Ontong Java Plateau eruption as a trigger for the early Aptian oceanic anoxic event

The Early Cretaceous Ontong Java Plateau was emplaced at the same time as marine biotic changes that culminated in oceanic event 1 (OAE1a). A causative link between these events been suggested, but direct evidence has been lacking until now. Os isotope measurements across the Lower Aptian “Selli Level” shale deposited during OAE1a in central Italy reveal two negative in marine 187Os/188Os ratios within a period of 2 Ma above the Barremian-Aptian boundary and ending just above Selli Level horizon, suggesting an order-of-magnitude increase the global fl ux of unradiogenic Os. The results are consistent with and major phases of eruption of the Ontong Java Plateau. The phase is estimated to have been as short as ~1 Ma and may have widespread oceanic stratifi cation that triggered OAE1a.