Understanding carbon dating
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).Very old trees such as North American Bristlecone Pine are ideal for constructing long and accurate records of the state of the atmosphere.Radiocarbon dating is simply a measure of the level of C isotopes in the atmosphere can vary.This is why calibration against objects whose age is known is required (14).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”.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.
As a test, the team took samples of acacia wood from two Egyptian Pharaohs and dated them; the results came back to within what was then a reasonable range: 2800BC /- 250 years whereas the earlier independent dates (largely the dendrochronology records) were 2625 /- 75 years (3), (5).
Stone and metal cannot be dated but pottery may be dated through surviving residue such as food particles or paint that uses organic material (8).
There are a number of ways to enter into a career in studying radiocarbon dating.
This allows researchers to account for variation by comparing the known records of C levels in the tree record, looking for a tree record that has the same proportion of radiocarbon.
The overlapping nature of the tree records means this is the most accurate record we have.