Pyrolysis-combustion 14C dating of soil organic matter

Hong Wang, Keith C. Hackley, Samuel V. Panno, Dennis D. Coleman, Jack Chao li Liu, Johnie Brown

Research output: Contribution to journalArticle

Abstract

Radiocarbon (14C) dating of total soil organic matter (SOM) often yields results inconsistent with the stratigraphic sequence. The onerous chemical extractions for SOM fractions do not always produce satisfactory 14C dates. In an effort to develop an alternative method, the pyrolysis-combustion technique was investigated to partition SOM into pyrolysis volatile (Py-V) and pyrolysis residue (Py-R) fractions. The Py-V fractions obtained from a thick glacigenic loess succession in Illinois yielded 14C dates much younger but more reasonable than the counterpart Py-R fractions for the soil residence time. Carbon isotopic composition (δ13C) was heavier in the Py-V fractions, suggesting a greater abundance of carbohydrate- and protein-related constituents, and δ13C was lighter in the Py-R fractions, suggesting more lignin- and lipid-related constituents. The combination of 14C dates and δ13C values indicates that the Py-V fractions are less biodegradation resistant and the Py-R fractions are more biodegradation resistant. The pyrolysis-combustion method provides a less cumbersome approach for 14C dating of SOM fractions. With further study, this method may become a useful tool for analyzing unlithified terrestrial sediments when macrofossils are absent.

Original languageEnglish (US)
Pages (from-to)348-355
Number of pages8
JournalQuaternary Research
Volume60
Issue number3
DOIs
StatePublished - Nov 2003

Keywords

  • Last glaciation
  • Loess
  • Midcontinent
  • Pyrolysis combustion

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Earth-Surface Processes
  • Earth and Planetary Sciences(all)

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    Wang, H., Hackley, K. C., Panno, S. V., Coleman, D. D., Liu, J. C. L., & Brown, J. (2003). Pyrolysis-combustion 14C dating of soil organic matter. Quaternary Research, 60(3), 348-355. https://doi.org/10.1016/j.yqres.2003.07.004