Archaeology

The goals of archaeology are to document and explain the origins and development of human culture, understand culture history, chronicle cultural evolution, and study human behaviour and ecology, for both prehistoric and historic societies.

Field methods

Survey

A modern archaeological project often begins with a survey. Regional survey is the attempt to systematically locate previously unknown sites in a region. Site survey is the attempt to systematically locate features of interest, such as houses and middens, within a site. Each of these two goals may be accomplished with largely the same methods.

Related Topics:
Survey - Middens

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Survey was not widely practiced in the early days of archaeology. Cultural historians and prior researchers were usually content with discovering the locations of monumental sites from the local populace, and excavating only the plainly visible features there. Gordon Willey pioneered the technique of regional settlement pattern survey in 1949 in the Viru Valley of coastal Peru, and survey of all levels became prominent with the rise of processual archaeology some years later.

Related Topics:
Gordon Willey - 1949 - Viru Valley - Peru

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Survey work has many benefits if performed as a preliminary exercise to, or even in place of, excavation. It requires relatively little time and expense, because it does not require processing large volumes of soil to search out artefacts. (Nevertheless, surveying a large region or site can be expensive, so archaeologists often employ sampling methods.) It avoids ethical issues (of particular concern to descendant peoples) associated with destroying a site through excavation. It is the only way to gather some forms of information, such as settlement patterns and settlement structure. Survey data are commonly assembled into maps, which may show surface features and/or artefact distribution.

Related Topics:
Sampling - Settlement patterns - Maps

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The simplest survey technique is surface survey. It involves combing an area, usually on foot but sometimes with the use of mechanised transport, to search for features or artefacts visible on the surface. Surface survey cannot detect sites or features that are completely buried under earth, or overgrown with vegetation. Surface survey may also include mini-excavation techniques such as augers, corers, and shovel test pits.

Related Topics:
Augers - Corers - Shovel test

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Aerial survey is conducted using cameras attached to aircraft, balloons, or even kites. A bird's-eye view is useful for quick mapping of large or complex sites. Aerial imaging can also detect many things not visible from the surface. Plants growing above a stone structure, such as a wall, will develop more slowly, while those above other types of features (such as middens) may develop more rapidly. Photographs of ripening grain, which changes colour rapidly at maturation, have revealed buried structures with great precision. Aerial survey also employs infrared, ground-penetrating radar wavelengths, and thermography.

Related Topics:
Aerial survey - Cameras - Aircraft - Balloons - Kites - Plants - Middens - Grain - Infrared - Radar - Thermography

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Geophysical survey is the most effective way to see beneath the ground. magnetometers detect minute deviations in the Earth's magnetic field caused by iron artefacts, kilns, some types of stone structures, and even ditches and middens. Devices that measure the electrical resistivity of the soil are also widely used. Most soils are moist below the surface, which gives them a relatively low resistivity. Features such as hard-packed floors or concentrations of stone have a higher resistivity.

Related Topics:
Geophysical survey - Magnetometers - Earth's magnetic field - Iron - Kilns - Stone structures - Electrical resistivity - Moist

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Although some archaeologists consider the use of metal detectors to be tantamount to treasure hunting, others deem them an effective tool in archaeological surveying. Examples of formal archaeological use of metal detectors include musketball distribution analysis on English Civil War battlefields, metal distribution analysis prior to excavation of a nineteenth century ship wreck, and service cable location during evaluation. Metal detectorists have also contributed to the archaeological record where they have made detailed records of their results and refrained from raising artifacts from their archaeological context. In the UK, metal detectorists have been solicited for involvement in the Portable Antiquities Scheme.

Related Topics:
Metal detectors - English Civil War - Portable Antiquities Scheme

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Regional survey in maritime archaeology uses side-scan sonar.

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Excavation

Archaeological excavation existed when the field was still the domain of amateurs, and it remains the source of the majority of data recovered in most field projects. It can reveal several types of information usually not accessible to survey, such as stratigraphy, three-dimensional structure, and verifiably primary context.

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Modern excavation techniques require that the precise locations of objects and features, known as their provenance or provenience, be recorded. This always involves determining their horizontal locations, and sometimes vertical position as well. Similarly, their association, or relationship with nearby objects and features, needs to be recorded for later analysis. This allows the archaeologist to deduce what artefacts and features were likely used together and which may be from different phases of activity. For example, excavation of a site reveals its stratigraphy; if a site was occupied by a succession of distinct cultures, artefacts from more recent cultures will lie above those from more ancient cultures.

Related Topics:
Provenance - Association - Stratigraphy - Cultures

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Excavation is the most expensive phase of archaeological research. Also, as a destructive process, it carries ethical concerns. As a result, very few sites are excavated in their entirety. Sampling is even more important in excavation than in survey. It is common for large mechanical equipment, such as backhoes (JCBs), to be used in excavation, especially to remove the topsoil (overburden), though this method is increasingly used with great caution. Following this it is usual to hand-clean the exposed area with trowels or hoes to ensure that all features are apparent.

Related Topics:
Ethical - Sampling - Backhoes - JCBs - Topsoil - Overburden

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The next task is to produce a site plan and then use it to help decide the method of excavation. Features dug into the natural subsoil are normally excavated in portions in order to produce a visible archaeological section for recording. Scaled plans and sections of individual features are all drawn on site, black and white and colour photographs of them are taken, and recording sheets are filled in describing the context of each. All this information serves as a permanent record of the now-destroyed archaeology and is used in describing and interpreting the site.

Related Topics:
Subsoil - Archaeological section - Plans - Context

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