Reviewing chronostratigraphic uncertainty of the Ediacaran–Cambrian transition

The Ediacaran–Cambrian transition archives the widespread disappearance of ‘Ediacaran-type’ soft-bodied biota and the appearance of most modern animal body plans, including a major diversification of skeletal animals and styles of animal-substrate interaction. Our ability to accurately interpret the series of macroevolutionary events that inform origination and extinction rates across the Ediacaran–Cambrian transition is challenged by underlying ambiguity in global stratigraphic correlation. Here, we review the chronology of stratigraphic data recorded by successions that are currently the most temporally well-constrained, discuss major uncertainties, and use this perspective to reconstruct a plausible global age framework for published biostratigraphy and chemostratigraphy. We collate these data to discuss broad integration of evolutionary patterns, carbon cycle instability, and other paleoenvironmental records across this­­ interval. While there remains ∼5 million years of uncertainty, holistic evaluation of existing chronostratigraphy suggests that the GSSP for the Ediacaran–Cambrian boundary falls between 538 and 533 Ma.