Fleshing out the Ediacaran period

Abstract The Flinders Ranges Ediacaran succession preserves an apparently primary palaeomagnetic record, distinctive stratigraphic events such as the Acraman ejecta layer, and fossils of the Ediacara biota at three well-separated levels. The fossil assemblage of the Ediacara Member includes both trace fossils and body fossils, and shares at least 65% of its taxa with the White Sea assemblages in northern Russia, suggesting they were coeval. Globally, Ediacaran successions are diverse in their lithostratigraphy but share many characteristics of biota, isotope signatures and events which can be calibrated with radiometric dating. Available radiometric dating of Ediacaran successions supports the concept of distinct Avalon (575 Ma–565 Ma), White Sea (558 Ma–555 Ma) and Nama (549 Ma–543 Ma) associations as a temporal succession rather than being controlled by environment or palaeobiogeography. The challenge to document the tempo and pattern of evolution of early animals and the associated changes in global climate make the subdivision and calibration of the Ediacaran a vital task for the next decade.