If the temperature exceeds 600°C, the carbonate can dissociate, releasing its carbon as carbon dioxide (CO2).
Upon cooling, any available CO2 will reform the carbonate.
NOTE – If you are not sure what might be dated for your pottery sherd, please contact us prior to sending your sample to the lab.
With radiocarbon dating, the greatest bias is always in the more recent direction as modern carbon adds both carbon by weight and radioactive 14C by content whereas older contamination (or very old clay) has less of an impact unless there has not been any secondary contamination by younger carbon.
If it is from marine food residues, it will have “reservoir effect” associated with it which must be corrected for.
If the soot is from old trees (tree trunks) the date could be too old.
Depending on the consistency of the soot, the pretreatments may be varied allowing for either acid or acid and alkali.
Accuracy relative to the time of use of the fires will depend upon the source of the soot.
Radiocarbon Basics Carbon comes in three “varieties” or isotopes: C is 5,730 years.
A straightforward reading of the Bible describes a 6,000-year-old universe, and because some carbon-14 (C) age estimates are multiple tens of thousands of years, many think that the radiocarbon method has soundly refuted the Bible’s historical accuracy.
However, these excessively long ages are easily explained within the biblical worldview, and C should be present in specimens that are even a little more than 100,000 years old!
If you have a 200 year-old tree that is living today, a date on the bark represents today and a date on the centermost ring represents 200 years ago even though the tree is still alive. You only need to include the confirmation code in the package.
Therefore, the accuracy of the radiocarbon date depends upon where the wood came from within the tree.