Triassic Period 251 to 200 mya

Summary

The Triassic was named after a distinctive and widely found type of three-layered rock dating from this period. The Triassic both began and ended with major mass-extinction events.

Pangaea was finally completed in the Triassic period. There was no ice and the climate was warm and dry.

Following the earlier mass extinction, life recovered and was able to diversify into the niches now left unoccupied. Conifers, seed ferns and cycad plants dominated the land. Major new animal groups appeared, especially the dinosaurs but also the first mammals.

In the oceans too life was diversifying to fill empty niches.

Continents

Earth 250 mya. Click here for key. Previous image. Next image. Image courtesy of TimeTrek

About 250 mya the continents were all gathered together into one large continent, Pangaea. The land mass was in the shape of a letter C which enclosed the Tethys Ocean.

 

Image courtesy of TimeTrek

Dinosaurs

After the Permo-Triassic mass extinction, one group of reptiles called dinosaurs started to dominate all others. Their name means terrible lizard. They were the commonest vertebrates for the next 150 million years. During their rule there were plant-eating and meat-eating ones, walking, flying and swimming dinosaurs, big ones, small ones.

At the time when the dinosaurs became dominant, all the land of the Earth was gathered together into Pangaea.

Image copyright Joe Tucciarone

Early mammals also appeared during the Triassic.

Mass Extinction

The Triassic ended, as it had begun, with a mass extinction event when half the species on Earth were eradicated.