Comment on “When did the Anthropocene begin? A mid-twentieth century boundary is stratigraphically optimal” by Jan Zalasiewicz et al. (2015), Quaternary International, 383, 196–203

Abstract We offer a comment on the paper: “When did the Anthropocene begin? A mid-twentieth century boundary is stratigraphically optimal” by Jan Zalasiewicz et al. (2015), Quaternary International , 383, 196–203. We consider this proposal in the context of the procedures and terminology employed by the International Union of Geological Sciences which underpin the formal designation of chronostratigraphic units. Our conclusion is that there is no practical value in establishing the lower boundary of a new interval of geological time in the mid-twentieth century; equally, there is no sound stratigraphical basis for designating an additional chronostratigraphic unit above the Holocene in the international Geological Time Scale.