Evolution and variability of the pleistocene ice ages: A new view

Abstract

The evolution and variability of Pleistocene glaciations is studied by comparison of the benthic 18O stack LR04 and the Orbital Climatic Diagram (OrCD). Taking into account that the OrCD construction is based on a very simple principal, it corresponds well to the LR04 data within the last 1.25 Myr. It is shown that along with cases of good evidence for climatic influence of joint action by precession and obliquity variations there are some concrete situations in the paleoclimatic record of the last 1 Myr when this evidence is absent. A shift in the main periodicity of glacial cycles (the Middle Pleistocene transition, MPT) took place at around 1.239 Myr ago. Some possible mechanisms of the MPT are considered, and we argue that parametric resonance is the underlying mechanism responsible for the MPT phenomenon.