Comparative 14C and OSL dating of loess-paleosol sequences to evaluate post-depositional contamination of n-alkane biomarkers

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Michael Zech - , Chair of Landscape studies and Geoecology, Martin Luther University Halle-Wittenberg, University of Bayreuth (Author)
  • Sebastian Kreutzer - , University of Bayreuth, Justus Liebig University Giessen, Université Bordeaux Montaigne (Author)
  • Roland Zech - , ETH Zurich, University of Bern (Author)
  • Tomasz Goslar - , Poznan Radiocarbon Laboratory (Author)
  • Sascha Meszner - , Chair of Physical Geography (Author)
  • Cameron Mcintyre - , ETH Zurich, University of Glasgow (Author)
  • Christoph Häggi - , ETH Zurich, University of Bremen (Author)
  • Timothy Eglinton - , ETH Zurich (Author)
  • Dominik Faust - , Chair of Physical Geography (Author)
  • Markus Fuchs - , Justus Liebig University Giessen (Author)

Abstract

There is an ongoing controversial discussion as to whether n-alkane lipid biomarkers - and organic matter of loess in general - reflect a synsedimentary paleoenvironmental/climate signal or whether they are significantly affected by postdepositional contamination, for example related to root and rhizomicrobial activity. In order to address this issue at our study site (the Middle to Late Weichselian loess-paleosol sequence Gleina in Saxony, Germany), we determined and compared radiocarbon ages of bulk n-alkanes and sedimentation ages, as assessed by optically stimulated luminescence (OSL) dating. The bulk n-alkanes of the four dated samples yielded calibrated 14C ages ranging from 24.1 to 49.7 cal ka BP (95.4% probability ranges). While the three uppermost n-alkane samples are well within the range or even slightly older than the OSL-inferred sedimentation ages, the lowermost n-alkane sample is slightly younger than the OSL ages. There is hence little or no evidence at our study site for n-alkanes in loess-paleosol sequences being significantly contaminated by deep subsoil rooting or microbial processes. We propose a 14C isotope mass balance calculation for estimating such contaminations quantitatively. Radiocarbon dating of bulk n-alkanes might have great potential for Quaternary research, and we encourage further comparative 14C and OSL studies.

Details

Original languageEnglish
Pages (from-to)180-189
Number of pages10
JournalQuaternary Research
Volume87
Issue number1
Publication statusPublished - 1 Jan 2017
Peer-reviewedYes

External IDs

Scopus 85040787704
ORCID /0000-0002-9586-0390/work/170107050

Keywords

Sustainable Development Goals

Keywords

  • Biomarker, n-alkane, OSL Dating, loess, Pleistocene, 14C dating