A new analysis by an international team of scientists shows that even before the asteroid impact, volcanic activity on Earth was strong enough to cause significant climate change. Scientists point out that even if there was no impact from space rocks, the fate of the dinosaurs would likely have been sealed.
The results and description of the research were published in the journal Science Advances (DOI: 10.1126/sciadv.adg8284).
Torabi to the dean
The new analysis is based on research on the so-called Deccan Corridors. These are large plains formed by hardened lava, forming the Deccan Plateau in India. They were created at the end of the Cretaceous period, about 66 million years ago, in what is now India, which was then a separate continent. The lava flows currently cover an area of about 500,000 square metres. km², although its original extent was probably much larger.
When examining rocks collected from the Deccan Gorges, scientists used a new technique they developed to measure sulfur concentration. In the laboratory, they estimated the amount of sulfur and fluorine released into the atmosphere due to massive volcanic eruptions that occurred over more than 200,000 years. Years before the extinction of the dinosaurs.
They found that violent volcanic eruptions may have played a major role in cooling the climate about 65 million years ago. The release of sulfur may have caused a global drop in temperatures around the world – a phenomenon known as volcanic winter.
Our research shows that climatic conditions were almost certainly unstable, with frequent volcanic winters that may have lasted decades before the dinosaurs became extinct. This instability made life difficult for all plants and animals and paved the way for the extinction of the dinosaurs. In this way, our work helps explain this great extinction, said the professor. Don Baker of McGill University in Canada.
Extinction of dinosaurs
Discovering evidence in ancient rock samples was no easy feat. In fact, a new method developed at McGill University has helped decipher the history made by volcanic activity.
The technique for estimating sulfur and fluorine emission is a bit like cooking pasta. -You can imagine making pasta at home. Boil water, add salt, then pasta. Some of the salt in the water ends up in the pasta, but not much of it, Baker explains. Likewise, some elements become trapped in minerals when they cool after a volcanic eruption. Just as the salt concentration in the water in which pasta was cooked can be calculated by analyzing the salt content in the pasta itself, the new technology has allowed scientists to measure the sulfur and fluorine content in rock samples. Thanks to this information, scientists were able to calculate the amount of gases emitted during massive volcanic eruptions before the extinction of the dinosaurs.
Models developed in this way indicated that persistent sulfur emissions from the Deccan Corridors were enough to cause a significant change in global climate. This volcanic region alone released a staggering 1 million cubic kilometers of molten rock. “Volcanoes in the Deccan Traps set the stage for a global biotic crisis by repeatedly worsening environmental conditions, causing frequent short volcanic winters,” the team concluded in the publication.
As a result, global temperatures may have periodically fallen by as much as 10°C over thousands of years. This, according to the researchers, led to a global decline in the number of non-bird dinosaur species even before the asteroid impact.
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