About 66 million years ago, a giant asteroid collided with our planet, unleashing a terrifying firestorm that obscured the sun and kill the dinosaur.
Or did you do it? A new study has cast doubt on the theory that dinosaurs were simply wiped out Asteroid the size of a mountain Instead of pointing the finger at the volcano.
Researchers believe massive volcanic eruptions spanning continents have caused mass extinctions, and others in Earth’s history.
They say the presence of the asteroid makes things worse.
Their study was published in Prosidente National Academy of Sciences (PNAS), argues that volcanic activity is the main driver of mass extinctions.
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In fact, some types of volcanic activity may also explain other mass extinctions in history, the researchers said.
“All the other theories trying to explain why dinosaurs, including volcanoes, were killed, accelerated when the Chickxulub impact crater was discovered,” said co-author Briannen Keeler, assistant professor of earth sciences at Dartmouth College. in New Hampshire.
But he added that there was very little evidence that a similar impact event coincided with another mass extinction despite decades of exploration.
“While it is difficult to determine whether a particular volcanic eruption caused a specific mass extinction, our results make it difficult to ignore the role of volcanoes in extinctions,” said Keeler.
The researchers found that four out of five mass extinctions occurred simultaneously with a type of volcanic flow called a basalt flood.
These eruptions have inundated vast areas – even entire continents – with lava in just a million years, in the blink of an eye.
They left giant fingerprints as evidence: vast areas of stepped igneous rock (solidified by the lava explosion) that geologists call the “great igneous province.”
To be considered “large,” an igneous province must contain at least 100,000 cubic kilometers of magma.
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For context, the 1980 eruption of Mount Sant’Elena involved less than one cubic kilometer of magma.
A series of volcanic eruptions in Siberia today triggered the most catastrophic mass extinction event some 252 million years ago, releasing giant pulses of carbon dioxide into the atmosphere and suffocating nearly all life.
This witness is the Siberian Traps, an area of volcanic rock about the size of Australia.
Volcanic eruptions also rocked the Indian subcontinent around the time the great dinosaurs died, giving rise to what is now known as the Deccan Plateau. This, like an asteroid attack, would have far-reaching global effects, blanketing the atmosphere in toxic dust and smoke, suffocating dinosaurs and other life forms, and altering the climate over long time scales.
The researchers compared the best available estimates of alluvial basalt volcanic eruptions with periods of violent killing of species on geological time scales, including but not limited to five mass extinctions.
“Our results suggest that there is likely to be a mass extinction at the Cretaceous boundary to a significant extent, regardless of whether there is an impact or not, which can now be demonstrated by a quantitative aspect.
“The fact that there is an effect makes things worse without a doubt.”
The speed with which the Deccan Traps exploded in India suggests that the theater would have been largely extinct even without the asteroid, lead author Theodore Green said.
Greene, who conducted the research as part of the first scholarship program at Dartmouth and is now a graduate student at Princeton University, added that the effect was a double blow that rung the death knell of the dinosaurs.
Greene said alluvial basalt eruptions are not uncommon in the geological record. The last of a similar but significantly smaller scale occurred about 16 million years ago in the Pacific Northwest of the United States.
“Although the total amount of carbon dioxide released into the atmosphere during modern climate change is still significantly less than the amount released by the great fireworks province, we fortunately emit it very quickly, which is cause for concern,” said Keeler. .
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