Then, we have wood for which we know the right answer.
So, carbon dating has been calibrated against the rings of California bristlecone pines, and Irish bog oaks, and the like.
It is sometimes possible to match up tree-ring patterns between different trees.
The C14 will undergo radioactive decay, and after 5730 years, half of it will be gone. So, if we find such a body, the amount of C14 in it will tell us how long ago it was alive. The method doesn't work on things which didn't get their carbon from the air.
This leaves out aquatic creatures, since their carbon might (for example) come from dissolved carbonate rock.
In the 70's: If this sort of thing interests you, you should find the journal Radiocarbon and read one of the issues devoted to calibration.
For example, see Radiocarbon 46,1029 (2005), which has a calibration curve that goes back 26,000 years.
It is also standard to coat fossils during their extraction and transport.
Acetone is sometimes used while extracting fossils, because it dissolves dirt.On the Web, you could visit a dating laboratory, visit a dating service, read an encyclopedia entry or read a critique.The Lake Suigetsu varve calibration was reported by ABC News and was published: Atmospheric Radiocarbon Calibration to 45,000 yr B.When this was first done, it turned out that carbon dating had been giving too-young dates for early civilizations.Apparently, the production of C14 by the Sun has changed by several percent across the last 10,000 years.If you hear of a carbon dating up in the millions of years, you're hearing a confused report. Second, they rarely contain any of the original carbon.