In geology, absolute dating can tell us the approximate age in years of the rock.
The main way absolute dating is carried out is by Radiometric dating.
Consider a lake that dries out or somehow contains older sediments that are washed into it.
The archaeologists record and analyze the changes in types and styles of human-made items from different levels according to the principle explained below.
Sediments are usually laid down in horizontal beds.
Prior to the availability of radiocarbon dates (and when there is no material suitable for a radiocarbon date) scientists used a system of relative dating.
Relative dating establishes the sequence of physical or cultural events in time.