Sources of error in radiocarbon dating
It causes ages to be over-assessed and arises when the material to be dated, such as mollusc shell or plant, synthesizes its skeleton under water and so uses bicarbonate derived in part from old, inert sources.
It is usually stated that the maximum possible error is equivalent to the half-life of C, 5,570 yr (Libby scale), but it rarely amounts to as much as this.
"The lower leg lower leg of the Fairbanks Creek mammoth had a radiocarbon age of 15,380 RCY, while its skin and flesh were 21,300 RCY." (Natural History 1949) 'Living mollusk shell were carbon dated as being 2,300 years old.' (Science 1963) 'A freshly killed seal was carbon dated as having died 1,300 years ago' (Antarctic Journal 1971) "One part of Dima (a baby frozen mammoth) was 40,000, another part was 26,000 and the 'wood immediately around the carcass' was 9-10,000." (Geological Survey Professional Paper 862 1975) 'Shells from living snails were carbon dated as being 27,000 years old.' (Science 1984) "The two Colorado Creek, AK mammoths had radiocarbon ages of 22,850 ±670 and 16,150 ±230 years respectively." (Quaternary Research 1992) "One part of the Vollosovitch mammoth carbon dated at 29,500 years old and another part at 44,000." (Geological Survey Professional Paper 862 1975) And one of my favorite extracts.The method was developed immediately following World War II by Willard F.Libby and coworkers and has provided age determinations in archeology, geology, geophysics, and other branches of science."No matter how 'useful' it is, though, the radiocarbon method is still not capable of yielding accurate and reliable results.There are gross discrepancies, the chronology is uneven and relative, and the accepted dates are actually selected dates.