Paleoarchean

Proposed redefinition(s)4031–3490 Ma
Gradstein et al., 2012
Proposed subdivisionsAcastan Period, 4031–3810 Ma

Gradstein et al., 2012
Isuan Period, 3810–3490 Ma

Gradstein et al., 2012
EtymologyName formalityFormalAlternate spelling(s)PalaeoarchaeanSynonym(s)Early Archean
Usage informationCelestial bodyEarthRegional usageGlobal (ICS)Time scale(s) usedICS Time ScaleDefinitionChronological unitEraStratigraphic unitErathemTime span formalityFormalLower boundary definitionDefined ChronometricallyLower GSSA ratifiedNot formally definedUpper boundary definitionDefined ChronometricallyUpper GSSA ratifiedNot formally defined

The Paleoarchean ( ), also spelled Palaeoarchaean (formerly known as the early Archean), is a geologic era within the Archean Eon. The name derives from Greek "Palaios" ancient. It spans the period of time 3,600 to 3,200 million years ago. The era is defined chronometrically and is not referenced to a specific level of a rock section on Earth. The earliest confirmed evidence of life comes from this era, and Vaalbara, one of Earth's earliest supercontinents, may have formed during this era.