then is that if you're in front of your class, you're teaching radioactive K you're shaking the shoe box. You've got your hundred thousand coins in there. You shake it for. one full shake and that is equal to 5,730 years in radiocarbon, a half lives. And then you open it up and you got to take out half of them to take out 50,000. Radiocarbon they'll remember in the upper atmosphere, nitrogen is turning into carbon. And so I'm sneaking up behind you. You know, I'm chucking some coins in your shoe box here, and I'm messing up this number. Like I'm messing this up actively, right? As soon as you die, then I stopped chucking coins in you get sick of me and lock me in your little office. And then your shoe box just works perfectly. It works beautifully, but the radiocarbon production rate is not constant. So the number of coins I'm throwing in = at any given time, whenever you open up that shoe box, I don't throw in the same number. I'm not throwing in 20,000 every time. I'm throwing in 20,001 time, 10,000, another time, maybe one, one time and maybe a hundred thousand one time. Like I'm throwing in a different number of coins so that if you randomly die, if you just get fed up with me, lock me in your office, you might have not a hundred thousand coins in that shoe box anymore, but you might have 150,000 coins in that shoe box, which means that the time it takes to get down to 100 atoms is not going to be 10 half lives. It might be 10.5 half lives or 11 half lives, or maybe nine half lives. So it kind of disturbs our clock a little bit here.

Chris Bolhuis: Okay, hold on now. Hold on. No, it does not actually. Um, it doesn't, uh, to me, I'm just thinking this through. It doesn't mess up the clock. What it messes up is the limit to where you can take it, Look, the decay rate doesn't change. That's where I'm a little bit confused about like, are you're dumping in coins, but it really doesn't matter.

Jesse Reimink: that is also true. I think limp, let's put it in a, in a real, sort of a real world analogy. Let's say, Chris, you find a, dead horse buried in some mud, swamp somewhere. And I want to know, when did this horse die? I give you the thing you make the measurement, you say, oh, the ratio of carbon 14 to carbon 12 is one to 10,000. For every one atom of carbon 14, there's 10,000 atoms of carbon 12. What does that mean for the. How do we know what that means for the age that gives us an age potentially, but do we go about calculating that age? Because that's all the information we have when we're doing radiocarbon dating. Well, we have to know what was the carbon 14 to carbon 12 ratio back through time, because then we can calculate how many half lives did this thing go? So we have to know, oh, actually back in time, there used to be, 1,014 items to 12 in the atmosphere and that's constant through time or it's varying through time.

Chris Bolhuis: Okay, I'm tracking now. Like I get ya. So that begs the question. Can we do this?

Jesse Reimink: Yes. That's absolutely.

Chris Bolhuis: Okay. Cause this leads to the misconceptions that we alluded to at the beginning of the episode. Jesse, let's go into that.

Jesse Reimink: let me ask you this, you probably run into these a lot in your classroom, do you run across misconceptions about radiocarbon? And if so, what are the greatest hits that you come across?

Chris Bolhuis: radiocarbon dating is the standard for all dating. Like that's the number one misconception that I come across. Like everything, comes back to well, carbon date, it cover it. Well, carbon dating is junk because. Yeah. There's so much out there about, radiocarbon dating and what it can do. And then some people know what radiocarbon can't do. And then people say, well, oh, if radiocarbon dating, can't do this. Then radiocarbon dating is junk.

Jesse Reimink: Correct.

Chris Bolhuis: And so that's the most popular thing that I come across is that, you know, radiocarbon dating is all over the map and it's not, actually, this is very solid. I think if you're talking about something, somebody that really has done a little poking around with it, the most common misconception centers around you don't know how much daughter isotope is present. Maybe there was a lot of daughter isotope present at the time the decay process started. And you're assuming that none of it was there. You're assuming then that the age is much older than what it really is. I encounter that fairly often.

