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posted by martyb on Wednesday September 21, @12:18AM   Printer-friendly

Arthur T Knackerbracket has processed the following story:

While some scientists think that asteroid and comet strikes are the cause of mass extinction events on Earth, new research from Dartmouth points to volcanic eruptions as the key driver.

What killed the dinosaurs 66 million years ago at the end of the Cretaceous Period? It has long been the topic of scientific debate, and many researchers have set out to determine what caused the five mass extinction events that reshaped life on planet Earth in a geological instant. Some experts believe that comets or asteroids that crashed into Earth were the most likely agents of mass destruction. Other scientists argue that immense volcanic eruptions were the primary cause of the extinction events. A new Dartmouth-led study published on September 12 in the Proceedings of the National Academy of Sciences (PNAS) reports that volcanic activity appears to have been the key driver of mass extinctions.

These new findings provide the most compelling quantitative evidence to date that the link between major volcanic eruptions and wholesale species turnover is not just coincidental. 

According to the researchers, four of the five mass extinctions are contemporaneous with a type of volcanic outpouring called a flood basalt. These eruptions flood vast areas—even an entire continent—with lava in a mere million years. In a geological time scale, that is just the blink of an eye. They leave behind massive fingerprints as evidence—extensive regions of step-like, igneous rock (solidified from the erupted lava) that geologists call “large igneous provinces.”

To count as “large,” a large igneous province must contain at least 100,000 cubic kilometers of magma. (One cubic kilometer is equal to 264 billion gallons or the volume of 400,000 Olympic swimming pools.) For context, the 1980 eruption of Mount St. Helens involved less than one cubic kilometer of magma. According to the researchers, most of the volcanoes represented in the study erupted on the order of a million times more lava than that.

The research team drew on three well-established datasets on geologic time scale, paleobiology, and large igneous provinces to examine the temporal connection between mass extinction and large igneous provinces.

“The large step-like areas of igneous rock from these big volcanic eruptions seem to line up in time with mass extinctions and other significant climatic and environmental events,” says lead author Theodore Green ’21, who conducted this research as part of the Senior Fellowship program at Dartmouth and is now a graduate student at Princeton.

[...] In fact, a series of eruptions in present-day Siberia triggered the most destructive of the mass extinctions about 252 million years ago, releasing an immense pulse of carbon dioxide into the atmosphere and nearly choking off all life. Bearing witness is the Siberian Traps, a large region of volcanic rock roughly the size of Australia.

Volcanic eruptions also rocked the Indian subcontinent around the time of the great dinosaur die-off, forming what is known today as the Deccan plateau. This, much like the asteroid strike, would have had far-reaching global effects, blanketing the atmosphere in dust and toxic fumes, suffocating dinosaurs and other life in addition to altering the climate on long time scales.

On the other hand, the investigators say, the theories in favor of annihilation by asteroid impact hinge upon the Chicxulub impactor, a space rock that crash-landed into Mexico’s Yucatan Peninsula around the same time that the dinosaurs went extinct.

Journal Reference:
Theodore Green, Paul R. Renne, and C. Brenhin Keller. Continental flood basalts drive Phanerozoic extinctions by Theodore Green, Paul R. Renne and C. Brenhin Keller, 12 September 2022, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2120441119

Original Submission

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  • (Score: 2, Funny) by Anonymous Coward on Wednesday September 21, @12:32AM

    by Anonymous Coward on Wednesday September 21, @12:32AM (#1272667)

    They have figured out what killed the radio stars. It's good that they are moving on to bigger and better mysteries.

  • (Score: 2, Interesting) by Anonymous Coward on Wednesday September 21, @12:42AM (2 children)

    by Anonymous Coward on Wednesday September 21, @12:42AM (#1272669)

    Would a big enough asteroid strike cause a flood basalt type event? (Asking as someone who knows nothing about geography.)

    • (Score: 3, Interesting) by khallow on Wednesday September 21, @02:14AM

      by khallow (3766) Subscriber Badge on Wednesday September 21, @02:14AM (#1272678) Journal
      Maybe. The Deccan Traps, for example, were somewhere near the antipode to the Chicxulub impact site and thought to have happened afterward. So it could be massive volcanism triggered by the impact. Maybe.
    • (Score: 2) by Nobuddy on Thursday September 22, @06:01PM

      by Nobuddy (1626) on Thursday September 22, @06:01PM (#1273031)

      Yes, this is what the full asteroid model says. The strike was bad. really bad. But the cascade of seismic events-including volcanoes- were the deciding factor.

      the earth is a big water balloon full of magma, with lots of pinholes and cracks in the balloon. And it got punched really hard.

  • (Score: 5, Funny) by istartedi on Wednesday September 21, @01:26AM

    by istartedi (123) on Wednesday September 21, @01:26AM (#1272676) Journal

    Maybe asteroids wouldn't strike if we paid them more.

  • (Score: 4, Touché) by maxwell demon on Wednesday September 21, @04:29AM (1 child)

    by maxwell demon (1608) Subscriber Badge on Wednesday September 21, @04:29AM (#1272689) Journal

    I don't see a reason why not both should have contributed to the extinction event (apart from the possible causal connection mentioned by another post).

    The Tao of math: The numbers you can count are not the real numbers.
    • (Score: 0) by Anonymous Coward on Wednesday September 21, @08:01AM

      by Anonymous Coward on Wednesday September 21, @08:01AM (#1272706)

      Why not neither?

      Far as I'm concerned, the entire earth is a wobbly testicle in Zeus' hairy nutsack and every few million years it pops off a few crackers.

  • (Score: 2) by stretch611 on Wednesday September 21, @06:10AM

    by stretch611 (6199) Subscriber Badge on Wednesday September 21, @06:10AM (#1272695)
    Now with 5 covid vaccine shots/boosters altering my DNA :P
  • (Score: 2) by Opportunist on Wednesday September 21, @10:30AM

    by Opportunist (5545) on Wednesday September 21, @10:30AM (#1272715)

    Colonel Mustard, with the lead pipe in the library?

  • (Score: 2) by dltaylor on Wednesday September 21, @07:30PM

    by dltaylor (4693) on Wednesday September 21, @07:30PM (#1272848)

    I have heard of no evidence that the Deccan Traps are contemporaneous with a global distribution of iridium. It is, however, known to have come from meteoric impacts, and, specifically, from the one that is most closely correlated with end of the Cretaceous.

    As has already been queried, it is not impossible that the strike may have triggered the Asian vulcanism.

    Ooooh, I know, it was the fabled nuclear war in ancient India.