To establish the age of a rock or a fossil, researchers use some type of clock to determine the date it was formed. Geologists commonly use radiometric dating methods, based on the natural radioactive decay of certain elements such as potassium and carbon, as reliable clocks to date ancient events.

What are the three ways to determine the age of a fossil?

So, how do we know how old a fossil is? There are two main methods determining a fossils age, relative dating and absolute dating. Relative dating is used to determine a fossils approximate age by comparing it to similar rocks and fossils of known ages.

What to do if you find a fossil?

Permission is required to collect on private lands. Always check with the landowner before removing any fossils. Private landowners have the right to keep any fossils found on their property. They are urged to report any fossil finds to the UGS (see below).