It’s a common argument made by creationists refuting radioisotope dating. There are dozens, perhaps hundreds, of examples of fossils that are millions of years old, even a hundred million years old, that radiocarbon dating shows are only a few thousand years old? How does a geologist explain that?
Our answer: because you can’t radiocarbon date fossils. If I had a nickel for every time I saw a question based on a fundamental misunderstanding of radiometric dating, I’d have… a whole goddamned lot of nickels.
Here’s the short version of the answer: carbon dating measures the ratio of radiogenic carbon, C-14 to C-12, in organic material.