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15 paź 2024 · The Archean Eon was preceded by the Hadean Eon, an informal division of geologic time spanning from about 4.6 billion to 4 billion years ago and characterized by Earth’s initial formation. Records of Earth’s primitive atmosphere and oceans emerge in the earliest Archean (Eoarchean Era).
- Granulite
granulite facies, one of the major divisions of the mineral...
- Witwatersrand System
Witwatersrand System, major division of Precambrian rocks in...
- Scourian Complex
Other articles where Scourian Complex is discussed:...
- Belts
Other articles where granulite–gneiss belt is discussed:...
- Acasta Gneiss
Other articles where Acasta gneiss is discussed: Archean...
- Amphibolite
Amphibolite, a rock composed largely or dominantly of...
- Granulite
For context, the Archean precedes the Proterozoic eon of 2.5 Ga to 541 ± 1 million years (Ma) ago, and Archean eras provide a timeline for our discussion: the Eoarchean (4 to 3.6 Ga ago), Paleoarchean (3.6 to 3.2 Ga ago), Mesoarchean (3.2 to 2.8 Ga ago), and Neoarchean (2.8 to 2.5 Ga ago).
The Archean Eon (IPA: / ɑːr ˈ k iː ə n / ar-KEE-ən, also spelled Archaean or Archæan), in older sources sometimes called the Archaeozoic, is the second of the four geologic eons of Earth's history, preceded by the Hadean Eon and followed by the Proterozoic.
During the beginning of the Archean Eon, about 4 billion years ago, as the frequency of meteorite impacts slowed, the Earth cooled, clouds formed, and the crust began to harden from the molten globe. The Earth was still a one-plate planet before the inception of plate tectonics.
Archean Eon, or Archaean Eon or Archeozoic Eon, Older of the two divisions of Precambrian time. The Archean begins with the formation of the Earth’s crust 4 billion years ago and extends to 2.5 billion years ago, up to the start of the Proterozoic Eon, the second division of the Precambrian Period.
11 kwi 2024 · The Archean Eon, which lasted from 4.0–2.5 billion years ago, is named after the Greek word for beginning. This eon represents the beginning of the rock record. Although there is current evidence that rocks and minerals existed during the Hadean Eon , the Archean has a much more robust rock and fossil record.
23 lis 2021 · Archean terranes do not contain evidence for major glaciations during the first two billion years of the Earth’s history indicating that a warmer climate (as suggested by high ocean temperatures; Robert and Chaussidon 2006) dominated during the eon.
