Radiocarbon dating charcoal
31 ka BP, and no evidence that these samples are associated with numerous midden shell dates at 34-37 ka BP.Samples used for radiocarbon dating must be handled carefully to avoid contamination.
While all pre-treatments are useful for routine sample processing, the results suggest that ABOX is the only technique that can provide reliable decontamination of charcoal of an age close to the dating limit of the radiocarbon dating technique.
Thus, Hy Py has confirms that there was no significant bias in the charcoal radiocarbon ages from more recent sedimentary organic matter.
A new analysis of previous results on conflicts between shell and charcoal dates and on burnt human bones, with new data presented here, suggests that alternative interpretations are possible for the archaeology and environmental history of the Willandra Lakes region.
The performance of ABOX was superior to that of both acid–base–acid (ABA) and hydrogen pyrolysis (hypy) treatments, with ABA performing better than hypy in most cases.
No technique was able to fully remove decontamination from the 300 °C charcoal (although ABOX again removed the most contamination), likely due to the incompletely pyrolized nature of the charcoal which is dominated by aromatic clusters of small ring size.
Degradation of the protein fraction can also occur in hot, arid conditions, without actual burning; then the degraded components can be washed away by groundwater.