I was at the University of Hawaii when a research cruise came across an EXTREMELY young lava flow on the East Pacific Rise. As the boat was coming back researchers were figuring out isotopic systems to use to date rocks that were weeks to months old instead of millions of years. The dates they found matched the date of seismic activity at the site. Cool!
This is something I used to wonder about a lot when I was a kid. Nobody ever explained it to me. It was a puzzle to me how we could rely on radiometric dating if we didn't first know what the initial conditions were of the thing we were trying to date.
The thing I forgot for the longest time was that the half-life sort of resets every time. I wondered why say, if a pound of naquadria decayed in one hundred years, thus completing one half-life, why would not the other pund decay completely in another hundred. If you think of the total resetting every half-life, that question falls away.
Half life works the way it does because radioactive decay is essentially a random process. An individual atom could decay at any time; the half life is just a measure of how long you need to wait for there to be a 50:50 chance you'll see it decay. Atoms which haven't decayed at that point then have a 50:50 chance of surviving the next half life, so after two half lives there's only a quarter of the original atoms left, and so on. This explains the ~50,000 year limit on carbon dating: carbon 14 has a half life of around 5,000 years, so after 50,000 years there's only 1/1024 of the original sample left.
It's important to note that radioactive decay is governed by the weak nuclear force - a fundamental force of physics that we never experience in person because it primarily acts on the quarks that exist inside protons and neutrons. This happens at a scale so unimaginably small, that macroscopic effects like temperature and pressure and microscopic effects like chemical reactions do not influence it in any way.
Thanks for this explanation. I asked my science teacher in high school how this reset and he admitted he didn't know. Now I finally know, thanks to you.
I used to be the TA that would also not know the answer to this question, I am so glad that I've looked into it now, it is so interesting! I can't wait for another student to ask me this now haha ;D
Thanks for your videos, especially liked this one. I used to argue with geochronologist often. They used to challenge my seismic interpretations, feelings were mutual. But when the dust settled and everything fits… I had heard much of what you said about a half century ago in college. No visuals though and your graphics were much appreciated! Thanks
Dang. I had this question in the back of my mind since junior high about dating rocks and you answered it beautifully! I wish the masses would watch this to see how science actually works.
Good to see you back! What an awesome lecture, thanks. This is basically like a 27 minute highlights video of my 2nd/3rd year geochemistry at uni. My lecturer Dr Mike Norry was mad as a box of frogs haha. The lecture would go off on numerous tagents, from K-Ar decay to the Cuban Missile Crisis in one breath. Hard to believe it's 10-11 years ago now. Glad you mentioned zircons!
I have long read reports that were based on radiometric dating, and almost as long have wondered about the “reset” question (although I didn’t conceive of it in that term). Your explanation was fantastic and I really appreciate your time and effort to provide it.
Hey, I'm not a student but rather just an old dude with a lifelong interest. Wanted to let you know how much I enjoy your videos and that I appreciate you sharing the knowledge - You are very good at it. Cheers.
Your channel is so informative and so underrated! In your country, are there any Young Earth Creationists who deny radioisotopic dating? Here in my country (Brazil) we are dealing with a new wave of Young Earth Creationists on RUclips who believe that the Earth is 6000 years old and all the sedimentary strata were deposited during a global flood. It's insane!
Thank you so much! :D Oh yea, I would say there are quite a few in the US (I am from Texas and still live in Texas, so I am very used to that). I mean I would never want to challenge or offend someone's belief system, but when they try to discredit science using it, then I am not a fan. I haven't noticed a great increase in terms of the amount of people on RUclips doing that lately, but I don't really watch that content, so I could just be missing it haha ;)
Yes, people with that view are definately found in the United States as well. My subjective impression is that there are many of them, but not a majority. Mostly I hear of it from conservative Christians, but I suppose there are some others (Muslims?) who hold a young earth view as well. As an aside, I will note that not all US Christians are young earth creationists, not even close. Not even all conservative Christians. I know because my father was a conservative Christian but did not subscribe to young earth creationism. It might have helped that he studied soil sciences at a Masters level to become a county agricultural agent. My uncle on the other hand, did believe in young earth creationism. (Incidently, my uncle was also a Christian missionary to Brazil, so maybe he's a small part of the reason for your current group of young earth creationists.) I guess my father came back from a Bible study at my uncle's church once muttering unhappily "they think dinosaurs still roam the earth." (I loved my father, devoutly religious AND respecting science and experts.)
Oh, @APRENDERDESENHANDO, one more thing, there is a channel called Gutsick Gibbon that often addresses and tries to debunk content from US and other English speaking young earth creationists. I mention it just in case you would be interested.
Thank you so much for this video. I too have always brushed off how isotope "reset" occurs during metamorphism and melting. I understand radioactive half-life and rock dating principles, but not the process of resetting to t=0 where you have 100% parent isotopes. It's all about ionic compatibility and incompatibility or exclusion in crystal formation/re-formation, what stage(s) in the process you're trying to date, the importance of comparing different minerals such as zircon vs feldspar vs monazite, etc., mineral selection, and age-correction models. So fascinating!
Yay! Geo Girl is back. You're a real gem. 😊 Cool shirt, cooler video. I really like these isotope videos. I think it's an aspect of geology that doesn't get talked about enough.
I'm glad that you emphasized the fact that single point sampling has many flaws. Multiple samples are needed, and a detailed understanding of how the material has been moved is vital to the dating scene. Some metamorphic rocks can be dated, but what if an event deposited a different age crystal in the lattice. Detailed observation and multiple sampling are imperative. Cosmic interference can change the actual date. Dust from meteorites finds it's way into samples. All that I am saying is that the dating process is more accurate than the human element involved.
Was thinking along similar lines, that sedimentary layer formed by significant flood events could mix up dates of layers IF you are trying to date layers. Along similar lines, a dinosaur killing asteroid is going to introduce foreign material and also cause, I assume, significant surface disruption.
I wonder how the Ice Age Missoula and Bonneville floods were dated. There's a mix of materials involved from eroded Columbia River basalts to sandstones. Maybe researchers looked at zircons and paleomagnetic data.
Awesome video. This is a question that has kind of tickled in the back of my brain every time I read about an isotopically derived age for something or other. It's great to finally have an answer.
This is great, thank you! It's been a long time since my undergrad courses that dealt with this, so a refresher is great, especially with some more current understandings included.
Great explanation. The 'arm-chair geologist' in me always knew "there's more to it..." and you've gone into that quite well. You've gone into a lot of detail about how 'resetting' works when the parent and daughter are actually different elements. Ionic or chemical differences can exclude the daughter element. It's important to point out though that if the parent-daughter are the same element (such as C-14 dating), there are other considerations about the initial concentrations that have to be considered. Not trying to say it isn't a well established dating method, just that there are different issues.
