DISCUSSION WHAT, IF ANYTHING, IS QUATERNARY?

The incorporation of Quaternary as a new Period/System, as voted by the ICS in May 2009, is a paradigm shift in the geological time scale. Until now the progressive, irreversible change of the earth’s biota has been the single governing principle in organizing the global stratigraphic record according to age. The Quaternary, on the other hand, is explicitly defined according to paleoclimatological criteria, and the ICS vote holds that the concept of “first glacial episode in the Northern Hemisphere ” supersedes the biochronological identity of the Neogene Period/System, the later part of which occupies the same interval. Furthermore, the primacy granted to this datum requires a 44 % expansion of the Pleistocene Epoch/Series in order to being it into conformity with the Quaternary concept, without regard for Lyell’s original “conchological ” meaning. These actions demonstrate that accomodating a time scale unit defined by non-paleontological criteria, with the goal of recognizing a special aspect of geological history, legitimizes ad hoc time scale boundaries without an inherent age and lacking a uniform philosophy. The increased potential for conflict between disciplines intent o