For example if you have a fossil trilobite and it was found in the Wheeler Formation.
Absolute dating is used to determine a precise age of a fossil by using radiometric dating to measure the decay of isotopes, either within the fossil or more often the rocks associated with it.
There are three major types of rocks, which are metamorphic, igneous, and sedimentary. There is actually no specific answer to this as rocks change over time.
What we do know is that the bottom layer of rocks in the oldest, and the layers of rock get younger as they pile on top of each other.
It’s often much easier to date volcanic rocks than the fossils themselves or the sedimentary rocks they are found in.
So, often layers of volcanic rocks above and below the layers containing fossils can be dated to provide a date range for the fossil containing rocks.
While people are most familiar with carbon dating, carbon dating is rarely applicable to fossils.