Markdown

Geological Time Periods - Markdown

Geological time periods systematically classify Earth's approximately 4.6 billion year history according to the International Chronostratigraphic Chart established by the International Commission on Stratigraphy (ICS). It is divided into four major divisions: the Precambrian (Hadean, Archean, Proterozoic) and the Phanerozoic (Paleozoic, Mesozoic, Cenozoic). Each geological period is distinguished based on geological evidence including biological evolution, continental drift, and climate change, forming the foundation for scientific research and education.

geology geological time chronostratigraphy Earth history paleontology Precambrian Phanerozoic Paleozoic Mesozoic Cenozoic

| code | slug | name | description | category | durationMa | endMa | startMa |
| --- | --- | --- | --- | --- | --- | --- | --- |
| EON-1 | precambrian | Precambrian | The period from Earth's formation to approximately 541 million years ago, comprising about 88% of Earth's history. | Supereon | 4059 | 541 | 4600 |
| EON-1-1 | hadean | Hadean | From Earth's formation to approximately 4.0 billion years ago. No evidence of life. | Eon | 600 | 4000 | 4600 |
| EON-1-2 | archean | Archean | Approximately 4.0 to 2.5 billion years ago. Evidence of the oldest life appears. | Eon | 1500 | 2500 | 4000 |
| EON-1-3 | proterozoic | Proterozoic | Approximately 2.5 billion to 541 million years ago. Appearance of eukaryotes and oxygen increase. | Eon | 1959 | 541 | 2500 |
| EON-2 | phanerozoic | Phanerozoic | From approximately 541 million years ago to present. Era of multicellular life proliferation. | Eon | 541 | 0 | 541 |
| ERA-1 | paleozoic | Paleozoic | Approximately 541 to 252 million years ago. 'Ancient life era.' | Era | 289 | 252 | 541 |
| PER-1-1 | cambrian | Cambrian | Approximately 541 to 485 million years ago. The Cambrian explosion occurred. | Period | 56 | 485 | 541 |
| PER-1-2 | ordovician | Ordovician | Approximately 485 to 444 million years ago. Marine invertebrates flourished. | Period | 41 | 444 | 485 |
| PER-1-3 | silurian | Silurian | Approximately 444 to 419 million years ago. Life began colonizing land. | Period | 25 | 419 | 444 |
| PER-1-4 | devonian | Devonian | Approximately 419 to 359 million years ago. 'Age of Fishes.' | Period | 60 | 359 | 419 |
| PER-1-5 | carboniferous | Carboniferous | Approximately 359 to 299 million years ago. Large forests and coal deposits formed. | Period | 60 | 299 | 359 |
| PER-1-6 | permian | Permian | Approximately 299 to 252 million years ago. Continents united and a great extinction occurred. | Period | 47 | 252 | 299 |
| ERA-2 | mesozoic | Mesozoic | Approximately 252 to 66 million years ago. 'Age of Reptiles.' | Era | 186 | 66 | 252 |
| PER-2-1 | triassic | Triassic | Approximately 252 to 201 million years ago. Dinosaurs and mammals appeared. | Period | 51 | 201 | 252 |
| PER-2-2 | jurassic | Jurassic | Approximately 201 to 145 million years ago. The golden age of dinosaurs. | Period | 56 | 145 | 201 |
| PER-2-3 | cretaceous | Cretaceous | Approximately 145 to 66 million years ago. Flowering plants and dinosaur extinction. | Period | 79 | 66 | 145 |
| ERA-3 | cenozoic | Cenozoic | Approximately 66 million years ago to present. 'Age of Mammals.' | Era | 66 | 0 | 66 |
| PER-3-1 | paleogene | Paleogene | Approximately 66 to 23 million years ago. Adaptive radiation of mammals. | Period | 43 | 23 | 66 |
| PER-3-2 | neogene | Neogene | Approximately 23 to 2.58 million years ago. Expansion of grasslands and ape evolution. | Period | 20.42 | 2.58 | 23 |
| PER-3-3 | quaternary | Quaternary | Approximately 2.58 million years ago to present. Ice ages and human evolution. | Period | 2.58 | 0 | 2.58 |