Can carbon dating work on stone
At any given moment all living plants and animals have approximately the same percentage of carbon-14 in their bodies.
When a plant or animal dies it stops bringing in new carbon-14.
Carbon-14 in the bodies of animals and plants is constantly decaying.
However, the decaying carbon-14 is constantly being replaced as the plant or animal consumes more carbon-14 from the air or through its food.
This rules out carbon dating for most aquatic organisms, because they often obtain at least some of their carbon from dissolved carbonate rock.
The age of the carbon in the rock is different from that of the carbon in the air and makes carbon dating data for those organisms inaccurate under the assumptions normally used for carbon dating.
This restriction extends to animals that consume seafood in their diets, as well.
Carbon dating also cannot be used on artifacts over about 50,000 years old.
Then, First, carbon-14 cannot be used to date biological artifacts of organisms that did not get thier carbon dioxide from the air.
This carbon-14 labeled carbon dioxide is taken up by plants in their normal process of photosynthesis.
Animals and people that eat these plants take the carbon-14 into their bodies as well.
However, the carbon-14 already in the organism's body continues to decay at a constant rate.
Therefore, the amount of carbon-14 in an artifact decreases at a predictable rate while the amount of carbon-12 remains constant.
Scientists now realize that production of carbon-14 has not been constant over the last 10,000 years, but has changed as the radiation from the sun has changed.