Underground magma triggered Earth’s worst mass extinction with greenhouse gases

From The Guardian

There are parallels between today’s and past greenhouse gas-driven climate changes

Italy’s Mount Etna, Europe’s tallest and most active volcano, spews lava as it erupts on the southern island of Sicily, Italy February 28, 2017. Photograph: Antonio Parrinello/Reuters

Howard Lee

Tuesday 1 August 2017 06.00 EDT Last modified on Tuesday 1 August 2017 06.02 EDT

Coincidence doesn’t prove causality, as they say, but when the same two things happen together over and over again through the vast span of geological time, there must be a causal link. Of some 18 major and minor mass extinctions since the dawn of complex life, most happened at the same time as a rare, epic volcanic phenomenon called a Large Igneous Province (LIP). Many of those extinctions were also accompanied by abrupt climate warming, expansion of ocean dead zones and acidification, like today.

Earth’s most severe mass extinction, the “Great Dying,” began 251.94 million years ago at the end of the Permian period, with the loss of more than 90% of marine species. Precise rock dates published in 2014 and 2015 proved that the extinction coincided with the Siberian Traps LIP, an epic outpouring of lava and intrusions of underground magma covering an area of northern Asia the size of Europe.

But those rock dates presented science with a new puzzle: why was the mass extinction event much shorter than the eruptions? And why did the extinction happen some 300,000 years after the lava began to flow?

Now in a new study published in Nature Communications, Seth Burgess of the US Geological Survey, along with James Muirhead of Syracuse University and Samuel Bowring of MIT, think they have the answer. As Burgess told me:

It’s clearly not the entirety of the LIP that’s guilty. There’s a subinterval that’s doing the work, and I set out to figure out which subinterval that was, and what makes it special.

Burgess noticed that the beginning of the mass extinction, as well as a jolt to the carbon cycle and abrupt climate warming, coincided exactly with a switch in the style of volcanic activity in the Siberian Traps. During the initial 300,000 years of the eruptions, basalt lava poured over a vast area of Siberia building to several kilometers thick. In this time there was some stress to life in the Northern Hemisphere, but no mass extinction. Life only began to disappear across the globe at exactly the same time that lava stopped erupting above ground, and instead began to inject as sheets of magma underground.

In Siberia you have got the Tunguska Basin which is a thick package of sediments that contain carbon-bearing rocks like limestone and coal. When you start intruding magma, [it] cooks those sediments and liberates the volatiles. So the deadly interval of magma in the entire Large Igneous Province is the first material to intrude and pond into the shallow crust

In other words, it wasn’t the lava, it was the underground magma that started the killing, by releasing greenhouse gases.

Norwegian scientist Henrik Svensen had earlier identified hundreds of unusual volcanic vents called “diatreme pipes” all over Siberia that connected underground intrusions of magma (“sills”) to the atmosphere, showing signs of violent gas explosions. This new work emphasizes the importance of Svensen’s 2009 conclusions:

The diatremes that have been mapped are the geologic representation of that gas escape on a catastrophic level. Our hypothesis is that the first sills to be intruded are the ones that really do the killing [by] large scale gas escape likely via these diatremes.

Svensen, who was not involved in Burgess’ study, commented:

The Burgess et al paper is a crucial step towards a new understanding of the role of volcanism in driving extinctions. It’s not the spectacular volcanic eruptions that we should pay attention too – it’s their quiet relative, the sub-volcanic network of intrusions, that did the job. The new study shows convincingly that we are on the right track.

Greenhouse gas as a killer

While other scientists have proposed that an array of killers may have been involved in the end-Permian mass extinction, from mercury poisoning to ultraviolet rays and ozone collapse to acid rain, Burgess argues that it was principally greenhouse gas emissions triggered by magma intrusions that caused the extinction through abrupt global warming and ocean acidification. I asked him to outline the evidence for that.

There are 3 primary lines of evidence that support that link. The first is: right before the onset of the mass extinction we have evidence for a massive input of isotopically light carbon into the marine system.

He went on to explain various lines of evidence that point to the source of that carbon being methane and carbon dioxide resulting from magma intruding and cooking organic-rich sediments. He continued:

Just prior to extinction and persisting after the mass extinction the sea surface temperature is thought to have gone up about 10°C. You get that increase by pumping greenhouse gas into the atmosphere. So that’s the second.

And then the third line of evidence is a physiologic selectivity to the marine mass extinction. Organisms that make their shells out of calcium carbonate suffer much higher mortality than organisms that make their shells out of silica, for example, which suggests that the ocean was acidified, and you get that by pumping gases like CO2 into the atmosphere.

That’s not to say that other factors had no role in ruining the environment:

There is a cacophony of kill mechanisms, and I think that this first pulse of sills is the trigger for quite a few of those, sitting at the top, and beneath it are a cascade of negative effects from ocean acidification to climate warming and on down the line.

A series of associated events

Coincidentally, Joshua Davies of the University of Geneva and colleagues have just narrowed down the trigger for the end-Triassic mass extinction, another of Earth’s biggest mass extinctions, to the underground phase of its associated Large Igneous Province. The Central Atlantic Magmatic Province (CAMP) is another enormous igneous province which stretches from Maine to South America, and includes the Palisade Sill visible from Manhattan.

They too used high precision rock dates on a vast sill that intruded organic rich sediments in the Amazon Basin, and found that this underground magma intrusion also coincided with the extinction. Like Burgess, Davies also argues that greenhouse gas baked from sediments drove climate change, which drove the mass extinction in a smaller repeat of the end-Permian events, this time 201.5 million years ago.

“I think CAMP is very similar to the Siberian Traps and that’s the reason why there’s an extinction at that time. I’m not surprised that they got similar results,” said Burgess.

Diatreme pipes from magma intrusions have also been identified as a likely cause for a more recent global warming and very minor extinction event – the Paleocene–Eocene Thermal Maximum (PETM) 56 million years ago. Again, prodigious quantities of greenhouse gases erupted from oil-rich deposits, although in that case it’s been hard to locate and date the “smoking gun” intrusions due to the fact that they are under the Atlantic Ocean.

Howard Lee is a geologist and science writer who focuses on past climate changes.

Read the full article here.


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August 9, 2017 8:11 pm

Interesting post
Thank you
What an amazing find has been charles the moderator

Reply to  chaamjamal
August 9, 2017 10:17 pm

He was here all along actually, long-term. I’ve had the pleasure of meeting him in person, along with Leif and Steven Mosher in the same 1 hour time-span. Call me a BSer but I’m not. I have the photos to prove it.
…. and then there was the oft quoted, slightly adapted “Some people will do anything to save the planet except …..
…. wait for it ….
… take a fkin science course”.