Totally! So glad you found it informative :) The 'there's more to it' thought is always a googd one to have, that is what makes a great scientist ;) Also, just as a side note, C-14 decays into N-14, so it does actually decay into a different element, but we do have to measure C-14 against other stable isotopes of C in the rock instead of going about it the same way we do for U-Pb in which we measure the parent to daughter ratios, so I see what you mean, and you are absolutely right! Each method has different factors we have to consider, and I really only focused on U-Pb in this one, but it's good to point out that other systems require other methods and considerations :)
The concentration of radioactive isotopes is related to age in a special way: The atomic nucleus is radioactive because heat has been stored in it, which came with the kinetic energy of the extra neutrons. Thus, radioactivity is actually vibrational energy stored in the nucleus, in other words heat (fire). This heat (energy) bound to the atomic nucleus can only be released in the form of radioactive radiation. The general diagram of the half-life follows the same form as the black body radiation diagram's descending part, because the half life diagram depicts the radiation of the nucleus as radiation from a black body. Thus, the heat bound to the atomic nucleus is transformed into another form according to the first law of thermodynamics. Second law of thermodynamics says that the sum of the entropies of the interacting thermodynamic systems never decreases. Thus, the atomic nucleus (one interacting system) and electron orbitals (second interacting system) are connected: When the thermal balance of the atomic nucleus changes due to radiation (black body radiation), the balance of electron orbitals must also change according to the second law of thermodynamics. In the end, the electron is a thermal vortex, a remnant from the "big bang". That's why it is called as an "elementary particle", when "elementary" means fire-element.
@@Lund.JWell, that's quite 'imaginative'. But there are radioactive isotopes that have FEWER neutrons than stable forms. And some which emit only a beta particle or alpha particle. Perhaps you should study some more atomic theory. As for the binding energy per nucleon, yes that looks vaguely like a black-body curve (well, a single-tailed distribution). Any pet theory as to why it peaks at Fe-56??
@@mikefochtman7164 Alpha, beta and gamma radiation are different (equilibrium) states of nuclear heat radiation. Beta radiation is "electricity flowing from the nucleus", having formed from electrons which are inwards-turned vortexes of heat. Gamma radiation can be considered somehow proportional to the states that the electron orbitals take: When an electron's excited state is released, it emits a quantum. Electron orbital's "vibration" is also heat-vibration (in that size-scale and density state of substance). A similar (kind of) event takes place inside the atomic nucleus, but in a much smaller space, with the density of the substance being much higher. The result is a gamma quantum (that carries heat out of nucleus). Alpha radiation is the ejection of a whole "fragment of matter" from the nucleus as a result of intense vibration. It can almost be compared to the vibration of sound breaking glass at its resonant frequency. The electric "charge" also increases the speed of the "shard". An atomic nucleus can heat up, that is, enter an unstable state of thermal equilibrium, in several ways. One of them is kinetic energy (heat) coming through neutron radiation; Fusion can also cause the nucleus to "heat up".. In that kind of situation, when the atomic nucleus splits into different atomic nuclei (as happens with alpha radiation), the parts of nucleus can be instable (thermally). The number of neutrons is secondary.. and the vibrational state of nucleus is primary.. Binding energy of iron is a sign, that the entropy of the iron atomic nucleus is the maximum possible and a certain thermal equilibrium state in that atomic nucleus has been reached. Binding energy gets smaller with more massive nucleuses and with less massive nucleuses because their entropy (in the size-scale of atomic nucleus) is smaller; Therefore those (other) nucleuses can break more easily, so that the entropy can grow according to the thermodynamical laws. What happens, depends of the size-scale: - "quark"-size scale - strong force - nucleus size-scale- weak force, radioactivity - electron orbital size-scale, "light" - macrocosmic size-scale, "gravitation" Depending on size-scale AND density state of substance, the forces of nature appear to be diffrent, but all of them are forms of heat vortexes. And according to the first law of thermodynamics, they can transform... Sorry for my bad language skills.
"She blinded me with science! SCIENCE!!" :P Seriously, this was a good explanation, a bit easier than in my copy of "Principles of Physical Geology" :P
I believe c14 dating is not done by measuring the n14 daughter isotope, but by measuring how much c14 there is compared to c12 and c13. There is so much n14 in most organic matter that getting a "pure" initial c14 sample would be nearly impossible. In the case of c14, the isotope clock starts ticking when the organism dies and c14 is no longer being replenished from the environment. I might be wrong about that.
Again for a student of history, who is interested in the real world application the varying dates of known objects with known dates are off the scale and very unhelpful for historical dating with carbon-14. It gets even worse when rocks have known formation dates because you could literally videotape the lava cooling into the rock, and it is stated at millions of years old when it is not even decades old. if it fails when we know the answer, it is likely failing when we don’t. Again a good idea, but it doesn’t seem to be working out and I know people don’t want to give up a theory that they like because of its elegance but I think this is pretty much defunct at least in my eyes it is.
This is just an ignorant comment. You would never use carbon-14 to date volcanic rock. You're obviously referring to an infamous fraud where creationists took some volcanic rock from Mt. Saint Helens and gave it to a lab under false pretenses to subject it to the wrong dating process so that they would get unreliable results and could present them as "proof" that geology is wrong. The purpose of these shenanigans was to prop up their unscientific belief that the world was created by a Canaanite storm god six thousand years ago.
"I believe c14 dating is not done by measuring the n14 daughter isotope, but by measuring how much c14 there is compared to c12 and c13." Concur. Nitrogen is not merely an isotope of carbon; it is an *element* . Plants take up a relatively fixed ratio of C-14 and C-12 while they live. Atmospheric C-12 is converted to C-14 by solar radiation. It is possible this starting ratio is not fixed over long periods of time. A plant will never have pure C-14, not in nature anyway. It will have whatever is the atmospheric ratio at the time.
I am amazed about the number and diversity of fields in which you have studied, all related to Earth&life evolution - your channel is therefore extremely precious because all those fields are (of course) intrinsically linked, so that we can either concentrate on some specific subject we are found of, or be more curious and explore the "why's" and the "how's". And since they are all explained by one person only, you really know and show how to link one topic to another. Thank you for doing all this
Just at the right time !! Im studiying geochronology right now and i see you just uploaded a video on it. I love listening lectures from you .. they are less like difficult lectures and more fun to listen…Thanks and love you!
Do your teachers ban you from studying leaf fossils .They tell us that todays co2 levels are historically very low,Try reading from texts written some 2 or 3 decades ago to bypass woke nonsense.
Thanks, this was helpful. I understood why carbon dating works, since its used for organic materials and the carbon ratios are based on isotope preference in biochemical processes. I was not sure when it came to isotopes used for dating rocks, and didn't stop to consider that the relevant isotopes decay into different elements that would thus have different chemical and physical properties.
This was the first time I watched this content creator. I subscribed half way through her presentation. I never commit to a channel that quickly. Well done young lady!
