Geoarchaeology:Site Prospection

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1 Site Prospection

[edit] Site Prospection

Many archaeological remains are buried, often deeply. Geoarchaeological techniques can be successfully applied to problems of "site prospection". That is not only the identification of new "sites", but also the mapping of areas of high archaeological potential, the delimitation of "areas of influence" (activity boundaries) around sites and the elucidation of physical structure and functional area divisions within sites. Even if sites are not going to be excavated, knowing where there is the potential for archaeological remains to survive can be important as land use and water extraction activities may damage remains without physically exposing them.

[edit] Mapping archaeological potential

Where sites are deeply buried, identifying sites and the potential for sites, can be difficult. Understanding the sedimentary record can be key to identifying areas of high archaeological potential.

Soil / sediment depth is an obvious factor. If the soils are very thin there is no potential for deep burial and hence the likeliood of there being unidentified archaeology is low. Coring, and soil / geology maps may help provide information about soil / sediment depth.
Areas of deep sediment may have accumulated prior to human settlement in an area. In such cases, despite the deep sediments and possibly ideal preservation conditions, the potential for archaeological remains is very low. Identifying the date and periodicting of sedimentation, therefore, can be important in understanding archaeological potential.
Archaeological potential will vary spatially according to the presence of stable land surfaces. For example deep alluvial deposits may represent not only an aggrading floodplain, but also palaeochannels and phases of lateral and vertical erosion. Settlement remains are most likely to be associated with stable landsurfaces, usually identified by the presence of a buried soil. Palaeochannels, however, may contain a wealth of palaeoenvironmental remains, and possibly archaeological material such as fishtraps or boats. Areas around palaeochannels may also have burial conditions most conducive to the preservation of organic material. Coring, testpitting, topographic and geophysical survey may help to identify palaeochannles and buried land surfaces.
Preservation conditions can vary over distances of a few metres with sediments and soils linked to localised changes in the watertable, rooting, sediment properties and the past history of sedimentation and stabilisation. Geoarchaeology can help predict where archaeological preservation, and hence potential, is likely to be highest.

[edit] Site location, stucture and boundaries

Geophysical and geochemical survey of sites prior to, or sometimes instead of, excavation can help confirm the location of archaeological structures and map the internal structure of wall, ditches, pits, floors, and hearths. This can provide provisional information on the nature and preservation of the site, may help identify targets for excavation, and may also help identify outlying features and the boundaries of "significant" site influence.