Bowyer, FT, Zhuravlev, AY, Wood, R et al. (7 more authors) (2022) Calibrating the temporal and spatial dynamics of the Ediacaran - Cambrian radiation of animals. Earth-Science Reviews, 225. 103913. ISSN 0012-8252
Abstract
The Ediacaran-Cambrian transition, which incorporates the radiation of animals, lacks a robust global temporal and spatial framework, resulting in major uncertainty in the evolutionary dynamics of this critical radiation and its relationship to changes in palaeoenvironmental geochemistry. We first present a new δ13Ccarb composite reference curve for the Ediacaran Nama Group of southern Namibia, and we then outline four new possible global age models (A to D) for the interval 551–517 million years ago (Ma). These models comprise composite carbonate‑carbon isotope (δ13Ccarb) curves, which are anchored to radiometric ages and consistent with strontium isotope chemostratigraphy, and are used to calibrate metazoan distribution in space and time. These models differ most prominently in the temporal position of the basal Cambrian negative δ13Ccarb excursion (BACE). Regions that host the most complete records show that the BACE nadir always predates the Ediacaran-Cambrian boundary as defined by the first appearance datum (FAD) of the ichnospecies Treptichnus pedum. Whilst treptichnid traces are present in the late Ediacaran fossil record, the FAD of the ichnospecies T. pedum appears to post-date the last appearance datums (LADs) of in situ representatives of the skeletal organisms Cloudina and Namacalathus in all environments with high-resolution δ13Ccarb data. Two age models (A and B) place the BACE within the Ediacaran, and yield an age of ~538.8 Ma for the Ediacaran-Cambrian boundary; however models C and D appear to be the most parsimonious and may support a recalibration of the boundary age by up to 3 Myr younger. All age models reveal a previously underappreciated degree of variability in the terminal Ediacaran, incorporating notable positive and negative excursions that precede the BACE. Nothwithstanding remaining uncertainties in chemostratigraphic correlation, all models support a pre-BACE first appearance of Cambrian-type shelly fossils in Siberia and possibly South China, and show that the Ediacaran-Cambrian transition was a protracted interval represented by a series of successive radiations.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2022 Elsevier B.V. This is an author produced version of a article published in Earth-Science Reviews. Uploaded in accordance with the publisher's self-archiving policy. |
Keywords: | Ediacaran, Cambrian, Evolution, Chronostratigraphy, Biostratigraphy, Chemostratigraphy, Carbon isotopes, Strontium isotopes, Temporal calibration, Geochronology |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Earth Surface Science Institute (ESSI) (Leeds) |
Funding Information: | Funder Grant number NERC (Natural Environment Research Council) NE/P013627/1 NERC (Natural Environment Research Council) NE/R010129/1 NERC (Natural Environment Research Council) NE/T008458/1 Royal Society WM150108 |
Depositing User: | Symplectic Publications |
Date Deposited: | 06 Jan 2022 13:13 |
Last Modified: | 17 Mar 2023 08:48 |
Status: | Published |
Publisher: | Elsevier |
Identification Number: | 10.1016/j.earscirev.2021.103913 |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:181896 |