I’m no expert on this, but my understanding is that carbon-based dating is not used on rocks. Carbon based dating can only go back 50,000 years and is used on the remains of living organisms. To date rocks, geologists have to use elements with much longer half-lives, such as potassium-40, etc.
I don’t think Carbon14 is reliable anywhere near to 50,000 years back.
Besides there is no way to confirm how much Carbon (or Potassium/Argon, or any other element) was present in the past. There are a number of assumptions implicit in these radioactive decay models. But those assumptions are very much un-testable.
They can’t carbon date the rocks, but they can date the soil “strata layers” the rocks are in and then date any carbon remains in those corresponding strata layers. But they can’t do this until organic carbon remains are found, many are still a mystery because the digs lack organic material to date.