Equatorial pacific seismic reflectors as indicators of global oceanographic events.

The origin of a series of regionally correlatable seismic horizons in the Neogene sediments of the central equatorial Pacific is examined through seismic modeling and the detailed analyses of stratigraphic and physical property relationships in Deep Sea Drilling Project cores. These regionally traceable reflectors are synchronous; the younger reflectors are the direct result of carbonate dissolution events, the older ones of stratigraphically selective diagenetic processes. The changes in ocean chemistry associated with these events appear to be linked to global reorganizations of surface and bottom-water circulation patterns, the most dramatic of which are associated with reorganizations of North Atlantic bottom waters. These deepwater seismic horizons appear to correlate with the major events on the "relative sea-level" curve of Vail et al. for the Neogene.

Rapid formation of ontong java plateau by aptian mantle plume volcanism.

The timing of flood basalt volcanism associated with formation of the Ontong Java Plateau (OJP) is estimated from paleomagnetic and paleontologic data. Much of OJP formed rapidly in less than 3 million years during the early Aptian, at the beginning of the Cretaceous Normal Polarity Superchron. Crustal emplacement rates are inferred to have been several times those of the Deccan Traps. These estimates are consistent with an origin of the OJP by impingement at the base of the oceanic lithosphere by the head of a large mantle plume. Formation of the OJP may have led to a rise in sea level that induced global oceanic anoxia. Carbon dioxide emissions likely contributed to the mid-Cretaceous greenhouse climate but did not provoke major biologic extinctions.