Mesoarchean

Mesoarchean
Mesoarchean
	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
←	Pongola glaciation
	Major Glacial period
	Events of the Mesoarchean.; Vertical axis scale: Millions of years ago
Proposed redefinition(s)	3490–2780 Ma; Gradstein et al., 2012;
Proposed subdivisions	Vaalbaran Period, 3490–3020 Ma; Gradstein et al., 2012; Pongolan Period, 3020–2780 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]

Life timeline

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Earliest multicellular life

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Hirnantian glaciation*

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Quaternary ice age*

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*Ice Ages

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.

^ Antarctica: A Keystone in a Changing World. National Academies Press. 2008. pp. 86–87. ISBN 9780309118545.
^ Zalasiewicz, Jan; Williams, Mark (2012). The Goldilocks Planet: The 4 billion year story of Earth's climate. Oxford University Press. p. 16. ISBN 978-0-19-959357-6.

[1] Antarctica: A Keystone in a Changing World. National Academies Press. 2008. pp. 86–87. ISBN 9780309118545.

[2] Zalasiewicz, Jan; Williams, Mark (2012). The Goldilocks Planet: The 4 billion year story of Earth's climate. Oxford University Press. p. 16. ISBN 978-0-19-959357-6.

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