Nitrogen dating archaeology
Luckily, we can measure these fluctuations in samples that are dated by other methods.Tree rings can be counted and their radiocarbon content measured.
Australia has two machines dedicated to radiocarbon analysis, and they are out of reach for much of the developing world.From these records a “calibration curve” can be built (see figure 2, below).A huge amount of work is currently underway to extend and improve the calibration curve.These new techniques can have a dramatic effect on chronologies.
With the development of a new method of cleaning charcoal called ABOx-SC, Michael Bird helped to push back the date of arrival of the first humans in Australia by more than 10,000 years.
The calibrated date is also presented, either in BC or AD or with the unit cal BP (calibrated before present - before 1950).