Taphonomy of Animal Organic Skeletons Through Time

Abstract

Investigations of organically preserved invertebrate fossils have focused on abundant taxa such as graptolites and arthropods. Analyses have shown that their composition cannot be explained either as a result of decay resistance, or the intro- duction of macromolecular material from surrounding sediment. The fossilization of organic materials is a result of the diagenetic transformation of lipids in the organism itself by a process of in situ polymerization which generates a composition with a significant aliphatic component. While this process causes the fossilized remains of different taxa, even plants and animals, to converge in composition they may still retain differences following diagenesis. Such chemosystematic signatures have the potential to be used in the identification of organic materials that lack diagnostic mor- phology. The diagenetic transformation of organic materials in macrofossils is simi- lar to the formation of kerogen – the final composition depends on original chemistry, decay and diagenesis. A better understanding of rates and controls on this process will require more experimental investigation of decay and maturation, as well as analyses of fossils of different ages and from different environmental settings.