The game of radiocarbon dating and calibration
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Date
2011-03-14
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Publisher
Australian Nuclear Science and Technology Organisation
Abstract
Archaeologists and geoscientists rely on continuous improvement in radioisotopic chronological techniques to generate accurate and reliable calibration curves by which measured data can be converted into an absolute age scale.
Various archives are included in providing radiocarbon data sets for calibration – tree rings,
corals, marine and lake sediments, and possibly some speleothems. This has generated
a number of calibration curves and statistical age-depth models. The IntCal Radiocarbon
Working Group recently released a terrestrial and marine radiocarbon calibration curve
(IntCal09 and Marine09) from 0 to 50 ka which effectively spans the full sensitivity of the
AMS method.
However all archives other than tree rings (0-12 ka of calibration curve) do not reflect
contemporary atmospheric 14C content. Dissolved inorganic 14C in corals and forams varies
with CO2 exchange at the atmospheric-ocean interface and admixture of 14C depleted
carbon from deep upwelling waters. Total 14C in speleothems depends on the admixture
of 14C depleted CO2 from soil and/or rock carbonate. Hence a dead-carbon fraction
or reservoir correction (modelled or otherwise) must be included to convert measured
radiocarbon to atmospheric equivalent prior to inclusion into a universal calibration curve.
These complexities, the different calibration curves and web-based program will be discussed and presented.
Description
Keywords
Carbon 14, Calibration, Archaeology, Age estimation, Records management, Historical aspects, Datasets, Tree rings
Citation
Hua, Q. (2011). The game of radiocarbon dating and calibration. Paper presented at the Italian - Australian Archaeology and Cultural Heritage Workshop. New scientific techniques in archaeology, palaeo-anthropology and cultural heritage, 14-17 March 2011, Rydges Hotel, Cronulla, Sydney.