In archaeology, excavation is the exposure, processing and recording of archaeological remains. An excavation site or "dig" is the area being studied. These locations range from one to several areas at a time during a project and can be conducted over a few weeks to several years.
The law of superposition is an axiom that forms one of the bases of the sciences of geology, archaeology, and other fields pertaining to geological stratigraphy. In its plainest form, it states that in undeformed stratigraphic sequences, the oldest strata will lie at the bottom of the sequence, while newer material stacks upon the surface to form new deposits over time. This is paramount to stratigraphic dating, which requires a set of assumptions, including that the law of superposition holds true and that an object cannot be older than the materials of which it is composed. To illustrate the practical applications of superposition in scientific inquiry, sedimentary rock that has not been deformed by more than 90° will exhibit the oldest layers on the bottom, thus enabling paleontologists and paleobotanists to identify the relative ages of any fossils found within the strata, with the remains of the most archaic lifeforms confined to the lowest. These findings can inform the community on the fossil record covering the relevant strata, to determine which species coexisted temporally and which species existed successively in perhaps an evolutionarily or phylogenetically relevant way.
In archaeological excavation, a feature is a collection of one or more contexts representing some human non-portable activity, such as a hearth or wall. Features serve as an indication that the area in which they are found has been interfered with in the past, usually by humans.
In archaeology a section is a view in part of the archaeological sequence showing it in the vertical plane, as a cross section, and thereby illustrating its profile and stratigraphy. This may make it easier to view and interpret as it developed over time.
In archaeology a posthole or post-hole is a cut feature used to hold a surface timber or stone. They are usually much deeper than they are wide; however, truncation may not make this apparent. Although the remains of the timber may survive, most postholes are mainly recognisable as circular patches of darker earth when viewed in plan. Archaeologists can use their presence to plot the layout of former structures, as the holes may define its corners and sides. Construction using postholes is known as earthfast or post in ground construction.
The Harris matrix is a tool used to depict the temporal succession of archaeological contexts and thus the sequence of depositions and surfaces on a 'dry land' archaeological site, otherwise called a 'stratigraphic sequence'. The matrix reflects the relative position and stratigraphic contacts of observable stratigraphic units, or contexts. It was developed in 1973 in Winchester, England, by Edward C. Harris.
In archaeological excavation, a plan is a drawn record of features and artifacts in the horizontal plane.
Lithostratigraphy is a sub-discipline of stratigraphy, the geological science associated with the study of strata or rock layers. Major focuses include geochronology, comparative geology, and petrology.
Relative dating is the science of determining the relative order of past events, without necessarily determining their absolute age. In geology, rock or superficial deposits, fossils and lithologies can be used to correlate one stratigraphic column with another. Prior to the discovery of radiometric dating in the early 20th century, which provided a means of absolute dating, archaeologists and geologists used relative dating to determine ages of materials. Though relative dating can only determine the sequential order in which a series of events occurred, not when they occurred, it remains a useful technique. Relative dating by biostratigraphy is the preferred method in paleontology and is, in some respects, more accurate. The Law of Superposition, which states that older layers will be deeper in a site than more recent layers, was the summary outcome of 'relative dating' as observed in geology from the 17th century to the early 20th century.
The following outline is provided as an overview of and topical guide to archaeology:
In archaeology, seriation is a relative dating method in which assemblages or artifacts from numerous sites in the same culture are placed in chronological order. Where absolute dating methods, such as radio carbon, cannot be applied, archaeologists have to use relative dating methods to date archaeological finds and features. Seriation is a standard method of dating in archaeology. It can be used to date stone tools, pottery fragments, and other artifacts. In Europe, it has been used frequently to reconstruct the chronological sequence of graves in a cemetery.
In archaeology, a phase refers to the logical reduction of contexts recorded during excavation to nearly contemporary archaeological horizons that represent a distinct "phase" of previous land use. These often but not always will be a representation of a former land surface or occupation level and all associated features that were created into or from this point in time. A simplified description of phase would be that "a phase is a view of a given archaeological site as it would have been at time X".
