Carbon-14 Method of Dating
Radiocarbon dating techniques was first developed by the american chemist willard F. Libby and his associates at the University of Chicago in 1947. This techniques are frequently useful in deciphering time-related problems in anthropology, pedology, oceanology, archeology, climatology and geology, etc.

Through metabolic activity, the level of carbon-14 in a living organism remains in constant balance with the level in the atmosphere or some other portion of the earth's dynamic reservoir, such as the ocean. upon the dead organism carbon-14 begins to disintegrate at a known rate, and no further replacement of carbon from atmospheric carbon dioxide can take place. The rapid disintegration of carbon-14 generally limits the dating period to approximately 50,000 years, although the method is sometimes extended to 70,000 years. Uncertainty in measurement increases with the age of the sample.

Although the method is suited to a variety of organic materials, accuracy depends on the half-life to be used, variations in levels of atmospheric carbon-14, and contamination. The half-life of radiocarbon was redefined in 1962, so some dates determined earlier required adjustment; and due to radioactivity more recently introduced into the atmosphere, radiocarbon dates are calculated from 1950AD. The radiocarbon time scale contains other uncertainties, as well, and errors as great as 2000 to 5000 years may occur. Postdepositional contamination, which is the most serious problem, may be caused by incorporation of older or younger carbon,percolating groundwater and contamination in the field or laboratory.