Cal bp radiocarbon dating
There is a small difference in the natural atmospheric C levels in the southern troposphere are therefore usually lower than those in the northern troposphere, and the radiocarbon ages of terrestrial materials in the Southern Hemisphere for a particular period of time are usually older than those in the Northern Hemisphere.
Alternatively, one can use the current internationally-ratified marine calibration curve Marine04 (Fig.
Beyond that, back to about 45,000 BP, correlation is made using multiple lines of evidence.
This information is compiled into internationally accepted databases which are updated on occasion.
These likelihoods are graphically represented by a shaded grey area on the plot (higher peaks being higher probability) and by percentage values reported next to each range.
The method is called the high-probability density (HPD) range method.
This more liberal approach to interpreting radiocarbon ages applies only to one single radiocarbon age measured.