EXPERIMENTAL FORMATION OF EDIACARAN-STYLE DEATH MASK

Soft-bodied Ediacaran fossils from the terminal Neoproterozoic lagerstätte of South Australia have been explained as the result of a microbially-mediated ‘death mask’ taphonomic regime. Although this model has been substantiated by the discovery of abundant microbially-induced sedimentary structures in close association with Ediacaran fossils, it has not been tested using experimental taphonomic studies under controlled laboratory conditions. Using XPS and ESEM-EDS we demonstrate the generation of iron sulfides and localized concentrations of common aluminosilicate cations (Al, K, Fe and Mg), a composition that has been frequently documented in association both with Ediacaran and other examples of soft tissue preservation. Furthermore, microbial mats are demonstrated to prolong the taphonomic window allowing for soft-tissue molding, while directly affecting the fidelity of preservation. These experiments are the first to investigate tissue decay in association with microbial mats, and provide necessary experimental support for the microbial death mask model responsible for exceptional preservation in the Ediacaran.