Radiocarbon dating history
Historical documents and calendars can be used to find such absolute dates; however, when working in a site without such documents, it is hard for absolute dates to be determined.As long as there is organic material present, radiocarbon dating is a universal dating technique that can be applied anywhere in the world.One good example would be the elevated levels of Carbon-14 in our atmosphere since WWII as a result of atomic bombs testing.
In 1949, American chemist Willard Libby, who worked on the development of the atomic bomb, published the first set of radiocarbon dates.
The numbers refer to the atomic weight, so Carbon-12 has 6 protons and 6 neutrons, Carbon-13 has 6 protons and 7 neutrons, and Carbon-14 has 6 protons and 8 neutrons.
The extra neutrons in Carbon-14’s case make it radioactive (thus the term, radiocarbon).
Plants are not the only organism that can process Carbon-14 from the air.
Plankton absorbs, Carbon-14 from the ocean much like terrestrial plants absorb Carbon-14 from the air.
More recently is the radiocarbon date of 1950 AD or before present, BP.