Well-made vid about a topic almost always brushed over. I especially enjoy the level of complexity you are able to include in a way that makes it still possible to follow for geologically illiterates like me, without sacrificing the soundness of the relevant points. Your ability to estimate successfully, down to which depth it is possible to cover a topic without loosing casually interested folks, impresses me. Subscribed.
I’m a physicist and have taught radioactive dating when going over nuclear physics-basics and have always just hand-waved the explanation for igneous rock/birthday/initial isotope ratios. Now I won’t have to.
Thank you. This actually illuminates some of the complexities involved in ascertaining a date. Much more intricate than some of the usual references made on the topic. I didn't know there was a reset. Much to be gleaned from study of crystallization of materials. Quite amazing.
Wow, thanks! I was wondering how Uranium was useful for radioisotope dating, because unlike the lighter parent radioisotopes used for dating Uranium isn't replenished within the mantle through the continuous decay of heavier elements... But you actually covered that question just as I started typing it. 😂
This excellent video answered almost all questions I had about radiometric dating that I was too lazy to actually look up myself. As a chemist it all made perfect sense to me. The only negative comment I have is about the thermodynamic and kinetic effects in crystallisation. I know little about crystallisation from molten salt mixtures, but that bit could have been clearer I think. I look forward to watching the rest of your video backlog.
Great to finally see such detailed explanations on this point. I've been wondering about it for a long time, searching around, asking around and I had partial answers (that the daughter elements don't get included into the crystal), but I didn't understand by what mechanisms that would happen. Thank you very much for explaining it so well and deeply!
Thank you for finally explaining this! It's not just you, every explanation I've seen of radioactive dating leaves out a detailed explanation of the intricacies of how this actually works! Another thing I've always wondered about is, how do scientists manage to date zircon crystals that are embedded in other minerals while still managing to ensure they are only dating the zircon crystals itself? It seems like it would be very difficult to remove something that small and ensure it's not contaminated in any way
Zircon is very stable chemically (which is why it's so resistant to weathering) so it's not hard to find solutions that would dissolve most everything else that might be mixed in with it and leave just the zircon grains behind.
Yes, the more I thought you put into this and into everything that could go wrong. He’s an experienced person, doubting its efficacy. People hold onto it because it is an elegant theory based on very creative thinking, but the problem is it doesn’t seem to work if a chemist got the same sort of results that you get from dating separate samples of the same material and materials with known dates we would likely not have a Advanced materials industry and advanced chemical industry. We have these because the science is accurate and by accurate I mean reproducible within a very thin margin of error, so that a bottle of Clorox bleach can, for all intents and purposes be considered a fungible item. If you’re not at that level, we’re talking junk science. PS I am not saying this can’t be improved or worked on in the future. I’m just saying as it is now it doesn’t work and I don’t understand how so many people can sit there and look at the results and pretend that this is giving you use for results it is not.
@@seaneustace9308 I think you might have misunderstood what I was saying. I know for certain that it is possible to date zircon crystals that are included in parent rock, but I was asking about the specific lab technique thats used to prepare those samples for testing in a way that produces an accurate result. Maybe that is something that @GEO GIRL can explain in a future video?
I think you could have made it even clearer: if the isotope decays, it becomes another element with a different chemistry. When the crystal grows, only the radioisotope is allowed in the crystal structure, and only being created by decay makes it possible to have the daughter isotope / element trapped in that crystal and it is thrown out (the clock resetted) by remelting.
Yeah, that was a little confusing to a non-geologist. Melting or re-melting causes the diffusion of lighter daughter isotopes into the surrounding rock and heavier parent isotopes to enter the crystal. The total amount of parent and daughter isotopes in the whole system, which includes both crystal and surrounding rock, stays the same because there's no nuclear fusion going on to create heavier isotopes.
This is fascinating! I'm an old health physicist and I just subscribed. Might you consider making the cursor a tad bigger or loud color because I (and other old people maybe) can't follow it. I've been trying to learn more about geology since I retired.
I’m going to check for that Radiogenic Isotope Geochemistry text book. And I just found a pdf version. But I’ll check the uni library tomorrow for a hard copy. Easier to browse, jump back and forth etc.
Well done Rachel! This video and others you made enables a good understanding of how the age of rocks and therefore that of planet Earth is determined and is very good at debunking Young Earth Creationist or other pseudo-scientific claims. I would like to do a geologic dating with you😉
Solid explanation. You choose a crystal which during solidification didn't want daughter isotopes in its lattice. After solidification the daughter elements from isotope decay can't move anymore (except via certain lattice defects I guess).
Love your content. Top tip: get yourself a footpedal, that way you won't have to divert your eyes or hands when switching slides! Keep up the great work, thanks.
I'm going to watch this again, but I think the answer is that the materials in the molten rock become separated as it cools. Maybe in ways that are similar to the way metals are separated during the smelting process? It seems like under some situations molten metals mix thoroughly to make alloys and in other situations metals separate as they cool. From the video, it seems like there are tests that can determine if the melting resulted in a thorough separation between the parent and child minerals or not.
21:16 - and the isotopes of the decay products are typically quite rare anyway, so a "random" selection of included daughter element is not likely to be a decay isotope in many situations
Nicely detailed video! Could you make a video about issues in radiometric dating of rocks (and ultra fast fossilisation of trees) at the Mount St. Helens, which exploded in 1980? There has been now plenty of scientific peer-reviewed studies about that.
Rachel🪻! Thank you 👏👏. Interesting stuff. I'd love to know the ratios of those big balanced boulders 🪨🪨 around Phoenix compared with the nearby mountains.
Thanks so much! From what I just briefly searched online it seems that the mountains around Phoenix are about 1.7 billion yrs old!! Which I didn't know and that is so cool! And the big balanced boulders it sounds like their ages are less precise, but most sources put them at still being Proterozoic aged but younger than the mountains. There are some more boulder type granites further east near Tucson that seem to be Cretaceous in age, so much younger, so I guess it depends on where in AZ you look. I wasn't aware of the amazing geology and diverse ages of AZ rocks until you asked this, so thank you for making me look this up haha! :D I am going to send you a link to a cool website in a follow up reply, just in case yt takes it down. :)
@@GEOGIRL Rachel, Thank you so much! I love the link & am so glad you did an internet search--strong 💪work! Hopefully YT will let you keep it posted 😉. If we never drove to phoenix to visit our son and DIL I would never have started this line of question & answers. AZ is fascinating. btw, The link says they had a boring billion too 😊! After reading that link and your reply I still think those balanced boulders are a product of erosion & not either a glacial or alluvial deposit. p.s. I love the "Earth Rocks by Age" slide/map. I found it and downloaded it to my computer and phone.
I really like your presentation of such a complex system🥰. I am interested in the absolute dating of sedimentary rocks, trying to find minerals and isotope systems that indicate the sediments' age themselves, instead of their mothers', but still in the beginning. Thank you so much.
