Dating sites for educators
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.
Crossdating is an important principle in dendrochronology.
It consists in comparing and matching two or more series of ring widths measured on different trees.
The partial overlap of sets of trees that died at different times allows the construction of average chronological sequences (courtesy Groupe de recherche en dendrochronologie historique; illustration C.
Dagneau)Wall where the Gore Creek skeleton bones were found in 1975, in a gully located near Pritchard, BC. Helens Y tephra (ash) dated at 3200 years BP, and the lower white line is from the Mount Mazama eruption that took place almost 7000 years ago (courtesy Jerome Cybulski).
Typology Typology is a method that compares reference objects in order to classify them according to their similarity or dissimilarity and link them to a specific context or period.
Following the death of an organism, any exchange ceases and the carbon 14, which is radioactive and therefore unstable, slowly begins to disintegrate at a known rate (half-life of 5730 years, ie, after this period only half of the total carbon 14 present at the time of death remains).
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.
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.