The Mesoarchean (//, also spelled Mesoarchaean) is a geologic era within the Archean Eon, spanning . The era is defined chronometrically and is not referenced to a specific level in a rock section on Earth. The Pongola glaciation occurred around . The first supercontinent Vaalbara broke up during this era about .
|3200 – 2800 Ma|
|Proposed redefinition(s)||3490–2780 Ma|
Gradstein et al., 2012
|Proposed subdivisions||Vaalbaran Period, 3490–3020 Ma|
Gradstein et al., 2012
|Regional usage||Global (ICS)|
|Time scale(s) used||ICS Time Scale|
|Time span formality||Formal|
|Lower boundary definition||Defined Chronometrically|
|Lower boundary GSSP||N/A|
|Upper boundary definition||Defined Chronometrically|
|Upper boundary GSSP||N/A|
Analysis of oxygen isotopes in Mesoarchean cherts led to an oceanic temperature estimate around 55-85 °C, while other studies of weathering rates postulate average temperatures below 50 °C. Dinitrogen content in the atmosphere is thought to have been fundamentally similar to today's, and the partial pressure of carbon dioxide was probably lower than 0.7 bar.
- Geologic time scale – system that relates geological strata to time
- Glacial period – Interval of time within an ice age that is marked by colder temperatures and glacier advances
- Ice age – Period of long-term reduction in temperature of Earth's surface and atmosphere
- Last glacial period
- Robert E. Kopp; Joseph L. Kirschvink; Isaac A. Hilburn & Cody Z. Nash (2005). "The Paleoproterozoic snowball Earth: A climate disaster triggered by the evolution of oxygenic photosynthesis". Proc. Natl. Acad. Sci. U.S.A. 102 (32): 11131–6. Bibcode:2005PNAS..10211131K. PMC 1183582. PMID 16061801. Retrieved 2011-06-19.
- Knauth, L. P. Lowe, D. R. High Archean climatic temperature inferred from oxygen isotope geochemistry of cherts in the 3.5 Ga Swaziland group, South Africa, Geol. Soc. Amer. Bull. 115 (2003) 566 – 580.
- Sleep, Norman H.; Hessler, Angela M. (January 2006). "Weathering of quartz as an Archean climatic indicator" (PDF). Earth and Planetary Science Letters. 241 (3–4): 594–602. Bibcode:2006E&PSL.241..594S. doi:10.1016/j.epsl.2005.11.020. Archived (PDF) from the original on 10 March 2018. Retrieved 10 March 2018.
- Marty, Bernard; Zimmermann, Laurent; Pujol, Magali; Burgess, Ray; Philippot, Pascal (4 October 2013). "Nitrogen Isotopic Composition and Density of the Archean Atmosphere". Science. 342 (6154): 101–104. arXiv:1405.6337. Bibcode:2013Sci...342..101M. doi:10.1126/science.1240971. ISSN 0036-8075. PMID 24051244.