I have only now discovered your channel and want to congratulate you on the excellent educational content! Please keep it up 👍 Here is my question: Environmental Factors: Conditions like heat or radiation can reset the "clock." And also constant decay rates and initial conditions might vary. What systemic errors arise from this as to dating?
Went through some of the videos and was super informative and love the articulation. I have one question though; If isotopes are used to Date rocks, what can I use to Date you? :p ; ok sorry thats cheezy I know, but worth a laugh. Ignore that, in the spirit of humor and youre super cool.. you rock! ok another pun. .. thanks , bye ! :)
All of the steps to achieve weapons grade Uranium are (thankfully!) difficult and labor intensive. The most difficult part is actually separating the U-235 from the U-238 since they are both the same element and are of near identical weights. Back in the days of WW 2, they mostly relied on incorporating all of the Uranium into a gas UF6 (Uranium Hexafluoride), similar to how you can turn solid Carbon into gaseous CO2. Then they painstakingly ran it through seemingly endless steps of gaseous diffusion by capitalizing on the fact that the UF6 molecules with the U-235 went through the barrier at a slightly different rate as the UF6 that had the U-238. When finished with that process, they returned it to its elemental state by getting rid of the Fluorine. Nowadays there are very high tech centrifuges that are machined to incredible precision and can separate the two different UF6 gasses.
Thanks for the explanation! James Mahaffey has a few very good audiobooks on the history of discovery of radioactivity and how nuclear science evolved up to and beyond WWII, he also has a book on nuclear accidents or "broken arrow" incidents that is scary but fascinating.@@chriskennedy2846
I own a ring made out of a meteorite that was dated using the Ur/Pb method and I was wondering exactly that: how do we know the start conditions? This video answered the question! Thank you!
Wow, thanks for that video! Still some doubts that would love to have answers (I don't really know a lot about geology...so sorry if those are too basic questions): 1) is Uranium 238 created also in some geological processes so that the diffusion can happen in the magma chambers?? Because Uranium is created in supernovas or inside stars right? So if in a supernova a Uranium 238 is created, its decay process starts there...and at some point all U238 should be gone! Same with the other non-stable isotops right? So, how there is always U238 available in the magma chamber to purely cristalyze. 2) Same question but with Carbon, why the fossils are 100% Carbon 14 originally when fossilyzed? This means that organic life material is Carbon 14 100% and then it starts the decay process when we die or fossilyze? If so, then is the C14 created by the organic processes?...
You answer questions I have always wondered about. I love it. However, I tend to learn better when I read books than watching videos so I'd like to find good vulgarization books on geology. To be more specific on what I'm looking for, I'd love to find the equivalent in geology of Richard Dawkins or Stephen Jay Gould books in evolution theory : books that really go into explaining the details, with a scientific mindset, but not too difficult for someone who has a decent scientific background. On the other end of the spectrum, there are authors like Neil Degrasse Tyson who's very good at vulgarizing, but usually only scratches the surface of things. That kind of books leave me frustrated when I read them. Also, I love the history of science, I love to know how we came up knowing all these things, how some scientists were initially mistaken and why, etc... I've been looking for such a book in geology for ages. Thanks for your help !
I need to know what that bright logo is on the front of your hoodie! Looks rad from the 5% of it i can see lol. Do you have a link i can look up for it? ^_^
Interesting hearing about crystal formation of these mineral nodes, makes sense. 1) As the formation of elements heavier than iron require supernova the amount of radioactive material earth has will have been decreasing over time since its formation, does this need to be factored in when dating extremely old samples? 2) Assuming these crystals work similar to most, if the temperature of the chamber is too high they re-dissolve, and when the temperature is too low they don't or are slow to swap out atoms which don't fit nicely into the lattice, however I imagine that at the right temperature and lower the crystal closer to the center is unable to rotate out decayed atoms. Is my understanding correct and if so is it considered that active deposits tend to be left by the volcanoes when the chamber is hottest, and that large crystals found may have more accurate concentrations on its surface than at the center? Thank you for the great explanatory video on this subject!!
Finally some rock solid dating advice.
Geologist humor! 😂
I always knew the key to having a stable daughter was the decaying process of her parents.
This is a highly under-rated pun comment 🤣
How dare you!
Impressive geology dad joke combo.
I was at the University of Hawaii when a research cruise came across an EXTREMELY young lava flow on the East Pacific Rise. As the boat was coming back researchers were figuring out isotopic systems to use to date rocks that were weeks to months old instead of millions of years.
The dates they found matched the date of seismic activity at the site. Cool!
❤❤ This is a prove that the reset theory is true, in fact. ❤❤
This is something I used to wonder about a lot when I was a kid. Nobody ever explained it to me. It was a puzzle to me how we could rely on radiometric dating if we didn't first know what the initial conditions were of the thing we were trying to date.
The thing I forgot for the longest time was that the half-life sort of resets every time. I wondered why say, if a pound of naquadria decayed in one hundred years, thus completing one half-life, why would not the other pund decay completely in another hundred.
If you think of the total resetting every half-life, that question falls away.
Half life works the way it does because radioactive decay is essentially a random process. An individual atom could decay at any time; the half life is just a measure of how long you need to wait for there to be a 50:50 chance you'll see it decay. Atoms which haven't decayed at that point then have a 50:50 chance of surviving the next half life, so after two half lives there's only a quarter of the original atoms left, and so on. This explains the ~50,000 year limit on carbon dating: carbon 14 has a half life of around 5,000 years, so after 50,000 years there's only 1/1024 of the original sample left.
It's important to note that radioactive decay is governed by the weak nuclear force - a fundamental force of physics that we never experience in person because it primarily acts on the quarks that exist inside protons and neutrons. This happens at a scale so unimaginably small, that macroscopic effects like temperature and pressure and microscopic effects like chemical reactions do not influence it in any way.
@philochristos We still don't, and we can't. It was never observed, and isn't repeatable, ergo all conjecture... unlike real science.
@@PressRecord777 Why can't they take a rock or mineral sample and measure it then melt it and after it cools remeasure it?
Thanks for this explanation. I asked my science teacher in high school how this reset and he admitted he didn't know. Now I finally know, thanks to you.
I used to be the TA that would also not know the answer to this question, I am so glad that I've looked into it now, it is so interesting! I can't wait for another student to ask me this now haha ;D
This question has been bugging me for decades. I did not realize there was an isotopic preference during crystalization.
I, too, have wondered about “resetting” before you gave me its name. Thorough explanation. Thank you.
Thanks for your videos, especially liked this one. I used to argue with geochronologist often. They used to challenge my seismic interpretations, feelings were mutual. But when the dust settled and everything fits…
I had heard much of what you said about a half century ago in college. No visuals though and your graphics were much appreciated!
