Argon argon radioactive dating method
Geologists have established a set of principles that can be applied to sedimentary and volcanic rocks that are exposed at the Earth's surface to determine the relative ages of geological events preserved in the rock record.
Mountains have been built and eroded, continents and oceans have moved great distances, and the Earth has fluctuated from being extremely cold and almost completely covered with ice to being very warm and ice-free.
Third, magnetism in rocks can be used to estimate the age of a fossil site.
This method uses the orientation of the Earth's magnetic field, which has changed through time, to determine ages for fossils and rocks.
Second, it is possible to determine the numerical age for fossils or earth materials.
Numerical ages estimate the date of a geological event and can sometimes reveal quite precisely when a fossil species existed in time.