Dynamic deep-water circulation in the northwestern Pacific during the Eocene: Evidence from Ocean Drilling Program Site 884 benthicforaminiferal stable isotopes (?18O and ?13C)

Аннотация

New benthic foraminiferal δ18O and δ13C data from Ocean Drilling Program (ODP) Site 884 (northwestern Pacific) add significant structure to a previous lower resolution record; our higher resolution detail and comparisons with published isotopic records provide new insights into paleoceanographic changes in the northwestern Pacific from the middle Eocene to the early Oligocene. From the early-middle until the mid-middle Eocene (ca. 49–43 Ma), a comparison of the Site 884 δ18O values with published ODP δ18O records from the Pacific (Site 1218), Atlantic (Site 1260), and Southern Ocean (Site 689) reveals that these basins were bathed by a common water mass, probably originating from the Southern Ocean, or by different water masses having a similar δ18O signature. From the mid-middle until the early-late Eocene (ca. 42–37 Ma), the Site 884 record reveals increasing complexity in deep-water circulation.