Thanks
Dang. I had this question in the back of my mind since junior high about dating rocks and you answered it beautifully! I wish the masses would watch this to see how science actually works.
Good to see you back! What an awesome lecture, thanks. This is basically like a 27 minute highlights video of my 2nd/3rd year geochemistry at uni. My lecturer Dr Mike Norry was mad as a box of frogs haha. The lecture would go off on numerous tagents, from K-Ar decay to the Cuban Missile Crisis in one breath. Hard to believe it's 10-11 years ago now. Glad you mentioned zircons!
those nutty professors are always great haha
I have long read reports that were based on radiometric dating, and almost as long have wondered about the “reset” question (although I didn’t conceive of it in that term). Your explanation was fantastic and I really appreciate your time and effort to provide it.
Thank you so much! I am so glad you found it informative! :)
@@GEOGIRL Can you please make a video showing the lab technique used to prepare samples for radiometeric dating?
Thanks, I’m in a relationship with my rock partner. This advice for dating rocks has been really helpful.
Hey, I'm not a student but rather just an old dude with a lifelong interest. Wanted to let you know how much I enjoy your videos and that I appreciate you sharing the knowledge - You are very good at it. Cheers.
Your channel is so informative and so underrated!
In your country, are there any Young Earth Creationists who deny radioisotopic dating?
Here in my country (Brazil) we are dealing with a new wave of Young Earth Creationists on RUclips who believe that the Earth is 6000 years old and all the sedimentary strata were deposited during a global flood. It's insane!
There are many YECs in the US that deny radioactive dating. Indeed, your YECs in Brazil are likely importing their beliefs from the US.
Thank you so much! :D
Oh yea, I would say there are quite a few in the US (I am from Texas and still live in Texas, so I am very used to that). I mean I would never want to challenge or offend someone's belief system, but when they try to discredit science using it, then I am not a fan. I haven't noticed a great increase in terms of the amount of people on RUclips doing that lately, but I don't really watch that content, so I could just be missing it haha ;)
Yes, people with that view are definately found in the United States as well. My subjective impression is that there are many of them, but not a majority. Mostly I hear of it from conservative Christians, but I suppose there are some others (Muslims?) who hold a young earth view as well.
As an aside, I will note that not all US Christians are young earth creationists, not even close. Not even all conservative Christians. I know because my father was a conservative Christian but did not subscribe to young earth creationism. It might have helped that he studied soil sciences at a Masters level to become a county agricultural agent. My uncle on the other hand, did believe in young earth creationism. (Incidently, my uncle was also a Christian missionary to Brazil, so maybe he's a small part of the reason for your current group of young earth creationists.) I guess my father came back from a Bible study at my uncle's church once muttering unhappily "they think dinosaurs still roam the earth." (I loved my father, devoutly religious AND respecting science and experts.)
Oh, @APRENDERDESENHANDO, one more thing, there is a channel called Gutsick Gibbon that often addresses and tries to debunk content from US and other English speaking young earth creationists. I mention it just in case you would be interested.
@@lethargogpeterson4083 I know Erika, her channel is one of my favorites!
Thank you so much for this video. I too have always brushed off how isotope "reset" occurs during metamorphism and melting. I understand radioactive half-life and rock dating principles, but not the process of resetting to t=0 where you have 100% parent isotopes. It's all about ionic compatibility and incompatibility or exclusion in crystal formation/re-formation, what stage(s) in the process you're trying to date, the importance of comparing different minerals such as zircon vs feldspar vs monazite, etc., mineral selection, and age-correction models. So fascinating!
Something I've been wondering about for a really long time, thanks for this.
Yay! Geo Girl is back. You're a real gem. 😊 Cool shirt, cooler video. I really like these isotope videos. I think it's an aspect of geology that doesn't get talked about enough.
I'm glad that you emphasized the fact that single point sampling has many flaws. Multiple samples are needed, and a detailed understanding of how the material has been moved is vital to the dating scene. Some metamorphic rocks can be dated, but what if an event deposited a different age crystal in the lattice. Detailed observation and multiple sampling are imperative. Cosmic interference can change the actual date. Dust from meteorites finds it's way into samples.
All that I am saying is that the dating process is more accurate than the human element involved.
Was thinking along similar lines, that sedimentary layer formed by significant flood events could mix up dates of layers IF you are trying to date layers. Along similar lines, a dinosaur killing asteroid is going to introduce foreign material and also cause, I assume, significant surface disruption.
I wonder how the Ice Age Missoula and Bonneville floods were dated. There's a mix of materials involved from eroded Columbia River basalts to sandstones. Maybe researchers looked at zircons and paleomagnetic data.
Awesome video. This is a question that has kind of tickled in the back of my brain every time I read about an isotopically derived age for something or other. It's great to finally have an answer.
This is great, thank you! It's been a long time since my undergrad courses that dealt with this, so a refresher is great, especially with some more current understandings included.
Great explanation. The 'arm-chair geologist' in me always knew "there's more to it..." and you've gone into that quite well. You've gone into a lot of detail about how 'resetting' works when the parent and daughter are actually different elements. Ionic or chemical differences can exclude the daughter element.
It's important to point out though that if the parent-daughter are the same element (such as C-14 dating), there are other considerations about the initial concentrations that have to be considered. Not trying to say it isn't a well established dating method, just that there are different issues.
Totally! So glad you found it informative :)
The 'there's more to it' thought is always a googd one to have, that is what makes a great scientist ;)
Also, just as a side note, C-14 decays into N-14, so it does actually decay into a different element, but we do have to measure C-14 against other stable isotopes of C in the rock instead of going about it the same way we do for U-Pb in which we measure the parent to daughter ratios, so I see what you mean, and you are absolutely right! Each method has different factors we have to consider, and I really only focused on U-Pb in this one, but it's good to point out that other systems require other methods and considerations :)
The concentration of radioactive isotopes is related to age in a special way:
The atomic nucleus is radioactive because heat has been stored in it, which came with the kinetic energy of the extra neutrons.
Thus, radioactivity is actually vibrational energy stored in the nucleus, in other words heat (fire).
This heat (energy) bound to the atomic nucleus can only be released in the form of radioactive radiation.
The general diagram of the half-life follows the same form as the black body radiation diagram's descending part, because the half life diagram depicts the radiation of the nucleus as radiation from a black body.
Thus, the heat bound to the atomic nucleus is transformed into another form according to the first law of thermodynamics.
Second law of thermodynamics says that the sum of the entropies of the interacting thermodynamic systems never decreases.
Thus, the atomic nucleus (one interacting system) and electron orbitals (second interacting system) are connected:
When the thermal balance of the atomic nucleus changes due to radiation (black body radiation), the balance of electron orbitals must also change according to the second law of thermodynamics.
In the end, the electron is a thermal vortex, a remnant from the "big bang".
That's why it is called as an "elementary particle", when "elementary" means fire-element.
