Carbon 14 dating depends on the amount of carbon 14 on the athmosphere along time. Dating is based on the assumption that the amount of carbon 14 isotope in athmosphere was fairly constant along time. Is it a solid assumption? What evidence is there on that? Someone knows?
Carbon 14 dating
| nisibdv wrote: |
| Carbon 14 dating depends on the amount of carbon 14 on the athmosphere along time. Dating is based on the assumption that the amount of carbon 14 isotope in athmosphere was fairly constant along time. Is it a solid assumption? What evidence is there on that? Someone knows? |
Yes, it's a fairly solid assumption. The C-14 concentration in the atmosphere over the last 22,000 years has been confirmed by analysis of sedminentary materials containing carbon compounds. The variation in atmospheric C-14 over the 22,000 year period was found not to exceed 10%. Variations in the C-14 level are documented and used by adding a 'correction' to the date of a particular sample. Also, C-14 ages are cross calibrated against numerical tree rings dates which provide measurements of the actual level of C-14 in the atmosphere.
(Unfortunately the technique is not so reliable for more recent dating since the industrial era has seen large amounts of C-14 released into the atmosphere.)
It is also important to know that C-14 dating is only used for organic samples of a few thousand years in age. It is also normally used in conjunction with other techniques and rarely used on it's own. For dating of more ancient samples other radiometric methods are used involving different radioactive elements.
http://www.asa3.org/ASA/resources/Wiens.html
http://www.c14dating.com/corr.html
| Bikerman wrote: |
| It is also important to know that C-14 dating is only used for organic samples of a few thousand years in age. It is also normally used in conjunction with other techniques and rarely used on it's own. |
These are points that are often not known or quickly glossed over by many people. Often C14 dates are amalgams of ages given by multiple techniques, not simply C14 ages... and if you're reading a paper that ages something with only one or two techniques, that's a good clue that they're biased researchers, found an answer they wanted and stopped looking
| Bikerman wrote: | ||
Yes, it's a fairly solid assumption. The C-14 concentration in the atmosphere over the last 22,000 years has been confirmed by analysis of sedminentary materials containing carbon compounds. The v[Chorus: 50 Cent & Olivia] [50 Cent] I take you to the candy shop I'll let you lick the lollypop Go 'head girl, don't you stop Keep going 'til you hit the spot (woah) [Olivia] I'll take you to the candy shop Boy one taste of what I got I'll have you spending all you got Keep going 'til you hit the spot (woah)http://www.asa3.org/ASA/resources/Wiens.html http://www.c14dating.com/corr.html |
Um... what?
With a name like pharmacymaster I just assumed that the posting was a result of pharmacological experimentation 
| Bikerman wrote: | ||
Yes, it's a fairly solid assumption. The C-14 concentration in the atmosphere over the last 22,000 years has been confirmed by analysis of sedminentary materials containing carbon compounds. The variation in atmospheric C-14 over the 22,000 year period was found not to exceed 10%. Variations in the C-14 level are documented and used by adding a 'correction' to the date of a particular sample. Also, C-14 ages are cross calibrated against numerical tree rings dates which provide measurements of the actual level of C-14 in the atmosphere. (Unfortunately the technique is not so reliable for more recent dating since the industrial era has seen large amounts of C-14 released into the atmosphere.) It is also important to know that C-14 dating is only used for organic samples of a few thousand years in age. It is also normally used in conjunction with other techniques and rarely used on it's own. For dating of more ancient samples other radiometric methods are used involving different radioactive elements. http://www.asa3.org/ASA/resources/Wiens.html http://www.c14dating.com/corr.html |
I would say that it isn't such a solid assumption. Most of the time, c-14 "dates" are correlated with sedimentary layers found throughout the earth. This correlation implies another assumption, which in my opinion isn't so solid either. The assumption being that sedimentary layers have been deposited on earth in a slow, methodical, measurable amount over a long period of time. Sedimentary layer ages are usually extrapolated from the fossils found in the layer and also by how deep the layer is from the surface.
Here's why I don't find either of these assumptions very agreeable. To put it simply, neither of them allow for catastrophies. Any catastrophic event can theoretically change the amount of c-14 in the atmosphere. As for the sediment layers, I find their ages very hard to swallow because they assume that the layers were deposited slowly over millions of years. The layers are so evenly distributed over the entire surface of the earth, with little to no exception that one wonders how erosion and other natural processes didn't effect them. Why are the layers so undisturbed if they were so slowly deposited? How did fossilization occur if they were so slowly deposited?? We all know that today fossilization hardly ever occurs. Why you ask? Because when something dies, it decomposes LONG before it gets buried. The very few exceptions occur in isolated areas with special circumstances. Why are there ocean fossils EVERYWHERE? Why are the layers so precisely divided? How did a long slow buildup create such stratified layers with such differences? Did the forces of erosion not exist? Did the climate change so drastically so many times as to produce each different layer??
