Siberian Traps likely culprit for end-Permian extinction

September 16, 2015 by Jennifer Chu, Massachusetts Institute of Technology

Around 252 million years ago, life on Earth collapsed in spectacular and unprecedented fashion, as more than 96 percent of marine species and 70 percent of land species disappeared in a geological instant. The so-called end-Permian mass extinction—or more commonly, the "Great Dying"—remains the most severe extinction event in Earth's history.

Scientists suspect that massive volcanic activity, in a large igneous province called the Siberian Traps, may have had a role in the global die-off, raising air and and releasing toxic amounts of greenhouse gases into the atmosphere over a very short period of time. However, it's unclear whether magmatism was the main culprit, or simply an accessory to the mass extinction.

MIT researchers have now pinned down the timing of the magmatism, and determined that the Siberian Traps erupted at the right time, and for the right duration, to have been a likely trigger for the end-Permian extinction.

According to the group's timeline, explosive eruptions began around 300,000 years before the start of the end-Permian extinction. Enormous amounts of lava both erupted over land and flowed beneath the surface, creating immense sheets of igneous rock in the shallow crust. The total volume of eruptions and intrusions was enough to cover a region the size of the United States in kilometer-deep magma. About two-thirds of this magma likely erupted prior to and during the period of mass extinction; the last third erupted in the 500,000 years following the end of the extinction event. This new timeline, the researchers say, establishes the Siberian Traps as the main suspect in killing off a majority of the planet's species.

"We now can say it's plausible," says Seth Burgess, who received his PhD last year from MIT's Department of Earth, Atmospheric, and Planetary Sciences and is now a postdoc at the U.S. Geological Survey. "The connection is unavoidable, because it's clear these two things were happening at the same time."

Burgess and Sam Bowring, the Robert R. Shrock Professor of Earth and Planetary Science at MIT, have published their results in the journal Science Advances.

A singular event

Around the time of the end-Permian extinction, scientists have found that the Earth was likely experiencing a sudden and massive disruption to the carbon cycle, abnormally high air and sea temperatures, and an increasingly acidic ocean—all signs of a huge and rapid addition of greenhouse gases to the atmosphere. Whatever triggered the mass extinction, scientists reasoned, must have been powerful enough to generate enormous amounts of greenhouse gases in a short period of time.

The Siberian Traps have long been a likely contender: The large igneous province bears the remains of the largest continental volcanic event in Earth's history.

"It's literally a singular event in Earth history—it's a monster," Burgess says. "It makes Yellowstone … look like the head of a pin."

It's thought that as the region erupted, magma rose up through the Earth's crust, essentially cooking sediments along the way and releasing enormous amounts of like carbon dioxide and methane into the atmosphere.

"The question we tried to answer is, 'Which came first, mass extinction or the Siberian Traps? What is their overall tempo, and does the timing permit magmatism to be a trigger for mass extinction?'" Burgess says.

Dates pinned

For the answer, Burgess, Bowring, and colleagues traveled to Siberia on multiple occasions, beginning in 2008, to sample rocks from the Siberian Traps. For each expedition, the team traveled by boat or plane to a small Siberian village, then boarded a helicopter to the Siberian Traps. From there, they paddled on inflatable boats down a wide river, chiseling out samples of volcanic rock along the way.

"We'd have a couple of hundred kilos of rocks, and would go to the market in Moscow and buy 15 sport duffle bags, and in each we'd put 10 kilos of rocks … and hope we could get them all on the plane and back to the lab," Burgess recalls.

Back at MIT, Burgess and Bowring dated select samples using uranium/lead geochronology, in which Bowring's lab specializes. The team looked for tiny crystals of either zircon or perovskite, each of which contain uranium and lead, the ratios of which they can measure to calculate the rock's age. The team dated various layers of rock to determine the beginning and end of the eruptions.

They then compared the timing of the Siberian Traps to that of the end-Permian extinction, which they had previously determined using identical techniques.

"That's important, because we can compare green apples to green apples. If everything is done the same, there's no bias," Burgess says. "Now we're able to say magmatism definitely preceded mass extinction, and we can resolve those two things outside of uncertainty."

Richard Ernst, a scientist-in-residence at Carleton University in Ottawa, Ontario, says the new timeline establishes a definitive, causal link between the Siberian Traps and the end-Permian extinction.

"This paper nails it," says Ernst, who was not involved in the study. "Given that they have dated a portion of the Siberian Traps occurring just before, during, and only for a short time after the extinction, this is the 'smoking gun' for this large igneous province being fully correlated with the extinction. At this point, additional dating and other studies will simply provide more details on the link."

Now that the team has resolved the beginning and end of the Siberian Traps eruptions, Burgess hopes others will take an even finer lens to the event, to determine the tempo of magmatism in the 300,000 years prior to the mass extinction.

