| Dictionary, Encyclopedia and Thesaurus - The Free Dictionary 1,778,010,891 visitors served. |
|
Dictionary/ thesaurus | Medical dictionary | Legal dictionary | Financial dictionary | Acronyms | Idioms | Encyclopedia | Wikipedia encyclopedia | ? |
Archean Eon |
Also found in: Dictionary/thesaurus, Wikipedia | 0.01 sec. |
Archean Eonor Archaean Eon or Archeozoic EonOlder of the two divisions of Precambrian time. The Archean begins with the formation of the Earth's crust 4 billion years ago and extends to 2.5 billion years ago, up to the start of the Proterozoic Eon, the second division of the Precambrian Period. The earliest and most-primitive forms of life (bacteria and cyanobacteria) originated more than 3.5 billion years ago in the middle of the Archean Eon (the Archean's alternative name, Archeozoic, means “ancient life”). How to thank TFD for its existence? Tell a friend about us, add a link to this page, add the site to iGoogle, or visit webmaster's page for free fun content. |
|
| ? Mentioned in | ? References in periodicals archive | |
|---|---|---|
billion years ago during the Archean eon (the oldest time from which rocks still exist) and, with one exception, has not erupted since. |
| Encyclopedia |
| Free Tools: |
For surfers:
Free toolbar & extensions |
Word of the Day |
Help
For webmasters: Free content | Linking | Lookup box | Double-click lookup | Partner with us |
|---|