How to Determine the Age of Volcanoes and other Rock Formations
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- čas přidán 2. 08. 2024
- When a geologist says that a volcanic rock is 300,000 years old, how do we arrive at that age? This video will discuss exactly how, which involves radioactive isotope dating, an analogy of pizza, and zircons. The three most common radioactive age dating methods include carbon-14, potassium-argon, and uranium-lead decay series.
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Graphics of eruption dates are courtesy of the Global Volcanism Program, Smithsonian Institute. volcano.si.edu/
0:00 An eruption in 50 BC
0:37 How the Age of a Rock is Determined
1:03 Carbon 14 Dating
1:43 Half Life
1:58 An Analogy of Pizza
3:04 K-Ar Dating
3:20 Uranium-Lead Dating
Google Earth imagery used in this video: ©Google & Data Providers
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Photo Credit at 1m48s: RondellMelling, Pixabay, Pixabay license
Photo Credit at 1m58s: igorovsyannykov, Pixabay, Pixabay license
I want to note that malicious actors who promote psuedoscience love love love to misrepresent carbon dating. They generally grab a 1.6 billion year old rock with no organic material beneath it (because complex life had not developed and carbon dating only works to 60,000 years ago, no older), get a junk result and nonsensibly claim “science bad”. Be sure to avoid these types of people.
THANK YOU for this comment not many people know this and a lot of people that dont know any better get swept up in conspiracies because of it. Keep up the great work!
not surprised by this considering how out there still believe the earth is flat and anything else is a conspiracy
Yes. Avoid these, we must.
@@SpaceLover-he9fj Shutting them down and highlighting their falsities is also a must.
True.
I think it is important to note that the carbon-14 is continually regenerated in the atmosphere from interactions between cosmic rays and nitrogen-14. Otherwise, there would be no carbon-14 left.
I learned Carbon 14 in Jr high and didn't know about the other two types of testing. Thank you for explaining this.
If you wanna learn even more, check out a channel called Miniminuteman. He talks about a wide range of archeological topics and goes over more methods of dating materials, and he's also pretty funny to boot. Not many videos as of yet, but each one is extremely informative and engaging.
Ice cores pulled from the Artic are also interesting. Each ash plume is distinct in its contents and the ice cores can be dated by the depth.
Argon-argon is another interesting method. It was tested with Mt Vesuvius rocks erupted in 79 AD, and was off by just a couple decades.
very clear and interesting explanation. you have succeeded where many teachers of all levels fail. really good work keep it up for those of us who enjoy your topics
I'd love to see a video about the Ancestral Rocky Mountains!
Thank you for this information, recently we (BS Geology students) hardly understand about "half-life" in chemistry.
When I saw the title to this, I thought it would've included the "strontium 706 line." It'd be cool if you did a video on that, and how it relates to continents/cratons and exotic terranes.
I always wondered how that was calculated, and now I have a little bit better of an understanding. Thanks.
Thank you, to have covered a request of mine. I appreciate it.
Greetings from Switzerland 🇨🇭
Have been waiting for this one quite a while now. Thanks for explaining.
I love the way you explain things although some is over my head I feel smarter...hahaha Good work!
You date them same way you date anyone else. Invite them to dinner. 🥁🥁🎉
...ive had better dates with rocks than most ppl.
Thats going to be rocky start....
😂
Lava cake for dessert?
@@Iamthelolrus 🤣👍
Thanks, GeologyHub!
I really like these kinds of videos, that explain the toolsand methods geologists use. Please make more of them.
I always knew about carbon dating but never the specifics. This was quite informative ^^ thank you.
Congratulations!
Does not sound complicated at all, videos like this one are great. I don't know about others but it's not just6 interesting to see the volcanoes but also to understand the geology. Before watching your videos I never understood why subducting plates cause lava to erupt. Now I know that the it's the melting point change caused by water in the rocks (chemically bonded water I assume). Some of those topic are on the very edge of our understanding of the inner workings of our planet and that's fascinating.
Thanks for the science refresher!
Wonderful explanation, I hope the YEC's don't flood the comments.
Thanks for the quick rundown.
A half-life is simply the time it takes for half of the isotope in question to decay. That decay may be to a more radioactive element. Decay is really a misnomer term because of the complexities of radioactive decay chains and specific activities of the products. Ultimately the chain will end with a stable element but there may be a lot of transformative steps along the way.
Great vid! Felt like I was back in Geoarchaeology class.
Kelimutu volcano in Indonesia would be interesting topic for a video with its crater lakes
I agree. I have planned an eventual video on this volcano.
In my college course, we have all of these and also Nd Sm dating which can date upto >4 billion yrs
Thanks for explaining.
Are some lava types somewhat magnetic as well? I thought the magnetic alignment of the poles at the time the rock cooled could be used as another very rough indicator of age.
This is correct.
And if you now think: "But why is there even a stable C14 concentration in living things, if it's radioactive?"
Well, I thought that too and dig in some research.
The radiation from the sun causes a N14 (standard nitrogen isotope) nucleus to switch to a C14 (not standard carbon isotope). This is done by a high energy electron that merges with a proton and becomes an (unstable) neutron.
Long story short, due to the long decay and the somewhat stable irradiation from the sun, the concentration of N14 to C14 is pretty stable. Which also means, the concentration of C14 to C12 (standard carbon isotope) is also quite stable, as long as people are in direct contact to atmospheric carbon.
Once something dies, this supply "fresh" C14 stops, and the remaining C14 decays.
Important is however: The criteria is NOT as long as it LIVES it has a stable C14 concentration. But as long as it METABOLIZES air, in some form or another.
