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Author Topic:   Carbon-14 Dating Debate Assistance Thread
JonF
Member (Idle past 283 days)
Posts: 6174
Joined: 06-23-2003


Message 21 of 38 (492545)
01-01-2009 9:10 AM
Reply to: Message 20 by Peg
01-01-2009 8:30 AM


Re: Bump for Peg to air her skepticism regarding carbon dating
No, it's just that it's true the U-Pb dating is less prone to contamination/variance issues than C14 dating is. It is not true that all C14 dates older than 6,000-10,000 years are wrong, nor is it true that all U-Pb dates are wrong. Therefore YECs are wrong about the age of the Earth and life.
You might reflect upon the fact that contamination invariably makes C14 dates wrong by making them appear younger than they really are ... so what does a C14 date of 40,000 years mean?

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JonF
Member (Idle past 283 days)
Posts: 6174
Joined: 06-23-2003


Message 26 of 38 (492578)
01-01-2009 2:43 PM
Reply to: Message 24 by Coyote
01-01-2009 11:45 AM


Re: Overview of C-14 for Peg to aid her skepticism regarding reports of "unreliability"
This site, BiblicalChronologist.org has a series of good articles on radiocarbon dating
It's worth pointing out that the biblical Chronologist is Dr. Gerald Aardsma, formerly of the ICR and still a YEC of sorts ... but one of the few YECs who doesn't just ignore or handwave-away the evidence.
Edited by JonF, : No reason given.

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JonF
Member (Idle past 283 days)
Posts: 6174
Joined: 06-23-2003


Message 35 of 38 (492712)
01-02-2009 10:13 AM
Reply to: Message 31 by Peg
01-02-2009 2:47 AM


You're not reading any of what others write, are you.
Peg, you really need to get your information from different sources. The sources you are using are totally ignorant of the subject. Or maybe they are lying. One way or another, they are useless as sources of true information.
Most of your points of contention are relevant to some measurements. For your beliefs to be true, you need to come up with some problem that makes all 14C measurements older than, say, 10,000 years false. Don't bother with anything that applies only to some samples.
contamination of the samples tested for instance. Its always possible that a bit of wood, for example, from the heart of an old tree might contain live sap. Or if it was extracted with an organic solvent (often made from petroleum), a trace of the solvent might be left in the portion analyzed. Charcoal could have been penetrated by rootlets from living plants. Any of these scenarios could affect the levels of C14
Yes they could. Of course, nobody would use an organic solvent to extract a 14C sample. The other scenarios are possible, but would make the sample appear younger than it really is… no help to you, you're arguing that the results are older than the samples really are.
These kinds of contamination can often be detected. For your charcoal sample, test samples from different parts of the piece of charcoal. If the results vary significantly, there's a problem.
Live shellfish have been found with carbonate from minerals long buried or from seawater upwelling from the deep ocean where it had been for thousands of years. Such things can make a specimen appear either older or younger than it really is.
Oh, please. This is an old canard. Read some of the links given in this thread before you spew such garbage. Of course shellfish don't carbon-date correctly, 14C dating works on samples that get their carbon from the atmosphere directly or near-directly. It's well known that shellfish and most marine life don't fit that requirement, and we don't use 14C dating on such samples.
there is also the assumption that the level of carbon 14 in the atmosphere has always been the same as it is now. But we know that the carbon level has increased a lot since the explosion of nuclear bombs into the atmosphere and since the use of burning fossil fuels. So how do we really know what the levels were thousands of years ago
Well, at least this is relevant to whether the method itself is useful. But, Lord love a duck, it's an even worse PRATT and one that has been already discussed in this very thread. No, there is absolutely no assumption that the level of 14C in the atmosphere has been stable. It is well known that it has not been stable (although it hasn't varied a heck of a lot). See Message 23, read it, make sure you understand it, especially the calibration curve part. Then we can continue.
volcanic eruptions also add to the stable carbon-dioxide reservoir, thus diluting the radiocarbon....so how do they account for all these possible variances in c14 in the atmosphere??? How can they honestly know how much to make allowance for???
By cross-correlation with other, independent measurements. See Message 23.
And read some or all of the links in Message 24

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JonF
Member (Idle past 283 days)
Posts: 6174
Joined: 06-23-2003


Message 37 of 38 (492721)
01-02-2009 12:26 PM
Reply to: Message 36 by Coyote
01-02-2009 11:28 AM


Re: Bump for Peg to air her skepticism regarding carbon dating
volcanic eruptions also add to the stable carbon-dioxide reservoir, thus diluting the radiocarbon....so how do they account for all these possible variences in c14 in the atmosphere??? How can they honestly know how much to make allowance for???
By tree rings! If you date a tree ring that is 11,000 years old (and you know its age by direct counting) then you can tell how far off the measured or conventional radiocarbon age is and correct for it, resulting in an accurately calibrated date.
And varves, and (my personal favorite) U-Th disequlibrium dating of corals, and ...

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