Neoarchean | |||||||||||
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![]() A reconstruction of the Earth's continents during the middle Neoarchean, c. 2.65 Ga.[citation needed] | |||||||||||
Chronology | |||||||||||
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Proposed redefinition(s) | 2780–2420 Ma Gradstein et al., 2012 | ||||||||||
Proposed subdivisions | Methanian Period, 2780–2630 Ma Gradstein et al., 2012 | ||||||||||
Etymology | |||||||||||
Name formality | Formal | ||||||||||
Alternate spelling(s) | Neoarchaean | ||||||||||
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[citation needed] | ||||||||||
Upper boundary definition | Defined Chronometrically | ||||||||||
Upper GSSA ratified | 1991[citation needed] |
The Neoarchean (/ˌniːoʊ.ɑːrˈkiːən/ NEE-oh-ar-KEE-ən; also spelled Neoarchaean) is the last geologic era in the Archean Eon that spans from 2800 to 2500 million years ago—the period being defined chronometrically and not referencing a specific level in a rock section on Earth. The era is marked by major developments in complex life and continental formation.