The efficiency of charcoal decontamination for radiocarbon dating by three pre-treatments – ABOX, ABA and hypy

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dc.contributor.authorBird, MIen_AU
dc.contributor.authorLevchenko, VAen_AU
dc.contributor.authorAscough, PLen_AU
dc.contributor.authorMeredith, Wen_AU
dc.contributor.authorWurster, CMen_AU
dc.contributor.authorWilliams, AGen_AU
dc.contributor.authorTilston, ELen_AU
dc.contributor.authorSnape, CEen_AU
dc.contributor.authorApperley, DCen_AU
dc.date.accessioned2016-06-17T06:35:26Zen_AU
dc.date.available2016-06-17T06:35:26Zen_AU
dc.date.issued2014-08-01en_AU
dc.date.statistics2016-06-17en_AU
dc.description.abstractHere we report results of a direct inter-comparison of the ability of three radiocarbon pre-treatment techniques to remove radiocarbon contamination introduced by exposing known-radiocarbon-free charcoal made at three different temperatures (300, 400 and 500 °C) to environmental contamination on a rainforest floor for one to three years. The initial charcoal had no measureable radiocarbon, but 14C activity increased after environmental exposure to ∼1 pMC after one year (apparent age of ∼40,000 yrs BP) and ∼5 pMC after three years (apparent age of ∼25,000 years). For the 400 and 500 °C samples, all techniques were able to reduce contamination by >90%. Acid–base oxidation (ABOX) provided the most reliable decontamination, reducing the radiocarbon activity of the one year samples to background, and reducing the radiocarbon activity of the three year samples to 0.04 ± 0.02 pMC or less (apparent age >56,900 yrs BP). 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. All the techniques rely on removing contaminant carbon faster than indigenous carbon and this condition is not met in the case of charcoal produced at temperatures below ∼350 °C. 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.© 2014, Elsevier B.V.en_AU
dc.identifier.citationBird, M. I., Levchenko, V. A., Ascough, P. L., Meredith, W., Wurster, C. M., Williams, A., Tilston, E. L., Snape, C. E. & Apperley, D. C. (2014). The efficiency of charcoal decontamination for radiocarbon dating by three pre-treatments – ABOX, ABA and hypy. Quaternary Geochronology, 22, 25-32. doi:10.1016/j.quageo.2014.02.003en_AU
dc.identifier.govdoc6705en_AU
dc.identifier.issn1871-1014en_AU
dc.identifier.journaltitleQuaternary Geochronologyen_AU
dc.identifier.pagination25-32en_AU
dc.identifier.urihttp://dx.doi.org/10.1016/j.quageo.2014.02.003en_AU
dc.identifier.urihttp://apo.ansto.gov.au/dspace/handle/10238/7019en_AU
dc.identifier.volume22en_AU
dc.language.isoenen_AU
dc.publisherElsevieren_AU
dc.subjectIsotope datingen_AU
dc.subjectCharcoalen_AU
dc.subjectEnvironmenten_AU
dc.subjectHydrogen peroxideen_AU
dc.subjectOxidationen_AU
dc.subjectDecontaminationen_AU
dc.titleThe efficiency of charcoal decontamination for radiocarbon dating by three pre-treatments – ABOX, ABA and hypyen_AU
dc.typeJournal Articleen_AU
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