New research published in Nature Geoscience supports the theory that the impact of the Chicxulub asteroid 66 million years ago led to a 15-year-long winter, resulting in the extinction of dinosaurs and three-quarters of life on Earth. Contrary to recent theories suggesting sulfur or soot from the impact caused prolonged darkness, this study indicates that ultra-fine silicate dust, originating from pulverized rock, remained in the atmosphere for 15 years. These minuscule particles, measuring between 0.8 and 8 micrometers, significantly reduced temperatures by up to 15°C due to the lack of sunlight, impacting the Earth’s climate.
In the 1980s, scientists Luis and Walter Álvarez proposed the asteroid impact theory for the demise of dinosaurs, which gained credibility with the discovery of the Chicxulub crater in the Yucatán Peninsula. However, the prevailing belief was that sulfur, not dust, altered the planet’s climate. A recent study, analyzing dust particles found in the Tanis fossil site in North Dakota, challenged this notion. Simulations revealed that 75% of the material in the atmosphere was dust, while 24% was sulfur, and the remainder was soot.
The dust particles completely hindered photosynthesis in plants for at least a year, leading to a “catastrophic collapse” of life, according to researcher Ozgur Karatekin of the Royal Observatory of Belgium. This study sheds new light on the events following the asteroid impact, emphasizing the significant role of silicate dust in shaping Earth’s prehistoric climate.