Triassic Period
251.9 – 201.4 million years ago · Mesozoic Era
The Triassic began in a devastated world and ended with the rise of the dinosaurs. It was the period in which many modern groups first appeared, including turtles, crocodile relatives, pterosaurs and mammals.
At a glance
- Began
- 251.9 Ma
- Ended
- 201.4 Ma
- Duration
- 50.5 million years
- Era
- Mesozoic
- Climate state
- Greenhouse (warm, little or no polar ice)
- Land above sea level (PaleoDEM)
- ~35.4%
- Dinosaurs on our map
- 0
The world in the Triassic
Open the interactive map at 230 Ma → Elevation view
What Earth was like
Pangea was still intact, centered on the equator. Late in the period, rifts opened between North America and Africa, flooding with lava and marking the first stage of the supercontinent’s breakup.
Climate
The Triassic was hot, with no polar ice. Pangea’s interior was largely arid, while monsoons brought seasonal rain to the coasts. The Carnian Pluvial Episode, around 232 million years ago, was a wet interval that reshaped ecosystems.
Life
After a slow recovery, archosaurs radiated into crocodile-line reptiles, pterosaurs and dinosaurs. The first dinosaurs, such as Eoraptor and Herrerasaurus, appeared around 233 million years ago; by the end of the period long-necked Plateosaurus roamed Europe. In the seas, ichthyosaurs and nothosaurs thrived.
Dinosaurs of the Triassic
None of the genera on our map had evolved yet, but the very first dinosaurs, such as Eoraptor and Herrerasaurus, appeared late in the Triassic, around 233 million years ago.
How it ended
The end-Triassic extinction, at 201.4 million years ago, coincided with massive eruptions of the Central Atlantic Magmatic Province as Pangea rifted. Many crocodile-line reptiles disappeared, clearing the way for dinosaurs to dominate.
Key facts
- The oldest known dinosaurs come from Argentina and Brazil.
- The first mammals were small, shrew-like animals.
- The end-Triassic extinction is one of the Big Five.
Data: land and sea
Across the Triassic, an average of 35.4% of Earth’s surface stood above reconstructed sea level (range 31.4–38.4%). Today the same model gives 31.8%.
Where this data comes from
- Continent positions: GPlates Web Service, Müller et al. (2019) plate model, covering 0–250 Ma.
- Elevation and shorelines: PALEOMAP PaleoDEMs, Scotese & Wright (2018), doi:10.5281/zenodo.5460860, CC BY 4.0.
- Period boundaries: ICS International Chronostratigraphic Chart (2023/09).
These are scientific reconstructions, not observations. Uncertainty grows the further back in time you go. About & data sources
Related reading
Keep exploring
- Geological periodsTwelve periods, each with a map, dinosaurs and climate.
- Earth's history4.5 billion years in one story, from a molten planet to today.
- Plate tectonicsHow plates move, collide and build mountains and oceans.
- LearnArticles on countries, dinosaurs and supercontinents.
- FAQQuick answers about Pangea and the map.
- About & data sourcesWhere the reconstructions and fossil data come from.