The Archean Eon (4–2.5 million years ago) is the second of Earth’s four major geologic eons, a time when the planet was mostly covered by oceans extending far deeper than those found today.

While this understanding helps illustrate some of the strange morphologies of these fossils, it isn’t definitive ... that timeline well into the Archean Eon. Most assume that the first cells ...

The Hadean eon represents the time from which Earth first formed. The subsequent Archean eon (approximately 3,500 million years ago) is known as the age of bacteria and archaea. The Proterozoic ...

Tajika and his team used a numerical model to simulate key aspects of biological, geological and chemical changes during the late Archean eon (3.0-2.5 billion years ago) of Earth's geologic history.

Tajika and his team used a numerical model to simulate key aspects of biological, geological and chemical changes during the late Archean eon (3.0–2.5 billion years ago) of Earth's geologic history.