Some quotes on radiocarbon dating:
"It is self evident that a contaminated sample will give an erroneous date, but it is frequently impossible to ascertain if a sample has indeed been contaminated."
R.S. Bradley, Quaternary Paleoeclimatology, London, Boston: Allen and Unwin, 1985, p. 54
"Relative ages are always subject to interpretation, and radiocarbon dates are often ignored or dismissed as a "bad date" if they do not fit an a priori hypothesis."
T.A. Thompson, G.S.Fraser and G. Olyphant, Establishing the altitude and age of past lake levels in the Great Lakes, Geological Society of America Abstracts with Programs 1988, 20(5) p. 392
"In the light what is known about the radiocarbon method and the way it is used, it is truly astonishing that many authors will cite agreeable determinations as a "proof" for their beliefs. The implications of pervasive contamination and ancient variations in carbon-14 levels are steadfastly ignored by those who based their argument upon the dates. 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. This whole blessed thing is nothing but 13th-century alchemy, and it all depends upon which funny paper you read."
Robert E. Lee, Radiocarbon: Ages in Error, Anthropological Journal of Canada, Vol 19, No 4 (1981) pp. 9-29
"C-14 dating was being discussed at a symposium on the prehistory of the Nile Valley. A famous American colleague,
professor Brew, briefly summarized a common attitude among archaeologists towards it as follows: "If a C 14 date supports our theories, we put it in the main text. If it does not entirely contradict them, we put it in a footnote. And if it is completely out of date, we just drop it. Few archaelogists who have concerned themselves with absolute chronology are innocent of having sometimes applied this method, and many are still hesitant to accept C 14 dates without reservation."
T. Säve-Söderbergh and Ingrid U. Olsson, C14 Dating and Egyptian Chronology, in Ingrid U. Olsson (ed.) Proceedings of the Twelfth Nobel Symposium. New York: John Wiley & Sons, Inc and Stockholm: Almqvist & Wiksell, 1970
"The Carbon-14 contents of the shells of the snails of Melanoides tuberculatus living today in artesian springs in
southern Nevada indicate an apparent age of 27,000 years."
Alan C. Riggs, Science, vol 224 (1984) 58-61
http://www.setterfield.org/RadiometricDating.htm
Now here is the big question, if radiometric dating requires so many assumption, why is it taken as fact?