Gelasian

Formerly part ofTertiaryPeriod/System
PlioceneEpoch/SeriesEtymologyName formalityFormalName ratifiedAugust 1996Usage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitAgeStratigraphic unitStageTime span formalityFormalLower boundary definition

• Base of magnetic polarity chronozone C2r (Matuyama)
• Extinction of the HaptophytesDiscoaster pentaradiatus and Discoaster surculus

Lower boundary GSSPMonte San Nicola Section, Gela, Sicily, Italy
37°08′49″N14°12′13″E / 37.1469°N 14.2035°E / 37.1469; 14.2035Lower GSSP ratifiedAugust 1996 (as base of Gelasian)Upper boundary definitionApproximately 8 m after the end of magnetic polarity chronozone C2n (Olduvai).Upper boundary GSSPVrica Section, Calabria, Italy
39°02′19″N17°08′05″E / 39.0385°N 17.1348°E / 39.0385; 17.1348Upper GSSP ratified5 December 2011 (as base of Calabrian)

The Gelasian is an age in the international geologic timescale or a stage in chronostratigraphy, being the earliest or lowest subdivision of the Quaternary Period/System and Pleistocene Epoch/Series. It spans from 2.58–1.80 million years ago, following the Piacenzian Age (from the Pliocene Epoch) and preceding the Calabrian Age.