Climatic-oceanic forcing on the organic accumulation across the shelf during the Early Cambrian (Age 2 through 3) in the mid-upper Yangtze Block, NE Guizhou, South China

•Integrated sedimentological and geochemical constraints on organic enrichment in the Early Cambrian, South China.•Extraordinary high bioproductivity was fueled by wind-induced upwelling during transgressions under a relatively arid climate.•Sulfidic water wedges only localized in the high-productivity zone on the shallow mid-upper slope of open shelf.•Nonsulfidic anoxic waters extensive in the deeper open shelf basin or intrashelf basins landwards.•Climatic-oceanic co-evolution controlled the high heterogeneities in productivity and redox states.