Abstract

Increasing oxygenation of the early Ediacaran Ocean is thought to have been responsible for the emergence of early animals. Although geochemical studies have suggested periods of oceanic oxygenation in the Ediacaran, direct evidence for seafloor oxygenation has been lacking. Here, we report frequent occurrences of distinctive, sub-millimetric, and early diagenetic pyrite-marcasite rosettes in phosphorites from the lower Ediacaran Doushantuo Formation (Weng’an, South China). They typically consist of a nucleus of framboidal pyrite, a cortex of radiating marcasite blades intergrown with quartz, and a rim of second-generation pyrite, recording partial oxidative dissolution of pyrite and co-precipitation of marcasite and quartz. This inference is further supported by near-zero carbon isotope values of the host dolostone, similarly low sulfur isotope values for pyrite and marcasite, and evident Fe-isotope fractionation between marcasite and pyrite. Collectively, our findings reveal intermittent bottom-water and porewater oxygenation events, providing direct evidence of high-frequency oxygenation of Ediacaran continental shelves.

The identification of distinct pyrite-marcasite rosettes in the Doushantuo Formation, South China using microscopy and stable isotope analysis, suggests frequent oxygenation events on the early Ediacaran continental shelves during the emergence of complex life.

Details

Title
Evidence for high-frequency oxygenation of Ediacaran shelf seafloor during early evolution of complex life
Author
Jiao, Liangxuan 1 ; She, Zhenbing 2   VIAFID ORCID Logo  ; Papineau, Dominic 3   VIAFID ORCID Logo  ; Zhang, Chao 4   VIAFID ORCID Logo  ; Algeo, Thomas J. 5 ; Dodd, Matthew S. 1   VIAFID ORCID Logo  ; Luo, Genming 2 ; Cao, Kenan 2 ; Li, Chao 1   VIAFID ORCID Logo 

 Chengdu University of Technology, State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation & Institute of Sedimentary Geology, Chengdu, China (GRID:grid.411288.6) (ISNI:0000 0000 8846 0060); China University of Geosciences, State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, Wuhan, China (GRID:grid.503241.1) (ISNI:0000 0004 1760 9015); Chengdu University of Technology, International Center for Sedimentary Geochemistry and Biogeochemistry Research, Chengdu, China (GRID:grid.411288.6) (ISNI:0000 0000 8846 0060) 
 China University of Geosciences, State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, Wuhan, China (GRID:grid.503241.1) (ISNI:0000 0004 1760 9015) 
 China University of Geosciences, State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, Wuhan, China (GRID:grid.503241.1) (ISNI:0000 0004 1760 9015); University College London, London Centre for Nanotechnology, London, UK (GRID:grid.83440.3b) (ISNI:0000000121901201); University College London, Department of Earth Sciences, London, UK (GRID:grid.83440.3b) (ISNI:0000 0001 2190 1201); University College London and Birkbeck College, Centre for Planetary Science, London, UK (GRID:grid.88379.3d) (ISNI:0000 0001 2324 0507) 
 Northwest University, Department of Geology, Xi’an, China (GRID:grid.412262.1) (ISNI:0000 0004 1761 5538); Leibniz University Hannover, Welfengarten 1, Institute of Mineralogy, Hannover, Germany (GRID:grid.9122.8) (ISNI:0000 0001 2163 2777) 
 China University of Geosciences, State Key Laboratory of Biogeology and Environmental Geology, School of Earth Sciences, Wuhan, China (GRID:grid.503241.1) (ISNI:0000 0004 1760 9015); China University of Geosciences, State Key Laboratory of Geological Processes and Mineral Resources, Wuhan, China (GRID:grid.503241.1) (ISNI:0000 0004 1760 9015); University of Cincinnati, Department of Geosciences, Cincinnati, USA (GRID:grid.24827.3b) (ISNI:0000 0001 2179 9593) 
Pages
429
Publication year
2023
Publication date
Dec 2023
Publisher
Nature Publishing Group
e-ISSN
26624435
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
2892420927
Copyright
© The Author(s) 2023. This work is published under http://creativecommons.org/licenses/by/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.