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

We improved upper Eocene to Oligocene deep‐sea chronostratigraphic control by integrating isotope ( 87 Sr/ 86 Sr, δ 18 O, δ 13 C) 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 ( 87 Sr/ 86 Sr, δ 18 O, δ 13 C) to the Geomagnetic Polarity Time Scale (GPTS). Empirical calibrations between the 87 Sr/ 86 Sr 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.