Wiki carbon dating
The New Zealand curve is representative for the Southern Hemisphere, the Austrian curve is representative for the Northern Hemisphere. This makes it possible to tell the age of substances that contain carbon. Dates obtained are usually written as before present ('present' is 1950).
The relatively short-lived C taken into organic matter is also slightly variable. However, under about 20,000 years the results can be compared with dendrochronology, based on tree rings.
For the most accurate work, variations are compensated by means of calibration curves.
The method was developed by Willard Libby and his colleagues at the University of Chicago in 1949.
If one was done in the middle of the ocean...unless it was reported..would never even know. These element podcasts connect A LOT of info to their 8th grade brains.
I have been a faithful fan of Radiolab for past 5 years.
The atomic weight represents the number of protons and neutrons that makeup an atom.