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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).
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 Archean Eon, which spanned from approximately 4 billion to 2.5 billion years ago, significant geological and biological events unfolded on Earth. Notably, this eon witnessed the formation of the first continents, the development of Earth’s early atmosphere, and the emergence of life in the form of simple, single-celled organisms ...
The Archean Eon (4 to 2.5 billion years ago) During the Archean Eon, methane droplets in the air shrouded the young Earth in a global haze. There was no oxygen gas on Earth. Oxygen was only in compounds such as water.
The atmosphere of the Archean eon—one-third of Earth’s history—is important for understanding the evolution of our planet and Earth-like exoplanets. New geological proxies combined with models constrain atmospheric composition.
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.
The Archean eon, which preceded the Proterozoic eon, spanned about 1.5 billion years and is subdivided into four eras: the Neoarchean (2.8 to 2.5 billion years ago), Mesoarchean (3.2 to 2.8 billion years ago), Paleoarchean (3.6 to 3.2 billion years ago), and Eoarchean (4 to 3.6 billion years ago).*
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.
The Archean Eon lasted from 4.0 to 2.5 billion years ago and 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.
Archean Eon, second of Earth’s three major geological eons of Precambrian time, extends from about 4.0 billion to about 2.5 billion years ago. It follows the Hadean Eon and precedes the Proterozoic Eon.