"We don't know if a little erupted for 250,000 years, and right before the extinction, boom, a vast amount did, or if it was more slow and steady, where the atmosphere reaches a tipping point, and across that point you have , but before that you just have critically stressed biospheres," Burgess says. "Now we've pinned it down in time, and others can go in with other techniques to get a more fully fleshed out timeline. But we need it to start someplace, and that's what we've got."

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FredJose
1.2 / 5 (18) Sep 16, 2015
It's pure habit these days to simply accept the long ages provided by the scientists - in this instance the 250 million years. One should question how they determined the "age" to that particular period since no one was there to witness, record or document any events described here. Because of such a lack of direct eye-witness account, it becomes sheer speculation.
Just going by this statement here -
"It's literally a singular event in Earth history—it's a monster," Burgess says. "It makes Yellowstone … look like the head of a pin."
coupled to the descriptions given earlier, one could equally well be describing another once-off cataclysmic event - the world wide flood described in the bible.
Consider this - the trigger to the flood could have been an accelerated nuclear decay that caused the earth mantle temperature to increase drastically, catastrophically in fact, releasing enough heat to cause the "springs of the deep" to erupt, to release billions of tons of H20..
FredJose
1.3 / 5 (15) Sep 16, 2015
The above scenario fits the evidence far better than a "death by volcanic activity" as proposed by the scientists. The reason is quite simple - we have the evidence of fossils in sedimentary rock all over the world with enough evidence that in many cases hot water was involved. There is a dearth of evidence for volcanic created fossils. Those are far fewer than the ones involving water. Furthermore, the fossils are not necessarily found where the animals died or lived, instead they are found in water traps where they have been transported to.
You may disagree, but that is definitely a valid scenario with supporting evidence - that is the nature of scientific inquiry.
Torbjorn_Larsson_OM
4.8 / 5 (16) Sep 16, 2015
Wow. I never thought I would see The Big One* settled! Now we have two more or less predicted mass extinctions. (Chixculub would be the other one.)

* Of course, one can argue that the Great Oxygenation Event likely was a larger killer. But that was "merely" extinguishing prokaryotes...

So to the innocent bystanders: Of course the troll is full throttle lying.

These are observed, factual dates and the clocks that are used are part of the material that are our interrogated witnesses. [ https://en.wikipe...ronology ] There is no mystery here, just the hard work of scientists - that the trolls despoil for their ugly selfish reasons.

Go hide under a bridge, ugly troll! =D
Jeffhans1
5 / 5 (5) Sep 16, 2015
How large of an impact would we need to cause the crust on the opposite side of the earth shatter and leak lava like this? The kinetic energy exits where the waves meet and mutually cancel or enhance each other with shear forces pulverizing portions of the crust. Once there are fractures and weak zones exist, we would see eruptions until the it clots and stops on its own.
victoryengineer
4.2 / 5 (5) Sep 16, 2015
How large of an impact would we need to cause the crust on the opposite side of the earth shatter and leak lava like this?


The same could be asked regarding Mars with it's Olympus Mons and fractured crust.
Bongstar420
1.4 / 5 (10) Sep 16, 2015
Predictably fixated on CO2

The SO2 had not effect I guess or the direct thermal input from the lava itself
Caliban
4.1 / 5 (9) Sep 16, 2015
Predictably fixated on CO2

The SO2 had not effect I guess or the direct thermal input from the lava itself


Why do you even bother?

The SO2 would have had a COOLING effect. The heat from the surface flows of lava would be episodic, and in any event would have been amplified by the increasing greenhouse effect from direct emissions of gases from the erupted lava, the combustion of anything living on the surface, and the burning or baking of any hydrocarbons in the overlying strata of sedimentary rocks --including massive coal deposits known to have been in place there at the time.

Most of this is addressed in the article itself, which you would have known --if you had read it-- before tossing off another of your glib non-observations.
matt_s
5 / 5 (8) Sep 17, 2015
matt_s
5 / 5 (9) Sep 17, 2015
As per the age of the Earth, the same site has another good article.

http://www.talkor...rth.html

In case you're wondering how they get the whole "millions of years" thing.
Osiris1
1 / 5 (1) Sep 20, 2015
We should like Dr Ramfino look for evidence of a large crater in a region that was antipodal to the Siberian traps at the time of the Siberian even 252 Million years ago. Knowing that continents drift, we should run the 'clock' back to see what Earth looked like four galactic years ago and then look for what was antipodal to it so we could look for such a crater. Of course given the size of the traps, that crater may look different too as in the differences between a volcano and a caldera, like maybe a really deeeeep scar in an ocean floor.

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