Upper Eocene to Oligocene isotope (87Sr/86Sr, δ18O, δ13C) standard section, Deep Sea Drilling Project Site 522


  • Kenneth G. Miller,

  • Mark D. Feigenson,

  • Dennis V. Kent,

  • Richard K. Olsson


We improved upper Eocene to Oligocene deep-sea chronostratigraphic control by integrating isotope (87Sr/86Sr, δ18O, δ13C) stratigraphy and magnetostratigraphy. Most previous attempts to establish the timing of isotope fluctuations have relied upon biostratigraphic age estimates which have uncertainties of 0.5 to over 4.0 m.y. Deep Sea Drilling Project (DSDP) Site 522 contains the best available upper Eocene to Oligocene magnetostratigraphic record which allows first-order correlations of isotope records (87Sr/86Sr, δ18O, δ13C) to the Geomagnetic Polarity Time Scale (GPTS). Empirical calibrations between the 87Sr/86Sr of foraminifera and magnetochronology at Site 522 allow more precise correlation of “unknown” samples with the GPTS. For example, shallow water and high-latitude sections may be tied into the deep-sea record. Sr-isotope stratigraphic resolution for the latest Eocene to Oligocene is approximately 2 m.y.