Pacific Equatorial Age Transect (PEAT): Summary

As the largest ocean, the Pacific is intricately linked to major changes in the global climate system that took place during the Cenozoic. Throughout the Cenozoic the Pacific plate has had a northward component. Thus, the Pacific is unique, in that the thick sediment bulge of biogenic-rich deposits from the currently narrowly focused zone of equatorial upwelling is slowly moving away from the equator. Hence, older sections are not deeply buried and can be recovered by drilling. Previous ODP Legs 138 and 199 were designed as transects across the paleo-equator to study the changing patterns of sediment deposition across equatorial regions. As we have gained more information about the past movement of plates, and when in time “critical” climate events took place, we now propose to drill an age transect (“flow-line”) following the position of the paleoequator in the Pacific, targeting selected time slices of interest where calcareous sediments have been preserved best (Fig. 1).