Miocene to early Pliocene oxygen and carbon isotope stratigraphy in the southwest Pacific, Deep Sea Drilling Project 90.

Abstract

The benthic oxygen isotope record exhibits several major features during the Neogene. During the remainder of the middle and late Miocene, benthic d18O values exhibit distinct fluctuations, but the average value remained unchanged. The isotopic data show two distinct episodes of climatic cooling close to the middle/late Miocene boundary. During the middle Pliocene, at about 3.4 Ma, a 0.4 per mille increase in benthic d18O documents a net increase in average global ice volume and cooling of bottom waters. During this interval of increased glaciation, surface waters warmed by 2-3oC in southern middle-latitude regions. -from Author