Auras Stefan, Wilde Volker, Scheffler Kay, Hoernes Stephan, Kerp Hans, Püttmann Wilhelm
Institut für Atmosphäre und Umwelt -Umweltanalytik, Johann Wolfgang Goethe-Universität, Georg-Voigt-Str. 14, 60054, Frankfurt, Germany.
Naturwissenschaften. 2006 Dec;93(12):616-21. doi: 10.1007/s00114-006-0150-x. Epub 2006 Oct 13.
Previous palaeobotanical and palynological studies on coals from Euramerican Pennsylvanian ( identical with Late Carboniferous) coal basins indicate a major change in coal-swamp floras, especially at the Westphalian-Stephanian ( approximately Kasimovian-Gzhelian, according to Geological Time Scale 2004) boundary. A flora dominated by arborescent lycophytes was replaced by a vegetation dominated by marattialean tree ferns in various Euramerican coal basins. Earlier combined palynological and organic geochemical studies on Westphalian/Stephanian coals and shales from the Saar-Nahe Basin (Germany) revealed that the distribution of aromatized arborane/fernane hydrocarbons in solvent extracts reflects the increasing importance of seed plants, especially cordaites (extinct group of gymnosperms), conifers and pteridosperms. However, the biological source of the precursor molecules could not be specified. To clarify if the arborane/fernane derivatives MATH, MAPH, DAPH 1, and DAPH 2 in Westphalian/Stephanian coals can be assigned to one of the three potential source plant groups, we analyzed coals, sediments and fossil plant remains from different Euramerican locations with respect to their biomarker composition and stable carbon isotopic composition. Thereby, stable carbon isotopic ratios showed only insignificant variations between Westphalian and Stephanian samples and proved to be an unsuitable tool to describe floral changes during the Westphalian/Stephanian of the Saar-Nahe Basin. In contrast, we were able to show for the first time that MATH, MAPH, DAPH 1 and DAPH 2 are prominent constituents only in extracts of cordaitean macrofossils and can therefore be regarded as biomarkers for this group of gymnosperms.
以往对欧美宾夕法尼亚纪（等同于晚石炭世）煤盆地煤的古植物学和孢粉学研究表明，煤沼泽植物群发生了重大变化，尤其是在威斯法阶-斯蒂芬阶（根据《2004年地质年代表》，大致为卡西莫夫阶-格热尔阶）边界。在欧美各煤盆地中，以树状石松类为主的植物群被以观音座莲目树蕨为主的植被所取代。早期对德国萨尔-纳赫盆地威斯法阶/斯蒂芬阶煤和页岩进行的孢粉学与有机地球化学联合研究表明，溶剂提取物中芳构化乔木烷/蕨烷烃的分布反映出种子植物，尤其是科达类（已灭绝的裸子植物类群）、针叶树和种子蕨的重要性日益增加。然而，前体分子的生物来源尚无法确定。为了弄清楚威斯法阶/斯蒂芬阶煤中的乔木烷/蕨烷衍生物MATH、MAPH、DAPH 1和DAPH 2是否可归属于三个潜在源植物群中的某一个，我们分析了来自欧美的不同地点的煤、沉积物和植物化石残骸的生物标志物组成和稳定碳同位素组成。由此可见，威斯法阶和斯蒂芬阶样品之间的稳定碳同位素比值仅显示出微不足道的变化，并且事实证明它并非描述萨尔-纳赫盆地威斯法阶/斯蒂芬阶植物群变化的合适工具。相比之下，我们首次能够证明，MATH、MAPH、DAPH 1和DAPH 2仅在科达类大化石的提取物中是主要成分，因此可被视为这类裸子植物的生物标志物。
