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Radiocarbon dating curve
Careful sample preparation by Strata Data is matched by the world class analysis by Beta Analytic Inc.
Non-marine as well as marine and terrestrial sediments can be dated using this method.
Each sample is prepared in the same way as for a micropalaeontological analysis.
Suitable specimens are selected by picking through the residue.
Price depends on the nature of the material and turnaround time required; the basic price for analysis with a turnaround time of less than 3 weeks is £395 plus the cost of sample preparation. C ratio therefore remains in equilibrium with the atmosphere.
However, upon death there is no further uptake of carbon and the 14C decays to 12N with a half life of 5730 years.
Measurement of the amount of C remaining in a dead organism will therefore give the date of its death.Using this method, the maximum detectable age is no greater than 50,000 years and over 40,000 years dates are unreliable.In addition, material from the last 300 years gives unreliable ages, mainly due to the widespread burning of fossil fuels and more recently the explosion of nuclear bombs, both of which have artificially increased the amount of C in the atmosphere.Thus, it is not possible to accurately date organisms which have died since 1950.Because of the small size of most industrial samples the Accerator Mass Spectrometry (AMS) method is used.This method can be used to radiocarbon date one milligram of carbon or less and has the added advantage that the small sample size permits more selective sampling.Suitable material includes molluscs, microfossils and wood from terrestrial, non-marine and marine environments.C dating have traditionally been quoted in “conventional radiocarbon years”, typically in years BP (before present) where the “present” is 1950.The initial assumption that the concentration of atmospheric C has been constant as measured in 1950 has been shown to be incorrect.Dating annual tree growth rings of known historical age has demonstrated that in the past there have been short term variations in atmospheric C levels.Tree ring dating has been used to construct a probabilistic calibration curve extending back to 11857 calendar years BP (see figure below).