Who could have imagined that dust was the cause of the disappearance of dinosaurs? However, this is what a study published in the scientific journal Nature reveals. 66 million years ago, an asteroid did indeed crash into the Atlantic Ocean, near the present-day port city of Chicxulub, Mexico. But “the crash is not really what caused the dinosaurs to die,” paleontologist Stephen Brusatte tells BBC Science Focus.
After the impact, the 12 kilometer diameter asteroid released fine silicate dust, which itself caused the sudden cooling of the Earth. The sun’s rays could no longer pass through the atmosphere for almost two years, so photosynthesis by plants became impossible. “Ecosystems collapsed like houses of cards,” concludes the paleontologist. Without plants to eat, herbivores suffered. Little by little, the entire food chain collapsed, including the dinosaurs.
Fifteen years of dust in the atmosphere
Different theories have been put forward over the years on this subject. For University of Tokyo professor Kunio Kaiho, it was not the diffusion of silicate in the atmosphere but rather the sulfur and soot released during the impact, causing major fires, which would have caused the extinction of dinosaurs. Although this hypothesis has since been refuted, the researcher’s work remains useful for understanding the different climate patterns that the Earth has experienced over the millennia.
“We can include these factors in our models and analyze the consequences: what happens when a huge amount of sulfur, soot or carbon dioxide is released? We can test these hypotheses and learn more about the chemical composition of our atmosphere,” emphasizes Sean Gulick, geologist at the University of Texas at Austin in a…
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