Reply to  chaamjamal
August 10, 2017 6:46 am

Wow ,are we in line for another mass extinction I,quote from last sentence of the first paragraph of the article ‘ Many of those extinctions were accompanied by…abrupt climate warming,expansion of ocean dead zones &acidification ,JUST LIKE TODAY.!!!huh really ? like 290myago

Reply to  kendo2016
August 11, 2017 12:06 pm

The KT extinction that occurred 66 million years ago was caused (largely if not entirely) by an impact off Mexico. That impact was into limestone-rich (carbonate) sediments, which must have considerably decomposed into CO2 injected into the atmosphere.

August 9, 2017 8:14 pm

Lol, what baloney. Actually, just 20,000 years ago we we’re on the verge of the Mother of All Extinctions …. where virtually everything, ALL plants and animals, would die. And that extinction would have been triggered if CO2 at 180ppm would have gone just a little bit lower.
And there’s a trend. Going back a million plus years at each glacial cycle the CO2 level has been going lower and lower. It’s thought that sea-shelled creatures are slowly sucking up the CO2 faster than nature can replenish it. Within a couple glacial cycles we could reach the CO2 starvation point and the consequent total extinction.
Patrick Moore: Human CO2 Emissions are Wholly Beneficial:

Tab Numlock
Reply to  Eric Simpson
August 10, 2017 5:34 am

Fortunately, we have a massive CO2 store in the form of limestone. When the fossil fuels are gone, we will probably need laws encouraging the use of concrete in order to keep CO2 at a healthy level.

John Harmsworth
Reply to  Eric Simpson
August 10, 2017 7:29 pm

The hypothetical disasterous warming would have come about from ani increase in CO2 levels in the region of from 1000 up to 2500. ppm We are told by 97% of self proclaimed experts and dozens of incorrect models that the warming effect is limited by a logarithmic function so I call crap.
I know CO2 is magic but I struggle with the idea that it was more powerful 290mya than it still isn’t today! More likely this guy went to some third rate school like Penn State and learned to spell CO2!

August 9, 2017 8:18 pm

You can always count on the Grauniad for a laugh.

August 9, 2017 8:23 pm

The full paper is available…
It doesn’t seem to be plagued with the same alarmist nonsense as the Wired article. Although it does jump to the “blame GHG’s” conclusion after presenting a decent argument for the massive sill emplacement being more closely associated with the Permian extinction than the flood basalt phase.
Irreverent discussion of Wired article here…

Kaiser Derden
August 9, 2017 8:45 pm

sounds to me like they made a stretch to create correlation but can’t begin to define correlation … fail …

Kaiser Derden
Reply to  Kaiser Derden
August 9, 2017 8:46 pm


Walter Sobchak
Reply to  Kaiser Derden
August 10, 2017 7:55 am

We really need an editorial function in the posting mechanism.

Robert B
Reply to  Kaiser Derden
August 9, 2017 10:14 pm

“This causal connection is supported by evidence for a striking temporal coincidence between the two phenomena4, 6,7,8, rapid introduction of isotopically light carbon into the marine system8, 9, an abrupt increase in global sea surface temperature (~ 10°C)”
The latter cites.
Sun, Y. et al. Lethally hot temperatures during the early triassic greenhouse.
From Science daily
A study jointly led by the University of Leeds and China University of Geosciences (Wuhan), in collaboration with the University of Erlangen-Nurnburg (Germany), shows the cause of this lengthy devastation was a temperature rise to lethal levels in the tropics: around 50-60°C on land, and 40°C at the sea-surface…
Sun and his colleagues collected data from 15,000 ancient conodonts (tiny teeth of extinct eel-like fishes) extracted from two tonnes of rocks from South China. Conodonts form a skeleton using oxygen. The isotopes of oxygen in skeletons are temperature controlled, so by studying the ratio of oxygen isotopes in the conodonts he was able to detect temperature levels hundreds of millions of years ago.

No. Not a stretch of the imagination at all.

Reply to  Robert B
August 10, 2017 1:13 am

That paper is worthless due to faulty correlations.

Pat Frank
August 9, 2017 8:58 pm

If magma intruded on subterranean organic rich sediments and coals, it would not produce CO2 because the heating is completely anoxic. The organics would get coked, releasing large plumes of hydrocarbons and reduced gases, including H2S and HCl. David knows better than most that coal is loaded with reduced sulfur (so are many oils).
Who knows how many gazillion tons of hydrocarbons would be released into the atmosphere, but a likely outcome might be millennia of photochemical smog worldwide. That alone might cause a mass extinction.
The H2S would oxidize to H2SO4, (sulfuric acid). That, and the other zillions of tons of mineral acids released, especially HCl, would likely irreversibly acidify the oceans; irreversible except on geological time-scales.
Some coals include arsenic, which, under reductive heating, would probably emerge as H3As gas. This will eventually oxidize to arsenic acid H3AsO4, and fall out in rain. Streams, lakes, and land surfaces could get acidified, and possibly toxicated by continually precipitated mineral poisons and organics.
These guys have found something interesting. But the fixation on CO2 is probably blinding them to other perhaps more likely explanations for the extinctions.

Reply to  Pat Frank
August 9, 2017 10:39 pm

Interesting. Would not such acids produce unusual chemical weathering with resulting chemical fingerprints?

Reply to  Dixon
August 10, 2017 8:58 am

Actually, the chemical fingerprints for massive SO2 release are found globally in marine sediments dating to the Permian extinction. Whether that came with the flood basalts or as a result of contact metamorphism along sills is of course unknowable.

Reply to  Pat Frank
August 10, 2017 1:15 am

H2S is exceptionally toxic, and another theory connects the P/Tr extinction with release of H2S from anoxic deep ocean waters.

Reply to  Pat Frank
August 10, 2017 1:28 am

Not much coal in the Tunguska basin. This is often claimed but seems to be a confusion with the Kuznetsk basin further south. There are very large organics-rich evaporite deposits though, and the Siberian traps also seem to have been exceptionally rich in volatiles such as Cl, F and S. So, yes a lot of nasty chemistry there.

Reply to  Pat Frank
August 10, 2017 5:51 am

More corroboration for Dr P Ward’s book Under A Green Sky. And of course, the reason to worry about Yellowstone’s carbon pool. There are several evidences to support this: research into fossils at western US national parks show evidence of bone growth linked to fluoride.
We constantly speculate about the ‘must be’ light gravity during dino times but what about fluoride exposure? After all the original use for fluoride was to encourage bone growth until it was discovered that the fluoride made bone grow in the wrong places.

Reply to  Pat Frank
August 10, 2017 10:23 am

Is the temperature of magma sufficient to decompose limestone to lime and CO2?

