Thread: Permian extinction - what caused it?

Hi everyone,

After numerous Google searches, I still can't find any conclusive reason for the cause of the Permian extinction. Would love to hear thoughts of the forum. I thought it was down to the release of methane gases over a long period of time from the bottom of the sea floor. If this theory is correct, how did it cause such a mass extinction?

Thanks, look forward to hearing your thoughts!

Cheers,
Sarah.

I don't think anyone could definitively tell you. That matter has been debated for many decades.
Whatever happened, we can make an educated guess that it was quite the catastrophe. As 96% of marine species and 70% of land species were wiped off the map.

you could do worse than read Michael J Benton's "When life nearly died"

it would appear that the massive lava outpourings which formed the Siberian traps caused a major anoxia event in the oceans and acid rain followed by a mass vegetation die-off on land resulting in a major erosion event
apart from a substantial rise of CO2, there's also a suspicion a massive release of methane from submarine clathrates

As Marnix said, the main theory is the outpouring of lava from the Siberian Traps. There is another idea that is complementary.

This idea is that a massive asteroid impact occurred diametrically opposite to the site of Siberian traps - opposite side of the world, and the converging pressure waves going round the globe stimulated those volcanoes into massive eruption.

Turns out that, allowing for continental drift, the point diametrically opposite at the time is a spot in Antarctica today, and that point is buried under kilometres of ice. However, it also is the site of a major gravity anomaly, which would be expected if a large asteroid hit at that point.

The only way to be sure would be to excavate through the ice and sample the underlying rock. A very expensive project, and not likely to happen any time soon.