Rates of radioactive decay are constant and measured in terms of half-life, the time it takes half of a parent isotope to decay into a stable daughter isotope.Some rock-forming minerals contain naturally occurring radioactive isotopes with very long half-lives unaffected by chemical or physical conditions that exist after the rock is formed.Relative dating techniques provide geologists abundant evidence of the incredible vastness of geologic time and ancient age of many rocks and formations.However, in order to place absolute dates on the relative time scale, other dating methods must be considered.Half-lives of these isotopes and the parent-to-daughter ratio in a given rock sample can be measured, then a relatively simple calculation yields the absolute (radiometric) date at which the parent began to decay, i.e., the age of the rock.
The relative dating is the technique in the Geology through which the age is determined with relation to the other objects.
In other words, we can say that in relative dating the archaeologist determines that which of the two fossil or the artifacts are older.
Contrary to this, the absolute dating is the technique, using which the exact age of the artifacts, fossils, or sites are ascertained.
For example, shells, wood, and other material found in the shoreline deposits of Utah’s prehistoric Lake Bonneville have yielded absolute dates using this method.
These distinct shorelines also make excellent relative dating tools.
Many sections of the Wasatch fault disturb or crosscut the Provo shoreline, showing that faulting occurred after the lake dropped below this shoreline which formed about 13,500 years ago.