Sedimentological and stratigraphic constraints on depositional environment for Ediacaran carbonate rocks of the São Francisco Craton: Implications for phosphogenesis and paleoecology

• New sedimentological data collected for Ediacaran carbonates of eastern Brazil. Revised depositional model: a remarkably energetic shallow platform environment. Early carbonate and phosphate cements co-occur in wave-swept microbial buildups. Limited extent phosphogenesis likely result local, not regional, processes. Proposed models related to local microbiology sediment supply. The Una Bambuí Groups northeastern central Brazil are remnants vast intracratonic formed on the São Francisco Craton during Period. Their basal stratigraphic units contain early phosphatic intraclasts association with elongate digitate stromatolites more northern Irecê Salitre paleobasins (Salitre Formation), laminites aragonite crystal fan pseudomorphs southern paleobasin (Sete Lagoas Formation). Previous studies have drawn comparisons other Precambrian phosphorites, as well modern phosphogenetic environments, suggesting mechanisms dependent accumulation porewater via activity low flow velocity such relatively quiescent tidal flats, where an absence wave-driven advection refreshment could allowed oversaturation respect fluorapatite. Here, we present new that characterize setting Sete formations shallow, notable its extensive high-energy lithofacies. In this setting, non-phosphatic stromatolite buildups within same facies, often close (meter- decimeter-scale) spatial one another. These suggest mineralization was function paleogeographically sheltered regions, but rather highly processes enrichment high-energy,