Article about dating
This method is primarily applied to projectile points and ceramic vessels.
Moreover, stratigraphic dating is sometimes based on the objects that are found within the soil strata.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.An initial reading dates the specimen which is then calibrated by considering this date and its correspondence with the measurable level of carbon 14 stored over time in the growth rings of certain tree species, including redwood and pine bristol.
The results of radiocarbon dating are expressed in years and include a time range (eg, 630± 60 BP).
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 approach helps to order events chronologically but it does not provide the absolute age of an object expressed in years.
Relative dating includes different techniques, but the most commonly used are soil stratigraphy analysis and typology.
Several sets of rings from different trees are matched to build an average sequence.