Theory behind radiocarbon dating
Radiocarbon dating may only be used on organic materials.
Typically (6): The above list is not exhaustive; most organic material is suitable so long as it is of sufficient age and has not mineralised - dinosaur bones are out as they no longer have any carbon left.
It also has some applications in geology; its importance in dating organic materials cannot be underestimated enough.
In 1979, Desmond Clark said of the method “we would still be foundering in a sea of imprecisions sometime bred of inspired guesswork but more often of imaginative speculation” (3).
AMS counts the quantity of C isotope is constantly formed in the upper atmosphere thanks to the effects of cosmic rays on nitrogen-14 atoms.
It is oxidised quickly and absorbed in great quantities by all living organisms - animal and plant, land and ocean dwelling alike.
This does not mean that we have a precise year of 3780BC, it means we then need to calibrate through other methods that will show us how atmospheric concentrations of the C isotope has changed - most typically through the dendrochronology records (tree ring data) (10).
The overlapping nature of the tree records means this is the most accurate record we have.When the half-life was corrected in 1950, the year was taken as a base date from which to calculate all resulting dates.Therefore, any expression of “before present” will mean “before 1950”.This new method was based on gas and liquid scintillation counting and these methods are still used today, having been demonstrated as more accurate than Libby's original method (3).Willard Libby would receive a Nobel Prize for Chemistry in 1960.