Hadean, Archean and Proterozoic Eons
Click here for the Phanerozoic Eon
| EON | ERA | PERIOD | EPOCH | YEARS |
|---|---|---|---|---|
| HADEAN | none | none | none | 4.6 – 4 bya |
| EON | ERA | PERIOD | EPOCH | YEARS |
|---|---|---|---|---|
| ARCHEAN | Eoarchean | none | none | 4 – 3.6 bya |
| ARCHEAN | Paleoarchean | none | none | 3.6 – 3.2 bya |
| ARCHEAN | Mesoarchean | none | none | 3.2 – 2.8 bya |
| ARCHEAN | Neoarchean | none | none | 2.8 – 2.5 bya |
| EON | ERA | PERIOD | EPOCH | YEARS |
|---|---|---|---|---|
| PROTEROZOIC | Paleoproterozoic | Siderian | none | 2.5 – 2.3 bya |
| PROTEROZOIC | Paleoproterozoic | Rhyacian | none | 2.3 – 2.05 bya |
| PROTEROZOIC | Paleoproterozoic | Orosirian | none | 2.05 – 1.8 bya |
| PROTEROZOIC | Paleoproterozoic | Statherian | none | 1.8 – 1.6 bya |
| PROTEROZOIC | Mesoproterozoic | Calymmian | none | 1.6 – 1.4 bya |
| PROTEROZOIC | Mesoproterozoic | Ectasian | none | 1.4 – 1.2 bya |
| PROTEROZOIC | Mesoproterozoic | Stenian | none | 1.2 – 1.0 bya |
| PROTEROZOIC | Neoproterozoic | Tonian | none | 1.0 – .850 bya |
| PROTEROZOIC | Neoproterozoic | Cryogenian | none | .850 – .635 bya |
| PROTEROZOIC | Neoproterozoic | Ediacaran | none | .635 – .542 bya |
“bya” means billions of years ago
The Earth’s geological ages are classified as follows:
4 eons, each of which lasts approximately a billion years.
10 eras, each lasting about several hundred million years.
22 periods, which last about a hundred million years each. Only the proterozoic and the phanerozoic eons are divided into periods.
34 epochs, each lasting tens of millions of years. Only the phanerozoic eon is divided into epochs.