Variations in decay rates.
decay rates are constants -- but this is a commone creationist position: suppose, ad hoc, the rates changed, just like the speed of light ad-hoc-ly did.
Variations in the production rate of 14C, which in turn causes variations in the amount of 14C in the environment.
Variations in the rate at which carbon is removed from the environment.
since carbon dating is done by the ratio of parent-to-daughter isotopes, these two are actually completely irrelevant.
Exchanges of carbon in samples with carbon from the environment.
this, however, is a good way to screw up c
14 dating: the addition of extra carbon after death. fire, apparently, is the preferred method.
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