Relative dating concept
Absolute dating is a method of determining the specific date of a paleontological or archaeological artifact or location based on a specific time scale or calendar.
As this example illustrates determining the age of a geologic feature or rock requires the use of both absolute and relative dating techniques.
If a geologist claims to be 45 years old, that is an absolute age.
Superposition: The most basic concept used in relative dating is the law of superposition.
Simply stated, each bed in a sequence of sedimentary rocks (or layered volcanic rocks) is younger than the bed below it and older than the bed above it.
This law follows two basic assumptions: (1) the beds were originally deposited near horizontal, and (2) the beds were not overturned after their deposition.
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.