Eozoic
Eozoic (from Greek: Eos , Ēōs = "dawn" and zôon = " living being ") is an outdated term for the Proterozoic - 2,500 to 542 mya , the section of earth's history in which life originated.
The geological period before the Eozoic was called the Azoic - 4,000 to 2,500 mya. By this one understood the earliest phase of the earth's development, in which there was certainly no life. The boundary between the Azoic and Eozoic (2,500 mya), like that of the Hadaic (4,000 mya), was controversial because of the small number of fossil finds.
In any case, the end of the Eozoic era was fixed at the beginning of the Cambrian , i.e. 542 million years ago, because fossils of most of the animal phyla known today have been preserved since the beginning of the “ Cambrian Explosion ” . It could therefore be assumed that the emergence of life was essentially completed with the beginning of the Cambrian.
Newer finds and methods of determining the oldest geological layers have led to a different division of the Precambrian , i.e. the period from the formation of the earth to the Cambrian. This period is now divided into three eons :
- Proterozoic 2,500 - 542 million years ago
- Archean 4,000 - 2,500 million years ago
- Hadaikum from the formation of the earth's solid crust up to 4,000 million years ago
The most recent eon, which begins with the Cambrian 542 million years ago and extends to our days, is called the Phanerozoic . It starts with the age of the Paleozoic era (Paleozoic), which also includes the Cambrian. This is followed by the Mesozoic (Earth Middle Ages) and Cenozoic (New Earth) ages .