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A form of radiometric dating used to determine the age of organic remains in ancient objects, such as archaeological specimens, on the basis of the half-life of carbon-14 and a comparison between the ratio of carbon-12 to carbon-14 in a sample of the remains to the known ratio in living organisms. A technique for measuring the age of organic remains based on the rate of decay of carbon 14.
Residues dated from an archaeological context showed promising results while emphasizing the crucial impact of contamination for age offsets.
Two adhesive residues from one stone tool, which yielded 33.30 μg C and 44.38 μg C, were dated within the expected Late Holocene time frame.
While radiocarbon dating of blood residues had been previously reported, dating accuracy required further substantiation.
Compromising effects had been described, however the real impact of contamination during sampling steps and analysis protocols remained unclear.
Wooden residues from a Mesolithic stone tool, containing 18.97 μg C, were dated successfully, and although deviating ~ 1000 years from the stratigraphical age measurement, the date may still represent the authentic age if taphonomic processes caused tool movement.
For the first time it has been shown that the measurement of residues with such small carbon masses yielded dates in or near agreement to the reference age.
When isotopes are to be designated specifically, the chemical symbol is expanded to identify the mass (for example, C is not stable.
Ninety-nine percent of these also contain six neutrons.
The 6 proton 6 neutron atoms are said to have a mass of 12 and are referred to as "carbon-12." The nuclei of the remaining one percent of carbon atoms contain not six but either seven or eight neutrons in addition to the standard six protons.
The rate at which C atoms, half of them will decay in 5730 years.
Since this rate is slow relative to the movement of carbon through food chains (from plants to animals to bacteria) all carbon in biomass at earth's surface contains atmospheric levels of C is present at atmospheric levels, the molecule must derive from a recent plant product.