Electron paramagnetic resonance (EPR) and stable isotope records of paleoenvironmental conditions during peat formation
Electron paramagnetic resonance (EPR) and stable isotope records of paleoenvironmental conditions during peat formation
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DOI：
10.1016/j.saa.2007.09.024
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发表时间：
2008-05-01
影响因子：
4.4
通讯作者：
Jedrysek, Mariusz O.
中科院分区：
文献类型：
--
作者：
Jezierski, Adam;Skrzypek, Grzegorz;Jedrysek, Mariusz O.
对采自美国黄石国家公园、英国苏格兰和波兰下西里西亚的4个泥炭样（1 ~ 2.5 m）进行了EPR波谱分析，研究了泥炭的形成过程。在所有调查的样品中确定的稳定的自由基是半醌型和g-参数范围从2.0030到2.0048。最高的g值是上部通气良好的泥炭层的特征，并随着深度逐渐降低。最低的g值是典型的相对较老的沼泽和沼泽，预计厌氧条件和碳化过程是先进的。g-参数值的降低与半醌单元与泥炭物质中逐渐增加的多环芳烃单元的共轭有关。一般来说，自由基浓度随深度增加而增加（0.05-5 × 10（17）自旋/克）。然而，g值，线宽参数，自旋浓度表现出强烈的变化，在一些泥炭层。这些参数的变化与碳稳定同位素组成的变化有关。对于保存较好的古老泥炭沉积（如苏格兰/英国，类似于5600 BP），EPR参数的变化可用于研究古氧化还原条件。(C)2007 Elsevier B. V.保留所有权利。
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 x 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, similar to 5600BP), variation of EPR parameters may be used to study paleo redox conditions. (C) 2007 Elsevier B.V. All rights reserved.