Radio carbon dating errors
Modern accelerator mass spectrometry (used for radiocarbon dating purposes to separate radiocarbon atoms from stable carbon atoms and count them) is quite precise.The technology involved is fascinating and impressive.A copy of this paper may be found in the Radiocarbon Home Page The radiocarbon age of a sample is obtained by measurement of the residual radioactivity. T (National Institute of Standards and Technology; Gaithersburg, Maryland, USA) Oxalic Acid I (C). The activity of 1890 wood is corrected for radioactive decay to 1950.This is calculated through careful measurement of the residual activity (per gram C) remaining in a sample whose age is Unknown, compared with the activity present in Modern and Background samples. Thus 1950, is year 0 BP by convention in radiocarbon dating and is deemed to be the 'present'.You can get an idea of the relationship between C14 and age at the Carbon Dating calculator page. 1950 was chosen for no particular reason other than to honour the publication of the first radiocarbon dates calculated in December 1949 (Taylor, 19). Ninety-five percent of the activity of Oxalic Acid from the year 1950 is equal to the measured activity of the absolute radiocarbon standard which is 1890 wood.Modern radiocarbon dating uses tree-ring chronologies to produce the calibration curve.Because the radiocarbon to stable carbon ratio in the atmosphere has fluctuated over time, there are "wiggles" in the calibration curve.
(For a good example of the role radiocarbon plays in biblical chronology see Is Bryant Wood's chronology of Jericho valid? Once such large-scale errors have been eliminated the precision of biblical chronology rivals that of dendrochronology. Radiocarbon is not generally useful for narrowing the range of such biblical chronology dates further because radiocarbon tends to have poorer precision than biblical chronology.Thus it is possible in some instances for two samples from a few decades apart to have the same radiocarbon concentration today, and hence the same apparent radiocarbon age.This happens whenever there is a wiggle in the curve at the time the samples died.The ratio of the activity of sucrose with 0.95 Ox was first measured by Polach at 1.50070.0052 (Polach, 1976b:122).Later inter-laboratory measurements put the ratio at 1.5081 (Currie and Polach, 1980).According to Stuiver and Polach (1977), all laboratories should report their results either directly related to NBS Oxalic acid or indirectly using a sub-standard which is related to it.It is vital for a radiocarbon laboratory to know the contribution to routine sample activity of non-sample radioactivity.This, in fact, is the most significant factor contributing to loss of precision in radiocarbon dates today.However, this contribution is usually only a few decades.For example, modern biblical chronology dates Noah's Flood to 3520 /- 21 B. Much of the information presented in this section is based upon the Stuiver and Polach (1977) paper "Discussion: Reporting of C14 data". 1890 wood was chosen as the radiocarbon standard because it was growing prior to the fossil fuel effects of the industrial revolution.