To determine the ages of these specimens, scientists need an isotope with a very long half-life. Some of the isotopes used for this purpose are uranium-238, uranium-235 and potassium-40, each of which has a half-life of more than a million years.

What isotope do archaeologists use to date fossils?

carbon-14 Radiocarbon helps date ancient objects—but its not perfect. For nearly 70 years, archaeologists have been measuring carbon-14 levels to date sites and artifacts. Nothing good can last—and in the case of carbon-14, a radioactive isotope found in Earths atmosphere, thats great news for archaeologists.

What isotope dates bones?

Carbon 14 The Carbon 14, or radiocarbon dating method is one of the best-known methods of dating human fossils and has been around since the late 1940s.

Are dinosaur bones carbon dated?

The most widely known form of radiometric dating is carbon-14 dating. But carbon-14 dating wont work on dinosaur bones. The half-life of carbon-14 is only 5,730 years, so carbon-14 dating is only effective on samples that are less than 50,000 years old.