@@Lund.JWell, that's quite 'imaginative'. But there are radioactive isotopes that have FEWER neutrons than stable forms. And some which emit only a beta particle or alpha particle. Perhaps you should study some more atomic theory.
As for the binding energy per nucleon, yes that looks vaguely like a black-body curve (well, a single-tailed distribution). Any pet theory as to why it peaks at Fe-56??
@@mikefochtman7164
Alpha, beta and gamma radiation are different (equilibrium) states of nuclear heat radiation.
Beta radiation is "electricity flowing from the nucleus", having formed from electrons which are inwards-turned vortexes of heat.
Gamma radiation can be considered somehow proportional to the states that the electron orbitals take:
When an electron's excited state is released, it emits a quantum. Electron orbital's "vibration" is also heat-vibration (in that size-scale and density state of substance).
A similar (kind of) event takes place inside the atomic nucleus, but in a much smaller space, with the density of the substance being much higher. The result is a gamma quantum (that carries heat out of nucleus).
Alpha radiation is the ejection of a whole "fragment of matter" from the nucleus as a result of intense vibration. It can almost be compared to the vibration of sound breaking glass at its resonant frequency. The electric "charge" also increases the speed of the "shard".
An atomic nucleus can heat up, that is, enter an unstable state of thermal equilibrium, in several ways.
One of them is kinetic energy (heat) coming through neutron radiation;
Fusion can also cause the nucleus to "heat up"..
In that kind of situation, when the atomic nucleus splits into different atomic nuclei (as happens with alpha radiation), the parts of nucleus can be instable (thermally).
The number of neutrons is secondary.. and the vibrational state of nucleus is primary..
Binding energy of iron is a sign, that the entropy of the iron atomic nucleus is the maximum possible and a certain thermal equilibrium state in that atomic nucleus has been reached.
Binding energy gets smaller with more massive nucleuses and with less massive nucleuses because their entropy (in the size-scale of atomic nucleus) is smaller;
Therefore those (other) nucleuses can break more easily, so that the entropy can grow according to the thermodynamical laws.
What happens, depends of the size-scale:
- "quark"-size scale - strong force
- nucleus size-scale- weak force, radioactivity
- electron orbital size-scale, "light"
- macrocosmic size-scale, "gravitation"
Depending on size-scale AND density state of substance, the forces of nature appear to be diffrent, but all of them are forms of heat vortexes.
And according to the first law of thermodynamics, they can transform...
Sorry for my bad language skills.
"She blinded me with science! SCIENCE!!" :P Seriously, this was a good explanation, a bit easier than in my copy of "Principles of Physical Geology" :P
I believe c14 dating is not done by measuring the n14 daughter isotope, but by measuring how much c14 there is compared to c12 and c13. There is so much n14 in most organic matter that getting a "pure" initial c14 sample would be nearly impossible. In the case of c14, the isotope clock starts ticking when the organism dies and c14 is no longer being replenished from the environment. I might be wrong about that.
Again for a student of history, who is interested in the real world application the varying dates of known objects with known dates are off the scale and very unhelpful for historical dating with carbon-14. It gets even worse when rocks have known formation dates because you could literally videotape the lava cooling into the rock, and it is stated at millions of years old when it is not even decades old. if it fails when we know the answer, it is likely failing when we don’t. Again a good idea, but it doesn’t seem to be working out and I know people don’t want to give up a theory that they like because of its elegance but I think this is pretty much defunct at least in my eyes it is.
This is just an ignorant comment. You would never use carbon-14 to date volcanic rock. You're obviously referring to an infamous fraud where creationists took some volcanic rock from Mt. Saint Helens and gave it to a lab under false pretenses to subject it to the wrong dating process so that they would get unreliable results and could present them as "proof" that geology is wrong. The purpose of these shenanigans was to prop up their unscientific belief that the world was created by a Canaanite storm god six thousand years ago.
"I believe c14 dating is not done by measuring the n14 daughter isotope, but by measuring how much c14 there is compared to c12 and c13."
Concur. Nitrogen is not merely an isotope of carbon; it is an *element* .
Plants take up a relatively fixed ratio of C-14 and C-12 while they live. Atmospheric C-12 is converted to C-14 by solar radiation. It is possible this starting ratio is not fixed over long periods of time. A plant will never have pure C-14, not in nature anyway. It will have whatever is the atmospheric ratio at the time.
@@seaneustace9308interesting. So you say radioactife dating are not actually working or very inaccurate?
I am amazed about the number and diversity of fields in which you have studied, all related to Earth&life evolution - your channel is therefore extremely precious because all those fields are (of course) intrinsically linked, so that we can either concentrate on some specific subject we are found of, or be more curious and explore the "why's" and the "how's". And since they are all explained by one person only, you really know and show how to link one topic to another. Thank you for doing all this
Just at the right time !! Im studiying geochronology right now and i see you just uploaded a video on it. I love listening lectures from you .. they are less like difficult lectures and more fun to listen…Thanks and love you!
So glad you enjoy my lectures! Best of luck with your studies! :D
Do your teachers ban you from studying leaf fossils .They tell us that todays co2 levels are historically very low,Try reading from texts written some 2 or 3 decades ago to bypass woke nonsense.
Thanks, this was helpful. I understood why carbon dating works, since its used for organic materials and the carbon ratios are based on isotope preference in biochemical processes. I was not sure when it came to isotopes used for dating rocks, and didn't stop to consider that the relevant isotopes decay into different elements that would thus have different chemical and physical properties.
It doesn’t work we can test things with known dates and you get dates that are all over the chart, including different samples from the same material.
It's a guess at best. I'm not even sure why anyone bothers trying to find any of this out. It doesn't mean anything in the world.
This is super important for everyone to understand! ty
Thank you, GeoGirl! I just thought I would give you some encouragement! Keep the interesting video content coming!
Thanks so much! :D
Oh my, that solves me tons of questions! good work!
Thank you! So glad to hear that :D
@@GEOGIRL thanks for the reply too! 💯
This is the most detailed review of how this process works I've seen online. Thanks
Very Good explanation of a very complicated phenomenon.Kudos to you.
Thank you for another wonderful video. You are fun to watch.
This was the first time I watched this content creator. I subscribed half way through her presentation. I never commit to a channel that quickly. Well done young lady!
Your explanations are often wonderful for clarity and comprehensibility. Excellent stuff.
Thank you so much! :D
@@GEOGIRL well deserved complements
Well-made vid about a topic almost always brushed over. I especially enjoy the level of complexity you are able to include in a way that makes it still possible to follow for geologically illiterates like me, without sacrificing the soundness of the relevant points. Your ability to estimate successfully, down to which depth it is possible to cover a topic without loosing casually interested folks, impresses me. Subscribed.
First time here. Really great lecture! Subscribed. Thank you for the uploads!
