Paleoarchean
| Paleoarchean | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Chronology | |||||||||||
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| Proposed redefinition(s) | 4031–3490 Ma Gradstein et al., 2012 | ||||||||||
| Proposed subdivisions | Acastan Period, 4031–3810 Ma Gradstein et al., 2012 | ||||||||||
| Etymology | |||||||||||
| Name formality | Formal | ||||||||||
| Alternate spelling(s) | Palaeoarchaean | ||||||||||
| Synonym(s) | Early Archean | ||||||||||
| Usage information | |||||||||||
| Celestial body | Earth | ||||||||||
| Regional usage | Global (ICS) | ||||||||||
| Time scale(s) used | ICS Time Scale | ||||||||||
| Definition | |||||||||||
| Chronological unit | Era | ||||||||||
| Stratigraphic unit | Erathem | ||||||||||
| Time span formality | Formal | ||||||||||
| Lower boundary definition | Defined Chronometrically | ||||||||||
| Lower GSSA ratified | 1991 | ||||||||||
| Upper boundary definition | Defined Chronometrically | ||||||||||
| Upper GSSA ratified | 1991 | ||||||||||
The Paleoarchean (/ˌpeɪlioʊ.ɑːrˈkiːən, ˌpæl-/ PAY-lee-oh-ar-KEE-ən, PAL-), 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.