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252 million years ago, Earth underwent its worst, most violent chapter in the form of the Permian-Triassic extinction event, or "The Great Dying". 70% of the terrestrial species and 95% of the marine species became extinct.

There was one thing that I had noticed in Permian and Triassic landmasses--both periods had Pangaea, all the world's continents clumped together into one singular landmass. And recent evidence has found that it took life ten million years to recover from the Great Dying.

So why did it take so long? Was the damage of the Great Dying that extensive? Or did Pangaea play a part in delaying the recovery process?

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    $\begingroup$ Relevant: earthscience.stackexchange.com/q/7731/87 $\endgroup$ – plannapus Jul 12 '16 at 8:09
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    $\begingroup$ Nice question to pose for a few years of PhD research. $\endgroup$ – Gordon Stanger Jul 12 '16 at 13:49
  • $\begingroup$ @plannapus That doesn't really answer the question as to whether Pangaea played a part in delaying the recovery process or if the damage from the Great Dying was that extensive. $\endgroup$ – JohnWDailey Jul 12 '16 at 14:33
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    $\begingroup$ @JohnWDailey which is why i said it was "relevant" and not "duplicate". It does not answer whether or not Pangaea played a part but it does explain some basics about recovery from a mass extinction, and about possible reasons behind the length of said recovery. In this case, I think (but I m not that up-to-date on the PT boundary event, so don't quote me on this) that the long recovery is merely a result of primary producers being directly affected by the event. $\endgroup$ – plannapus Jul 12 '16 at 14:48
  • $\begingroup$ I'll check on the literature and get back to you on that when i'll have time. I do have an additional question though: when you ask if Pangaea had a role in delaying the recovery process, do you have a specific mechanism in mind? $\endgroup$ – plannapus Jul 12 '16 at 15:08
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A recent 2016 Stanford University study reported in the article "Oxygen-starved oceans held back life's recovery after the 'Great Dying'", suggests that

Analysis of ancient seabed rocks from disparate locations reveal that life did not rebound until anoxia had fully ebbed.

Specifically, the researchers found evidence from a lot of places around the world that, according to the researchers, point to a possible conclusion that globally

anoxic conditions reduced seawater oxygen levels by 100-fold at the onset of the mass extinction. Oxygen levels then slowly rose, only returning to pre-extinction levels after 5 million years, corresponding to when the climate became more stable and life regained its former diversity.

This research paints a picture that the mass extinction event resulted in a global anoxic event, that took the Earth a considerable amount of time to recover from.

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Let me propose that if an anoxia event were a cause of the P-T marine extinction; then it wouldn't be Pangaea that would slow recovery, but Panthalassa; the global ocean counterpart to Pangaea.

Here is a map of the oceanic conveyor:

enter image description here

Its complex structure is driven by the location of the continents. Without continents spread around the world, the ocean circulation would look more like the Pacific ocean, with three separate gyres (probably four if Antarctica was not there, as in the Permian) and much smaller areas of upwelling water:

enter image description here

Reduced complexity of ocean circulation could reduce the ability of the ocean recover oxygen levels. Deep water anoxia especially would take far longer to correct with reduced upwelling currents.

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