Posted by Steve Price on June 24, 1999 at 04:44:48:
In Reply to: Re: Sources of error in Carbon-14 dating? posted by Wendel Swan on June 23, 1999 at 15:03:29:
Dear Wendel,
Thanks for the URL on C-14 dating. It is fairly thick going, but very informative and useful.
First, the random errors in the method are unlikely to be reduced to where the spread of uncertainty is less than 100-200 years as a 95% confidence interval. That is, it is possible to do so in principle but unlikely to happen in practice. This is disturbing when we are trying to use the method in a range of less than 500 years.
Second, the systemic errors are horrendous. Jim Allen mentions that Kajitani believes washing a rug can make it appear to be 100 years older by C-14. Exposure to smoke can add up to 1,000 years to the apparent age. Exposure to certain seawaters can add hundreds of years. All of these systemic errors are in the same direction. Any rug we have is likely to have been washed, every tribal rug can be assumed to have been exposed to smoke, and there's no way of knowing which ones had an ocean voyage en route to our collectors. It would appear to me that, on the basis of what I know so far, C-14 dating can only set a maximum age on a piece, and even that will have a very large uncertainty associated with it.
Does anyone out there know the Arizona C-14 folks well enough to ask them to post a professional's take on the subject? It might really help a lot.
Regards,
Steve Price