Geological Eras
| Eon | Era | Period | Epoch | Began* | Geology | Life on Earth |
|
|
|
QUATERNARY | Holocene | 0.01 | Glaciers recede; our world emerges |
Homo sapiens dominates |
| Pleistocene | 2.00 | Glaciation and melt affect sea levels |
Primitive man appears | |||
| TERTIARY | Pliocene | 5.1 | Continents near
their present positions |
Some extinctions; primates flourish |
||
| Miocene | 24.6 | Sea levels continue
to fall; mountains erode |
Grasses widespread; grazing mammals |
|||
| Oligocene | 38.0 | Sea levels fall; new mountains form |
Crabs and snails appear; grasses appear |
|||
| Eocene | 54.9 | Mountain formation and glaciation |
Whales, jungles
established. Mammals continue to develop |
|||
| Palaeocene | 65.0 | Extensive land
subsidence; widespread volcanic activity |
First primates
appear; giant reptiles disappear on land and sea |
|||
|
|
CRETACIOUS | Late | 97.5 | Extensive
swamps; limestone and alluvial desposition. Continents move apart |
Turtles
and rays appear; flowering plants established; dinosaurs disappear |
|
| Early | 144 | |||||
| JURASSIC | Malm | 163 | Mountain
erosion; limestone forms. Atlantic Ocean opens |
Marine
reptiles and land dinosaurs dominate. First birds appear |
||
| Dogger | 188 | |||||
| Lias | 213 | |||||
| TRIASSIC | Late | 231 | Extensive
desertification, turning to hot and wet conditons |
Ichthyosaurs
and crustcea appear; mammals and dinosaurs appear |
||
| Middle | 243 | |||||
| Early | 248 | |||||
|
|
PERMIAN | Late | 258 | Mountain
formation; glaciation in the southern hemisphere |
Deciduous
plants appear; reptiles and insects abundant |
|
| Early | 286 | |||||
| CARBONIFEROUS | Pennsylvania | 320 | New land
rises from the sea; extensive swamps; coal formation |
Amphibians;
sharks; evergreen forests; reptiles; winged insects appear |
||
| Mississippian | 360 | |||||
| DEVONIAN | Late | 374 | Continents
collide, raising mountain ranges; seas deeper and narrower |
Abundant
fish; early sharks and amphibians; leafy plants; first insects appear |
||
| Middle | 387 | |||||
| Early | 408 | |||||
| SILURIAN | Pridoli | 414 | Varying
sea levels. New mountain ranges form |
Large
marine vertebrates; first plants colonise the land |
||
| Ludlow | 421 | |||||
| Wenlock | 428 | |||||
| Llandovery | 438 | |||||
| ORDOVICIAN | Ashgill | 448 | Continental
drift and sedimentation |
First
vertebrates appear; coral reefs develop |
||
| Caradoc | 458 | |||||
| Llandeilo | 468 | |||||
| Llanvirn | 478 | |||||
| Arenig | 488 | |||||
| Tremadoc | 505 | |||||
| CAMBRIAN | Merioneth | 525 | Extensive
volcanic activity and marine sedimentation |
Trilobites appear | ||
| St David's | 540 | |||||
| Caerfai | 590 | |||||
|
|
|
VENDIAN | 650 | Warm with shallow seas | Seaweed, algae and invertebrates appear |
|
| RIPHEAN | Late | 900 | Violent
upheavals and metamorphism |
First marine life and fossils | ||
| Middle | 1300 | |||||
| Early | 1600 | |||||
| EARLY PROTEROZOIC |
2500 | Carbonate sediments form | First
stromatolites appear
|
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 |
ARCHAEAN (AZOIC) |
4600 | Crust and oceans form |
