Half life and carbon 14 dating
Thus, no one even considers using carbon dating for dates in this range.
In theory, it might be useful to archaeology, but not to geology or paleontology.
The rate of decay of N in 5,730 years (plus or minus 40 years).
A "Back to Genesis" way of thinking insists that the Flood of Noah's day would have removed a great deal of the world's carbon from the atmosphere and oceans, particularly as limestone (calcium ate) was precipitated.
Once the Flood processes ceased, C-14 began a slow build-up to equilibrium with C-12—a build-up not yet complete.
This also has to be corrected for. Second, the ratio of C in the atmosphere at that time to be estimated, and so partial calibration of the “clock” is possible.
Accordingly, carbon dating carefully applied to items from historical times can be useful.
The changing ratio of C-12 to C-14 indicates the length of time since the tree stopped absorbing carbon, i.e., the time of its death.