Re-examination of the linkages between the Ontong Java volcanism and Cretaceous oceanic anoxic event

Abstract

Ontong Java Plateau is the largest oceanic plateau on the Earth and its association with the mid-Cretaceous Oceanic Anoxic Event (OAE) 1a has been debated so far. Deep Sea Drilling Project (DSDP) Site 167 is an oceanic core that was drilled at the Magellan Rise. The core contains thick volcanic ash intercal which is considered to be derived from the Ontong Java volcanism. In this study, we reconstructed bio-, osmium isotope, and carbon isotope stratigraphy of this core and constrained the sedimentary ages of volcanic ash interval. As a result, we found that the deposition of volcanic ash is almost contemporaneous with the oceanic anoxic event 1a. Our results suggest the causal linkages between these two events.