IF something is NOT living on the surface of the earth, but actually in a completely separated ecosystem, i.e. segregated volcanic cave or hot steamer in the deep ocean, it can be, that those can actually not be dated by the C14 method.
Thank you so very much. If you have info on how volcanic ages have been corrected over the last few decades, I'd love it.
I am curious about the kimberlite in Kansas. I watch your Videos daily btw, great stuff. Thank you.
I loved this.
Excellent summary
Appreciate your explanation. One question is what do you do for things that range from 50,000 years to 100,000 years?
I have the same question !?
Panic. All jokes aside, there is a reason why dates between 50,000 and 1 million years old have a very high margin of error. Generally K-Ar is still used, but it is not very accurate. Of course, other decay chains do exist.
I believe Uranium Disequilibrium Dating Methods are used. It's a family of dating methods that also could be called Thorium-230 Dating, Uranium-Thorium Dating, or U-Series Dating. Though the method itself is accurate up to 500,000 years.
Loved this episode.
Great explanation! Thanks
Excellent!!
Radioactive pizza... that is gunna be my new band name 😎
Thanks!
Thank you 🙏
Perfection 👍🏻
Can you a video of dating of mafic rocks? So, zirconsless igneous rocks?
i've heard it's quite hard compared to zircons, due to mobility differences but i'm still not quite sure what the best technique would be.
Others can ofc. also add on to this.
always been wondering about this,
Nicely explained 🖐👴👍
Thanks for your very interesting videos as always. What about cosmogenic dating technique for volcanoes ? It's new but it seems to be used more and more in various geological domains.
Nothing helps with dating samples between 50k-100k years old?
Loved your channel, always extremely interesting, i was wondering are able to tell me what this is: 56.74058° N, 6.12951° W
It's pretty easy! It's when they stop telling teenage jokes, then you know you've got a mature volcano
For the inorganic dating methods, do scientists sample the solidified lava or the surrounding material?
Does anything affect the rate of decay of carbon 14, such as temperature or environmental factors?
Thanks for the explanation, and also for letting me realize why I Could Not be a scientist 🙄
Clear as mud, but thank you ALL stay safe
? How old is the Carbon14 when the tree lays it down in its structure what is the base line to start with
See the Comment by Aurel Specker a couple of hours before yours.
To test the age of a volcano, give the lava a quick lickeroo.
That's the reason why scientists know the age of Earth and know the age of some interstellar meteorite because it's older than our solar system. (all asteroid in out solar system are 4,5 billion years old)
I thought 14C dating worked by measure the ratio of 14C to 12C or 13C. The amount of 14N in the sample will be highly variable relative to carbon, so how would the C/N ratio mean anything sensible?
Indeed for high accuracy you will want to calibrate it with the ratios of other carbon isotopes and the presence of nitrogen 14 without both there is still quite a bit of uncertainty.
@@Dragrath1 I don't see how measuring 14N can help at all. The amount of natural 14N there will be vastly larger than the 14N produced by 14C decay, and the initial concentration is not sufficiently well constrained. The measurement will tell you nothing.
In practice, it's the ratio of carbon isotopes that is measured. The only effect 14N might have is to confuse the measuring process (by producing ions of almost the same mass); this is why tandem accelerators are used (the process with ion stripping effectively eliminates ions of nitrogen.)
Easy stuff.
Check the tree-ring chronology database - you may be surprised how much earth history is datable to the year.
Every thing you say is true except you left out that there is a debate ongoing in the scientific community as to just how accurate carbon 14 dating is. That is why scientists use ranges of date and rarely if ever use exact dates. i think it is the height of huberious to think you can calculate it to that precise a date.
when geologists say a date, they are just dropping the +/- part of the range (usually can find it in the papers, though), as they often are just counting the centuries as significant (IMO). unless it's in the last 40 decades, does it really matter if it is a couple off?
CHALUPAS caldera and CHACANA caldera
"Simply dating a layer of rock without an organic product in it using this method [carbon dating] will never work."
Cue Potholer54 shouting, "There no f-ing carbon in it!"
I can understand the methodologies of dating. What I can NOT understand is why somebody would put CORN on a pizza!
Sounds straight forward to me. But then, I'm a physicist.
The dating of rock is not accurate, geologist have said it's not really possible to date rock.
I dont think they have a clue how old anything really is, its all just guess work they think they have figured out.
That’s not quite true. For example, dendrology, but he study of trees’ rings can date thousands of years into the past accurately and very precisely show years with major climatic events. Ice cores can be used in a similar fashion. Even rock strata can be, such as the very distinct line of rock rich in iridium at the K-Pg boundary. When one reads all of these clues relating them back to other similar methods, one can go back a very long way. Radioactive decay is fairly well understood and is just another tool
@@tristanmelling410 A lot of assumptions go into that though, they have to make alot of assumptions, the only way you can really do it is to have access to the past which is impossible until time travel is created, this is why so many of the dating methods have had issues and sooner or later get over turned.
how can anything be dated radioactively and be accurate, when radioactive decay is pure randomness? half lives of isotopes are an average, not a constant.
trying to determine geological age via radio decay and being close to accurate, is like throwing a dart at a target while blindfolded.
I don't think it's a good idea to eat a radioactive pizza lol
Somebody needs to stop eating volcanoes!!
Great explanation but how about you start using BCE/CE versus outdated BC/AD since the majority of the world is not Christian and that is an old reference method
How to date your geologist LOL
*Common Era (Original Hawaiians weren't christian, and didn't speak latin. A.D. is a bad abbreviation in this case)
Not this petty argument again
In what way is it petty?