STUDIES IN EDIACARAN PRESERVATION

The fossil record is biased, and as such the preservational history of a fossil must be considered before any signal can be retrieved. Konservat-Lagerstätten, sites that preserve soft-bodied organisms, represent the richest fossil source of anatomical information and offer more complete views of organismal diversity and disparity patterns in deep time. Understanding the early evolution and diversification of animals, as written in the Ediacaran fossil record, is reliant on our understanding of the preservational constraints affecting the fossilization of soft tissues in Ediacaran Lagerstätten. We have employed a two-pronged approach to aid in unraveling the geobiological intricacies in Ediacaran preservation. On the one hand, advanced instrumentation such as environmental scanning electron microscopy (ESEM), energy dispersive X-ray spectroscopic elemental mapping analyses (EDS)x-ray, photoelectron spectrometry (XPS), and electron probe microanalyzer wavelength dispersive X-ray spectroscopy (EPMA-WDS), was performed on sectioned Ediacaran fossils from Newfoundland and Namibia, revealing the importance of clay minerals and the precipitation of iron sulfides such as pyrite in casting the external morphology of the organisms. On the other hand, decay experiments conducted under controlled laboratory settings allowed for investigations into the replication of soft-tissue preservation, which identified controls on rates of tissue decay and early mineralization. This combined two-pronged approach provides a conceptual framework for understanding the distribution of Ediacaran-style preservation in time and space, and will help frame the paleoenvironmental settings and conditions where body fossils are preserved in the Neoproterozoic.