Neoarchean
Neoarchean | |||||||||||
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Chronology | |||||||||||
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Proposed redefinition(s) | 2780–2420 Ma Gradstein et al., 2012 | ||||||||||
Proposed subdivisions | Methanian Period, 2780–2630 Ma Gradstein et al., 2012 | ||||||||||
Etymology | |||||||||||
Name formality | Formal | ||||||||||
Alternate spelling(s) | Neoarchaean | ||||||||||
Usage information | |||||||||||
Celestial body | 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 Neoarchean (
Complex life
This era saw the rise of oxygen in the atmosphere after
Oxygenic photosynthesis may have been limited earlier in the Archean era from a lack of phosphorus stemming from poor biological recycling in anaerobic conditions. This issue was alleviated in the Neoarchean with the abundance of phosphorus in magmatic rocks, which when combined with other evolving geodynamics such as increasing organic matter burial and higher oxidative states in volcanic sulfur and magmatic iron contributed to a large buildup of oxygen in the atmosphere, leading to the Great Oxidation Event in the Paleoproterozoic era.[1]
The earliest evidence of microbial oxidation of sulphur, dating to approximately 2.52 Ga, comes from the Gamohaan Formation of South Africa, revealing that sulphur-oxidising bacteria had evolved prior to the Great Oxidation Event.[2]
Continental formation
During this era, the supercontinent Kenorland is proposed to have formed about 2.7 billion years ago.[3] Kenorland is of particular interest due to it containing deposits of volcanic-hosted massive sulphide, gold, and uranium found in the Canadian Shield. With new research, the validity of Kenorland has been questioned in favor of other Neoarchean supercontinent proposals Superia or Vaalbara.[3] Improved geologic knowledge suggests that a part of Kenorland, specifically the Churchill Province, was instead a continental development that formed after the Neoarchean era, Nuna, closer to 1.9 billion years ago.[3] This challenge to the reconstruction is based on research studying northern Kenorland's Paleoproterozoic cover as well as the suture between the Rae and Hearne cratons.
The
See also
References
- ^ S2CID 225413847. Retrieved 22 January 2023.
- doi:10.1130/G38150.1. Retrieved 22 January 2023.
- ^ ISSN 0301-9268.