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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. The Archean represents the time period from (million years
Early Archean: Usage information; Celestial body: ... is a geologic era within the Archean Eon. ... It is likely that during the Paleoarchean era, there was a large ...
ɑːr ˈ k iː ə n / EE-oh-ar-KEE-ən; also spelled Eoarchaean) is the first era of the Archean Eon of the geologic record. It spans 431 million years, from the end of the Hadean Eon 4031 Mya to the start of the Paleoarchean Era 3600 Mya. Some estimates place the beginnings of life on Earth in this era, while others [2] place it earlier.
The Phanerozoic Eon (Greek: period of well-displayed life) marks the appearance in the fossil record of abundant, shell-forming and/or trace-making organisms. It is subdivided into three eras, the Paleozoic , Mesozoic and Cenozoic , with major mass extinctions at division points.
Artist's impression of Earth during its second eon, the Archean. The eon started with the Late Heavy Bombardment around 4.031 billion years ago. As depicted, Earth's planetary crust had largely cooled, leaving a water-rich barren surface marked by volcanoes and continents, eventually developing round microbialites.
Early Earth also known as proto-earth is loosely defined as encompassing Earth in its first one billion years, or gigayear (Ga, 10 9 y), [1] from its initial formation in the young Solar System at about 4.55 Ga to some time in the Archean eon in approximately 3.5 Ga. [2] On the geologic time scale, this comprises all of the Hadean eon, starting ...
The Mesoarchean (/ ˌ m iː z oʊ. ɑːr ˈ k iː ə n, ˌ m ɛ z oʊ-/ MEE-zoh-ar-KEE-ən, MEZ-oh-, also spelled Mesoarchaean) is a geologic era in the Archean Eon, spanning , which contains the first evidence of modern-style plate subduction and expansion of microbial life.
The Neoarchean (/ ˌ n iː oʊ. ɑːr ˈ k iː ə n / NEE-oh-ar-KEE-ən; also spelled Neoarchaean) is the last geologic era in the Archean Eon that spans from 2800 to 2500 million years ago—the period being defined chronometrically and not referencing a specific level in a rock section on Earth.