Molecular palaeontology of the earliest Danian at Geulhemmerberg (the Netherlands)

Abstract

Organic compound distributions in extracts of three selected clay samples from the lowermost Danian section at Geulhemmerberg were analysed in order to enhance the understanding of the depositional environment immediately after the Cretaceous/Tertiary (K/T) boundary. A highly dominant C40:2 ethyl ketone is identified. This compound is probably derived from specific, highly abundant non-coccolithophorid Prymnesiophyte algae which may already have been present in late Maastrichtian times. Fatty acids as well as their randomly oxidized hydroxy- and keto counterparts are also abundant. These compounds probably indicate bacterially transformed biochemicals of terrestrial origin, although they are probably not derived from the Bryophyte moss spores abundantly present in these sediments. Their distributions are, however, strikingly similar to those of fatty acids in Antarctic soils. ω16-, ω17 -, and ω22- keto- and hydroxy fatty acids with highly specific distribution patterns and a clear even over odd carbon number preference are thought to be of marine origin. The biochemical relationships between these compounds and the C40:2 ethyl ketone suggest that they may originate from the same algae. This presence of highly functionalized organic compounds demonstrates the extreme immaturity and excellent preservation of the unique Geulhemmerberg K/T boundary sediments.