Radiometric dating only works if you know the starting conditions
I find Carbon dating less problematic in it's assumptions because you can assume a certain amount of carbon isotopes in the atmosphere being the same in the past as today but I did not say that it is not problematic
Other dating methods are more problematic in my opinion
Let's say you have Uranium turn to lead and try to find the date by the ratio of Uranium to Lead
What was it before 100% Uranium
The variation in the 14
C/12
C ratio in different parts of the carbon exchange reservoir means that a straightforward calculation of the age of a sample based on the amount of 14
C it contains will often give an incorrect result. There are several other possible sources of error that need to be considered. The errors are of four general types:
https://en.wikipedia.org/wiki/Radiocarbon_dating_considerations
@pepsi_man @TrevorGoodchild
Variations in the 14
C/12
C ratio in the atmosphere, both geographically and over time
Isotopic fractionation
Variations in the 14
C/12
C ratio in different parts of the reservoir
Contamination
https://en.wikipedia.org/wiki/Radiocarbon_dating_considerations
Four categories of errors in carbon dating according to wikipedia