However, this method is sometimes limited because the reoccupation of an area may require excavation to establish the foundation of a building, for instance, that goes through older layers.
In this case, even if the foundation of the building is found in the same stratigraphic level as the previous occupation, the two events are not contemporary.
This method is primarily applied to projectile points and ceramic vessels.
These present many characteristics that are used for comparing them, such as morphology and raw materials in the case of stone tools, and decorative techniques and motifs in the case of ceramics.
Several sets of rings from different trees are matched to build an average sequence.
Subsequently, overlapping series of average sequences from trees that died at different times and come from various sources (ie, the wood of historic buildings, archaeological and fossil woods) are used to build a chronological sequence covering several hundred years which becomes a reference.
Stratigraphy Inspired by geology, stratigraphy uses the principle of the superposition of strata which suggests that, in a succession of undisturbed SOILS, the upper horizons are newer than the lower ones.
Generally, each stratum is isolated in a separate chronological unit that incorporates artifacts.
These methods usually analyze physicochemical transformation phenomena whose rate are known or can be estimated relatively well.For those researchers working in the field of human history, the chronology of events remains a major element of reflection.Archaeologists have access to various techniques for dating archaeological sites or the objects found on those sites.Indeed, some items whose exact or approximate age is known are called "diagnostic artifacts." Examples of such objects include very specific stone tools, different pottery styles, objects that belong to a specific period (eg, the historic period or the French regime), coins with a production date, or other items bearing a trademark and whose history can be traced in historical records.Their presence on archaeological sites is used to date the soil layers and the objects and events they are associated with and thus contributes to refine the chronology of sites.Radiocarbon Dating Radiocarbon dating is the most widely used dating technique in archaeology.It relies on a natural phenomenon that is the foundation of life on earth.There are two main categories of dating methods in archaeology: indirect or relative dating and absolute dating.Relative dating includes methods that rely on the analysis of comparative data or the context (eg, geological, regional, cultural) in which the object one wishes to date is found.Subsequently, the calibration of that date provides a time interval where the event or object being dated can be situated (eg, 1275-1425 AD).Radiocarbon dating, however, can only be used for dating objects that are less than 50 000 years.