Abstract—

Collected in situ rhizoliths (>20) from Devonian and Early Carboniferous paleosols in the southern part of the Russian Platform (Kaluga, Belgorod, and Voronezh oblasts) were studied by means of scanning electron microscopy, X-ray diffraction, XRF and mass spectrometry. In Devonian paleosols developed from volcanic–sedimentary deposits, rhizoliths are represented by petrified individual roots of different plants, rooting systems, and their diagenetically transformed products—ferruginous concretions and wedges. Mineralogically, they are dominated by goethite and siderite in different proportions. Some of them include charcoals and/or pyrite-substituted plant tissues. This kind of rhizoliths was developed under reducing conditions in (semi)hydromorphic paleosols or under flooding during the soil burial stage. In the Carboniferous period, paleosols developed from marine limestones contained several types of rhizoliths: casts (predominate), imprints and root channels (less abundant), and few rhizocretions with arbuscular mycorrhiza. All of them are characterized by complete mineralization of plant tissues. Casts and rhizocretions are substituted with calcite. The isotopic composition of C in the latter is within –5.68 < δ¹³C < –1.16‰. The data obtained show that rhizoliths are important sources of information on biodiversity, physiology of plants, and paleoenvironments at different scales, including the global scale. The volume of information depends on the type of rhizolith.

中文翻译：

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泥盆纪和石炭纪古土壤中的根石及其古生态学解释

摘要-

通过扫描电子显微镜，X射线衍射，XRF和质谱分析，研究了从俄罗斯平台南部（卡卢加州，别尔哥罗德州和沃罗涅日州）泥盆纪和早石炭纪古土壤中收集的原地根状岩（> 20）。在由火山沉积沉积物发育而成的泥盆纪古土壤中，根状岩的代表是不同植物，生根系统及其介电转化产物（铁质凝结物和楔形物）的石化个体根。在矿物学上，它们以针铁矿和菱铁矿的比例不同。其中一些包括木炭和/或黄铁矿取代的植物组织。这种根状茎是在还原条件下在（半）水状古土壤中或在土壤掩埋期淹没的情况下开发的。在石炭纪时期，由海洋石灰石发育的古土壤含有几种类型的根茎：铸型（占主导地位），烙印和根部通道（数量较少），以及很少有丛枝菌根的根瘤菌。它们的全部特征是植物组织的完全矿化。用方解石代替铸件和根瘤菌。后者中C的同位素组成在–5.68 <δ之内¹³ C <–1.16‰。所获得的数据表明，根茎植物是包括全球范围在内的不同规模的生物多样性，植物生理和古环境信息的重要来源。信息量取决于根茎的类型。