Natural materials such as rocks, soil, and traces of plants and animals settle on the earth’s surface and over time can accumulate in layers.
Each layer, or stratum, may be distinguished by its physical characteristics: color, texture, and structure.

These layers, called strata, form a record of past events that archaeologists analyze and interpret.
The materials deposited first are the oldest and are always found at the bottom of a given stratigraphic section.
Archaeologists use many different techniques to determine the age of a particular artifact, site, or part of a site.
Two broad categories of dating or chronometric techniques that archaeologists use are called relative and absolute dating.
On the other hand, absolute dating includes all methods that provide figures about the real estimated age of archaeological objects or occupations.
These methods usually analyze physicochemical transformation phenomena whose rate are known or can be estimated relatively well.
This approach helps to order events chronologically but it does not provide the absolute age of an object expressed in years.
Relative dating includes different techniques, but the most commonly used are soil stratigraphy analysis and typology.
This process of ingesting C-14 continues as long as the plant or animal remains alive.