@Quehoniaomath,
"all dating is tentative..."
That's total bs because every year new data re: selective C14 uptake from old calcite deposists is cautionary. When that error was made, there were several additional (duplicate) groups of samples to provide the statistical ranges . And when these stat ranges appeared out of range, the article reported the concern by itself.
certain gastropods do take up old carbonate minerals and convert it to C14 depleted ragonite.
OTHER gastropods DO NOT and all ostracods do not. Rther than being a "n embarrassing discovery s the ldy suggests" science hs celebrated the QA procedures such a result hs prompted.
This goes entirely to the field of C14 dating by using CArbonate minerals which ws a new technique in the early 80's
THIS IS 2014 and , just as the original methods of sample "cleanup" hve been codified, so have Carbonate carbon dating methods.
Its an accusation with no problem.
Hres a paper on the methodology
Quote:
Pigati, J. S., Quade, J., Shanahan, T. M., and Haynes, C. V. 2003. Radiocarbon dating of minute gastropods and new constraints on the timing of late Quaternary spring discharge deposits in southern Arizona. Palaeogeography, Palaeoclimatology, and Palaeoecology v. 3244, p. 1-13.