In archaeology and archaeological stratification, a cut or truncation is a context that represents a moment in time when other archaeological deposits were removed for the creation of some feature, such as a ditch or pit. In layman's terms, a cut can be thought of as a hole that was dug in the past, though cut also applies to other parts of the archaeological record such as horizontal truncations like terraced ground. A cut context is sometimes referred to as a "negative context", as opposed to a "positive context". The term denotes that a cut has removed material from the archaeological record or natural at the time of its creation, as opposed to a positive context, which adds material to the archaeological record. A cut has zero thickness and no material properties of its own and is defined by the limits of other contexts. Cuts are seen in the record by virtue of the difference between the material it was cut through and the material that back-fills it. This difference is seen as an "edge" by the archaeologists on site. This is shown in the picture, where a half sectioned Saxon pit has had half its backfill removed and we can clearly see a difference between the ground the pit was cut into, and the material originally filling the pit. Sometimes these differences are not clear and an archaeologist must rely on experience and insight to discover cuts.
An archaeological relationship is the position in space and by implication, in time, of an object or context with respect to another. This is determined, not by linear measurement but by determining the sequence of their deposition – which arrived before the other. The key to this is stratigraphy.
Single context recording was initially developed by Ed Harris and Patrick Ottaway in 1976, from a suggestion by Laurence Keen. It was further developed by the Department of Urban Archaeology from where it was then exported, in the mid-1980s by Pete Clarke to the Scottish Urban Archaeological Trust and Nick Pearson to the York Archaeological Trust. It has become a popular system of recording and planning being used in many countries in Europe and in Lebanon, it is especially suited to the complexities of deep, typically urban, archaeology. Each excavated context is given a unique "context number" and is recorded by type on a context sheet and perhaps being drawn on a plan and/or a section. Depending on time constraints and importance contexts may also be photographed, but in this case a grouping of contexts and their associations are the purpose of the photography. Finds from each context are bagged and labelled with their context number and site code for later cross-reference work carried out post excavation. The height above sea level of pertinent points on a context, such as the top and bottom of a wall are taken and added to plans sections and context sheets. Heights are recorded with a dumpy level or total station by relation to the site temporary benchmark. Samples of deposits from contexts are sometimes also taken, for later environmental analysis or for scientific dating.
In archaeology a fill is the material that has accumulated or has been deposited into a cut feature such as ditch or pit of some kind of a later date than the feature itself. Fills are an important part of the archaeological record as their formation and composition can throw light on many aspects of archaeological study.
Sequence dating, an archaeological relative dating method, allows assemblages to be arranged in a rough serial order, which is then taken to indicate time. Sequence dating is a method of seriation developed by the Egyptologist Sir William Matthew Flinders Petrie. By linking styles of pottery with different time periods, he was able to establish the relative chronology of the site.
Gatecliff Rockshelter (26NY301) is a major archaeological site in the Great Basin area of the western United States that provides remarkable stratigraphy; it has been called the "deepest archaeological rock shelter in the Americas". Located in Mill Canyon of the Toquima Range in the Monitor Valley of central Nevada, Gatecliff Rockshelter has an elevation of 7,750 feet (2,360 m). David Hurst Thomas discovered Gatecliff Rockshelter in 1970 and began excavations in 1971. Full scale excavations occurred at Gatecliff Rockshelter for about seven field seasons in which nearly 33 feet (10 m) of sediments were exposed for a well-defined stratigraphic sequence. The well-preserved artifacts and undisturbed sediments at Gatecliff Rockshelter provides data and information have been applied to a range of research topics. Based on the analysis of the artifacts at Gatecliff Rockshelter, it can be determined that it was most likely a short-term field camp throughout prehistory. The latest evidence for human usage at Gatecliff occurs between ca. 5500 B.P. to 1250 B.P.
In the field of archaeology, a spit is a unit of archaeological excavation with an arbitrarily assigned measurement of depth and extent. It is a method of excavation employed without regard to the archaeological stratigraphy that may be identifiable at the archaeological site under investigation. The method of excavating in arbitrary spits is most frequently encountered at site excavations which lack any visible or reconstructable stratigraphy in the archaeological context, or when excavating through intrusive or fill deposits.
This page is a glossary of archaeology, the study of the human past from material remains.
