Mesoarchean | ||||||||||||||||
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![]() A reconstruction of the Earth's continents during the middle Mesoarchean, c. 3 Ga.[citation needed] | ||||||||||||||||
![]() Artist impression of the Archean eon | ||||||||||||||||
![]() Banded iron formation created during the Mesoarchean era | ||||||||||||||||
Chronology | ||||||||||||||||
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Proposed redefinition(s) | 3490–2780 Ma Gradstein et al., 2012 | |||||||||||||||
Proposed subdivisions | Vaalbaran Period, 3490–3020 Ma Gradstein et al., 2012 | |||||||||||||||
Etymology | ||||||||||||||||
Name formality | Formal | |||||||||||||||
Alternate spelling(s) | Mesoarchaean | |||||||||||||||
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] |
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The Mesoarchean (/ˌmiːzoʊ.ɑːrˈkiːən, ˌmɛzoʊ-/ MEE-zoh-ar-KEE-ən, MEZ-oh-, also spelled Mesoarchaean) is a geologic era in the Archean Eon, spanning 3,200 to 2,800 million years ago, which contains the first evidence of modern-style plate subduction and expansion of microbial life. The era is defined chronometrically and is not referenced to a specific level in a rock section on Earth.