Jesse Reimink: so that's a really interesting point because I think that brings us really nicely into the later stages of radiocarbon here is how do we calibrate this curve? We've talked about, you know, I'm throwing coins into your box here, or nitrogen is turned into carbon at different rates back in time. How do we calibrate that thing? Well, there's several ways to do this. First off tree rings are a really great one. So tree rings really old trees. We can count the years so we can start at today and go back in time. We can link up different trees. So dead trees plus living trees. We can link up the tree rings to make a longer tree ring segment. You know, if we say, oh, there's three really bad years and three really good years and four really bad years, that makes a little barcode that we can match up. So we can go back actually really far with tree rings and we can radio card. Quote unquote, date, those interior tree rings, and we can calibrate our production curve, our carbon 14 production curve to a tree ring, which is a great way to calibrate this. We can also do it with artifacts of known ages. So, you know, really well known ages that are seven 50 a D we could radiocarbon date that, and it helps us calibrate this production curve. And that's actually how scientists first discovered that carbon 14 production rates changed back in time, was looking at artifacts with known ages, and they were slightly off. There were a few years off. And so the, production of carbon 14 had to have shifted back in time. So we can do this really well.

Chris Bolhuis: that is one of the most interesting points about this whole discussion to me is how carbon 14 has changed. Like kind of organically as time goes on. Right? Let me give an example. My dad love you, dad. He's an old bird.

Jesse Reimink: He said old bird.

Chris Bolhuis: has Melbourne.

Jesse Reimink: that. That is such a gentle way of, uh, that is great. I'm going, gonna use that. That

Chris Bolhuis: I do love you dad, but he was alive during the fifties and sixties. And

Jesse Reimink: Great point.

Chris Bolhuis: we were doing a lot of above ground testing of nuclear bombs and that process created a lot more carbon 14. and then through photosynthesis and through what we eat, right? These people that were alive at that time have more carbon 14 in their brain stems, then you and I do.

Jesse Reimink: it's just so interesting, right? I mean, humans have changed the radiocarbon production curve or the carbon 14 to carbon 12 ratio a lot. And another way that we've done it is by burning fossil fuels. So Chris, how much carbon 14 is there in oil any fossil fuel, really

Chris Bolhuis: Are you quizzing me right now? The, you are, you're a dirty bastard, right?

Jesse Reimink: a little quiz.

Chris Bolhuis: Well, jesse, this ain't my first rodeo. Um,

Jesse Reimink: been around the block

Chris Bolhuis: bet around the block. There's none. There's no carbon 14. No, because this stuff was during the Carboniferous time period. This is coal

Jesse Reimink: the production of hydrocarbons oil, that stuff was all formed from rocks. The stuff died long time ago, tens of millions years ago, hundreds of millions years ago, right? Like,

Chris Bolhuis: Longer than 57,000 years ago.

Jesse Reimink: that's right. So when we burn those hydrocarbons. We put a lot of carbon into the air and it has no carbon 14,

Chris Bolhuis: Which means it's enriched in carbon 12. Yep. That's right.

Jesse Reimink: so we're basically diluting the carbon 14 in the atmosphere now. So humans have messed up the carbon 14 to carbon 12 ratio a lot more than it normally would do with this, variations in the production of carbon 14 via nitrogen bombardment. so, you know, 5,000 years from now, humans are going to have to do a little bit more careful calibration of radiocarbon dates. But I think it's a really interesting thing that this production curve, at least I find this interesting, Chris, you're probably going to find, you're going to tell me I'm being a little bit too. Professor professor Loreal or nerdy or whatever right now, two doctorate. That's the term two doctors that'd be two doctor, but it, it gives these really Production rate curve, the variations in radiocarbon production rate. So carbon 14 production rate, give us weird uncertainties. For instance, some of the dead sea scrolls have been dated by radiocarbon and because of this calibration curve, there's variation in the production of carbon 14 back in time, it gives us. Two different age range, possibilities. Like I'm used to thinking of uncertainties as, oh, that rock is 10 million years old plus or minus 1 million years. So it could be nine or it could be 11 with radiocarbon. However, we get like age groupings. So for, one of the dead sea scrolls, there's a 15% chance that it dates from 3 55 to 2 95 BC. And then there's an 84% chance that it dates between two, 10 and 45 BC. So there's kind of like two clusters of probability. It could be between here and here, or it could be between here and here and it, but it couldn't be in between those things. So it's a really interesting sort of nuance of radiocarbon dating.

Chris Bolhuis: All right.

Jesse Reimink: You're giving me that. Look again, chris. Um, am I totally in the weeds?

