Why do archaeologists take soil samples and how do they decide when to take them?

Archaeologists take soil samples in order to recover small material which may not be visible with the naked eye. This may include tiny plant and animal remains which can provide clues to the ancient environment and land use or tiny tools or other artifacts.

A sampling strategy is often part of an excavation plan and before excavation begins it may be decided that a certain percentage of the site will be taken in soil samples. During the excavation an archaeologist may also decide to sample interesting areas, that might show more charcoal, organic material or may be part of hearth or cremation deposits.