In such cases subjective element cannot be ruled out.
But, for a single culture site the method is quite reliable.
C-14 is produced when high-energy particles from solar radiation hit the earth’s atmosphere and make the unstable element called C-14.
As time goes by, this C-14 slowly changes back to stable atoms.
Carbon-14 is continually formed in nature by the interaction of neutrons with nitrogen-14 in the Earth’s atmosphere; the neutrons required for this reaction are produced by cosmic rays interacting with the atmosphere. is absorbed from the air by green plants and then passed on to animals through the food chain.
When a new fossil is discovered, geologists assign a date for when they think the plant or animal lived.
They normally use radiometric dating methods to date the fossil, and many promote these methods as being accurate.
Radiocarbon decays slowly in a living organism, and the amount lost is continually replenished as long as the organism takes in air or food.
Once the organism dies, however, it ceases to absorb carbon-14, so that the amount of the radiocarbon in its tissues steadily decreases.