Chris Bolhuis: how does that, okay. No, no, I don't think so. I think that's super interesting. How does that support the idea that radiocarbon dating is solid science

Jesse Reimink: Ooh, good question. Two things, it says that, Hey, we're very aware of the uncertainties in this system. We're very aware of it. We're aware of this back in time, this, variation in the carbon 14 production curve. We're aware of that. We know that it's a potential problem, and we need to incorporate that in our uncertainties. So when somebody says it's a 15% chances in this range and an 85% chance it's in this. That means they're being careful. That means that we understand the system enough to accurately apply on certainty to it and be honest about the uncertainties. So I think it shows that we're doing it really well. Actually, if you can say, I know how good I am at this, it's like, you know, I don't know. I love basketball. a good player. Isn't necessarily somebody who's always good at shooting threes. You can have a really good player. Who's terrible at shooting threes and just stays away from shooting threes. They're really good player. And it's this kind of toolbox thing like radiocarbon is really good for certain things. You also shouldn't use it to try and data 10 million year old rock. Cause you're going to get a wrong answer. It's just not gonna be.

Chris Bolhuis: that is such a good point. I'm really glad you brought that up because that is Uh, this is an important point regarding radiometric dating that depending on what your dating appropriate isotopes need to be used. Not any radioactive isotope will do. And that's a very like popular misconception with this.

Jesse Reimink: that's right. You cannot use radiocarbon to date, most rocks, most rock types. It just doesn't work actually, really any rock type for the most part, historical artifacts, ancient carbon deposits, that sort of stuff, but nothing more than 50 or maybe even a hundred thousand years old. So.

Chris Bolhuis: Yeah. Even with artifacts, people think that you should be able to date, um, bricks or mortar using radiocarbon dating. And that doesn't work because there's no like there's no carbon that's inherent in those products

Jesse Reimink: Gotta have something that died and you're dating the time of death.

Chris Bolhuis: That's right. That's right. That's

Jesse Reimink: Uh, well, I don't know, Chris, what, what do you think, is this a, sort of a wrap?

Chris Bolhuis: hope it's a wrap. It was a fun discussion. Um, these are the kinds of things that you and I sit on my front porch and we. We talk about

Jesse Reimink: That's right. That's right. Sit there. Having a couple beers, maybe whiskey talking about, carbon dating. It's so good. I think it's just really cool and radiocarbon dating. If you ever have the chance to go into a radiocarbon dating lab, they're totally cool. it's a huge room that stores these instruments to do this type of analysis is really difficult. And, it's gotta be really good to do it. There just impressive stuff. Uh, this whole technique is really, really great.

Chris Bolhuis: I guess the summary then that I want to end this episode with is a statement by you about radiocarbon dating. how solid are we talking?

Jesse Reimink: Oh, very solid when applied appropriately. radiocarbon is super solid. We understand the system really well. don't try and date a rock with it, cause you're just using the wrong tool. You're using a screwdriver for a nail. Like what are you doing? You're being an idiot, you know? Uh, so go use something more appropriate. Use uranium, lead your chronology, potassium, argon, something like that. Uh, radiocarbon is great though. It is so cool. And it has been such a massively important development for the geoscience community, the archeology community, the history community. It's one of these techniques. That has its fingers in all sorts of scientific disciplines. Now

Chris Bolhuis: And again, one of the coolest things for me about radiocarbon dating and the way it's done is it involves mass spectrometers. And the idea that a mass spec can pick up the difference in mass between carbon 12 carbon 13 and carbon 14. That blows my mind,

Jesse Reimink: it's so cool.

Chris Bolhuis: go back to our episode on geoscientific discuss. It was an interview where I talked to Jesse specifically about mass spectrometry and how it's done. amazing stuff.

Jesse Reimink: Yeah, we do cover mass spectrometers. I, you don't get me go and we should end it before we get on the

Chris Bolhuis: Yeah, we should reset.

Jesse Reimink: be here all night.

Chris Bolhuis: Yup. But I think that's a wrap. I think that's good. There's a

Jesse Reimink: yeah,

Chris Bolhuis: for us, but lot of fun, I loved it. It's been too long, so

Jesse Reimink: totally glad to get back at it, Christopher. Hey, follow us on all the social medias we're at planet cast. Send us an email planetgeocast@gmail.com. We have a listener question episode coming up pretty quick. So get your questions in and we'll throw them in there. The best thing you can do. Well, not the best thing. The second best thing you can do is leave us a review and a rating on your podcast platform. That really helps the algorithm.

Chris Bolhuis: And the best thing you can do is share this with somebody that you think I would love planet geo and who cares about our amazing planet.

Jesse Reimink: There you go

Chris Bolhuis: That's all right. Cheers.