This technique uses well established tree ring sequences to date events.
Reconstruction of environmental occurrences, droughts for example, which took place when the trees were growing, is also possible based on traits such as changes in tree ring thickness.
Using a compiled master chronology of pole reversals, scientists can then date the specimen.
Because the time between pole reversals is so large, this technique can only be used to date objects to an accuracy of a few thousand to tens of thousands of years.
Examples include trace element analysis to determine the source of obsidian used to manufacture arrowheads, and chemical analysis of the growth rings of fossilized sea shells to determine seasonal variations in local temperature over time.The technique has been used to date human remains in the Siwalki Hills of India, in the Olduvai Gorge in Kenya, and in the Hadar region of Ethiopia.Archaeomagnetism makes use of the fact that the magnetic North Pole has shifted position over time.The longest individual tree ring chronologies developed to date have been for an 8, 700-year California bristlecone pine sequence, and a 10,000-year sequence in Europe.Besides chronological information, archeological tree ring dating yields information about the way wood was used in an ancient culture, and about past climates.Radioactive decay (fission) of uranium U-238 causes microscopic tracks of subatomic particles to develop in minerals and glass.