Bill Yarber
Reply to  Pat Frank
August 10, 2017 12:38 pm

Summary: its not the CO2 exhaust, its all the toxic gases and chemicals that are released into the atmosphere by the incomplete combustion of the coal and other carbon based sediment!

Reply to  Pat Frank
August 10, 2017 2:26 pm

If magma intruded on subterranean organic rich sediments and coals, it would not produce CO2 because the heating is completely anoxic.
When magma breaches coal beds, lots of methane is released.
See Methane release from igneous intrusion of coal during Late Permian extinction events.
Then, once in the atmosphere, methane degrades into CO2.

Paul Blase
Reply to  Pat Frank
August 10, 2017 8:02 pm

That’s what I was wondering. Why jump to the “global warming” conclusion when plain old poisoning would do the trick?

August 9, 2017 9:00 pm

Hypothesis has been in general dispute for 2 years now. Negative correlations, etc. Not enough lava fields. C02 in eruptions are associated with underground organic material, but not these eruptions.

August 9, 2017 9:07 pm

Sigh, I keep reading, and hearing, all the experts going on and on about the Siberian Faults being the cause of the greatest mass extinction of all time, and keep asking myself, “Have they ever thought of what could cause all this volcanic activity? Don’t they realize that the Siberian Faults didn’t blow their tops without a cause to all this.
Don’t they realize that almost all major events are caused by Impactors from space? And don’t they know that a huge crater half way around the globe, in Antarctica, fits the very timeline with all this activity. If something like one or more huge comets were to strike the planet, the ripple effect would radiate evenly around the globe and come together at…..you guessed it, Siberia. Duhh!
To my thinking this is all shallow thinking to blame the Siberian Faults as the ultimate cause here, rather than just an ‘effect’. It seems like Common Sense 101 that the real cause was at least one, or more, huge comets that caused the volcanic activity that led to this extinction event.
But what do I know, I’m just a lowly physical anthropologist, and should stick with such things as Quaternary Science. 🙁

Reply to  John L Kelly
August 10, 2017 8:51 am

I suggest keeping it “simple” for the
“laser-focused, tunnel vision”, “kow tow to CO2 religious-believe” folk.
…isn’t it amazing what $$$ will do to smart, rational folk?
Think of a mushy ball full of Kevlar threads shooting around the sun
Now, a small tyke shoots a BB at hit, and it hits.
What happens to the mushy ball?
Why, where the BB hits, it goes “splash”,
and 180 degrees away (depends on mechanical angle, actually)
…it goes splash, just like the Siberian Traps.

Reply to  John L Kelly
August 10, 2017 12:57 pm

Except that, if the gravity anomalies in the Wilkes Land, Ross Sea, central continental and Weddell Sea sectors of Antarctica indeed do result from impact craters, which is far from certain, none of them is of the right age.
The Permian–Triassic boundary outcrops in Victoria Land and the central Transantarctic Mountains. No well-defined impact ejecta layer has been found there. Thus, there is no evidence of an impact capable of excavating a feature as big as the hypothetical Wilkes Land crater at this time.

Reply to  Gloateus
August 15, 2017 9:25 pm

What about the South Georgia/ South Sandwich island arc? A nearly vertical impact would have rung the planet like a bell, with a shock wave traveling to the Siberian traps nearly opposite the impact. You have to go beyond the ‘golf ball splashing in sand’ concept and believe an impactor several miles across, traveling at orbital speeds, is capable of puncturing the thin lithosphere and imparting a shock wave to the mantle, though.

Reply to  John L Kelly
August 10, 2017 2:15 pm

“Thus, there is no evidence of an impact capable of excavating a feature as big as the hypothetical Wilkes Land crater at this time.”
GRACE gravity evidence for an impact basin in Wilkes Land, Antarctica finds a rather large gravity anomaly, however.

Reply to  jonesingforozone
August 10, 2017 2:22 pm

The gravity anomalies might be craters, but, as noted, if they are, none could have been made at the right time.

Reply to  jonesingforozone
August 10, 2017 2:36 pm

“The gravity anomalies might be craters, but, as noted, if they are, none could have been made at the right time.”
The “right time?”
Some time immediately prior to the volcanism is all that is required for the antipodal theory.
The sea extinctions have already occurred by this point.

Reply to  John L Kelly
August 10, 2017 4:28 pm

As noted in my comment, there is no evidence of an impact in Antarctic outcrops from the Permian-Triassic boundary. Hence, even if the anomalies are “craters”, they couldn’t have caused the extinction, either directly or by a purely hypothetical antipodal effect.

John Harmsworth
Reply to  John L Kelly
August 10, 2017 7:42 pm

I think this is close but the impact was probably closer to the traps with the impact remains obscured by geologic changes. There is Iridium in the traps but other than that it’s just an hypothesis . Just like this lava hyperbole,I mean hypothesis.

Reply to  John L Kelly
August 11, 2017 1:42 am

“…there is no evidence of an impact in Antarctic outcrops from the Permian-Triassic boundary”
Nonetheless, you have no evidence that the outcropping did not exist, or that the outcropping does not currently exist under the mile-thick ice sheet.
In Figure 3 (b) of the paper, Gravity anomalies of the Antarctic lithosphere, an outcropping-like formation is visible in the gravimetric data.

Reply to  jonesingforozone
August 11, 2017 1:02 pm

I don’t know how to make this any plainer. The alleged crater(s) on Antarctica, even if they exist, cannot possibly have caused the Siberian Traps or end Permian extinctions for the simple reason that the impact, if it occurred, did not happen then.
Had it done so, then the Permian-Triassic boundary outcrops would be strewn with ejecta, which is not in evidence.
You seem to think that the outcrops themselves are the issue. They aren’t. It’s the fact that they are utterly lacking in the inevitable signatures of an impact so nearby. Hence, even if the anomalies are craters, they could not have been formed at the right time.

Reply to  John L Kelly
August 11, 2017 1:08 pm

Nor are other mass extinction events associated with impacts, as you assert, except for the end Cretaceous MEE. But even it is also associated with the Deccan Traps.
So you have it bass ackwards. Most MEEs are associated with flood volcanisms, not impacts.
Which is not to say that CO2 is the cause, but the other, truly nasty, poisonous gases released then could be.

Reply to  John L Kelly
August 11, 2017 2:05 pm

“Had it done so, then the Permian-Triassic boundary outcrops would be strewn with ejecta, which is not in evidence.”
Likely the only ejecta evidence that would survive ice one mile thick would be that evidence that is provided by the gravimetric data, the crust being deformed by the weight of the ice above it.
You are rather light on citations, by the way, Gloateus.

