Despite the massive size of eruptions from supervolcanoes, such as the Yellowstone Caldera
in Wyoming, no single supervolcano has ever been linked to a mass extinction event.
These drastic events tend to only effect the climate of the planet in the short term.
However, there exists a group of volcanoes on the planet which DID cause a mass extinction.
This mass extinction, often referred to as "the great dying" occurred 252 million years
ago, and resulted in the extinction of more than 90% of species on the planet.
The volcanoes which caused the worst extinction to ever occur are referred to as the Siberian
Traps, which are an incredibly rare type of volcanoes referred to as "flood basalts".
The Siberian traps are a massive volcanic province located in both central Russia and
northern Kazakhstan.
In a span of only 1 million years, the entire area I have marked on screen, about 5 million
square kilometers in total, were covered with layer after layer of basaltic lava and ash.
In one location, the deposits from these eruptions are more than 3500 meters thick!
So, what caused all of this lava to erupt in such a short timespan?
Around the mantle of the earth, there are areas of convection which cause large quantities
of molten rock to push upwards towards the crust.
These areas of convection are called mantle plumes, and are believed to be shaped like
a mushroom.
As an example, the Hawaiian island chain was formed by one of these smaller mantle plumes,
as intermittent quantities of lava erupt onto the surface.
There, the area currently reaching the surface is the equivalent of the stalk of the mantle
plume.
In contrast, 252 million years ago, a much larger mantle plume reached the earth's crust.
The so called "head" of the mushroom shaped mantle plume reached the surface first, causing
widespread incredibly large volume effusive and explosive eruptions.
Due to the vast volume of magma inserted into the crust, hundreds of vents erupted simultaneously
over a large region, erupting layer after layer of basaltic lava in what is termed a
flood basalt eruption.
Before I explain further about the duration and scope of this flood basalt eruption, I
want to note something, and I assure you this is relevant.
About 3.9 billion years ago, a large asteroid impacted Mercury, forming a 1,600 kilometer
wide impact crater.
What makes this impact of particular note is that on the exact opposite of the planet,
called an antipode, the area experienced a sudden and dramatic uplift along with associated
large scale volcanic activity.
Thus, it could be theorized, that an impact event can cause volcanic activity on the opposite
side of the planet.
Back on earth, adjusting for the placement of continents 252 million years ago, we can
go to the antipode opposite where the Siberian traps began.
This takes us to Antarctica, where a probable 480 kilometer wide impact crater has been
located beneath the ice.
Although this impact event has not been dated, its placement indicates that it may have led
to the formation of the Siberian traps, although this is a controversial hypothesis.
Regardless of how the Siberian traps formed, a large volume of lava erupted onto the surface
beginning 252.3 million years ago.
For approximately 150,000 to 200,000 years straight, 12 cubic kilometers of lava was
erupted every year from numerous vents in the region.
For some context on what effects this volume of lava might have, we need to look no further
back than than to the 1783 to 1784 fissure eruption of Laki in Iceland.
There, a similar quantity of lava erupted, which led to global crop failures, especially
hard hitting in Europe.
This eruption had such severe societal impacts that it is listed as one of the causes of
the French Revolution.
Now, imagine that a similar eruption occurred each year for 200,000 years straight.
This is the true horror of the Siberian traps.
`` Although large scale eruptions continued for
the next 800,000 years, the vast majority of lava erupted in the aforementioned 200,000
year timespan.
By the time the Siberian traps eruptive series had ended, a total of 3 million cubic kilometers
of lava had erupted.
The vast amount of released greenhouse gasses caused the concentration of carbon dioxide
in the atmosphere to increase from 500 to a whopping 8000 parts per million.
This caused large sections of the world's oceans to become acidic and then completely
void of oxygen, resulting in the extinction of 96% of species in the seas.
Famous groups of species that went extinct included 100% of trilobites, 100% of Eurypterids,
98% of crinoids, and 97% of ammonites.
Animals on land were also hard hit, as 70% of species became extinct.
One group of ocean faring organisms that were not particularly hard hit were bivalves, of
which only 59% went extinct.
After the recovery from this mass extinction event, bivalves would become one of the most
common organisms in the oceans.
Speaking of the recovery period, it took various sections of the planet between 2 and 10 million
years to fully recover from this catastrophic mass extinction, termed the Permian Triassic
extinction event.
I hope that you enjoyed this video.
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