Wikipedia radiocarbon dating uranium lead dating Adult web cam fighting
Divisions in the geological time scales still use fossil evidence and mark major changes in the dominance of particular life forms.
For example, the Devonian Period is known as the 'Age of Fishes', as fish began to flourish at this stage.
The precision of a dating method depends in part on the half-life of the radioactive isotope involved.
principle sources: Australian Museum https://au/the-geological-time-scale Wikipedia https://en.wikipedia.org/wiki/Radiometric_dating Carleton University numerical (or "absolute") age is a specific number of years, like 150 million years ago.
A relative age simply states whether one rock formation is older or younger than another formation.
However, the end of the Devonian was marked by the predominance of a different life form, plants, which in turn denotes the beginning of the Carboniferous Period.
The different periods can be further subdivided (e.g.