Archaeology prehistoric dating methods
Stratigraphy is based on the law of superposition--like a layer cake, the lowest layers must have been formed first.
Oxford has helped pioneer many of the scientific dating methods used today and still has significant active research into Radiocarbon, Luminescence and Tephrochronology.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.Each tree then, contains a record of rainfall for the length of its life, expressed in density, trace element content, stable isotope composition, and intra-annual growth ring width.The basis for stratigraphy seems quite intuitive today, but its applications were no less than earth-shattering to archaeological theory.For example, JJA Worsaae used this law to prove the Three Age System.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.
Without those, the archaeologists were in the dark as to the age of various societies. The use of tree ring data to determine chronological dates, dendrochronology, was first developed in the American southwest by astronomer Andrew Ellicott Douglass.
In 1901, Douglass began investigating tree ring growth as an indicator of solar cycles.
In addition to the department's own research, we host the national NERC (National Environment Research Council) facility for radiocarbon dating archaeological material, and provide facilities for dating by radiocarbon, luminescence and tephra correlation for a broad range of researchers.
These facilities are the catalyst for research collaborations with many other institutions.
This research is focussed both on methodological advances and on a whole range of applications of chronological research to archaeological questions, from the replacement of Neanderthals by modern humans to the precise placement of the Egyptian historical chronology.