Impact of the Chicxulub asteroid: dust responsible for the extinction of dinosaurs?
66 million years ago, an asteroid impact off the coast of what is now Mexico caused a mass extinction of life on Earth, including the famous dinosaurs. This theory, put forward since the 1980s by Luis and Walter Alvarez, father and son, was confirmed by the discovery of the massive Chicxulub crater in the Mexican Yucatan Peninsula. However, until recently, the exact nature of the impact and its consequences on the climate remained subject to debate.
A recent study, published in the journal Nature Geoscience, provides new information on this cataclysmic event. She suggests that it was the dust raised by the asteroid impact that would have darkened the sky in a lasting manner, leading to a long winter and the extinction of three-quarters of living species.
According to this study, fine particles of silica, coming from the sand pulverized during the impact, would have persisted in the atmosphere for approximately fifteen years. This darkness would have caused a significant drop in average temperatures, making life difficult for many species.
This new theory challenges previous assumptions that sulfur released by the impact or soot from fires were the main culprits for the glacial climate that followed. Researchers used climate models to determine that 75% of the material thrown into the atmosphere was dust, compared to just 24% sulfur and 1% soot.
It is also worth noting that the dust particles are likely to have affected photosynthesis, a vital process for plants. This interruption of photosynthesis would have led to a “catastrophic collapse” of plant life and, therefore, a major disruption of all levels of the food chain.
In conclusion, this study provides new evidence supporting the idea that it was the dust raised by the impact of the asteroid Chicxulub that caused a long winter and the extinction of many species, including dinosaurs. These results highlight the importance of understanding the complex mechanisms of past events to better understand the impact of current climate changes.