Cenozoic ice-volume history: Development of a composite oxygen isotope record

To view Cenozoic ice-volume and ocean-temperature history, a composite δ¹⁸O time series was constructed for tropical shallow-dwelling planktonic foraminifers and for deep-water benthic foraminifers. We conclude that Cenozoic benthic δ¹⁸O primarily reflect considerable deep-ocean temperature variation and that tropical planktonic δ¹⁸O afford the best record of Cenozoic ice volume. The planktonic composite indicates the presence of a significant ice budget for the past 40 m.y. The difference between the benthic and planktonic δ¹⁸O composites suggests that low-latitude production of warm saline bottom water dominated Tertiary thermohaline circulation.