Terra Nova Terra Nova 0954-4879 1365-3121 02 2019 31 1 10.1111/ter.2019.31.issue-1 https://onlinelibrary.wiley.com/toc/13653121/31/1 New high‐resolution age data from the Ediacaran–Cambrian boundary indicate rapid, ecologically driven onset of the Cambrian explosion Ulf Linnemann Senckenberg Collections of Natural History Dresden Museum of Mineralogy and Geology Dresden Germany http://orcid.org/0000-0003-0970-0233 Maria Ovtcharova Département des Sciences de la Terre University of Geneva Genève Switzerland Urs Schaltegger Département des Sciences de la Terre University of Geneva Genève Switzerland Andreas Gärtner Senckenberg Collections of Natural History Dresden Museum of Mineralogy and Geology Dresden Germany Michael Hautmann Paläontologisches Institut und Museum Zürich Switzerland Gerd Geyer Bayerische Julius‐Maximilians‐Universität Lehrstuhl für Geodynamik und Geomaterialforschung Würzburg Germany Patricia Vickers‐Rich Department of Chemistry and Biotechnology Swinburne University of Technology Melbourne (Hawthorne) Victoria Australia Museums Victoria Melbourne Victoria Australia School of Earth, Atmosphere and Environment Monash University Melbourne (Clayton) Victoria Australia Tom Rich Museums Victoria Melbourne Victoria Australia Birgit Plessen Helmholtz‐Zentrum Potsdam Deutsches GeoForschungsZentrum GFZ Potsdam Germany Mandy Hofmann Senckenberg Collections of Natural History Dresden Museum of Mineralogy and Geology Dresden Germany Johannes Zieger Senckenberg Collections of Natural History Dresden Museum of Mineralogy and Geology Dresden Germany Rita Krause Senckenberg Collections of Natural History Dresden Museum of Mineralogy and Geology Dresden Germany Les Kriesfeld School of Earth, Atmosphere and Environment Monash University Melbourne (Clayton) Victoria Australia Jeff Smith School of Earth, Atmosphere and Environment Monash University Melbourne (Clayton) Victoria Australia Abstract

The replacement of the late Precambrian Ediacaran biota by morphologically disparate animals at the beginning of the Phanerozoic was a key event in the history of life on Earth, the mechanisms and the time‐scales of which are not entirely understood. A composite section in Namibia providing biostratigraphic and chemostratigraphic data bracketed by radiometric dating constrains the Ediacaran–Cambrian boundary to 538.6–538.8 Ma, more than 2 Ma younger than previously assumed. The U–Pb‐ CA ‐ ID TIMS zircon ages demonstrate an ultrashort time frame for the LAD of the Ediacaran biota to the FAD of a complex, burrowing Phanerozoic biota represented by trace fossils to a 410 ka time window of 538.99 ± 0.21 Ma to 538.58 ± 0.19 Ma. The extremely short duration of the faunal transition from Ediacaran to Cambrian biota within less than 410 ka supports models of ecological cascades that followed the evolutionary breakthrough of increased mobility at the beginning of the Phanerozoic.

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