Electron paramagnetic resonance (EPR) and stable isotope records of paleoenvironmental conditions during peat formation

EPR spectroscopy was performed on four peat cores (1–2.5 m depth) collected from Yellowstone National Park (USA), Scotland (UK) and Lower Silesia (Poland) to study peat formation process. The stable free radicals identified in all investigated samples are semiquinone type and g-parameters range from...

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Bibliographic Details
Published in:Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Molecular and biomolecular spectroscopy, 2008-05, Vol.69 (5), p.1311-1316
Main Authors: Jezierski, Adam, Skrzypek, Grzegorz, Jezierski, Piotr, Paul, Debajyoti, Jedrysek, Mariusz O.
Format: Article
Language:English
Subjects:
Electron Spin Resonance Spectroscopy
Environment
EPR
Free Radicals
Fresh Water
Isotopes
Paleoenvironmental
Paleontology
Peat
Poland
Semiquinones
Soil
Stable isotope
United Kingdom
United States
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Summary:EPR spectroscopy was performed on four peat cores (1–2.5 m depth) collected from Yellowstone National Park (USA), Scotland (UK) and Lower Silesia (Poland) to study peat formation process. The stable free radicals identified in all investigated samples are semiquinone type and g-parameters range from 2.0030 to 2.0048. The highest g-values are characteristic of upper well-aerated peat layers and gradually decrease with depth. The lowest g-values are typical of relatively old fens and bogs where anaerobic conditions are expected and carbonization processes are advanced. The decrease in g-parameter value is connected with conjugation of semiquinone units with gradually augmented polyaromatic units in the peat substance. Generally the radical concentration increases with depth (0.05–5 × 10 17 spins/gram). However the g-values, line width parameters, and spin concentrations exhibit strong variations in some peat layers. Variation of these parameters observed for certain peat horizons correlate with the variation of carbon stable isotopic composition. For the old well-conserved peat deposits (e.g. Scotland/UK, ∼5600BP), variation of EPR parameters may be used to study paleo redox conditions.
ISSN:1386-1425
DOI:10.1016/j.saa.2007.09.024