Rotten fossils: understanding how taphonomy biases the fossil record

Earth Surface Science Institute seminar. Speaker Dr. Thomas Clements, University College Cork



The fossil record is our only ‘window’ into the evolution of animals and plants throughout geological history. Unfortunately, this window is murky, because nature favours obliteration of organic material - predominately through decay - which acts to remove information from the fossil record. Of course, organics do preserve, and these are usually tissues that have a high preservation potential (are more decay-resistant) such as biomineralised tissues (bones, teeth, shells etc.) which explains their dominance in the fossil record. There are, however, processes in certain depositional environments that allow an organism’s soft-tissues to enter the inorganic lithosphere. These soft-tissue fossils are important as they allow more accurate reconstructions of ancient ecosystems and because they retain vital anatomical information which can be used to investigate animal evolution, especially during pivotal periods of Earth’s history, like the Cambrian Explosion. The science of taphonomy seeks to understand the processes that control preservation of organics, from the immediate moments after death and subsequent burial (biostratinomy), mineralisation, diageneses, and geological processes. My talk will introduce experimental taphonomy and will showcase three tiers of taphonomic bias: 1) preservational potential of different tissue types within an organism, 2) varying preservational potential of related organisms and 3) the impact of paleogeography on soft-tissue preservation.

About the speaker