Earth 250 Million Years Ago: Pangea, the Supercontinent

250 million years ago, at the boundary between the Permian and Triassic periods, nearly all of Earth’s land formed one supercontinent: Pangea. It stretched from pole to pole in a giant “C” around the Tethys Ocean, while a single world ocean, Panthalassa, covered the rest of the planet.

The interior of Pangea lay thousands of kilometres from the sea, so much of it was hot and dry. The poles had no ice caps, and the average global temperature was well above today’s.

This is also the moment of the Great Dying, the end-Permian mass extinction about 252 million years ago. Huge volcanic eruptions in Siberia (the Siberian Traps) poured out carbon dioxide, heating the planet and stripping oxygen from the oceans. Around 90% of marine species and 70% of land vertebrate families disappeared. The survivors went on to give rise to the dinosaurs and the first mammals in the Triassic.

Over the next 70 million years Pangea began to split apart. The rifts that opened became the central Atlantic Ocean, and the pieces drifted towards the continents on the map today.