Volcanoes may have played a decisive role in the extinction of the dinosaurs. The asteroid only increased their effect

(ORDO NEWS) — A study led by geologists at Dartmouth College concluded that it was volcanic activity that was the main cause of the mass extinction that killed the dinosaurs 66 million years ago.

The fall of the asteroid only accelerated the process.

Volcanic eruptions have long been considered the main cause of the Cretaceous-Paleogene extinction. Then they were supplanted by the impact hypothesis – the fall of an asteroid. But not all paleontologists agreed with her.

What killed the dinosaurs 66 million years ago at the end of the Cretaceous period is still the subject of scientific debate.

Many scientists are trying to understand what caused the mass extinction that changed the life of the Earth in a geological instant.

Today, most scientists are inclined to the hypothesis that the most likely cause of extinction was the fall of an asteroid, but there are others who claim that volcanic eruptions led to this.

A new study led by geologists at Dartmouth College concludes that volcanic activity was the main cause of the mass extinction that killed the dinosaurs.

Magma spills

The researchers analyzed all the mass extinctions on Earth and came to the conclusion that four out of five global catastrophes occurred simultaneously with volcanic eruptions, in which there was a massive outpouring of basalt.

Such eruptions can flood an entire continent with lava. Moreover, this happens very quickly according to the geological clock – in just a million years. Such spills leave behind giant “fingerprints” – vast areas of stepped, hardened lava, which geologists call “eruption provinces.”

To be considered “large”, such an igneous province must contain at least 100,000 cubic kilometers of magma. This is a lot. For example, the 1980 eruption of Mount St. Helens ejected less than one cubic kilometer of magma.

“The large stepped areas of igneous rock left by these large volcanic eruptions seem to coincide with mass extinctions and other significant climatic and environmental events,” lead author Theodore Green said.

Scientists cite a series of eruptions in present-day Siberia that caused the most devastating mass extinction ( Permian ) around 252 million years ago.

Volcanoes released a huge amount of carbon dioxide into the atmosphere and practically suffocated life on Earth. Evidence of this eruption is the Siberian traps, a large area of ​​volcanic rock roughly the size of Australia.

Volcanic eruptions also shook the Indian subcontinent about 66 Ma during the extinction of the dinosaurs ( the Cretaceous–Paleogene extinction event ), creating what is today known as the Deccan Plateau.

This had global consequences, releasing dust and toxic fumes into the atmosphere. And as a result, dinosaurs and other living creatures simply suffocated.

Chicxulub

“All other theories that tried to explain what killed the dinosaurs, including volcanism in the Deccan Plateau, collapsed when the Chicxulub impact crater was discovered,” says co-author Brenhin Keller.

But, he notes, there is very little evidence of similar collisions coinciding with other mass extinctions, despite decades of research.

The speed of the eruption in India’s Deccan Plateau suggests that the conditions for a mass extinction were poised even without the asteroid, Green said. His strike sounded like a death bell for dinosaurs, he adds.

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