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252 Mya
End of Permian Extinction

At the end of the Permian period, about 252 million years ago, some 70% of land life and more than 80% of marine life died. It is thought that this was due to massive flows of lava contaminating the Earth and its atmosphere. It was also responsible for the largest extinction of insects.

There have been several mass extinctions throughout the history of the Earth, 5 are well known, but this one was the biggest.

The flood basalt eruptions that produced the Siberian Traps constituted one of the largest known volcanic events on Earth and covered over 2,000,000 square kilometres. This is almost twice the area of South Africa. These are thought to be the initial cause of the extinction.

Massive amounts of basaltic lava were extruded over a comparatively short period. Life in the immediate area was of course extinguished, but it is the effects on the entire globe that gave rise to the mass extinction over the entire planet and in all environments.

The volcanic activity included the emission of large amounts of gases. These were primarily carbon dioxide and sulphur dioxide. The other parts of the emission were dust and other debris.

The CO2 content of the atmosphere was around 400ppm roughly what it is at present. After the eruptions it rose to around 2,500ppm. This caused a huge temperature increase, which was compounded by the release of methane from the surrounding rocks that were inundated by the lava flows.

The sulphur dioxide formed Sulphuric acid as soon as it came into contact with atmospheric moisture.

There were other elements released from the surrounding land that may have also had a deleterious effect, for instance Mercury.

This acidification was carried into the marine environment, and particularly affected creatures with shells and carapaces that contained calcium carbonate, which dissolves in an acid environment.

Along with this acidification, the global temperatures soared. Prior to the eruptions the average global temperature was around 18oC. After the effects of CO2 and methane, temperatures rose to around 35oC. This followed an immediate drop in temperature caused by the blocking out of the sun by the dust emissions.

There is some evidence from reptile fossils in the Karoo that there was a preliminary extinction that took place some 8 million years prior to the main event. This could have been due to the fact that S Africa was situated towards the centre of Pangaea, the supercontinent that consisted of all the world’s land masses and became very arid.

With all these factors combined, it is little wonder that the end Permian mass extinction is known as “The Great Dying”

252 Mya End of Permian Extinction

252 Mya
End of Permian Extinction