Sure, I'll correct it -- as usual, AnswersInGenesis is full of crap, which is why I yet again have to wonder why you keep linking them at every available opportunity, instead of bothering to use *reliable* sources from actual science journals. Hint: AiG is in the business of propagandizing against real science, and they're not above completely twisting the truth to do it.
Dave, why do you keep using their material? Is it out of a complete disregard for accuracy, or out of outright dishonesty?
Let's take your above bit of nonsense, straight from AiG as an example. You mindlessly parrot them saying, "Really, anything over about 50,000 years old, should theoretically have no detectable 14C left". This is, of course, completely horse crap. 50,000 years is 8.7 half-lives of 14C, so after 50,000 years 2^(-8.7) or 0.24% of the original 14C will be present. This is hardly the same as "theoretically no detectable 14C" -- neither in theory NOR in practice. That's far above the sensitivity of AMS (Accelerator Mass Spectrometry) equipment,, and radiocarbon dating under good conditions can be accurately achieved on samples up to 58,000 years old. See for example ABOX radiocarbon dating of archaeological charcoal. AiG also "forgets" to mention, during all of its hand-waving attempts to try to dishonestly raise false doubts about radiocarbon dates, that the results of such testing -- even up to 58,000 years (well beyond the 50,000 that AiG claims is "impossible" even in "theory") -- matches the dates given by COMPLETELY INDEPENDENT methods of dating the same samples, such as optically stimulated luminescence (OSL) techniques for example. How does AiG explain *THAT*? Oh, right, they don't. They wouldn't want to call their readers' attention to any facts that make it obvious that AiG is spinning bulls**t.
Dave, how about this -- if I can go through the two links you just provided, and show you, say, five examples of gross "error", and five examples of gross misrepresentation in an attempt to dishonestly "spin" the impression in the direction that AiG wants the reader to get (i.e., in order to falsely give an impression that radiocarbon dating is entirely unreliable), will you agree to finally stop posting their lies?
Or do you not *care* that you're providing grossly misleading and grossly inaccurate "information" to your fellow Freepers?
Depends on the lab, sample, and methods.
There are experiments for the AMS (Accelerator Mass Spectrometry) method going back toward 80,000 years, but that is experimental, not yet a standard, commercially-available practice.
For some materials, contamination is a problem, and I would be careful. Charcoal can absorb humic acids, which, while the labs try to remove them, can be a problem with extremely old samples.
The smaller the quantity of remaining 14C (i.e., the older the sample) the more care needs to be taken with sample selection. That's why creationists are able to find dinosaur bones which date 35,000 or so years old--they get samples bone contaminated by groundwater. They love such contamination! Real scientists do their best to get clean samples. (How many samples did the creationists obtain with results like >50,000 years before they got one contaminated enough that they liked the result?
Lesson: Never rely on only one sample! If you have an old and important specimen, do several or many different samples and use a couple of different labs. Make sure the sample is not contaminated. (If its just a piece of shell from a 3,000 year old site, no big deal. The dates will come out just fine.)
And never, never, ever listen to the young earth types or creation websites when it comes to this kind of science. Their belief blinds them to actual data, and they will stretch things any old which way to try and match their beliefs. Scientists are not like that; if the data heads in an unexpected direction, we can accept it.
As Heinlein noted,
Belief gets in the way of learning.Robert A. Heinlein, Time Enough for Love, 1973