Chronometric dating techniques provide
In 1929, they found a charred log near Show Low, Arizona, that connected the two patterns.
It was now possible to assign a calendar date to archaeological sites in the American southwest for over 1000 years.
His research culminated in proving that tree ring width varies with annual rainfall.
Not only that, it varies regionally, such that all trees within a specific species and region will show the same relative growth during wet years and dry years.
The scholar most associated with the rules of stratigraphy (or law of superposition) is probably the geologist Charles Lyell.
The basis for stratigraphy seems quite intuitive today, but its applications were no less than earth-shattering to archaeological theory.
There are dendrochronological records for Europe and the Aegean, and the International Tree Ring Database has contributions from 21 different countries.
Cross-dating of sites, comparing geologic strata at one site with another location and extrapolating the relative ages in that manner, is still an important dating strategy used today, primarily when sites are far too old for absolute dates to have much meaning.Clark Wissler, an anthropologist researching Native American groups in the Southwest, recognized the potential for such dating, and brought Douglass subfossil wood from puebloan ruins.