The story of this great change in the conception of the history of Earth is not a simple one.
The chronicle of this great change can be broken into five periods; ran from AD 1600-1700.
Levels of carbon-14 become difficult to measure and compare after about 50,000 years (between 8 and 9 half lives; where 1% of the original carbon-14 would remain undecayed).
The question should be whether or not carbon-14 can be used to date any artifacts at all? There are a few categories of artifacts that can be dated using carbon-14; however, they cannot be more 50,000 years old.
However, by itself a fossil has little meaning unless it is placed within some context.Others had tried to find an answer in geological processes—e.g.the pattern was caused by the way the magma was emplaced or how it crystallized. But Drs Humphreys and Baumgardner realized that in other cases there were many independent lines of evidence that suggested that huge amounts of radioactive decay had indeed taken place.For example, based on the primate fossil record, scientists know that living primates evolved from fossil primates and that this evolutionary history took tens of millions of years.By comparing fossils of different primate species, scientists can examine how features changed and how primates evolved through time.