Clay Mineral Factory and Atmospheric-Oceanic Oxygenation in the Early Ediacaran

The early Ediacaran Period (ca. 635–580 Ma) records a profound reorganization of ecosystem complexity and the earliest diversification of multicellular life following the Marinoan glaciation. Accumulating evidence points to episodic atmospheric–oceanic oxygenation as a plausible catalyst for this ecological revolution, given its role in ameliorating shallow-marine habitats. However, the fundamental drivers underlying these oxidation events remain largely unconstrained from a quantitative perspective. Here, we present high-resolution mineralogical and geochemical data, including iron speciation, phosphorus speciation, and potassium isotopes compositions from the Doushantuo Formation Member II on the Yangtze Platform, South China. Our results reveal a pronounced increase in both detrital and authigenic clay minerals within early Ediacaran shallow-water continental shelf deposits, a trend that likely reflects intensified continental weathering and consequent reverse weathering effects. Integrating these observations with a global biogeochemical model, we propose that enhanced clay mineral abundances accelerated the aggregation and sedimentation of organic carbon while simultaneously suppressing its remineralization, thereby increasing organic carbon burial efficiency on continental shelves. This cascade of processes, in turn, promoted the accumulation of atmospheric oxygen, ultimately driving a sustained improvement in shallow-marine ecological conditions and facilitating the radiation of early metazoans.