Paleoarchean: Difference between revisions
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During this era, a large asteroid, about {{convert|37|to(-)|58|km}} wide, collided with the Earth in the area of South Africa about 3.26 billion years ago, creating the features known as the [[Barberton greenstone belt]].<ref>[http://news.agu.org/press-release/scientists-reconstruct-ancient-impact-that-dwarfs-dinosaur-extinction-blast/ “Scientists reconstruct ancient impact that dwarfs dinosaur-extinction blast”, American Geophysical Union, April 9, 2014]</ref> |
During this era, a large asteroid, about {{convert|37|to(-)|58|km}} wide, collided with the Earth in the area of South Africa about 3.26 billion years ago, creating the features known as the [[Barberton greenstone belt]].<ref>[http://news.agu.org/press-release/scientists-reconstruct-ancient-impact-that-dwarfs-dinosaur-extinction-blast/ “Scientists reconstruct ancient impact that dwarfs dinosaur-extinction blast”, American Geophysical Union, April 9, 2014]</ref> |
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The average temperatures on the era were about 32-35 degrees celsius, dropping to 26 degrees at the start of [[Mesoarchean]].{{dubious|date=October 2021}} |
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==References== |
==References== |
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Revision as of 03:15, 22 October 2021
| Paleoarchean | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Chronology | |||||||||||
| |||||||||||
| Proposed redefinition(s) | 4031–3490 Ma Gradstein et al., 2012 | ||||||||||
| Proposed subdivisions | Acastan Period, 4031–3810 Ma Gradstein et al., 2012 | ||||||||||
| Etymology | |||||||||||
| Name formality | Formal | ||||||||||
| Alternate spelling(s) | Palaeoarchaean | ||||||||||
| Synonym(s) | Early Archean | ||||||||||
| 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 boundary GSSP | N/A | ||||||||||
| Lower GSSP ratified | N/A | ||||||||||
| Upper boundary definition | Defined Chronometrically | ||||||||||
| Upper boundary GSSP | N/A | ||||||||||
| Upper GSSP ratified | N/A | ||||||||||
The Paleoarchean (/ˌpeɪlioʊɑːrˈkiːən/), also spelled Palaeoarchaean (formerly known as early Archean), is a geologic era within the Archaean Eon. It spans the period of time 3,600 to 3,200 million years ago—the era is defined chronometrically and is not referenced to a specific level of a rock section on Earth. The name derives from Greek "Palaios" ancient. The oldest ascertained life form of fossilized bacteria in microbial mats, 3,480 million years old, found in the Dresser Formation in Western Australia, is from this era.[2][3] The first supercontinent Vaalbara formed during this era.
During this era, a large asteroid, about 37 to 58 kilometres (23–36 mi) wide, collided with the Earth in the area of South Africa about 3.26 billion years ago, creating the features known as the Barberton greenstone belt.[4]
References
- ^ Caredona, Tanai (6 March 2018). "Early Archean origin of heterodimeric Photosystem I". Heliyon. 4 (3): e00548. doi:10.1016/j.heliyon.2018.e00548. PMC 5857716. PMID 29560463. Retrieved 25 February 2021.
- ^ Borenstein, Seth (13 November 2013). "Oldest fossil found: Meet your microbial mom". AP News. Retrieved 15 November 2013.
- ^ Noffke, Nora; Christian, Daniel; Wacey, David; Hazen, Robert M. (8 November 2013). "Microbially Induced Sedimentary Structures Recording an Ancient Ecosystem in the ca. 3.48 Billion-Year-Old Dresser Formation, Pilbara, Western Australia". Astrobiology. 13 (12): 1103–24. Bibcode:2013AsBio..13.1103N. doi:10.1089/ast.2013.1030. PMC 3870916. PMID 24205812.
- ^ “Scientists reconstruct ancient impact that dwarfs dinosaur-extinction blast”, American Geophysical Union, April 9, 2014
External links
Paleoarchean.
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