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A timeline of geologic periods in accordance with the dates and nomenclature proposed by the International Commission on Stratigraphy.
(not shown to scale)
| Years Ago3,6 | Epoch | Period/Age4,5 | Era | Eon | Major Events | |
|---|---|---|---|---|---|---|
| Present day | Holocene | Quaternary | Cenozoic | Phanerozoic | End of ice age and rise of modern civilization | |
| 11430 | Pleistocene | Extinction of many large mammals. Evolution of fully modern humans | ||||
| 1.81 million | Pliocene | Tertiary | Neogene | |||
| 5.33 million | Miocene | |||||
| 23.0 million | Oligocene | Paleogene | ||||
| 37.2 million | Eocene | Appearance of first "modern" mammals | ||||
| 55.8 million | Paleocene | |||||
| 65.5 million* | Cretaceous | Mesozoic | Dinosaurs reach peak, become extinct. Primitive placental mammals | |||
| 146 million | Jurassic | Marsupial mammals, first birds, first flowering plants | ||||
| 200 million | Triassic | First dinosaurs, Egg-laying mammals, breakup of Pangea into Gondwana and Laurasia | ||||
| 251 million* | Permian | Paleozoic | Permian extinction event- 95% of life on Earth becomes extinct | |||
| 299 million | Carboniferous1 | Pennsylvanian | Abundant insects, first reptiles, coal forests | |||
| 318 million | Mississippian | Large primitive trees, first land vertebrates | ||||
| 359 million | Devonian | First amphibians, clubmosses and horsetails appear, progymnosperms (first seed bearing plants) appear | ||||
| 416 million* | Silurian | First vascular land plants, first jawed fish | ||||
| 443 million* | Ordovician | Invertebrates dominant, first land plants | ||||
| 488 million* | Cambrian | Major diversification of life in the Cambrian explosion | ||||
| 542 million* | Ediacaran | Neoproterozoic | Proterozoic2 | First multi-celled animals | ||
| 630 million*,8 | Cryogenian | Possible snowball Earth period, Rodinia begins to break up | ||||
| 850 million | Tonian | First acritarch radiation | ||||
| 1.0 billion | Stennian | Mesoproterozoic | Formation of Rodinia | |||
| 1.2×109 | Ectasian | |||||
| 1.4×109 | Calymmian | |||||
| 1.6×109 | Statherian | Paleoproterozoic | First complex single-celled life | |||
| 1.8×109 | Orosirian | Transition to oxygen atmosphere | ||||
| 2.05×109 | Rhyacian | |||||
| 2.3×109 | Siderian | |||||
| 2.5×109 | Neoarchean | Archaean2 | ||||
| 2.8×109 | Mesoarchean | |||||
| 3.2×109 | Paleoarchean | |||||
| 3.6×109 | Eoarchean | Simple single-celled life | ||||
| 3.8×109 | Hadean2,7 | 4.1×109 - Oldest known rock; 4.4×109 - Oldest known mineral; 4.57×109 - Formation of Earth | ||||
1) In North America, the Carboniferous is subdivided into Mississippian and Pennsylvanian Periods.
2) The Proterozoic, Archean and Hadean are often collectively referred to as Precambrian Time, and sometimes also as the Cryptozoic.
3) Dates are slightly uncertain with differences of a few percent between various sources being common. This is largely due to uncertainties in radiometric dating and the problem that deposits suitable for radiometric dating seldom occur exactly at the places in the geologic column where we would most like to have them. Dates with an * are radiometrically determined based on internationally agreed to GSSPs. The dates quoted above are according to the International Commission on Stratigraphy 2004 time scale. All dates given are for the end of the interval in question.
4) Paleontologists often refer to faunal stages rather than geologic Periods. The Stage Nomenclature is quite complex. See for an excellent time ordered list of faunal stages. Also see the article on GSSPs.
5) In common usage the Tertiary-Quaternary and Paleogene-Neogene-Quaternary Periods are treated as equivalents to the Mesozoic and Paleozoic Periods. The term 'Period|Age' (e.g. 'Neogene Period|Age') is sometimes used instead of 'Period'.
6) The time shown in the "Years Ago" column is that of the end of the interval named beside it.
7) Hadean was sometimes called Priscoan.
8) The GSSP for the base of the Ediacaran, ratified in 2004, is a climatic/geochemical marker rather than biostratigraphic. It represents the end of a widespread glaciation event.
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