Mesoarchean

Mesoarchean
3200 – 2800 Ma Pha. Proterozoic Archean Had.
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
−3200 — – −3150 — – −3100 — – −3050 — – −3000 — – −2950 — – −2900 — – −2850 — – −2800 — – A r c h e a n Paleoarchean Mesoarchean Neoarchean   ← Pongola glaciation[1][2]   Major Glacial period Events of the Mesoarchean. 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]

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.