The sedimentary record of an archaeological site provides critical environmental and stratigraphic information. Less well appreciated is that sediments are also of assistance in interpreting settlement patterns and subsistence activities. The reason is that archaeological sediments typically include a mix of physical, biogenic, and cultural components:
1. Physiogenic components reflect the fundamental physical processes modal to the site, with or without the activity of humans or animals. They result from erosion, transfer, and deposition normal to the general site locale or to specific microdepositional environments within the site. Eolian dust, water-laid silt and sand, slope movements, and cave spall and flowstone can be cited as examples.
2. Biogenic components result mainly from the activity of animals visiting or resident in a site, such as domesticated stock, household animals, rodents, earthworms, snails, and insects in a village-mound settlement, or wasps, owls, bats, porcupines, hyenas, felids, and bears in a cave. The cave denizens introduce a range of external material to the cavern, and the mound dwellers may introduce matter or may mix and process organic-mineral sediment. Biogenic activity in caves is most important during breaks in occupation or after site abandonment. In village mounds, biogenic input is reduced after abandonment, but the various subsurface organisms then aid decomposition of surface rubble, favoring biochemical soil formation.