I’m a physicist and have taught radioactive dating when going over nuclear physics-basics and have always just hand-waved the explanation for igneous rock/birthday/initial isotope ratios. Now I won’t have to.
❤Thank you! I knew for years about isotopes & half life, but had no clue about the reset process, so was wondering about hour 'zero' all the time. ❤
Thank you. This actually illuminates some of the complexities involved in ascertaining a date. Much more intricate than some of the usual references made on the topic. I didn't know there was a reset. Much to be gleaned from study of crystallization of materials. Quite amazing.
Outstanding video. Always wondered about this. Thank you!!!!!!
Thanks for a great video, it answered lots of questions.
Fascinating, and clear. Thanks for the hard work and prep in putting this together.
Wow, thanks! I was wondering how Uranium was useful for radioisotope dating, because unlike the lighter parent radioisotopes used for dating Uranium isn't replenished within the mantle through the continuous decay of heavier elements... But you actually covered that question just as I started typing it. 😂
This excellent video answered almost all questions I had about radiometric dating that I was too lazy to actually look up myself. As a chemist it all made perfect sense to me. The only negative comment I have is about the thermodynamic and kinetic effects in crystallisation. I know little about crystallisation from molten salt mixtures, but that bit could have been clearer I think. I look forward to watching the rest of your video backlog.
Great to finally see such detailed explanations on this point. I've been wondering about it for a long time, searching around, asking around and I had partial answers (that the daughter elements don't get included into the crystal), but I didn't understand by what mechanisms that would happen.
Thank you very much for explaining it so well and deeply!
Great Video Geo Girl! This was an adequately comprehensive explanation to a question that had always bugged me. You are awesome!
Thank you so much! ;D
Thank you for finally explaining this! It's not just you, every explanation I've seen of radioactive dating leaves out a detailed explanation of the intricacies of how this actually works!
Another thing I've always wondered about is, how do scientists manage to date zircon crystals that are embedded in other minerals while still managing to ensure they are only dating the zircon crystals itself? It seems like it would be very difficult to remove something that small and ensure it's not contaminated in any way
Zircon is very stable chemically (which is why it's so resistant to weathering) so it's not hard to find solutions that would dissolve most everything else that might be mixed in with it and leave just the zircon grains behind.
Yes, the more I thought you put into this and into everything that could go wrong. He’s an experienced person, doubting its efficacy. People hold onto it because it is an elegant theory based on very creative thinking, but the problem is it doesn’t seem to work if a chemist got the same sort of results that you get from dating separate samples of the same material and materials with known dates we would likely not have a Advanced materials industry and advanced chemical industry. We have these because the science is accurate and by accurate I mean reproducible within a very thin margin of error, so that a bottle of Clorox bleach can, for all intents and purposes be considered a fungible item. If you’re not at that level, we’re talking junk science. PS I am not saying this can’t be improved or worked on in the future. I’m just saying as it is now it doesn’t work and I don’t understand how so many people can sit there and look at the results and pretend that this is giving you use for results it is not.
@@seaneustace9308 I think you might have misunderstood what I was saying. I know for certain that it is possible to date zircon crystals that are included in parent rock, but I was asking about the specific lab technique thats used to prepare those samples for testing in a way that produces an accurate result. Maybe that is something that @GEO GIRL can explain in a future video?
Cool topic. Great video. Awesome presenter. Thanks.
I think you could have made it even clearer: if the isotope decays, it becomes another element with a different chemistry. When the crystal grows, only the radioisotope is allowed in the crystal structure, and only being created by decay makes it possible to have the daughter isotope / element trapped in that crystal and it is thrown out (the clock resetted) by remelting.
Yeah, that was a little confusing to a non-geologist. Melting or re-melting causes the diffusion of lighter daughter isotopes into the surrounding rock and heavier parent isotopes to enter the crystal. The total amount of parent and daughter isotopes in the whole system, which includes both crystal and surrounding rock, stays the same because there's no nuclear fusion going on to create heavier isotopes.
Geo Girl always makes my day! ❤🎉😊
This is fascinating! I'm an old health physicist and I just subscribed. Might you consider making the cursor a tad bigger or loud color because I (and other old people maybe) can't follow it. I've been trying to learn more about geology since I retired.
In addition to U-238/Pb-206 dating, Rachel, there is also U-235/Pb-206 dating and IIRC those two Uranium/Lead ratios are used together
You’re not only Dr. Who…. But what?, where?, and how?. That’s why I love you so much!!! ❤😂👍🏻
Thank you so much! I am so glad to hear that :D
Thank you for explaining this. That these elements are chosen for the property that they "reset" makes a lot of sense but was not how I imagined it.
I’m going to check for that Radiogenic Isotope Geochemistry text book.
And I just found a pdf version. But I’ll check the uni library tomorrow for a hard copy. Easier to browse, jump back and forth etc.
Yes. Thank you. Greatly informative.
Awesome! Excellent explanation. I have been wondering about this for years!
YAY, this is what I've been looking for as a lay person.
Yay! Hope it helps! :D
Thanks for the explanation. Had no idea a phase change like that can reset isotope ratios.
Well done Rachel! This video and others you made enables a good understanding of how the age of rocks and therefore that of planet Earth is determined and is very good at debunking Young Earth Creationist or other pseudo-scientific claims. I would like to do a geologic dating with you😉
Excellent presentation. Thanks!
Thank you for an excellent explanation!
gona have watch these multiple times to ingests all thhis, but soooo interesting!!!
Excellent presentation, thank you!
Thanks! So glad you enjoyed it ;D
Solid explanation. You choose a crystal which during solidification didn't want daughter isotopes in its lattice. After solidification the daughter elements from isotope decay can't move anymore (except via certain lattice defects I guess).
Another banger of a video from the geo girl
Fascinating. You covered a lot if ground. Very interesting
Love your content. Top tip: get yourself a footpedal, that way you won't have to divert your eyes or hands when switching slides! Keep up the great work, thanks.
I haven't watched the video yet, but I'm happy already. I've had this exact question for years. And now an answer?
I'm going to watch this again, but I think the answer is that the materials in the molten rock become separated as it cools. Maybe in ways that are similar to the way metals are separated during the smelting process? It seems like under some situations molten metals mix thoroughly to make alloys and in other situations metals separate as they cool. From the video, it seems like there are tests that can determine if the melting resulted in a thorough separation between the parent and child minerals or not.
Very helpful fact-filled video. 🙂
Thanks! Really enjoyed this.
It makes sense that you explain the “dating” of rocks, as particular ones and other materials have so much _chemistry_ together. 😁 🌎🪨❤️⚛️⚗️🧪👩🏻🔬🥰
21:16 - and the isotopes of the decay products are typically quite rare anyway, so a "random" selection of included daughter element is not likely to be a decay isotope in many situations
Thank you! Very understandable!
