Pacific Pleistocene paleoclimatic stratigraphies: A comparative analysis of results

Global atmospheric and oceanic circulation effects of expansion of continental ice sheets initiated upwelling in the western equatorial Pacific and simultaneously intensified upwelling in the eastern equatorial Pacific; contraction of the ice sheets reversed the process. Published Pleistocene paleoclimatic stratigraphies correlated across the entire equatorial Pacific exhibit eight such cycles in the Brünhes epoch. The extrapolated chronostratigraphies for the equatorial Pacific compare favorably with published paleoclimatic schemes for the southeastern, eastern, and northern Pacific Ocean. The Southern Ocean record exhibits fewer, and possibly also consistently older, climatic variations. A time progression or lack of synchrony of marine Pleistocene climatic events is not inconsistent with modified “Milankovitch” hypotheses, such as that involving Antarctic ice-sheet instability.