Deccan volcanism contribution to K-Pg mass extinction (free pdf)

[Ben Creisler]

Ben Creisler

bcre...@gmail.com

A new paper:

Free pdf:

Vivek S. Kale, Devdutt Upasani, Madhu Rajput, Gauri Dole & Shilpa Patil Pillai (2025)
Spatio-temporal volume recalibration shows Deccan volcanism caused Terminal Cretaceous Mass Extinction
GSA Bulletin (advance online publication)
DOI: https://doi.org/10.1130/B38412.1
https://pubs.geoscienceworld.org/gsa/gsabulletin/article/doi/10.1130/B38412.1/666415/Spatio-temporal-volume-recalibration-shows-Deccan


The recognition of Deccan flood basalts as a causal mechanism for the Terminal Cretaceous Mass Extinction has been contentious. Our computation of their spatio-temporal distribution reiterates that ∼1.5 million km3 of the Deccan flood basalts erupted in <700 k.y., during Chron C29r (66.31−65.73 Ma) straddling the 66.05 Ma Cretaceous-Paleogene boundary (KPgB). Unlike earlier projections, we demonstrate that ∼70% of these lavas erupted in the terminal Maastrichtian before the KPgB. The toxic degassing of the lavas in the ∼300 k.y. prior to the KPgB set the stage for mass extinction. The early Danian lavas contributed to the delayed biotic recovery.

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[Gregory Paul]

I like saying Deccan Traps:) Sounds like way cool. 

Super lave flow formations often erode in a manner that looks like great stairs, and in Swedish trappa means stair. The dude who did the major work on traps was Nordic. 

And I have always been suspicious that that little rock from space did it on its adorable own. Really, it wasn't THAT big compared to the planet. 

GSPaul

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[Sean McKelvey]

The only issue I have here is the article being titled " Spatio-temporal volume recalibration shows Deccan volcanism caused Terminal Cretaceous Mass Extinction".

That implies that the Deccan Traps were the sole cause of the extinction, when the paper itself clearly states that it was a contributing factor, and not the sole cause.

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[Sean McKelvey]

>  And I have always been suspicious that that little rock from space

I wouldn't exactly call it little, Greg. In comparison to the planet itself, sure. But it was a darned big rock no matter how you slice it.

> on its adorable own

Was the adorable bit really necessary? or are you just trying to be dismissive? You can disagree with something without belittling it.

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[Gregory Paul]

Oh knock it off people. I am getting very tired of when I have a little rhetorically fun on this list that someone just has to get after me about it. Lighten up, this is not a academic publication site. I have been doing paleo for half a century I and don't appreciate people lecturing me. Please cease being so controlling. Jeez. 

An Everest size object IS very very small compared to this planet. Not even visable if viewing Earth from say 20000 miles. Like taking a 22 cal kid's rifle bullet in the leg. Can do some real damage but not be lethal if healthy. But if already seriously ill might tip one into death. (Different from the essentially 22 cal diameter slug from an AR-15 which is much longer and sent by a much more powerful charge.)

That's called an analogy. 

GSPaul

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[Sean McKelvey]

Greg, I don't care how long you've been doing this. It means nothing to me. 

Furthermore, at no point did I claim that the asteroid was the sole culprit, I merely questioned your choice of words. Sorry if you don't like that, but I feel I am entirely within my right as a citizen of a free country to do so. 

It's very simple, if you do not want people to "go after you" then it might be worth considering your wording more carefully. 

> this is not a academic publication site

Correct, which means I'm free to criticize what you say in the same way I would with anyone else.

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[Stephen Poropat]

As it is with most things in life, size was clearly not everything with respect to the Chicxulub impactor. 

The speed, strike angle and position of the impactor, its composition and that of the rocks it hit, the state of the planet in terms of climate, atmospheric composition and continental position, what organisms were around, and so many other countless parameters would all have been contributing factors to how severe the extinction event was. Adjust any or all of these and the effect might have been quite different. 

Exploring the following questions would be interesting:

1) Whether the Deccan Traps would have caused an extinction event on the scale of the K-Pg alone without the Chicxulub impactor; or

2) Whether the Chicxulub impactor would have caused an extinction event on the scale of the K-Pg in a world unaffected by Deccan Traps volcanism.

I'm fairly sure that this has, at least to some extent, been done; however, I have either forgotten or am ignorant of the work if it exists I look forward to being corrected and incorporating the relevant research into my teaching.

Agreed, Sean, that the title of the present paper is highly misleading; the second last sentence of the abstract completely undercuts it.

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Dr Stephen F. Poropat

Deputy Director

Western Australian Organic and Isotope Geochemistry Centre

School of Earth and Planetary Sciences

Curtin University

Bentley, Western Australia

Australia 6102

https://stephenporopat.weebly.com/

[Alberta Claw]

There was Chiarenza et al. (2020), which used a climate modeling approach to assess the relative climate effects of the Chicxulub impact vs. the Deccan traps.

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[Sean McKelvey]

As with most things in life, it was likely a little from column A and a little from column B. I do have a question though, do we see any evidence of declining diversity related to the Deccan traps? It is my understanding they were erupting consistently over a long period of time, so in theory if they were playing a role in the extinction we should see a noticeable decline prior to the impact event? 

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[Grant Hurlburt]

In the 1980's Charles B. Officer proposed that the Deccan traps outgassing lead to the KT extinctions. Exchanges between Alvarez and him got quite nasty.  Odd that this current paper doest mention him at all.  As I recall, triple-shocked quartz (which an asteroid impact can produce) occurred in the Iridium layer whereas volcanic output yields only double-shocked so the Asteroid hypothesis "triumphed". I'm glad to see that people are now considering least two complementary causes.

SOURCES. (From "Enormous Eruptions and Disappearing Seaways:

Evidence for the Volcanic Extinction Hypothesis https://courses.geo.utexas.edu/courses/302d/Mistaken%20Extinction/Chapter%2004.pdf. )

2. Officer, C. B. and C. L. Drake. 1983. The Cretaceous-Tertiary transition. Science, v. 219: 1383-1390.

3. Officer, C. B. and C. L. Drake. 1985. Terminal Cretaceous environmental events. Science, v. 227:1161-1167.
4. Officer, C. B., et al. 1987. Late Cretaceous and paroxysmal Cretaceous/Tertiary extinctions. Nature, v. 326: 143-149.
5. Courtillot, V. E. 1990. What caused the mass extinction? A volcanic eruption. Sci. American, October: 89-90. Note: Another more extensive and detailed analysis of emissions and resulting environmental effects is provided in Officer, C. B., et al. 1987, Late Cretaceous and paroxysmal Cretaceous/Tertiary extinctions, Nature, v. 326, pp.145-
146. Estimated amounts and intensity of effects vary with those reported by Courtillot to some extent; however, the interpreted general effects are similar.

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Gerta Keller has been among the few scientists to continue arguing for the importance of the Deccan Traps Vulcanism in the K-T extinctions. https://en.wikipedia.org/wiki/Gerta_Keller

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Grant Hurlburt