Early Toarcian black shales: A response to an oceanic anoxic event or anoxia in marginal basins?

The Early Toarcian, organic-rich, black shales of the Cleveland Basin, Yorkshire UK, are the type sediments for the supposed early Toarcian oceanic anoxic event. The sediments have values of Cd/Mo that are <0.1 and values of Co (mg/kg) × Mn (%) that are >0.4. These values are typical of sediment deposited in modern basins that are hydrographically restricted and show that the Cleveland Basin was hydrographically restricted when depositing...