Reply to  jonesingforozone
August 12, 2017 3:53 pm

Here’s my colleague Retallack, et al’s, classic paper on the subject:
Search for evidence of impact at the Permian-Triassic boundary in Antarctica and Australia
Gregory J. Retallack, Abbas Seyedolali, Evelyn S. Krull, William T. Holser, Clifford P. Ambers, Frank T. Kyte
DOI: 10.1130/0091-7613(1998)0262.3.CO;2 Published on November 1998, First Published on November 01, 1998
Life on Earth was almost destroyed some 250 m.y. ago in the most profound of all known mass extinction events. We investigated the possible role of impact by an extraterrestrial bolide through chemical and mineralogical characterization of boundary breccias, search for shocked quartz, and analysis for iridium in Permian-Triassic boundary sections at Graphite Peak and Mount Crean, Antarctica, and Wybung Head, Australia. Thin claystone breccias at the isotopically and paleobotanically defined boundary at all three locations are interpreted as redeposited soil rather than impact ejecta. The breccias at all three locations also yielded shocked quartz, but it is an order of magnitude less abundant (0.2 vol%) and smaller (only as much as 176 micrometers m diameter) than shocked quartz at some Cretaceous-Tertiary boundary sites. Faint iridium “anomalies” were detected (up to 134 pgṁg−1). These values are an order of magnitude less than iridium anomalies at some Cretaceous-Tertiary boundary sites. Furthermore, peak iridium values are as much as 1 m below the isotopically and paleobotanically defined boundary. The idea that impact caused the extinctions thus remains to be demonstrated convincingly.
A 2007 follow-up:
Coalsack Bluff is not covered by ice.

Reply to  jonesingforozone
August 12, 2017 4:00 pm

Return to Coalsack Bluff and the Permian–Triassic boundary in Antarctica
Gregory J. Retallack. Tara Greaver. A. Hope Jahren.
Coalsack Bluff was the first discovery site in Antarctica for the latest Permian to earliest Triassic reptile Lystrosaurus. This together with discovery of Permian Glossopteris leaves during the heroic age of Antarctic exploration, indicated not only that Antarctica was part of Gondwanaland, but also that Antarctic rocks recorded faunas from the greatest of all mass extinctions at the Permian–Triassic boundary. Pinpointing the exact stratigraphic level of this life crisis has recently become possible using δ13C values in terrestrial organic matter. Multiple, short-lived events of 13C depletion may reflect carbon cycle crises, with the isotopic change a measure of terrestrial and atmospheric disequilibrium. Additional evidence for ecosystem reorganization came from changes in paleosol types and their root traces. Such studies previously completed at the Antarctic localities of Graphite Peak, Mount Crean, Portal Mountain, Shapeless Mountain and Allan Hills, are here extended to Coalsack Bluff. Carbon isotopic values in Permian rocks at Coalsack Bluff average − 23.08 ± 0.25‰, but begin to decline within the last coal with leaves (Glossopteris), roots (Vertebraria) and permineralized stumps (Araucarioxylon) of glossopterids. The low point in ä13C values is − 27.19‰ at 5.6 m above the last coal, which is capped by unusually abundant pyrite, and a claystone breccia with common clasts of redeposited clayey soils. Above this are massive quartz-rich sandstones of braided streams, considered a geomorphic response to deforestation and soil erosion following the mass extinction. Distinctive berthierine-bearing paleosols (Dolores pedotype) within these sandstones have unoxidized iron taken as evidence of severe groundwater hypoxia. Other paleosols at this stratigraphic level are like those in other Early Triassic rocks of Antarctica, which indicate unusually warm and humid conditions for such high paleolatitude lowlands. Waterlogging is also indicated by newly discovered kinds of paleosol (Ernest pedotype) with groundwater calcretes. The lack of peat accumulation in such waterlogged lowlands, berthierine in paleosols and large negative carbon isotopic shift at Coalsack Bluff support the idea of atmospheric pollution with methane from submarine and permafrost clathrates as a cause for the Permian–Triassic mass extinction. Hypoxic soils would have killed lowland plants by preventing root respiration and hypoxic air would have challenged vertebrates with pulmonary edema. Causes for catastrophic methane release remain unclear. Flood basalt eruptions, dolerite intrusions into coal measures, submarine landslides, tectonic faulting, and bolide impact suggested for episodes of methane release at other times are also plausible for the Permian–Triassic boundary.

Reply to  jonesingforozone
August 12, 2017 4:11 pm

comment image
In the foreground are rocks of “meteorite moraine.” The prominent dark feature in the center background is Coalsack Bluff in the Transantarctic Mountains, where the first Antarctic Lystrosaurus fossil was discovered in 1969-70 by Edwin H. Colbert and his team. Lystrosaurus is found in the lower Triassic of southern Africa as well as in India and China. The Antarctic discovery of Lystrosaurus was one of the last and most compelling arguments to sway opponents of the theory of “continental drift.” Randy Korotev took the photo in 1989 while searching for meteorites as part of the ANSMET program. If the image looks familiar, it’s because the mural over the E&PS library is based on the photo.
Dept. of Earth and Planetary Sciences, Washington U., St. Louis.

Reply to  jonesingforozone
August 12, 2017 4:14 pm

As you may know, Lystrosaurus dominated the devastated Early Triassic, after the end Permian mass extinction. Species of this genus are found all over what was then Pangaea.

Reply to  jonesingforozone
August 12, 2017 6:07 pm

Thank you for your thoughtful replies.
The iridium signature assumes that a bolide object would have similar composition to the one implicated in the K–T extinction.
Also assumed is a relatively uniform K–T extinction-like boundary with ejecta signature identifiable almost everywhere: “In 1980, a team of researchers led by Nobel prize-winning physicist Luis Alvarez, his son, geologist Walter Alvarez, and chemists Frank Asaro and Helen Vaughn Michel discovered that sedimentary layers found all over the world at the Cretaceous–Paleogene boundary (K–Pg boundary; formerly called Cretaceous–Tertiary (K–T) boundary) contain a concentration of iridium hundreds of times greater than normal.”[1] It was not until 1996 that the Chicxulub impact was connected with the iridium layer.[2]
Note that, for even this extinction event, “The Chicxulub impact likely triggered state shift of ecosystems already under near-critical stress.”[3]
The Permian-Triassic extinction event is somewhat more complicated in that numerous events, including geomagnetic and sea level reversals, have greatly fragmented boundaries marked by three distinct layers of ash and, in many places, severe erosion.[4][5]
Since numerous layers do exist near these P-T boundaries, it may be necessary to have trial ejecta material in already hand to identify the specific P-T layer in which it might exist.

