Eocene-Oligocene boundary reference sections in the Pacific.

DSPD site 292 on the Benham Rise represents the best reference section for the low latitude Pacific Ocean. Two microtectite horizons are seen in zones P16 and P15 and an anomalously high Ir reading was obtained in zone P15 associated with the microtectite horizon and dated at c38.2 Ma. Microtectite correlations are discussed. Discoaster barbadiensis and D. saipanensis are last observed below the E/O boundary as defined by Globorotalia cerroazulensis. DSDP site 592 on Lord Howe Rise is the best middle latitude site with LO of typical forms occurring at the E/O boundary. The slight diachronism noted is discussed. Concludes that it is necessary to separate high and low latitude reference sections and suggests calibrating sections by means of the oxygen isotope record. -after Authors