TY - JOUR

T1 - Evidence for high-frequency oxygenation of Ediacaran shelf seafloor during early evolution of complex life

AU - Jiao, Liangxuan

AU - She, Zhenbing

AU - Papineau, Dominic

AU - Zhang, Chao

AU - Algeo, Thomas J.

AU - Dodd, Matthew S.

AU - Luo, Genming

AU - Cao, Kenan

AU - Li, Chao

N1 - Funding Information: This work was financially supported by National Natural Science Foundation of China (grant# 41825019, 42130208 and 41821001), the National Key Research and Development Program of China (2023YFC2906601 and 2022YFF0800102). Z.S. and L.J. thank Ingo Horn (Hannover) for help with Fe isotope analysis, Jiasheng Wang and Meng Cheng for inspiring discussions, and Yaguan Zhang, Guoyong Chen, Qun Chen and Chao Deng for help with fieldwork. Z.S. acknowledges support from the Bureau of Geology and Mineral Resources of Guizhou Province for sampling permission in their core library.

PY - 2023/11/22

Y1 - 2023/11/22

N2 - 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.

AB - 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.

UR - http://www.scopus.com/inward/record.url?scp=85177664658&partnerID=8YFLogxK

U2 - 10.1038/s43247-023-01080-1

DO - 10.1038/s43247-023-01080-1

M3 - Article

AN - SCOPUS:85177664658

VL - 4

JO - Communications Earth and Environment

JF - Communications Earth and Environment

M1 - 429

ER -