Reply to  jonesingforozone
August 12, 2017 6:26 pm

The fact is that the characteristic signs of impacts, ie tektites and shocked quartz, don’t exist where they would have to be in order for the Wilkes Land “crater”, if it is a crater, to have been made at the end of the Permian.
The low quantity of ET markers like iridium are secondary. Without the telltale terrestrial traits of bolide impacts, there is simply no evidence to support the hypothesis that whatever causes the gravity anomalies in Antarctica is responsible for the P-Tr MEE.

Reply to  jonesingforozone
August 12, 2017 6:35 pm

Yes, Gloateus, however the the suspected impact site is under a mile of ice. In addition, the state of the site is unknown. For example, we can not tell using gravimetric data how much sediment is deposited over the impact breccia, if any.

Reply to  jonesingforozone
August 12, 2017 6:40 pm

The dispositive fact is that there is no sign of an impact in exposed strata from the end Permian and earliest Triassic from sites so close to the supposed crater that those layers would have to be strewn with them. Nor are there such ejecta fields in Australia, which at that time was conjoined with Antarctica.
This conclusively rules out Wilkes Land as an end Permian impact site, if it is a crater at all.

Reply to  jonesingforozone
August 12, 2017 6:46 pm

The telltale ejecta are not to be found in end Permian rocks from Wilkes Land, Victoria Land nor Australia, which was contiguous with Wilkes Land 250 Ma:
Compare this with the strewn fields in the Caribbean, Central, South and North America from the much smaller Yucatan impact of 66 Ma.

Reply to  jonesingforozone
August 12, 2017 6:50 pm

Gloateus, these layers are fragmented and complex. As noted above, the trial samples of ejecta may be necessary in order to find a match in the P-T layers for the Siberian or the Emeishan Traps.

Reply to  jonesingforozone
August 12, 2017 6:56 pm

No Permian-Triassic boundary exposure in Australia, Antarctica or any other place shows the ejecta that would have to be there for the hypothesis to be confirmed. It must be considered falsified until and unless the missing ejecta show up somewhere.
Unless the impact were in Panthalassa and none of the ejecta made it onto any continent, there is no evidence in support of an impact.
Now, it is possible that earth’s hot spots have been made by big impacts penetrating straight through the crust, which in the case of oceanic crust is fairly easy. Hence the Reunion Island and Hawaiian hot spots, but North America is also now passing over one, currently at Yellowstone. It however might have been formed before the continental plate started crossing it.
Some think that the Siberian Traps might, like the Deccan Traps (formed when the Indian Plate crossed the Reunion hot spot), result from a continent passing over a hot spot.

August 9, 2017 9:07 pm

Yes, yes. Just like burning fossil fuels, I am sure. Just like burning fossil fuels except for creating wealth at the same time.

August 9, 2017 9:10 pm

Sigh, I keep reading, and hearing, all the experts going on and on about the Siberian Faults being the cause of the greatest mass extinction of all time, and keep asking myself, “Have they ever thought of what could cause all this volcanic activity? Don’t they realize that the Siberian Faults didn’t blow their tops without a cause to all this.
Don’t they realize that almost all major events are caused by Impactors from space? And don’t they know that a huge crater half way around the globe, in Antarctica, fits the very timeline with all this activity. If something like one or more huge comets were to strike the planet, the ripple effect would radiate evenly around the globe and come together at…..you guessed it, Siberia. Duhh!
To my thinking this is all shallow thinking to blame the Siberian Faults as the ultimate cause here, rather than just an ‘effect’. It seems like Common Sense 101 that the real cause was at least one, or more, huge comets that caused the volcanic activity that led to this extinction event.
But what do I know, I’m just a lowly physical anthropologist, and should stick with such things as Quaternary Science. 🙁

Reply to  jlk103144
August 10, 2017 6:50 am

That’s what I was going to say.

John Nicol
August 9, 2017 9:39 pm

Since carbon dioxide ion any concentration cannot cause global warming this idea is quite wrong.

August 9, 2017 9:44 pm

Because it’s always greenhouse gases.

Reply to  Richard
August 10, 2017 3:02 am

Exactly right, no matter what the problem might be, the explanation is greenhouse gases. It’s amazing how the climate religion finds its way into science.
CO2 is obviously the devil.

August 9, 2017 9:55 pm

“Earth’s most severe mass extinction, the “Great Dying,” began 251.94 million years ago at the end of the Permian period, …….”
And they have the temerity to laugh at the Bishop.
“As indicated earlier, the Bible does not fix the age of the earth, contrary to the claims of Answers in Genesis.1 Historically, their claim comes from the work of James Ussher, Bishop in the Church of Ireland, from 1625 to 1656. Archbishop Ussher took the genealogies of Genesis, assuming they were complete, and calculated all the years to arrive at a date for the creation of the earth on Sunday, October 23, 4004 B.C.”

Michael S. Kelly
Reply to  getitright
August 9, 2017 10:56 pm

At 4:30 pm Eastern Standard Time….

August 9, 2017 10:24 pm

“Just prior to extinction and persisting after the mass extinction the sea surface temperature is thought to have gone up about 10°C. You get that increase by pumping greenhouse gas into the atmosphere.”
Assuming everything in this article is true, let’s put this in perspective. The trend in SST’s since 1982 is about 0.4C per century, I saw a NASA chart that gets about the same trend since the late 1800’s. So let’s say anywhere between 0.5-0,6 C historical warming of the oceans per CO2 doubling. Does anybody think that CO2 emissions from fossil fuels could possibly cause ocean warming on this scale?

Ian W
Reply to  Kurt
August 10, 2017 2:48 am

As the (claimed) effect of CO2 reduces logarithmically the entire premise is incorrect.

August 9, 2017 10:30 pm

If the article that claimed the ‘Great Dying’ commenced at the end of the Permian period, one could accept such an assertion of worthy for further consideration. However, as the article claims that the said event commenced 251.94 million years, it suggests that the author has had little exposure to sound scientific method, and can therefore be relegated to the trash can without hesitation.
Similarly to Flannery’s ‘The Weathermakers’, it is a concoction of truths, half-truths and outright inaccuracies.

Michael S. Kelly
Reply to  Asp
August 9, 2017 11:03 pm

No, no. They great dyeing is due to the lack of FDA regulation over coal-tar derived hair coloring.

