Extensive marine anoxia during the terminal Ediacaran Period
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Date
2018-06-20
Authors
Zhang, Feifei
Xiao, Shuhai
Kendall, Brian
Romaniello, Stephen J.
Cui, Huan
Meyer, Mike
Gilleaudeau, Geoffrey J.
Kaufman, Alan J.
Anbar, Ariel
Journal Title
Journal ISSN
Volume Title
Publisher
American Association for the Advancement of Science
Abstract
The terminal Ediacaran Period witnessed the decline of the Ediacara biota (which may have included many stemgroup
animals). To test whether oceanic anoxia might have played a role in this evolutionary event, we measured
U isotope compositions (d238U) in sedimentary carbonates from the Dengying Formation of South China to obtain
new constraints on the extent of global redox change during the terminal Ediacaran. We found the most
negative carbonate d238U values yet reported (−0.95 per mil), which were reproduced in two widely spaced coeval
sections spanning the terminal Ediacaran Period (551 to 541 million years ago). Mass balance modeling
indicates an episode of extensive oceanic anoxia, during which anoxia covered >21% of the seafloor and most
U entering the oceans was removed into sediments below anoxic waters. The results suggest that an expansion
of oceanic anoxia and temporal-spatial redox heterogeneity, independent of other environmental and ecological
factors, may have contributed to the decline of the Ediacara biota and may have also stimulated animal motility.
Description
Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution NonCommercial License 4.0 (CC BY-NC).