Finally, absolute dating is obtained by synchronizing the average sequences with series of live (and thus datable) trees and thus anchors the tree-ring chronology in time.Dendrochronology mainly uses softwood species that are sensitive to changes in growth conditions, while hardwoods show rather little variation in ring width.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.On the other hand, absolute dating includes all methods that provide figures about the real estimated age of archaeological objects or occupations.These methods usually analyze physicochemical transformation phenomena whose rate are known or can be estimated relatively well.The amount of carbon 14 remaining in the material to date is compared to a reference standard (ratio 14C/total carbon, 12C and 13C) to calculate the time elapsed since its occurrence.
Moreover, stratigraphic dating is sometimes based on the objects that are found within the soil strata.
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).
Stratigraphic dating remains very reliable when it comes to dating objects or events in undisturbed stratigraphic levels.
For example, the oldest human remains known to date in Canada, found at Gore Creek, have been dated using soil stratification.