History of carbon dating
History of carbon dating - Free hookup websutes
The C14 technique has been and continues to be applied and used in many, many different fields including hydrology, atmospheric science, oceanography, geology, palaeoclimatology, archaeology and biomedicine.There are three principal isotopes of carbon which occur naturally - C12, C13 (both stable) and C14 (unstable or radioactive).
Writing of the European Upper Palaeolithic, Movius (1960) concluded that "time alone is the lens that can throw it into focus".Nyerup's words illustrate poignantly the critical power and importance of dating; to order time.Radiocarbon dating has been one of the most significant discoveries in 20th century science.The radiocarbon method was developed by a team of scientists led by the late Professor Willard F.Libby of the University of Chicago in immediate post-WW2 years.Libby and his team intially tested the radiocarbon method on samples from prehistoric Egypt.
They chose samples whose age could be independently determined.
By measuring the C14 concentration or residual radioactivity of a sample whose age is not known, it is possible to obtain the countrate or number of decay events per gram of Carbon.
By comparing this with modern levels of activity (1890 wood corrected for decay to 1950 AD) and using the measured half-life it becomes possible to calculate a date for the death of the sample.
Renfrew (1973) called it 'the radiocarbon revolution' in describing its impact upon the human sciences.
Oakley (1979) suggested its development meant an almost complete re-writing of the evolution and cultural emergence of the human species.
The half-life () is the name given to this value which Libby measured at 556830 years. After 10 half-lives, there is a very small amount of radioactive carbon present in a sample.