Rekonstruktion der Ablagerungsbedingungen mitteldeutscher paläogener und neogener Kohleflöze anhand kohlenpetrographischer Untersuchungen

Maceral percentages, ash yield, carbon and sulfur contents of 114 samples of lignite and their country rocks from Sachsen-Anhalt were determined and RockEval pyrolysis was performed. The samples represent 12 seams with an Eocene to early Miocene age. The aim of the study was to reconstruct depositional environments and to document their variation through time. All coal samples are ash-rich, a result of frequent flooding events. Relatively clean coal (2.5 %) and is controlled by marine ingressions and/or carbonate-rich water flowing into the mires. The lower Eocene Leuna and Rossbach seams and the lower Oligocene Wienrode seam are characterized by relatively low sulphur contents, whereas the upper Oligocene Breitenfeld seam is very rich in sulphur. The Eocene and lower Oligocene seams are characterized by poor tissue preservation. This suggests an angiosperm-dominated flora, a result which is also supported by biomarker data. Hydrogen Index values (HI) correlate with liptinite contents and the amount of extractable organic matter. The maximum HI values occur in the Bruckdorf seam (upper Eocene) which is used for the production of Montanwax. This seam also contains the highest percentage of carbonate minerals.