The Early Pleistocene is a subseries in the international geologic timescale in chronostratigraphy, representing the earliest division of the Pleistocene Epoch within the ongoing Quaternary Period. It is currently estimated to span the time between 2.580 ± 0.005 Ma (million years ago) and 0.773 ± 0.005 Ma. The term Early Pleistocene encompasses both the Gelasian Age and the Calabrian Age.Cohen K.M. & Gibbard, P., 2019, Global chronostratigraphical correlation table for the last 2.7 million years, version 2019 QI-500. Quaternary International, 500, 20–31.
The Gelasian and the Calabrian have officially been defined by the International Union of Geological Sciences (IUGS) to effectively constitute the Early Pleistocene. Notes