2023-10-30 19:46:19
But the exact nature of the phenomenon caused by the Chicxulub asteroid remained a matter of debate. The most recent theories were that sulfur released by the impact, or soot released by colossal fires, blocked sunlight and plunged the world into a long winter.
A study published Monday gave new life to an earlier theory: the dust raised by the asteroid darkened the sky for a long time. Fine silica dust, pulverized sand, would have persisted in the atmosphere for fifteen years. The lack of light would have caused average temperatures to plunge by up to 15 degrees Celsius, according to the study published in Nature Geoscience.
In the 1980s, a father and son, Luis and Walter Alvarez, suggested that dinosaurs became extinct following an asteroid impact changed the climate by enveloping the Earth in dust. A theory doubted, until the discovery ten years later of the massive crater caused by Chicxulub in the current Mexican peninsula of Yucatan.
“Completely prevented photosynthesis”
The theory that sulfur, rather than dust, may have changed the climate gained ground because it was thought the dust was not the right size “to stay in the atmosphere,” a co-author explained. of the study, Ozgur Karatekin, researcher at the Royal Observatory of Belgium.
An international team was able to identify dust particles from the asteroid impact found in the Tanis fossil site in North Dakota, United States. They measure between 0.8 and 8 micrometers.
By entering their data into climate models similar to those used today, the researchers determined that this dust had played a much larger role than previously estimated. The simulations revealed that of the total quantity of material projected into the atmosphere, three-quarters was made up of dust, 24% of sulfur and only 1% of soot.
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