SYNONYMS OR RELATED TERMS: chronometric dating; absolute dates; absolute chronology; absolute age determination (antonym: relative dating)CATEGORY: chronology; technique DEFINITION: The determination of age with reference to a specific time scale, such as a fixed calendrical system or in years before present (B.
P., BP), based on measurable physical and chemical qualities or historical associations such as coins and written records.
Today, many different radioactive elements have been used, but the most famous absolute dating method is radiocarbon dating, which uses the isotope C.
This isotope, which can be found in organic materials and can be used only to date organic materials, has been incorrectly used by many to make dating assumptions for non-organic material such as stone buildings.
It does not, however, allow one to independently assign an accurate estimation of the age of an object as expressed in years.
The most common relative dating method is stratigraphy.
Two broad categories of dating or chronometric techniques that archaeologists use are called relative and absolute dating.
Stratigraphy is the oldest of the relative dating methods that archaeologists use to date things.
This also works with stone tools which are found abundantly at different sites and across long periods of time.
The absolute dating method first appeared in 1907 with Lord Rutherford and Professor Boltwood at Yale University, but wasn’t accepted until the 1950s.
The first method was based on radioactive elements whose property of decay occurs at a constant rate, known as the half-life of the isotope.
Stratigraphic dating is based on the principle of depositional superposition of layers of sediments called strata.
This principle presumes that the oldest layer of a stratigraphic sequence will be on the bottom and the most recent, or youngest, will be on the top.