Peter Foster
August 9, 2017 10:32 pm

The claim fails in the second paragraph. The extinction did not begin at 252 mya, that is when they ended. That is when the rate of extinction equalled the rate of new species evolution..
Any examination of biodiversity for that period shows that extinctions began about 15 million years earlier and accelerated toward 252 mya and then stopped
The key to understanding the Permian extinction is to look at atmospheric oxygen which hovered around 35% until the end of the ice age at 275 mya. Then it plummeted down to 15% at 252 mya. Respiratory systems were not what they are today so animals could not cope with that.
The oceans or parts of them became anoxic and then sulphur bacteria caused a massive increase in hydrogen sulphide (more toxic than cyanide) causing widespread death of marine creatures.
All this happened before the Siberian Traps volcanoes started so to blame them is a nonsense.
The theory best fitting the observations is that from the mid Carboniferous to mid Permian CO2 was at pre industrial levels of around 300 ppm. This level was insufficient to maintain oxygen levels once the ice had melted and exposed iron bearing rock. The fact that oxygen increased at the onset of the ice age and dropped when it ended is strong evidence for ice cover affecting the rate of oxygen uptake by mineral reactions.
Truth I suspect is that the prime cause of the Permian extinction was the low CO2.
In today’s mania people forget that all the oxygen in the atmosphere is put there by plants and is kept there by plants. Without CO2 there is no food for anybody and no oxygen.
How dumb can they get.
The extinctions ended at 252 mya when CO2 levels rose above 1600ppm, high enough for photosynthesis to slow the decline of O2 and start the rebuild..

Reply to  Peter Foster
August 10, 2017 9:06 am

Interesting hypothesis. I studied the Permian extinction as a possible essay for ebook Vlowing Smoke, but draft did not make the final cut. Do you have any references, as I had not come across that one.

Reply to  Peter Foster
August 12, 2017 9:11 pm


August 9, 2017 10:35 pm

Just prior to extinction and persisting after the mass extinction the sea surface temperature is thought to have gone up about 10°C. You get that increase by pumping greenhouse gas into the atmosphere.

By what mechanism do the authors claim the ocean warmed by radiation from the increased amount of carbon dioxide? I have not read or heard of a mechanism for this. IPCC does not describe one. It’s my considered opinion that the CO2 in an entire atmospheric column of one square metre does not equal at the air-water interface the heating power of a hair dryer, yet a hair dryer could not warm even the underlying half a cubic metre of water by 10°C. I must read the paper. In the meantime, I”ll look out here for your explanations of how the water apparently warmed in such an absurd fashion.

Reply to  Richard Treadgold
August 10, 2017 1:41 am

Just my thought. An experiment in school (sometime during the 7-9 grades, late 70’s), demonstrated that it require an extreme amount of energy and time to heat water with (warmer) air. Nothing the atmosphere can produce. Cooling effect from below, often ‘forgotten’, also has to be considered.

Reply to  Richard Treadgold
August 10, 2017 6:44 am

The energy is put into the water by the sun. How fast that energy leaves the oceans depends on the temperature of the air. If the air gets warmer, then less energy escapes and the waters warm until balance is restored.

Pat Frank
Reply to  MarkW
August 10, 2017 9:10 am

When the air gets warmer over the ocean, surface evaporation increases. Sensible heat becomes latent heat, and no rise in water temperature need occur.

August 9, 2017 10:56 pm

Looks like Grauniad is encouraging people to relax about toxic or corrosive emissions of volcanic proportion, provided they don’t contain the sixth most common chemical element in the universe, carbon.
Except it happens to be the second most common in the human body. More abundant chemical elements on our planet are presumed to be:

August 9, 2017 11:05 pm

My thoughts are with the S2 releases as H2S and SO2, with SO2 being about the same Tg of release of CO2. Sulphates would bind with water forming sulphuric acid (acid rain) but also make clouds brighter and remove water vapour from the atmosphere. Massive changes in sea level would indicate cooling and warming in quick session. The Siberian traps also had large ash plumes as well, cooling. Massively changing sea levels would mess with anything on continental shelfs, acid rain combined with carbonic acid would have made shell making difficult. A world of suck that these events are. Just CO2 would have been able to be dealt with IMO.

Reply to  Mydrrin
August 10, 2017 8:15 am

I didn’t give details of materials estimated: 8.5 × 10^7 Tg CO2, 4.4 × 10^6 Tg CO, 7.0 × 10^6 Tg H2S and 6.8 × 10^7 Tg SO2 by 2013, QY Tang

August 9, 2017 11:09 pm

So they went to the trouble of digging up a bunch of eel teeth in order to calculate temperature over that time period, then simply concluded that “it must be CO2”. You’d think they would have bothered to come up with a reconstruction of CO2 concentrations also to see if they confirm the central conclusion of their paper? Wouldn’t that have made sense?
Even easier, they could have used any of the many papers already done on temperature and CO2 in the geological record. Ooops, CO2 rises AFTER temps in the geological record. Woulda kinda messed up their theory so, hey, just assume that CO2 rose and then temps went up?

August 10, 2017 12:02 am

From my knowledge of carbonisation and gasification of coal and other organics, the gas that is always released in large quantities and is very toxic to animals is Carbon Monoxide (CO). This gas would kill us all long before CO2 or trace quantities of supposed greenhouse gases. There is always enough oxygen contained in organic material to allow CO production when organics are heated with no gaseous oxygen present.

Sandy In Limousin
August 10, 2017 12:15 am

What about the Eocene and PETM in all this?
Didn’t life flourish across and ice free world, with an atmosphere high in CO2 only to suffer a mass extinction when the climate cooled at the end of the Eocene?

Reply to  Sandy In Limousin
August 10, 2017 1:33 am

Indeed yes. And this is a large problem, because somehow LIP (Large Igneous Provinces) are apparently no longer very dangerous. There have been three during the age of mammals (North Atlantic, Snake River, Ethiopia-Yemen) and none of them had any discernible negative effects.

August 10, 2017 12:33 am

“article” fails to mention that the gasses *directly killed* and it wasn’t “climate change” that caused the extinctions.

Moderately Cross of East Anglia
August 10, 2017 2:09 am

This entire claimed causation seems to be driven first and foremost by the preconceived need to blame greenhouse gases first and foremost for seemingly every extinction event in Earth’s history and as such constitutes polemics rather than open minded science.
I agree with comments like those of TTY and Kurt and find the claim that the ocean temperature was raised by 10C by a subterranean lava pipe and sill event a pretty unconvincing stretch on little more than a highly selective mechanism. Why didn’t the much greater heat released when the lava came to the surface create this effect then and in subsequent eruptions? We’ve seen highly articulate explanations on WUWT as to why atmosphere doesn’t much warm oceans, now this is disapplied to incriminate in a highly speculative way CO2.
Just happens to be highly convenient pandering to the alarmist agenda. Another example of causation no doubt.

August 10, 2017 4:06 am

Whaddaya know. Carbon monixide and some other gases poisonous to organisms and others readily combinable into strong acids and bases are also greenhouse gases. Not too much differentiation discussed in this material. Material?

