Hostname: page-component-669899f699-cf6xr Total loading time: 0 Render date: 2025-04-25T12:29:02.220Z Has data issue: false hasContentIssue false
  • English
  • Français

Radiocarbon Dating of “Old” Charcoal Using a Wet Oxidation, Stepped-Combustion Procedure

Published online by Cambridge University Press:  18 July 2016

M I Bird ,
L K Ayliffe ,
L K Fifield ,
C S M Turney ,
R G Cresswell ,
T T Barrows  and
B David
M I Bird
Affiliation:
Research School of Earth Sciences, Australian National University, Canberra A.C.T. 0200, Australia
L K Ayliffe
Affiliation:
Research School of Earth Sciences, Australian National University, Canberra A.C.T. 0200, Australia
L K Fifield
Affiliation:
Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra A.C.T. 0200, Australia
C S M Turney
Affiliation:
Research School of Earth Sciences, Australian National University, Canberra A.C.T. 0200, Australia
R G Cresswell
Affiliation:
Department of Nuclear Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra A.C.T. 0200, Australia
T T Barrows
Affiliation:
Research School of Earth Sciences, Australian National University, Canberra A.C.T. 0200, Australia
B David
Affiliation:
Geography and Environmental Science, Monash University, Clayton, Victoria, 3168 Australia
Rights & Permissions [Opens in a new window]

Abstract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

We present results that validate a new wet oxidation, stepped-combustion procedure for dating “old” charcoal samples. An acid–base–wet oxidation (ABOX) pretreatment procedure has been developed that is used in place of the conventional acid-base-acid (ABA) pretreatment. Combustions and graphitizations are performed in a vacuum line that is insulated from the atmosphere by a second backing vacuum to eliminate the risk of atmospheric leakage into the line at any stage of the procedure. Combustions are performed at 3 temperatures (330 °, 630 ° and 850 °) with a graphite target produced from the CO2 evolved during each combustion step. In this way, the removal of any contamination can be monitored, and a high degree of confidence can be placed on the final age. The pretreatment, combustion, graphitization, and measurement blank for the procedure, based on the analysis of a “radiocarbon-dead” graphite, is 0.5 ± 0.5 μg C (1σ, n=14), equivalent to 0.04 ± 0.02 pMC or an “age” of approximately 60 ka for a 1 mg graphite target. Analyses of a “radiocarbon-dead” natural charcoal after ABOX pretreatment and stepped combustion suggest that the total blank (including contamination not removed by pretreatment) may be higher than for graphite, ranging up to 0.10 ± 0.02 pMC. Additional experiments confirm good agreement with accepted values for the international low-14C “New Kauri” standard (0.16–0.25 pMC). They also confirm excellent reproducibility, with 3 separate dates on different aliquots of a charcoal sample from Ngarrabullgan Cave (Queensland, Australia) ranging from 35.2 to 35.5 ka 14C BP. It is also demonstrated that the ABOX pretreatment, in conjunction with the new vacuum line described here, is able to remove contamination not removed by the conventional ABA pretreatment, suggesting that the technique can be used to produce reliable 14C dates on charcoal up to at least 50 ka.

Type
Articles
Information
Radiocarbon , Volume 41 , Issue 2 , 1999 , pp. 127 - 140
Copyright
Copyright © The American Journal of Science 

References

Allen, J, Holdaway, S. 1995. The contamination of Pleistocene radiocarbon determinations in Australia. Antiquity 69:101–12.Google Scholar
Bird, MI, Gröcke, DR. 1997. Determination of the abundance and carbon isotope composition of elemental carbon in sediments. Geochimica et Cosmochimica Acta 61:3413–23.CrossRefGoogle Scholar
Cachier, H, Bremond, MP, Buat-Menard, P. 1989. Determination of atmospheric soot carbon with a simple thermal method. Tellus 41B:379–90.Google Scholar
Chappell, J, Head, J, Magee, J. 1996. Beyond the radiocarbon limit in Australian archaeology and Quaternary research. Antiquity 70:543–52.Google Scholar
David, B, Roberts, R, Tuniz, C, Jones, R, Head, J. 1997. New optical and radiocarbon dates from Ngarrabullgan Cave, a Pleistocene archaeological site in Australia: implications for the comparability of time clocks and for the human colonization of Australia. Antiquity 71:183–8.Google Scholar
Gagnon, AR, Jones, GA. 1993. AMS-graphite target production methods at the Woods Hole Oceanographic Institution during 1986–1991. Radiocarbon 35(2): 301–10.Google Scholar
Gillespie, R. 1997. Burnt and unburnt carbon: dating charcoal and burnt bone from the Willandra Lakes, Australia. Radiocarbon 39(3):225–36.CrossRefGoogle Scholar
Gillespie, R, Hammond, AP, Goh, KM, Tonkin, PJ, Lowe, DC, Sparks, RJ, Wallace, G. 1992. AMS radiocarbon dating of a Late Quaternary tephra site at Graham's Terrace, New Zealand. Radiocarbon 34(1):21–8.CrossRefGoogle Scholar
Hogg, AG, Higham, T, Robertson, S, Beukens, R, Kankainen, T, McCormack, FG, van der Plicht, J, Stuiver, M. 1995. Radiocarbon age assessment of a new, near-background IAEA 14C quality assurance material. Radiocarbon 37(2):797–803.CrossRefGoogle Scholar
Kitagawa, H, Masuzawa, T, Makamura, T, Matsumoto, E. 1993. A batch preparation method for graphite targets with low background for AMS 14C measurements. Radiocarbon 35(2):295–300.CrossRefGoogle Scholar
Mull, G, Zhu, WD, Kapteijn, F, Moulijn, JA. 1998. The effect of NOx and CO on the rate of transition metal oxide catalysed black carbon oxidation – an exploratory study. Applied Catalysis B – Environmental 17:205–20.Google Scholar
O'Connell, JF, Allen, J. 1998. When did humans first arrive in greater Australia and why is it important to know? Evolutionary Anthropology 6:132–46.Google Scholar
Roberts, RG, Jones, R, Spooner, NA, Head, MJ, Murray, AS, Smith, MA. 1994. The human colonisation of Australia: optical dates of 53,000 and 60,000 years bracket human arrival at Deaf Adder Gorge, Northern Territory. Quaternary Science Reviews 13:575–83.CrossRefGoogle Scholar
Vandeputte, K, Moens, L, Dams, R. 1998. Study of the decontamination potential of C-impurities in CuO and Fe. Radiocarbon 40(1):103–10.Google Scholar
Vogel, JS, Nelson, DE, Southon, JR. 1987. 14C background levels in an accelerator mass spectrometry system. Radiocarbon 29(3):323–33.Google Scholar
Vogel, JS, Southon, JR, Nelson, DE, Brown, TA. 1984. Performance of catalytically condensed carbon for use in accelerator mass spectrometry. In: Wolfli, W, Polach, HA, Anderson, HH, editors. Proceedings of the 3rd International Symposium on Accelerator Mass Spectrometry. Nuclear Instruments and Methods in Physics Research B233:289–93.Google Scholar