https://gcmd.earthdata.nasa.gov/kms/concept/8dff752e-939d-4b16-a735-bb4af8dbd785
broader |
|
|||||||||
---|---|---|---|---|---|---|---|---|---|---|
change note |
|
|||||||||
definition | The Eoarchean is the first era of the Archean Eon of the geologic record for which the Earth has a solid crust. It spans 400 million years from the end of the Hadean Eon 4 billion years ago (4000 Mya) to the start of the Paleoarchean Era 3600 Mya. The beginnings of life on Earth have been dated to this era and evidence of cyanobacteria date to 3500 Mya, just outside this era. At that time, the atmosphere was without oxygen and the pressure values ranged from 10 to 100 bar (around 10 to 100 atmospheres). | |||||||||
reference |
|
|||||||||
type |
|
|||||||||
in scheme | chronounits original |