Re-Assessment of the Eocene-Oligocene Age Model of ODP Hole 647A, with Implications for Correlation of Paleoceanographic Events from Very High to Low Latitudes

Ocean Drilling Program (ODP) Hole 647A in the southern Labrador Sea (~53° N) is the highest latitude Eocene to Oligocene cored sediment sequence with abundant carbonate that overlies oceanic crust. New paleomagnetic and palynologic stratigraphy of this site is tied to the higher latitude magneto-biostratigraphy of Eldrett et al., (2004) for the carbonate-barren Norwegian-Greenland Sea, which in turn allows for a stratigraphic comparison to the carbonate-barren Eocene sediments from the Arctic Ocean (IODP Exp. 302). This new data, along with new planktonic foraminiferal biostratigraphy and stable isotope stratigraphy, has been integrated with previous and updated calcareous nannofossil and diatom biostratigraphies, which has enabled us to better constrain the overall age model and sedimentation rates of this high latitude North Atlantic Eocene to Oligocene sequence. Finally, high-resolution logging data and core physical properties data provide (a) evidence for sediment cyclicity in both the Eocene and Oligocene, (b) independent estimates of sedimentation rates to compare with those calculated by the new magneto-biostratigraphic age model, and (c) evidence of changes in sedimentation rates over certain time intervals that are less well-constrained by the magneto-biostratigraphy. With new age calibrations of dinoflagellate cysts, calcareous nannofossils, planktonic foraminifers, and diatoms to the Geomagnetic Polarity Time Scale, this site provides a unique stratigraphic bridge to correlate certain E-O paleoceanographic events between the carbonate-barren Paleogene of the high northern latitudes to the carbonate and biosilica-rich sediments of the middle and lower latitudes of the Atlantic Ocean, and perhaps to other ocean basins. 2004 Eldrett, J.S., Harding, I.C., Firth, J.V. and Roberts, A.P. Magnetostratigraphic calibration of Eocene to Oligocene dinoflagellate cyst biostratigraphy from the Norwegian-Greenland Sea. Marine Geology, 204: 91-127. ODP Site 647 and DSDP Site 112 in the Southern Labrador Sea