Археологиялық шөгінділерді мерзімдеу мақсатында зерттеу

Study of archaeological sedimentation for dating purposes

Stratigraphy is a key concept to modern archaeological theory and practice. Modern excavation techniques are based on stratigraphic principles. The concept derives from the geological use of the idea that sedimentation takes place according to uniform principles. When archaeological finds are below the surface of the ground (as is most commonly the case), the identification of the context of each find is vital in enabling the archaeologist to draw conclusions about the site and about the nature and date of its occupation. It is the archaeologist's role to attempt to discover what contexts exist and how they came to be created. Archaeological stratification or sequence is the dynamic superimposition of single units of stratigraphy, or contexts. Contexts are single events or actions that leave discrete, detectable traces in the archaeological sequence or stratigraphy. They can be deposits (such as the back fill of a ditch), structures (such as walls), or "zero thickness surfaces", better known as "cuts". Cuts represent actions that remove other solid contexts such as fills, deposits, and walls. An example would be a ditch "cut" through earlier deposits. Stratigraphic relationships are the relationships created between contexts in time, representing the chronological order in which they were created. One example would be a ditch and the back fill of said ditch. The temporal relationship of "the fill" context to the ditch "cut" context is such that "the fill" occurred later in the sequence; you have to dig a ditch before you can back fill it. A relationship that is later in the sequence is sometimes referred to as "higher" in the sequence, and a relationship that is earlier, "lower", though this does not refer necessarily to the physical location of the context. It is more useful to think of "higher" as it relates to the context's position in a Harris matrix, a two dimensional representation of a site's formation in space and time.

Understanding a site in modern archaeology is a process of grouping single contexts together in ever larger groups by virtue of their relationships. The terminology of these larger clusters varies depending on the practitioner, but the terms interface, sub group, and group are common. An example of a sub group could be the three contexts that make up a burial; the grave cut, the body, and the back filled earth on top of the body. Sub groups can then be clustered together with other sub groups by virtue of their stratigraphic relationship to form groups, which in turn form "phases." A sub group burial could cluster with other sub group burials to form a cemetery, which in turn could be grouped with a building, such as a church, to produce a "phase". Phase implies a nearly contemporaneous Archaeological horizon, representing "what you would see if you went back to time X". The production of phase interpretations is the first goal of stratigraphic interpretation and excavation.

One issue in using stratigraphic relationships is that the date of artifacts in a context does not represent the date of the context, but just the earliest date the context could be. If one looks at the sequence in figure A, one may find that the cut for the construction of wall 2, context 5, has cut through layers 9 and 10, and in doing so has introduced the possibility that artifacts from layers 9 and 10 may be redeposited higher up the sequence in the context representing the backfill of the construction cut, context 3. These artifacts are referred to as "residual" or "residual finds". It is crucial that dating a context is based on the latest dating evidence drawn from the context. We can also see that if the fill of cut 5 – the wall 2, backfill 3 and trample 12 — are not removed entirely during excavation because of "undercutting", non residual artifacts from these later "higher" contexts 2, 3 and 12 could contaminate the excavation of earlier contexts such as 9 and 10 and give false dating information. These artifacts may be termed intrusive finds.

Stratigraphic data is a required component in archaeological archives, but there is a growing problem for digital data archives, where stratigraphic data are often only held on paper or as scanned image copies (PDFs) of matrix diagrams. This means that they cannot be easily re used in further analysis. Some recommendations are being made to address this problem.