Hostname: page-component-78c5997874-lj6df Total loading time: 0 Render date: 2024-11-19T04:02:51.679Z Has data issue: false hasContentIssue false

Stepped-Combustion 14C Dating of Bomb Carbon in Lake Sediment

Published online by Cambridge University Press:  18 July 2016

J McGeehin
Affiliation:
US Geological Survey, Reston, Virginia, USA. Corresponding author. Email: [email protected]
G S Burr
Affiliation:
University of Arizona, Tucson, Arizona, USA.
G Hodgins
Affiliation:
University of Arizona, Tucson, Arizona, USA.
S J Bennett
Affiliation:
State University of New York, Buffalo, New York, USA.
J A Robbins
Affiliation:
National Oceanic and Atmospheric Administration, Ann Arbor, Michigan, USA.
N Morehead
Affiliation:
National Oceanic and Atmospheric Administration, Ann Arbor, Michigan, USA.
H Markewich
Affiliation:
US Geological Survey, Atlanta, Georgia, USA.
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.

In this study, we applied a stepped-combustion approach to dating post-bomb lake sediment from north-central Mississippi. Samples were combusted at a low temperature (400 °) and then at 900 °. The CO2 was collected separately for both combustions and analyzed. The goal of this work was to develop a methodology to improve the accuracy of 14C dating of sediment by combusting at a lower temperature and reducing the amount of reworked carbon bound to clay minerals in the sample material. The 14C fraction modern results for the low and high temperature fractions of these sediments were compared with well-defined 137Cs determinations made on sediment taken from the same cores. Comparison of “bomb curves” for 14C and 137Cs indicate that low temperature combustion of sediment improved the accuracy of 14C dating of the sediment. However, fraction modern results for the low temperature fractions were depressed compared to atmospheric values for the same time frame, possibly the result of carbon mixing and the low sedimentation rate in the lake system.

Type
Part II
Copyright
Copyright © The Arizona Board of Regents on behalf of the University of Arizona 

References

Abbott, MB, Stafford, TW Jr. 1996. Radiocarbon geochemistry of modern and ancient arctic lake systems, Baffin Island, Canada. Quaternary Research 45: 300–11.Google Scholar
Bennett, SJ, Rhoton, FE. 2003. Physical and chemical characteristics of sediment impounded within Grenada Lake, MS. USDA-ARS National Sedimentation Laboratory Research Report No. 36. 161 p.Google Scholar
Bergan, TD. 2002. Radioactive fallout in Norway from atmospheric nuclear weapons tests. Journal of Environmental Radioactivity 60:189208.Google Scholar
Delqué Količ, E. 1995. Direct radiocarbon dating of pottery: selective heat treatment to retrieve smoke-derived carbon. Radiocarbon 37(2):275–84.CrossRefGoogle Scholar
Donahue, DJ, Linick, TW, Jull, AJT. 1990. Isotope-ratio and background corrections for acceleratory mass spectrometry radiocarbon measurements. Radiocarbon 32(2):135–42.Google Scholar
Levin, I, Kromer, B, Schoch-Fischer, H, Bruns, M, Münnich, M, Berdau, D, Vogel, J, Münnich, KO. 1985. Twenty-five years of tropospheric 14C observations in Central Europe. Radiocarbon 27(1):119.Google Scholar
McGeehin, J, Burr, GS, Jull, AJT, Reines, D, Gosse, J, Davis, PT, Muhs, D, Southon, JR. 2001. Stepped-combustion 14C dating of sediment: a comparison with established techniques. Radiocarbon 43(2A):255–61.Google Scholar
O'Malley, JM, Kuzmin, YZ, Burr, GS, Donahue, DJ, Jull, AJT. 1999. Direct radiocarbon accelerator mass spectrometric dating of the earliest pottery from the Russian Far East and Transbaikal. In: Evin, J, Oberlin, C, Daugas, J-P, Salles, J-F, editors. 14C and Archaeology: 3rd International Conference. Lyon, France. 6–10 April 1998.Google Scholar