August 10, 2017 4:07 am

One day of VEI5 eruptions in today’s world produces 0.5C of cooling lasting a few years.
1 million straight years of VEI7 volcanoes produces warming 251 million years ago.

Reply to  Bill Illis
August 10, 2017 9:11 am

Bi, its more complicated. It takes a minimum VEI5 to inject stratospheric aersols with sufficiently long lives to produce any cooling. Essay Blowing Smoke in namesake ebook. But not evem all VEI6 do this. St. helen’s is an example. Flood basalts never do by definition of the nature of the eruption.

Reply to  ristvan
August 10, 2017 10:01 am

“Flood basalts never do by definition of the nature of the eruption.”
The only flood basalt eruption in historical times (Laki 1783-4) most certainly did. Which is not at all surprising when you read the contemporary descriptions. Lava fountains up to 1,000 meters high, and “curtains of fire” hundreds of meter high extending for several kilometers. Such eruptions would easily generate enough heat to “punch through” the tropopause.
By the way Laki left a tephra layer in the Greenland icecap. How did that get there?

Reply to  ristvan
August 10, 2017 1:02 pm

Here is a handy summation of the global effects of the Laki eruption:

August 10, 2017 4:33 am

If the reader is supposed to infer that a past catastrophe was caused by greenhouse gases,
therefore we should worry about our current level of greenhouse gases, then this article is
totally misleading and leads the reader to a completely invalid conclusion. Much like trying to discredit a chemical that in large quantities can kill, but in small quantities can save lives.
A 10 degree Celsius warming is totally inconceivable as due to man-made emissions, as is an ocean acid enough to harm anything. CO2 is being accumulated in the atmosphere these days at a relatively slow rate and that rate will drop drastically with the advent of two imminent technologies :
advanced nucear reactors (molten salt, primarily, possibly accompanied by some small number of fast neutron reactors), and electric cars. We are at a point where it is impossible to deny that those technologies will not dominate the future. So arguing for the continued large scale usage of fossil fuel power generation a losing proposition : not even simple economics argues for fossil fueled power, or renewables either. I would argue that the future danger lies in too little CO2 in the atmosphere, which can have a deadly effect primarily on humans. Implying that man would ever or could ever produce the prodigious amounts of greenhouse gases described in this article is a complete, and quite stupid, fantasy. Current elevated levels of CO2 are totally beneficial – they have NO negative effects. This would also be true if those levels ascended from the current 400PPM to 500 PPM as well. Even doubling the levels to 800PPM would have relatively small effects – perhaps 1 or, less likely, 2 degrees warming. Articles like this will only have an effect on those who possess limited knowledge of the issues involved in global warming. Unfortunately, that includes a lot of
pretty ignorant and scientifically illiterate folk (Al Gore, for example) . But they can read, unfortunately.

August 10, 2017 4:33 am

Of course, irrespective of gas release, all those lava flows and near-surface magma would make biosphere temperatures warm considerably. Why the need for greenhouse gas ‘warming’?

Reply to  Lank
August 10, 2017 6:23 am

That’s what I thought, too. Seems more reasonable than CO2.

Reply to  Lank
August 10, 2017 10:03 am

No. The direct heat emission from even the largest eruption is small in a global context.

Reply to  Lank
August 10, 2017 11:02 am

Lank, it’s a piece of cake when compared to the magical manmade trace gas in the outside air, especially when ocean temperatures are concerned.
The place of hottest water on earth: https://www.newscientist.com/article/dn14456-found-the-hottest-water-on-earth/

Gary Pearse
August 10, 2017 5:16 am

PETM, I don’t think so. Here is a chunk of redwood from 53 million years ago found at 300 metres deep in the Ekati diamond mine at the Arctic Circle. The volcanic pipe blasted to the surface in the middle of a redwood forest. Just because it was warm there is no need to start jumping on extinction bandwagons.
Looks like Garden Earth to me!

August 10, 2017 5:22 am

Just prior to extinction and persisting after the mass extinction the sea surface temperature is thought to have gone up about 10°C.

How do they know that? They analyze sediments. The Earth’s crust can move around a lot in a million years. link I can see plenty of opportunity for error to creep in on that account.
What is usually thought to cause mass extinctions?

Factors in mass extinctions include continental drift, changes in atmospheric and marine chemistry, volcanism and other aspects of mountain formation, changes in glaciation, changes in sea level, and impact events. link

Global warming due to increased CO2 is a novel idea when it comes to mass extinctions. Just saying.

August 10, 2017 6:55 am

Missing in the article is any estimations of CO2 concentrations. If I am not mistaken, submariners become concerned when CO2 levels inside the submarines rise above 11,000PPM. I believe anything above 14,000PPM is lethal. We are currently at 395ppm, rising from 280ppm a few hundred years ago.
There are actually two issues at play. The first is llethality of high amounts of CO2 to life; the second and most studied is the sensitivity of CO2 to global temperatures. This article conflates the two issues, hinting that current increases of CO2 are synonymous to the CO2 increases associated with the Great Dying of 250 million years ago. But, the article failed to say what the CO2 levels were during that period.

August 10, 2017 7:29 am

So what, geologically speaking, was the CO2 concentration in ppm that wreaked all that havoc? Just like today…

August 10, 2017 7:43 am

The extinction events were likely caused by a series of disasters, ending in dead biomass accumulations and volcanism.
The paper The Threat to Life from Eta Carnea and Gamma-Ray Bursts argues that earth supernovae may have been the immediate cause, triggering sea life extinctions with deadly cosmic ray cannon balls in Ordovician period (some 435 My ago), the late Devonian (357 My ago), the final Permian, (251 My ago), the late Triassic (198 My ago) and the final Cretaceous (65 My ago). Then, the expanding supernovae shock wave jostled the Oort Cloud, raining asteroids upon earth.
The specific threat from Eta Carinae is refuted in this paper, Superluminous supernovae: No threat to life from Eta Carinae , owing, for example, to its distance from earth, about 8,000 light years.
The cause of the Paleocene-Eocene boundary event, on the other hand, is less certain. However, the introduction to Environmental precursors to rapid light carbon injection at the Palaeocene/Eocene boundary argues against a prior build up of greenhouse gasses: “The lag of 3,000 years between the onset of warming in New Jersey shelf waters and the carbon isotope excursion is consistent with the hypothesis that bottom water warming caused the injection of 13C-depleted carbon by triggering the dissociation of submarine methane hydrates, but the cause of the early warming remains uncertain.”

