What Caused the End Permian Mass Extinction?

[billiards]

A new hypothesis has emerged in the search for the cause of Earth's greatest ever mass extinction: The Permian-Triassic Mass extinction event (~250 million years ago).

A study published today in Nature Geoscience1 suggests that one trigger for the near-apocalyptic 'great die-off', which killed 96% of marine species and 70% of land-based vertebrate organisms, was a volcanic explosion in coal and shale deposits in Siberia. Within days, ash from the eruption, raining down onto the Canadian Arctic, sucked oxygen from the water and released toxic elements.

...

"The magma went through a juicy bit of crust that it can release a lot of nasty things from," says Paul Wignall, a palaeontologist at the University of Leeds, UK, who studies mass extinction events.

...

This may have been the tipping point, says Wignall. Studies have suggested the volcanoes released 3 trillion tonnes of carbon, enough to trigger massive climate change. The eruptions also caused acid rain and emitted sufficient halogens to create an ozone hole, he says. Toxic fly ash, on top of all this, may have been the final blow.

"I can't suggest that this is the answer to the mass extinction story, but it is a new component to it," he says. "It is like throwing the kitchen sink at the world."

http://www.nature.com/news/2011/110121/full/news.2011.38.html

 

[Studiot]

This book detailing the 30 odd years of study leading up to this theory and written by one of its leading architects, is absolutely fascinating.

http://palaeo.gly.bris.ac.uk/essays/permian.html

 

[nucleus]

Another article:
http://www.ucalgary.ca/news/utoday/january24-2011/biggestextinction

 

[billiards]

This book detailing the 30 odd years of study leading up to this theory and written by one of its leading architects, is absolutely fascinating.

http://palaeo.gly.bris.ac.uk/essays/permian.html

Yes, a good book, I am reading it at the moment, so far about half way through. The book actually goes right back to before even Lyell, and discusses the geologist who first identified the Permian period (can't remember his name off the top of my head) and how Lyell's rejection of catastrophism held back the study of mass extinctions for a century.

Another article:
http://www.ucalgary.ca/news/utoday/january24-2011/biggestextinction

Yes the research was done by the Geological Survey of Canada and Calgary University.


The novel element of this research appears to be connecting the Siberian Traps volcanism to the toxification of the ocean.

Here we present analyses of terrestrial carbon in marine sediments that suggest a substantial amount of char was deposited in Permian aged rocks from the Canadian High Arctic immediately before the mass extinction. Based on the geochemistry and petrology of the char, we propose that the char was derived from the combustion of Siberian coal and organic-rich sediments by flood basalts, which was then dispersed globally. The char is remarkably similar to modern coal fly ash, which can create toxic aquatic conditions when released as slurries. We therefore speculate that the global distribution of ash could have created toxic marine conditions.

(from the abstract: Grasby et al. Catastrophic dispersion of coal fly ash \par into oceans during the latest Permian extinction. Nat Geosci (2011) vol. 4 (1) pp. 1-4)

 

[Ophiolite]

The book actually goes right back to before even Lyell, and discusses the geologist who first identified the Permian period (can't remember his name off the top of my head) and how Lyell's rejection of catastrophism held back the study of mass extinctions for a century.

IIRC Alan Sedgewick. Since there are few fossils in the Permian of the UK Sedgewick needed somwhere that was both fossiliferous and had a continuous sequence - with few diastems or disconformities. I believe he went on an expedition to the Urals where he found such a sequence near Perm.

I'm doing this of the top of my head also, so it may not have been Sedgewick. It might have been Murchison. Aggh! No time to check. Will edit if necessary.

 

[Studiot]

I think the book (author) has a particularly admirable quality.

He is not determined to prove one particular theory at all costs.
Instead he examines and sifts the evidence and re-evaluates as new material comes to light.

A model for other scientists to follow.