On radiocarbon dating
Thus, one carbon 14 atom exists in nature for every 1,000,000,000,000 C12 atoms in living material.
The radiocarbon method is based on the rate of decay of the radioactive or unstable carbon isotope 14 (14C), which is formed in the upper atmosphere through the effect of cosmic ray neutrons upon nitrogen 14.
There are three principal isotopes of carbon which occur naturally - C12, C13 (both stable) and C14 (unstable or radioactive).
These isotopes are present in the following amounts C12 - 98.89%, C13 - 1.11% and C14 - 0.00000000010%.
For radiocarbon dating to be possible, the material must once have been part of a living organism.
This means that things like stone, metal and pottery cannot usually be directly dated by this means unless there is some organic material embedded or left as a residue.
Plants and animals which utilise carbon in biological foodchains take up 14C during their lifetimes.
In general it is always better to date a properly identified single entity (such as a cereal grain or an identified bone) rather than a mixture of unidentified organic remains.Writing of the European Upper Palaeolithic, Movius (1960) concluded that "time alone is the lens that can throw it into focus".The radiocarbon method was developed by a team of scientists led by the late Professor Willard F.The rapidity of the dispersal of C14 into the atmosphere has been demonstrated by measurements of radioactive carbon produced from thermonuclear bomb testing.14C also enters the Earth's oceans in an atmospheric exchange and as dissolved carbonate (the entire 14C inventory is termed the carbon exchange reservoir (Aitken, 1990)).