title: Thermal structure of the deep pacific ocean in the early pliocene.
abstract: The thermal structure of the Pacific Ocean between water depths of about 1 and 4.5 kilometers is estimated from the oxygen isotopic ratio of benthonic foraminifera from deep-drilled and piston cores of early Pliocene age (about 3 to 5 million years ago). The ratio of oxygen-18 to oxygen-16 in the early Pliocene at each site varies by an average of only +/- 0.12 per mil (1 standard deviation). A plot of the oxygen isotopic ratio against modern bottom-water temperature is adequately fit by a line having a slope of - 0.26 per mil per degree Celsius (the equilibrium temperature dependence of calcite-water fractionation), suggesting that the temperature gradient of the Pacific Ocean during the early Pliocene was similar to that of today.
authors.forename: L D
authors.initials: LD
authors.lastname: Keigwin
authors.forename: M L
authors.initials: ML
authors.lastname: Bender
authors.forename: J P
authors.initials: JP
authors.lastname: Kennett