Hi General,
Over time Creationists have created a rather large library of supposed problems with radiocarbon dating, and while I guess we could get into these at some point it seems better to address the most significant issue first, tree ring data:
The General writes:
Tree ring studies have determined what the C-12/C-14 ratio was before the Industrial Revolution. All radiocarbon dating is made with this in mind. But what was the ratio like, say, 1000 years ago. We do not know...
Ah, but we *do* know. As PaulK has already pointed out, the tree ring studies go back 11,000 years. See this section titled
How tree rings are used as a radiocarbon record from the
Waikato Radiocarbon Dating Laboratory.
Other dating confirmation comes from lake varves and glacial ice layers, variously going back 10,000-15,000 years.
Taken together this means we have broad confirmation of the reliability of radiocarbon dating going back at least 10,000 years.
Coincidentally, I was at the Boston Museum of Fine Arts yesterday and was able to look at some 6400 year-old pottery fragments from the Badarian era of Egypt. While this was the oldest pottery at MFA, which after all is an art museum and not an archeological museum, archeologists have discovered pottery as old as 15,000 years or so.
--Percy