Maximum effective dating range for carbon 14 dating
It is based on the fact that some of the radioactive isotope of Potassium, Potassium-40 (K-40) ,decays to the gas Argon as Argon-40 (Ar-40).
By comparing the proportion of K-40 to Ar-40 in a sample of volcanic rock, and knowing the decay rate of K-40, the date that the rock formed can be determined.
If one of these protons is hit by a beta particle, it can be converted into a neutron.
We can get reasonable accuracy to 50,000 years, better accuracy more recently.
This calibration is what limits the accuracy because we know that with a given amount of carbon-14, it absolutely will decay at a very tightly controlled rate.100,000 years is out of the question. It can set a frame, or a parameter for the occurence of one event or another, but it has only the most recent reference for the age of any matter whatsoever. We have only arbitrary concepts of the age of matter as we know it. The theory being that once the material (presumably organic) has trapped the 'day zero' carbon-13/-14 mix in it's molecules that mix ratio begins to change.
With 18 protons and 22 neutrons, the atom has become Argon-40 (Ar-40), an inert gas.
For every 100 K-40 atoms that decay, 11 become Ar-40.