Carbon dating cannot be used on most fossils, not only because they are almost always allegedly too old, but also because they rarely contain the original carbon of the organism that has been fossilized.Also, many fossils are contaminated with carbon from the environment during collection or preservation procedures.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 diet.This technique is not restricted to bones; it can also be used on cloth, wood and plant fibers.
These artifacts have gone through many carbon-14 half-lives, and the amount of carbon-14 remaining in them is miniscule and very difficult to detect.
Scientists attempt to check the accuracy of carbon dating by comparing carbon dating data to data from other dating methods.
Other methods scientists use include counting rock layers and tree rings.
The various confounding factors that can adversely affect the accuracy of carbon-14 dating methods are evident in many of the other radioisotope dating methods.
Although the half-life of some of them are more consistent with the evolutionary worldview of millions to billions of years, the assumptions used in radiometric dating put the results of all radiometric dating methods in doubt. Although the half-life of carbon-14 makes it unreliable for dating fossils over about 50,000 years old, there are other isotopes scientists use to date older artifacts.