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Abstract: This study focuses on the reconstruction of the environment during peat swamp development. Eight coal and sedimentary organic rock bearing seam successions were examined all belonging to the Duckmantian (Pennsylvanian, Late Carboniferous). 410 samples were analysed with coal petrographical methods, 155 of these also by palynological methods. In addition, on 55 samples organic geochemical investigations were carried out with respect to n-alkanes and iso-alkanes. The established coal petrographical parameters gelification index (GI), tissue preservation index (TPI), groundwater index (GWI) and vegetation index (VI) were used to characterize different periods of peat swamp development. Furthermore, the new index WCI (=Water Cover Index) was introduced to reflect water level conditions by using the ratio between hydrophilous/hygrophilous and mesophilous plants. In this study the index is based on palynological data but can be equally applied when quantitative macrofloral counts are available. GI versus TPI values show two general trends of peat swamp evolution: low GI and TPI values as indicator for drier swamp conditions like ombrogenous mires and high GI and TPI values which show a trend to water covered environments like topogenous mires. In addition, ash yields and GWI versus VI data also emphasize a general trend from topogenous to ombrogenous mires. A decrease in water level towards the top of the seams and thus resulting in the development of domed mires is reflected by the newly introduced WCI. Hence, these parameters show recurrent peat swamp successions, characterized by mineral- and vitrinite-rich coals, typical for topogenous swamps and an evolution towards inertinite/liptinite-rich coals with low ash yield, typical for ombrogenous swamps. n-alkane ratios like the carbon preference index (CPI), pristane/n-C17, phytane/n-C18, pristane/phytane and the n-C17/n-C27 relationship indicate a strong correlation of these parameters with thermal maturity, e.g. CPI values correlate with vitrinite reflectance. Sulphur/organic carbon (S/TOC) ratios are quite uniform in clastic rocks with low to moderate TOC contents, but highly variable in coals, probably reflecting variable sulphate availability during deposition of peats. Sphenophyll-rich floral assemblages are restricted to low sulphur environments. [Copyright &y& Elsevier]

Abstract: For this study, six seam sequences of Duckmantian age from the Ruhr Basin, western Germany, were analysed. 155 samples from drill cores were examined, including coal samples, as well as organic-rich and clastic sedimentary rocks. All samples were analysed using palynological and coal petrographical techniques. Based on published information of in situ miospores the encountered dispersed miospores were assigned to their parent plants in order to reconstruct the vegetation history. Six vegetational associations were identified using Detrended Correspondence Analyses (DCA): lepidocarpacean association I, lepidocarpacean association II, lepidocarpacean–sigillarian association, lepidocarpacean–sphenophyll association, lepidocarpacean–fern association, and the subarborescent lycopsid association. Lycospora is the most important constituent in the miospore association as in 75% of all samples the genus is represented with more than 50% relative abundance. Lepidocarpaceans such as Lepidophloios and Lepidodendron are very common among the plant fossils. Hence, arborescent lycopsids dominated the vegetation of the Ruhr Basin during the mid and late Duckmantian, forming flood plains and planar forest mires. Variations in the plant environment are reflected by greater influence of sigillarians, which were typical for swamp margins or for domed swamps, characterized by stunted vegetation. Fern-dominated environments were rare during the Duckmantian. A typical rhythmic succession shows an evolution from clastic flood plains through peat substrate planar mires, followed by a doming of the swamps and formation of ombrogenous mires. Floodplains reappeared during periods of subsidence, accompanied by a rise in water level. [Copyright &y& Elsevier]