The Deplorable Vlad the Impaler
August 10, 2017 8:10 am

Add to the other comments, that most of the Siberian event actually took place during the Early Triassic:
Established boundary time: 251.94 ma (GTS 2016)
Siberian LIP: 252.4 to 248.2 ma
The ‘terminal’ (end of the Permian Period) extinction is thought to have occurred on a geologically-rapid time scale, about 100,000 years, and this estimate keeps getting shorter and shorter, as we find new information. About the time that the evidence points to less than 50,000 years for the ‘terminal’ event, it will become more difficult to tie-in some event in Siberia to a global extinction, in my opinion.

August 10, 2017 8:16 am

Climate scientists do not understand the earth’s long-term climate processes today, and we are now asked to believe that earth climate processes 250 million years ago can be understood with the additional complication of an epic volcanic eruption. Give me a break! Today’s eruption is the sudden spewing out of a lot of science fiction based on the largely disparaged premise that CO2 is the culprit of global warming. I see these stories as nothing more than obfuscation and fear mongering.

Coach Springer
August 10, 2017 8:17 am

There are a series of leaps to conclusions in a cascading effect in the article.

Coach Springer
Reply to  Coach Springer
August 10, 2017 8:17 am

Runaway global reasoning.

DeLoss McKnight
Reply to  Coach Springer
August 10, 2017 9:33 am

For some reason, your comment reminded me of this scene. https://www.youtube.com/watch?v=Fxf5GDZ_o1w

August 10, 2017 8:22 am

extinction happen some 300,000 years after the lava began to flow
yikes. only 300,000 years to prepare.
It seems likely that a whole lot of bad thing could happen in 300k years, quite independent of the lava flows. how do we know it wasn’t one of these other ‘bad things’?
It really does sound like the paper started with a conclusion (CO2 is what done it) and then fit the facts to match, while ignoring other possibilities.

August 10, 2017 9:30 am

When the only tool in the toolbox is labelled “CO2”, then it is no surprise that all the answers are “greenhouse gas”.

August 10, 2017 9:40 am

The CO2 cult has gone full stupid and it’s infecting other areas of science.

Mike Smith
August 10, 2017 10:21 am

The True Believers continue to throw anything and everything at the wall…

Don Easterbrook
August 10, 2017 1:44 pm

What a bunch of nonsense! This is beyond bad science, it’s not science at all. The so-called ‘explosive diatremes’ in Siberia are pingos, a perfectly natural extrusion of ice and melting of core ice that go on all the time all over the Arctic. Ask competent geomorphologist and he/she will confirm that they are NOT explosive and have nothing whatsoever to do with climate change.
As for the correlation between CO2 and global temp, remember that CO2 ALWAYS lags global warming, never precedes it, both long term and short term. The data is conclusive. Temp causes increase in CO2, not the other way around.

August 10, 2017 3:18 pm

Well, now I’ve read the paper and also some of the papers they reference and I simply don’t understand how they get the results they claim. Everything hinges on precise dating of the events, but when you dig into it, it just doesn’t hold water.
Their dates for the beginning and end of the various stages of the Siberian eruptions are averages of averages while the actual individual radiometric dates vary by several hundred thousand years. Their placement of the main extinction pulse hinges entirely on matching radiometric dates from Siberia and China (there is no biostratigraphic control, since there are no marine deposits in the Tunguska basin). However when you line up the Chinese and Siberian sections their way the magnetostratigraphy doesn’t match at all, and it doesn’t even match between their Siberian sections. To me it all points to an uncertainty of the order of at least +- 200 ka for all the dates.
And even if their matching is correct it would seem that the main extinction pulse was actually near the end of the extrusive phase, not in the early sill-emplacement phase.

Reply to  tty
August 10, 2017 7:39 pm

Extensive use of confirmation bias, gross assumptions and waffle words.

Pamela Gray
August 11, 2017 8:47 am

I find it interesting that early investigations (pre 2000) into this event are thorough and wide ranging in terms of multiple catalysts related to sudden flora and fauna change. But then climate change came into view for the Siberian Traps and suddenly CO2 was the only cause. There are still serious investigations that refute the “Only CO2 is the culprit” meme. But they don’t get much press. Not alarming enough I guess.

Pamela Gray
Reply to  Pamela Gray
August 11, 2017 9:40 am

Just a thought: Could this be the end stages of trying to squeeze the last drop of AGW money out of the tube? Take something that has been elsewhere studied and determined to be one thing, then restudy it so that it implicates CO2?

August 11, 2017 2:28 pm

“Coincidence doesn’t prove causality, as they say, but when the same two things happen together over and over again through the vast span of geological time, there must be a causal link.”
Sorry, not true. Or at least not in the way you meant it to be interpreted. What you describe as “two things happen[ing] together over and over again through the vast span of geological time” is still just coincidence (a repeated coincidence, but a coincidence nonetheless). And it does NOT imply causality, at least not between the two things of interest. It is true that there is usually some “causal link”, but the link is often indirect, i.e., the two things are not linked directly in a causal relationship, but both are independently linked, in a causal relationship, to a third thing. For example (and at the risk of offending females everywhere, but sorry, this is the best example I could come up with on short notice), there is a “coincidence” of menstrual bleeding and moodiness in women. And it happens to a billion young women, every month, for as long as human women (and for that matter female mammals) have existed on this planet. So if you’re talking about the sheer number of times “two things happen together”, this has any coincidence you speak of here beat by 10 or more orders of magnitude. And yet, there is still no DIRECT causal relationship. The bleeding does not cause the moodiness and the moodiness does not cause the bleeding. Instead, both are caused by a sudden surge in the levels of certain hormones.
Now, after this error in the first paragraph, you go on to describe a “coincidence” that I would be hard-pressed to argue does not have a direct causal link. In fact, the argument is very convincing, and I would, until and unless some better theory comes along, accept as likely the direct causal link between underground lava sills (the cause) and mass extinctions (the effect), which is as close as any scientist can come to saying, “it’s true”. So for the sake of argument, let’s say it IS true that underground lava sills cause mass extinctions. That still does not make your opening general statement about coincidences and causal links true. Unless, of course, your use of “causal link” is intended to include indirect causal links such as the menstrual blood and moodiness link described here, and in the context of the article as a whole, that is clearly not the case.
(Note that i myself am guilty of misusing a word here. Usually, a “direct” causal link means that one thing causes another with no transitory cause/effect (being the effect of the ultimate cause and the cause of the ultimate effect) between them (i.e., the link between hormone surge and menstrual bleeding, technically is not “direct”, in this sense of the word, because the hormone surge causes the falopian tube to flush out the egg, which in turn causes the bleeding; but the link between hormone surge and moodiness IS direct, or at least as direct as we can understand when it comes to human psychology). But in the sense that I am using the word, a “direct” causal link can have multiple linkages (so call it a “multiple-order direct causal link), so long as there is a “one-way” line of causation through the all linkages from ultimate cause to ultimate effect.)

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