Archean eon


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Related to Archean eon: Proterozoic eon, Phanerozoic eon

Archean eon

The first eon in Earth’s history (4.6–2.5 billion years ago).
ThesaurusAntonymsRelated WordsSynonymsLegend:
Noun1.Archean eon - the time from 3,800 million years to 2,500 million years ago; earth's crust formed; unicellular organisms are earliest forms of life
Precambrian, Precambrian aeon, Precambrian eon, Precambrian period - the eon following the Hadean time and preceding the Phanerozoic eon; from about 3,800 million years ago until 544 million years ago
References in periodicals archive ?
Toward the end of the Archean Eon, about 2.5 billion years ago, cyanobacteria were producing small amounts of free oxygen as a byproduct of photosynthesis.
25 ( ANI ): During the Archean eon, about 3.8 billion years - 2.5 billion years ago, the Sun was about 20 to 25 percent fainter, and with less sunlight, the oceans may have frozen on Earth, but geological evidence suggests that this did not happen.
Evidence of the paradox comes from clues in the rock record that indicate the presence of flowing water as far back as the Archean eon, 3.8 billion to 2.5 billion years ago.
The new 3-D model of the Archean Eon on Earth that lasted from about 3.8 billion years to 2.5 billion years ago, incorporates interactions between the atmosphere, ocean, land, ice and hydrological cycles, said CU-Boulder doctoral student Eric Wolf of the atmospheric and oceanic sciences department.