Mesoarchean

Mesoarchean
3200 – 2800 Ma
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
Proposed redefinition(s)3490–2780 Ma
Gradstein et al., 2012
Proposed subdivisionsVaalbaran Period, 3490–3020 Ma

Gradstein et al., 2012
Pongolan Period, 3020–2780 Ma

Gradstein et al., 2012
Etymology
Name formalityFormal
Alternate spelling(s)Mesoarchaean
Usage information
Celestial bodyEarth
Regional usageGlobal (ICS)
Time scale(s) usedICS Time Scale
Definition
Chronological unitEra
Stratigraphic unitErathem
Time span formalityFormal
Lower boundary definitionDefined Chronometrically
Lower GSSA ratified1991[citation needed]
Upper boundary definitionDefined Chronometrically
Upper GSSA ratified1991[citation needed]

The Mesoarchean (/ˌmz.ɑːrˈkən, ˌmɛz-/ 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.

  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.