In2Cretaceous – evaluating the potential of equatorial Pacific Shatsky Rise sedimentary deposits for extending high resolution paleoceanographic reconstructions from the Maastrichtian into the Campanian (72 to 84 million years before present)

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Climate records from Late Cretaceous unconsolidated sedimentary deposits containing unaltered carbonate rich microfossils from scientific ocean drilling are extremely rare. Carbonate microfossil rich deposits from the deep sea floor are the prime target of paleoceanographic research. They harbor compounds that allow, for example, to reconstruct past global temperature changes, polar ice sheet variations and global carbon cycle dynamics on time scales of thousand to millions of years. To be able to correctly read past climate information out of the microscopic fossil shells, their initial geochemical composition must be retained unaltered. One outstanding example for the recovery of still soft carbonate rich mud from the Late Cretaceous by scientific ocean drilling is the Ocean Drilling Program (ODP) Expedition 198 to Shatsky Rise, a medium-sized volcanic plateau in the west-central Pacific. At several drill sites carbonate ooze was recovered spanning Maastrichtian to Campanian age (66 to 84 Ma). Several paleoceanographic studies using this material revealed important insight to the development of climate and biota during Late Cretaceous greenhouse conditions. However, with respect to state-of-the-art paleoclimatic reconstructions from the Cenozoic, the last 66 million years, studies of the Late Cretaceous lack resolution and completeness to rigorously read past climate dynamics. Recently, this frontier was moved back in time to 72 million years by establishing a new composite drill record and stable isotope stratigraphy from soft sediments of Shatsky Rise. The objectives of this project are to push this frontier even further back in time by developing a complete composite record for the Campanian, 72 to 84 Ma, using sediment deposits drilled on the Shatsky Rise. The composite record will be defined based on the correlation of X-ray fluorescence core scanning data generated from all available cores from Shatsky Rise. Additionally, a bulk stable carbon and oxygen isotope record will be generated from the new composite to establish a global geochronological reference for the Campanian Stage to guide future paleoceanographic research. The second goal of the project is to contribute to the development of an international scientific drilling expedition proposal to Shatsky Rise to recover unconsolidated sediments at new drill sites to cover existing gaps and expand the recovery of complete sedimentary sequences deep into the Late Cretaceous.