For example if you have a fossil trilobite and it was found in the Wheeler Formation which has been dated to approximately 507 million years old, you know the fossil in it is approximately 507 million years old.Scientists use certain types of fossils referred to as index fossils to assist in relative dating via correlation.One example of this is ironstone nodules in the Mazon Creek fossil beds that contain amazingly details fossil plants and insects.
This uses radioactive minerals in the rocks and fossils almost like a geological clock.
Carbon-14, the radioactive isotope of carbon used in carbon dating breaks down too fast.
It can only be used to date fossils younger the 75,000 years.
The atoms in some chemical elements have different forms, called isotopes.
These isotopes break down at a very consistent rate over time through radioactive decay.
There are two main types of fossils; body and trace. The absence of heat or compression which might destroy the fossil Fossils are most often preserved within sediments that were deposited in water, such as wetlands, river basins, or the ocean.