archaeology Archaeology or archeology is the study of human activity through the recovery and analysis of material culture. The archaeological record consists of Artifact (archaeology), artifacts, architecture, biofact (archaeology), biofacts or ecofacts, ...

, natural is a term to denote a layer (stratum) in the stratigraphic record where there is no evidence of

human impact on the environment Human impact on the environment (or anthropogenic environmental impact) refers to changes to biophysical environments and to ecosystems, biodiversity, and natural resources caused directly or indirectly by humans. Modifying the environment to ...

. While there may be "natural" layers interbedded with archaeologically interesting layers, such as when a site was abandoned for long periods between occupations, the top (or horizon) of the natural layer below which there is no anthropogenic activity on site, and thus where the

archaeological record The archaeological record is the body of physical (not written) evidence about the past. It is one of the core concepts in archaeology, the academic discipline concerned with documenting and interpreting the archaeological record. Archaeological t ...

begins, is the point to terminate digging.Barker, Philip (1993) ''Techniques of archaeological excavation'' Psychology Press, New Yor
page 79
Usually it is the underlying

geological Geology (). is a branch of natural science concerned with the Earth and other astronomical objects, the rocks of which they are composed, and the processes by which they change over time. Modern geology significantly overlaps all other Earth s ...

makeup of the site that was formed by geologic processes. It is the goal of complete excavation to remove the entirety of the archaeological record all the way to the "natural", leaving only the natural deposits of pre-human activity on site. If the excavation is related to development, the impact assessment may stipulate excavation will cease at a certain depth, because the nature of the development will not disturb remains below a certain level. Such an excavation may not reach a natural or sterile layer.

Issues of definition

Natural is becoming a blurred term in archaeology due to an increased understanding by researchers of natural processes. In addition, through the development of

geoarchaeology Geoarchaeology is a multi-disciplinary approach which uses the techniques and subject matter of geography, geology, geophysics and other Earth sciences to examine topics which inform archaeological and chronological knowledge and thought. Geoarc ...

, scholars believe the

natural landscape A natural landscape is the original landscape that exists before it is acted upon by human culture. The natural landscape and the cultural landscape are separate parts of the landscape. However, in the 21st century, landscapes that are totally ...

has a bearing on interpretation of subsequent human activity on any given site. As geoarchaeology continues to influence the interpretation of processes that occur within the archaeological record, the term "natural" has become less useful.Albarella, Umberto (2001) ''Environmental archaeology: meaning and purpose'' Kluwer Academic Publishers, Dordrecht, the Netherlands
page 56
Natural can be a relative term. On urban sites, where research interests may make a detailed examination of the earliest part of the record impractical, rudimentary human or

prehistoric Prehistory, also called pre-literary history, is the period of human history between the first known use of stone tools by hominins million years ago and the beginning of recorded history with the invention of writing systems. The use o ...

activity may go unrecorded, as opposed to an equivalent horizon on a rural site for which the study team's agenda is to look for prehistoric evidence. Chemical and soil process over time often obscure and cause decomposition of cultural materials, and thus a human-occupied layer may look natural. Additionally, early prehistoric tools were manufactured from natural materials, such as bone, stone and fiber; they do not stand out as clearly as metal, glass and plastic. The effect of decompositional processes is that the older an archaeological deposit is, the more it will appear similar to the underlying geology. For some archaeologists, a basic rule of thumb is "the greater the contrast a

context In semiotics, linguistics, sociology and anthropology, context refers to those objects or entities which surround a ''focal event'', in these disciplines typically a communicative event, of some kind. Context is "a frame that surrounds the event ...

has with the natural, the younger it is." Similarly, United States prehistoric archaeologists often rely on significantly diminished counts of lithic flake

debitage In archaeology, debitage is all the material produced during the process of lithic reduction – the production of stone tools and weapons by knapping stone. This Assemblage (archaeology), assemblage may include the different kinds of lithic fla ...

to assess the excavation unit's trend toward natural stratigraphy. While a trend may be recognized, a stratum is not called natural or sterile, unless it is void of cultural materials.

Notes

{{Reflist Methods in archaeology Stratigraphy