American Chemical Society National Historic Chemical Landmarks.
Discovery of Radiocarbon Dating (accessed October 31, 2017). Sheridan Bowman, Radiocarbon Dating: Interpreting the Past (1990), University of California Press Accelerator Mass Spectrometry Radiocarbon Dating Calibration of Carbon 14 Dating Results Radiocarbon Dating and Bomb Carbon About AMS Dating Accelerator Mass Spectrometry (AMS) dating involves accelerating ions to extraordinarily high kinetic energies followed by mass analysis.
A radiocarbon measurement is termed a conventional radiocarbon age (CRA).
The CRA conventions include (a) usage of the Libby half-life, (b) usage of Oxalic Acid I or II or any appropriate secondary standard as the modern radiocarbon standard, (c) correction for sample isotopic fractionation to a normalized or base value of -25.0 per mille relative to the ratio of carbon 12/carbon 13 in the carbonate standard VPDB – Cretaceous belemnite formation at Peedee in South Carolina, (d) zero BP (Before Present) is defined as AD 1950, and (e) the assumption that global radiocarbon levels are constant.
Radiocarbon Dating Groundwater The application of radiocarbon dating to groundwater analysis can offer a technique to predict the over-pumping of the aquifer before it becomes contaminated or overexploited.
Radiocarbon, or carbon 14, is an isotope of the element carbon that is unstable and weakly radioactive. Carbon 14 is continually being formed in the upper atmosphere by the effect of cosmic ray neutrons on nitrogen 14 atoms.
It is rapidly oxidized in air to form carbon dioxide and enters the global carbon cycle.
Plants and animals assimilate carbon 14 from carbon dioxide throughout their lifetimes.
Background radiocarbon activity is measured, and the values obtained are deducted from the sample’s radiocarbon dating results.
Background samples analyzed are usually geological in origin of infinite age such as coal, lignite, and limestone.