Fossils are formed when minerals in groundwater replace materials in bones and tissue, creating a replica in stone of the original organism or of their tracks.
The study of fossils is the domain of paleontology.
This technique is widely used on recent artifacts, but educators and students alike should note that this technique will not work on older fossils (like those of the dinosaurs alleged to be millions of years old).
"beard worms" that are allegedly 530 million years old!
(See 60 similar discoveries.) Here, RSR presents the scientific journals reporting, the kinds of biological material found so far, and the dinosaurs yielding up these exciting discoveries: Scientific Journals: , and others below in our chronological catalog, "the web's most complete list of dinosaur soft tissue discoveries," as published in many leading journals, according to a co-author of one of those papers.
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.