Scientific dating methods archaeology taiwandating
The main drawback to dendrochronology is its reliance on the existence of relatively long-lived vegetation with annual growth rings.Secondly, annual rainfall is a regional climatic event, and so tree ring dates for the southwest are of no use in other regions of the world.For example, JJA Worsaae used this law to prove the Three Age System.For more information on stratigraphy and how it is used in archaeology, see the Stratigraphy glossary entry.Stratigraphy is the oldest of the relative dating methods that archaeologists use to date things.Stratigraphy is based on the law of superposition--like a layer cake, the lowest layers must have been formed first.Using local pine trees, Douglass built a 450 year record of the tree ring variability.
There are dendrochronological records for Europe and the Aegean, and the International Tree Ring Database has contributions from 21 different countries.
Douglass believed that solar flares affected climate, and hence the amount of growth a tree might gain in a given year.
His research culminated in proving that tree ring width varies with annual rainfall.
It was now possible to assign a calendar date to archaeological sites in the American southwest for over 1000 years.
Determining calendar rates using dendrochronology is a matter of matching known patterns of light and dark rings to those recorded by Douglass and his successors.
Search for scientific dating methods archaeology:
Unfortunately, the wood from the pueblos did not fit into Douglass's record, and over the next 12 years, they searched in vain for a connecting ring pattern, building a second prehistoric sequence of 585 years.