When Was The Triassic Period & How Long Did It Last? Triassic Period Questions Answered!

When was the Triassic Period? How long ago was the Triassic Period? How long did the Triassic Period last? On this page you’ll find the answers to all of these questions and more…

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There were no flowering plants in the Triassic Period. Vegetation would have consisted of cycads (a modern variety of which is shown above), ginkgoes, conifers and seed ferns.

The Triassic Period was a momentous time in Earth’s natural history. It saw the world recovering from a catastrophic extinction event that saw around 90% of all species become extinct.

The new conditions at the beginning of the Triassic Period paved the way for reptiles to become the dominant animal group.

Although dinosaurs appeared in the Triassic Period, they were not to become dominant until the Jurassic Period. Instead it was the fearsome, crocodile-like Pseudosuchians that would rule the Triassic world.

Let’s find out more about the Triassic Period…

When Was The Triassic Period?

The Triassic Period began 251.9 million years ago (Mya) and ended 201.3 Mya.

How Long Did The Triassic Period Last?

The Triassic Period lasted 50.6 million years.

What Came Before the Triassic Period?

The period that came before the Triassic Period was the Permian Period. This was the last period of the Paleozoic era; with the end of the Permian Period came not just the start of the Triassic Period, but also the start of the Mesozoic Era.

What Came After the Triassic Period?

The Triassic Period was followed by the Jurassic Period, the second of the three periods of the Mesozoic Era.

Luperosuchus - a genus of large rauisuchian pseudosuchian that lived from the Middle Triassic to the Late Triassic. It was animals such as these, rather than dinosaurs, that dominated the Triassic Period. Image by Dmitry Bogdanov ([email protected]) [CC BY 3.0]

Which Era is the Triassic Period Part Of?

As we’ve found, the Triassic Period is the first of three periods that make up the Mesozoic Era. The other periods of the Mesozoic Era are the Jurassic Period, which spanned from 201.3 million years ago (Mya) to 145 Mya, and the Cretaceous Period, which spanned from 145 Mya to 66 Mya.

Let’s Dig Deeper: The Geologic Time Scale

rock layers
Each period of the Geologic time scale corresponds to a layer of rock.

The Triassic Period is a period of time in the Geologic Time Scale. Like all of the periods in the Geologic time scale, it corresponds to a certain layer (or layers) of rock.

In the case of the Triassic Period, those layers of rock are the three layers of rock collectively known as the ‘Trias’.

The Trias are layers of sedimentary rock – that is, rock made of small fragments of organic matter and / or minerals that were originally carried in water. These fragments gradually settled, accumulated and hardened into rock.

The Triassic Period relates to the period of time in Earth’s history during which the Trias were formed.

The Trias were first identified by German geologist Friedrich August von Alberti in 1834. He realized that the layers were related to each other, and that they contained fossils that represented a separate chapter in Earth’s development.

Fossils in Triassic Rock

The fossilised bones of animals such as this Saurosuchus appear in Triassic rocks. Photo by Kentaro Ohno (Flickr: 地球最古の恐竜展) [CC BY 2.0]
Because new rock layers form over older rock layers, the deeper you dig, the older the rock you find. Any fossils you find in the upper layers are likely to be newer than those found in deeper layers.

Fossils found in Triassic rock layers were made by animals that were alive during the Triassic Period. By studying the fossils found in the Triassic rocks, paleontologists can build up a picture of life in the Triassic Period.

Global Extinction Events Before & During the Triassic Period

volcano erupting
Mass volcanic eruptions may have caused the Triassic-Jurassic extinction event.

The Permian Period ended with a global extinction event that caused around 90% of all species on Earth to become extinct. The Permian–Triassic extinction event, as it is now known, is the worst known extinction event to have befallen Earth. Due to its severity it has become known as ‘the Great Dying’.

At the end of the Permian Period it had been the Therapsids – a group of animals that contained the ancestors of mammals – who had been the dominant land animals. All that changed in the Triassic Period; most of therapsids became extinct in the Great Dying.

With their main competition gone, it was the reptiles whose turn it was to thrive. The Mesozoic Era is known as the ‘Age of Reptiles’. This is because during the 186 million years of the Mesozoic Era it was the reptiles who were the dominant animal group.

The Triassic Period ended, as it had begun, with a global extinction event. Although not as severe as the Great Dying, the Triassic–Jurassic extinction event saw between 70 and 75% of all species becoming extinct.

By the end of the Triassic Period the dominant land animals were a group of reptiles called the Pseudosuchians. The Triassic–Jurassic extinction event saw most pseudosuchians become extinct. The Jurassic Period saw another group of reptiles take their place: it would be the turn of the dinosaurs to rule the Earth!

When Was the Triassic Period: Conclusion

We hope this page has answered some of your questions about the Triassic Period. You can find plenty more information on the Mesozoic Ear and dinosaurs at Active Wild. Check out some of these pages to get started…

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