Anyway...all of these things are hard to explain when you make the two assumptions I stated above. I don't accept c-14 dates as accurate. I don't accept sedimentary layer dates as accurate either. I don't think fossil record dates are therefore accurate because they are based on faulty assumptions.
| Satori wrote: |
| I would say that it isn't such a solid assumption. Most of the time, c-14 "dates" are correlated with sedimentary layers found throughout the earth. |
You just stopped here, which makes me scratch my head. What you say is true, but incomplete. Yes, C-14 dates are considered reliable because they corroborate with dating by sedimentation layers in the geologic record. But that is not the only way they have been tested. In fact, wherever possible, C-14 dates have been corroborated with dozens of other sources. Bikerman's favourite example is tree rings in very old trees, but the dates are also corroborated even by the human historical record because C-14 date brackets are relatively short.
You go on to criticize the assumption that sedimentation was largely slow and "methodical", and suggest that by calling that into doubt, C-14 dates are also in doubt. But you have ignored the truckloads of other sources of dating information that corroborate both assumptions.
Or to put it another way (using your argument's examples as a starting point), we say that C-14 dates are correct because they agree with geological sedimentation evidence... then we say that C-14 dates and the rate of geological sedimentation are correct because they both agree with X (which could be the composition of arctic ice, the rings of old trees, whatever)... then we say that C-14 dates and the rate of geological sedimentation and X are correct because they all agree with Y... and so on. You can pick out any two and nitpick about uncertainty, as you have, but as you add more and more bits of evidence - and there are a lot - that uncertainty gets smaller and smaller. In fact, it is true that initial methods were based on some assumptions that turned out to be false by comparison with various other sources... but these inaccuracies have all been accounted for, and calibration curves are used to correct new values, such that dates are now considered to be very reliable, and very accurate.
| Satori wrote: |
| Here's why I don't find either of these assumptions very agreeable. To put it simply, neither of them allow for catastrophies. Any catastrophic event can theoretically change the amount of c-14 in the atmosphere. |
Catastrophes are, by definition, catastrophic. Anything big enough to change the composition of the atmosphere can hardly have done nothing to be noticed by any of the other means of checking dates. Your objection would make sense if there were really only one means of corroborating C-14 dates as you implied. But given that there are many ways to check the date, the objection doesn't fly.
| Satori wrote: |
| As for the sediment layers, I find their ages very hard to swallow because they assume that the layers were deposited slowly over millions of years. The layers are so evenly distributed over the entire surface of the earth, with little to no exception that one wonders how erosion and other natural processes didn't effect them. Why are the layers so undisturbed if they were so slowly deposited? How did fossilization occur if they were so slowly deposited?? We all know that today fossilization hardly ever occurs. Why you ask? Because when something dies, it decomposes LONG before it gets buried. The very few exceptions occur in isolated areas with special circumstances. Why are there ocean fossils EVERYWHERE? Why are the layers so precisely divided? How did a long slow buildup create such stratified layers with such differences? Did the forces of erosion not exist? Did the climate change so drastically so many times as to produce each different layer?? |
You have asked no less than seven explicit questions and made a couple of other statements that are either false or incomplete - many of which would require a very long and detailed technical explanation. i am going to assume that you are not serious about these questions and are using them for rhetorical effect only, because it is irresponsible to simply dump such a large group of widely ranging issues (most of which are actually not related to the topic) and expect answers.
However, if you do want answers to any of these questions, it would probably be beneficial to you and to everyone else who may be confused by them to ask them in a separate thread, where they can be given their due space.
| Satori wrote: |
| Anyway...all of these things are hard to explain when you make the two assumptions I stated above. I don't accept c-14 dates as accurate. I don't accept sedimentary layer dates as accurate either. I don't think fossil record dates are therefore accurate because they are based on faulty assumptions. |
Yes, they are hard to explain... if you only make the two assumptions you stated. As i explained, you have ignored the dozens of other ways that the dates are corroborated. If you take all of the scientific evidence into account - rather than picking two items out of the multitude - and realize that it is all inter-corroborative, your objection becomes illogical.
I think 14 is too young for carbon to be dating,
idealy it should be 18 too make mature decisions,
but at least 16. yep.
..........sorry I couldn't help myself.
idealy it should be 18 too make mature decisions,
but at least 16. yep.
..........sorry I couldn't help myself.
Yep, beaten by KronikSindrome (nice new hair, btw, 
)
Of course radioactive dating works: the more radio-isotopes the better and the results can be truly astounding. There's a star, nearby in our galaxy, that is aged by three separate radio-chronologies at something close to 13 billion years! Possibly a first- or second-generation star (i.e. closest to the epoch of last scattering) in our own 'hood. Wow! ed.
e.g. at http://www.universetoday.com/2005/04/18/audio-oldest-star-discovered/
)
Of course radioactive dating works: the more radio-isotopes the better and the results can be truly astounding. There's a star, nearby in our galaxy, that is aged by three separate radio-chronologies at something close to 13 billion years! Possibly a first- or second-generation star (i.e. closest to the epoch of last scattering) in our own 'hood. Wow! ed.
e.g. at http://www.universetoday.com/2005/04/18/audio-oldest-star-discovered/
 |