So glad to hear that! I was hoping I explained it in a way that was understandable! :D
Nicely detailed video! Could you make a video about issues in radiometric dating of rocks (and ultra fast fossilisation of trees) at the Mount St. Helens, which exploded in 1980? There has been now plenty of scientific peer-reviewed studies about that.
Came here to leave a rock dating pun, stayed for the good content.
Rachel🪻! Thank you 👏👏. Interesting stuff. I'd love to know the ratios of those big balanced boulders 🪨🪨 around Phoenix compared with the nearby mountains.
Thanks so much! From what I just briefly searched online it seems that the mountains around Phoenix are about 1.7 billion yrs old!! Which I didn't know and that is so cool! And the big balanced boulders it sounds like their ages are less precise, but most sources put them at still being Proterozoic aged but younger than the mountains. There are some more boulder type granites further east near Tucson that seem to be Cretaceous in age, so much younger, so I guess it depends on where in AZ you look. I wasn't aware of the amazing geology and diverse ages of AZ rocks until you asked this, so thank you for making me look this up haha! :D I am going to send you a link to a cool website in a follow up reply, just in case yt takes it down. :)
Here's the cool AZ geology website I found: rockingwiththerocks.com/phoenix_geology.html Enjoy!
@@GEOGIRL Rachel, Thank you so much! I love the link & am so glad you did an internet search--strong 💪work! Hopefully YT will let you keep it posted 😉. If we never drove to phoenix to visit our son and DIL I would never have started this line of question & answers. AZ is fascinating. btw, The link says they had a boring billion too 😊! After reading that link and your reply I still think those balanced boulders are a product of erosion & not either a glacial or alluvial deposit.
p.s. I love the "Earth Rocks by Age" slide/map. I found it and downloaded it to my computer and phone.
Good information, however it explains the many problems with dating techniques. Indeed, expectations drive the process.
That was interesting, thank you 👍😌
I really like your presentation of such a complex system🥰. I am interested in the absolute dating of sedimentary rocks, trying to find minerals and isotope systems that indicate the sediments' age themselves, instead of their mothers', but still in the beginning. Thank you so much.
thank you, I've wondered this for years
I have only now discovered your channel and want to congratulate you on the excellent educational content! Please keep it up 👍 Here is my question: Environmental Factors: Conditions like heat or radiation can reset the "clock." And also constant decay rates and initial conditions might vary. What systemic errors arise from this as to dating?
Went through some of the videos and was super informative and love the articulation. I have one question though; If isotopes are used to Date rocks, what can I use to Date you? :p ; ok sorry thats cheezy I know, but worth a laugh. Ignore that, in the spirit of humor and youre super cool.. you rock! ok another pun. .. thanks , bye ! :)
Another key to geologic dating is to bring the cute geologist some pretty rocks. 🙂
For a second I thought the episode was about the social life of geology students...
Sorry, I couldn't help myself
Just what l always wondered. Thanks!
Fantastic! This sounds a way to conduct isotope separation. I wondering if the enriched Uranium for power plants/weapons is obtained in this fashion 😅
All of the steps to achieve weapons grade Uranium are (thankfully!) difficult and labor intensive. The most difficult part is actually separating the U-235 from the U-238 since they are both the same element and are of near identical weights. Back in the days of WW 2, they mostly relied on incorporating all of the Uranium into a gas UF6 (Uranium Hexafluoride), similar to how you can turn solid Carbon into gaseous CO2. Then they painstakingly ran it through seemingly endless steps of gaseous diffusion by capitalizing on the fact that the UF6 molecules with the U-235 went through the barrier at a slightly different rate as the UF6 that had the U-238. When finished with that process, they returned it to its elemental state by getting rid of the Fluorine. Nowadays there are very high tech centrifuges that are machined to incredible precision and can separate the two different UF6 gasses.
Thanks for the explanation! James Mahaffey has a few very good audiobooks on the history of discovery of radioactivity and how nuclear science evolved up to and beyond WWII, he also has a book on nuclear accidents or "broken arrow" incidents that is scary but fascinating.@@chriskennedy2846
I own a ring made out of a meteorite that was dated using the Ur/Pb method and I was wondering exactly that: how do we know the start conditions? This video answered the question! Thank you!
Wow, thanks for that video! Still some doubts that would love to have answers (I don't really know a lot about geology...so sorry if those are too basic questions):
1) is Uranium 238 created also in some geological processes so that the diffusion can happen in the magma chambers?? Because Uranium is created in supernovas or inside stars right? So if in a supernova a Uranium 238 is created, its decay process starts there...and at some point all U238 should be gone! Same with the other non-stable isotops right? So, how there is always U238 available in the magma chamber to purely cristalyze.
2) Same question but with Carbon, why the fossils are 100% Carbon 14 originally when fossilyzed? This means that organic life material is Carbon 14 100% and then it starts the decay process when we die or fossilyze? If so, then is the C14 created by the organic processes?...
Thank you. I’ve always wondered about that
Great stuff. Thanks
cheers from Toronto thanks for the content.
This explains SOOO much! 😍
This is amazing! You are the best🎉🎉🎉
But, oooooh Girl, the Creationists gonna come after you for this.
Good to know. Thank you for the explanation ~♡
Radiogenic dating? Sounds great!
I've always hated _Speed dating_ and _Tinder_ leaves me cold.
You answer questions I have always wondered about. I love it. However, I tend to learn better when I read books than watching videos so I'd like to find good vulgarization books on geology. To be more specific on what I'm looking for, I'd love to find the equivalent in geology of Richard Dawkins or Stephen Jay Gould books in evolution theory : books that really go into explaining the details, with a scientific mindset, but not too difficult for someone who has a decent scientific background. On the other end of the spectrum, there are authors like Neil Degrasse Tyson who's very good at vulgarizing, but usually only scratches the surface of things. That kind of books leave me frustrated when I read them. Also, I love the history of science, I love to know how we came up knowing all these things, how some scientists were initially mistaken and why, etc... I've been looking for such a book in geology for ages. Thanks for your help !
I need to know what that bright logo is on the front of your hoodie! Looks rad from the 5% of it i can see lol. Do you have a link i can look up for it? ^_^
I once dated a geomorphologist, but she looked for faults everywhere.
very nice video.
Interesting hearing about crystal formation of these mineral nodes, makes sense.
1) As the formation of elements heavier than iron require supernova the amount of radioactive material earth has will have been decreasing over time since its formation, does this need to be factored in when dating extremely old samples?
2) Assuming these crystals work similar to most, if the temperature of the chamber is too high they re-dissolve, and when the temperature is too low they don't or are slow to swap out atoms which don't fit nicely into the lattice, however I imagine that at the right temperature and lower the crystal closer to the center is unable to rotate out decayed atoms. Is my understanding correct and if so is it considered that active deposits tend to be left by the volcanoes when the chamber is hottest, and that large crystals found may have more accurate concentrations on its surface than at the center?
Thank you for the great explanatory video on this subject!!