Mezoic Time

The Archean era is the earliest Precambrian era, archean means "ancient" or "beginning". The Archean era starts with the oldest known rocks, about 4.6 billion years ago.

The Archean era is the earliest Precambrian era, archean means "ancient" or "beginning". The Archean era starts with the oldest known rocks, about 4.6 billion years ago.

The Archean era is the earliest Precambrian era, archean means "ancient" or "beginning". The Archean era starts with the oldest known rocks, about 4.6 billion years ago.

Oxygen was generally absent from the atmosphere during the Early Archean Era.