Sesqui- and diterpenoid biomarkers preserved in Taxodium-rich Oligocene oxbow lake clays, Weisselster basin, Germany

Several diterpenoids of the abietane, pimarane and phyllocladane type, and three cadalanetype sesquiterpenoids have been identified in the organic solvent extracts of Lower Oligocene clay sediments (Haselbach strata, Saxony, Germany). The sediment contains needles and cone scales of a fossil Taxodium species which represents the only conifer in the samples. A clear correlation between the observed conifer biomarkers and Taxodium is evident. Apart from diterpenoids detected previously in other sediments, a new diaromatic totarane diterpenoid is reported. In isolated fossil and Recent Taxodium needles and cone scales as well as in the Haselbach clays a phenolic diterpenoid of the abietane-type, ferruginol, has been identified. The results indicate that the Taxodium-rich clay samples contain several diterpenoids which so far have been used as biomarkers for other conifer families and thus the chemotaxonomical use of diterpenoid biomarkers for the differentiation of fossil conifer families has to be revised.