Collagen survives long after death and the collagen content of a bone, measured by the amount of nitrogen present, yields information as to its relative date.
In areas where variations in the Earth's magnetic field are known it is possible to date a pottery sample on a curve.
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.
The test is used mainly in association with the fluorine test and radiometric assay, as in the cases of Piltdown and Swanscombe Man. The basis of cross-dating is the occurrence of finds in association.
The assumption is that a particular type of artifact, for example a type of sword, when found in an undated context will bear a similar date to one found in a dated context, thus enabling the whole of the undated context to be given a chronological value.
It is fairly reliable for deep-sea sediments as the temperature is generally more stable.