Quick Reference
THE EARTH - GEOLOGICAL PERIODS
Composition of the Earth | Global Statistics | Glossary | Geological Periods
PERIOD |
MILLIONS OF YEARS AGO |
EVENTS |
LIFE FORMS |
PRE-CAMBRIAN
| ARCHAEAN | 4600-2500 | Solidification of crust | Protozoa |
| PROTEROZOIC | 2500-600 | Free oxygen in the atmosphere | Metazoa |
PALAEOZOIC
| CAMBRIAN | 600-500 | Invertebrates (trilobites). Corals | |
| ORDOVICIAN | 500-425 | Sea covers most of the planet | Vertebrates |
| SILURIAN | 425-405 | Land plants, giant fishes | |
| DEVONIAN | 405-345 | Amphibians | |
| CARBONIFEROUS | 345-280 | Swamps and coal bearing rocks | Reptiles, insects, ferns. |
| PERMIAN | 80-230 | Formation of Pangea | Conifers. |
MESOZOIC
| TRIASSIC | 230-181 | First dinosaurs. | |
| JURASSIC | 181-135 | Height of dinosaurs. Mammals and birds. | |
| CRETACEOUS | 123-63 | Break up of Pangea | End of the dinosaurs. Flowering plants. |
CENOZOIC
| TERTIARY | 63-5 | Himalayas and Alps folded | Evolutionary separation of apes and monkeys. Most mammals established. |
| QUATERNARY | 5 | Last ice age | Modern man |
