Molecular composition of a leaf- and root-bearing Oligocene Oxbow Lake Clay in the Weisselster Basin, Germany

A plant fossil bearing clay profile from the Upper Oligocene Thierbach strata (Weisselster Basin, Germany) has been sectioned into horizons and the plant macrofossils of each section surface have been identified by morphological and anatomical studies. In the upper half of the profile leaves from Populus germanica and Carpinus grandis and branchlets from the conifer Taxodium balticum vel T. dubium dominate the horizons while the lower part contains only root remains of unknown higher plants. In the Soxhlet-extracted samples from each section n-alkanes, n-alkanols, n-carboxylic acids, and several terpenoids [β-amyrin, 24,25-dinoreleana-1,3,5(10),12-tetraene, olean-12-en-3-one, simonellite, and hop-17(21)-ene] were identified by combined gas chromatography-mass spectrometry. The comparison of the extracted chemical compounds and the macrofossil record of the profile shows that simonellite occurs preferentially in the Taxodium bearing horizons. n-Alkanes, n-alkanols, n-carboxylic acids, and β-amyrin were found in all sections, but are enriched in the root-containing part of the profile. The distribution of hop-17(21)-ene is independent of the input of higher plant remains.