Archaeomagnetic dating limitations
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.
Additional complications come from the burning of fossil fuels such as coal and oil, and from the above-ground nuclear tests done in the 1950s and 1960s.Two examples of dating of archaeological structures, medieval and pre-Roman, are presented based on the new SV curve for the UK and the implications for archaeomagnetic dating are discussed.It has long been acknowledged that an archaeomagnetic date is only as reliable as the calibration curve from which it is derived.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.
Particular emphasis is placed on archaeomagnetic dating procedures in Britain.
A different approach to calibration is proposed which draws on recent advances in this subject in the USA, in particular the use of a weighted moving window method of averaging, leading to a secular variation curve with an associated error estimate.
It comprises 620 archaeomagnetic (directional) data and 238 direct observations of the geomagnetic field, and includes all relevant information available about the site, the archaeomagnetic direction and the archaeological age.
A thorough examination of the data was performed to assess their quality and reliability.
However, until recently, objective approaches to the construction of regional calibration curves have been restricted by lack of data.