Shallow-marine redox conditions during the Ediacaran in the Yangtze Plateform and its impact on bio-evolution
The environmental changes in the Ediacaran epigenetic system of the Earth are closely linked to the evo-lution of organisms.However,there is still ongoing debate surrounding their interaction.This study focuses on the carbonate sedimentary sequences of the Ediacaran Doushantuo Formation in the Jiulongwan section of the Three Gorges Region,South China.The rare earth elements information was extracted from the carbonate phase using di-lute acetic acid distribution leaching.The obtained data was then utilized to construct the evolution curve of Ce anomalies,which underwent a process involving of reduction/manganization-strong oxidation-suboxidation-strong oxidation-weak oxidation/reduction.Two significant negative Ce anomalies were observed,indicating the occur-rence of two significant oxygenation stages during the prolonged oxidation process of the Ediacaran Doushantuo shal-low water.These two oxygenation events align with the periodic oxidation of deep water at 632 Ma and 580 Ma,re-spectively.Moreover,Ce negative anomalies were also found in contemporaneous sedimentary sequences in Australia,suggesting that global oxygenation events occurred in the Ediacaran Doushantuo ocean.The fossil record of the Doushantuo Formation in the Yangtze Plateform reveals that the duration of Doushantuo ocean oxidation corresponds to the production strata of major fossil groups.This finding supports the understanding that marine oxidation facilita-ted the origin and evolution of Ediacaran Doushantuo metazoans.
国家科技期刊平台
NSTL
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