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Asteroid that annihilated the dinosaurs formed these fossils 1:01
(CNN) - Since a giant crater was discovered in the Yucatan Peninsula, in Mexico, in the early 1990s, scientists have believed that an asteroid crashed into the Earth 66 million years ago and ended the Dinosaurs and most of life on the planet.
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But the cause has never been definitively resolved, and some scientists question the widely spread theory of "sudden asteroid death." That field of science believes that massive volcanic eruptions, which may have released gases that changed the climate of the planet in a region that is the size of Spain and is known as the stairs of the Decan, played an important role.
However, now a group of researchers from Yale University says that the only culprit in the extinction was the asteroid.
They point out that any environmental impact of the eruptions and lava flows that occurred on the stairs of the Decan - located in what is now India - occurred long before the extinction event that annihilated the dinosaurs, which scientists call K-Pg .
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"Many people have speculated that volcanoes are important to K-Pg, and we are saying, 'No, they weren't,'" said Pincelli Hull, assistant professor of geology and geophysics at Yale and lead author of the study, which was published. this Thursday in Science.
“Our study took 40 years of research and adds a lot of new research. Combine this in the most quantitative tests you can do and it really doesn't seem like they were (the volcanoes), ”he explained.
Some researchers believe that emissions from volcanoes, which released gases such as sulfur dioxide and carbon dioxide, weakened the ecosystem so that dinosaurs became more easily extinct when the asteroid hit Earth.
The stairs of the Decan are located in what is now India.
The Yale-led study investigated the timing of this degassing by modeling the effects of carbon dioxide and sulfur emissions on global temperatures and comparing them with paleotemperature records that encompass extinction.
They discovered that at least 50% or more of the main degassing of the Decan's stairs occurred long before the asteroid hit the Earth, and only its impact coincided with the mass extinction event.
The volcanoes did "cause a warming event," but their effect had disappeared by the time of extinction, said Michael Henehan, a former Yale researcher who is now at the GFZ Geosciences Research Center in Germany.
Researchers observe rock cores extracted from the seabed.
"The volcanic activity in the upper Cretaceous [period] caused a gradual global warming event of approximately two degrees, but not a mass extinction," said Henehan, who compiled the Paleolithic temperature records that encompass the extinction event.
To verify changes in temperature at the time, Henehan used records based on several sources, including chemical traces in fossils and other biomarkers.
- READ: Earth was on the other side of the galaxy when dinosaurs reigned
The researchers also examined rock cores extracted from the sea floor, which show when the asteroid struck.
“You can see rock fragments melted by the impact. It's very, very clear in these rock cores, ”added Henehan.
So, does this result put an end to the debate about what extinguished the dinosaurs?
I should, says Hull.
“If someone comes up with some compelling evidence tomorrow, I would be willing to say that we are wrong. But it really doesn't seem so based on what we know today, ”he concluded.
Asteroid Dinosaurs Extinction Dinosaur Extinction
