Archean
Geologic time period
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The Archean Eon, 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 4,031 to 2,500... Wikipedia
Occurred: 4,000 million years ago - 2,500 million years ago
Eras: Eoarchean, Paleoarchean, Mesoarchean, and more
Synonym(s): Eozoic;
Alternate spelling(s): Archaean, Archæan
Celestial body: Earth
Chronological unit: Eon
Lower boundary definition: Ten oldest U-Pb zircon ages