31 October 2023 , 15:32
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Dinosaurs were not made extinct by the direct impact of an asteroid as was previously thought, a new study has revealed.
A team of scientists announced on Monday that the ancient creatures were instead killed off by the debris ejected by an asteroid that hit the Earth. The huge rock slammed into modern-day Mexico around 66 million years ago and caused a global catastrophe.
Approximately three quarters of the world's species were wiped out along with the sun being completely blocked, which left the planet's vegetation to starve. The reign of dinosaurs, which had lasted for around 180 million years, came to an abrupt end.
The 66-million-year-old Chicxulub crater in Mexico was discovered in 1978 (Getty Images/Stocktrek Images)New modelling from experts at the Royal Observatory of Belgium showed that the amount of dust caused by it was about 2,000 gigatonnes - more than 11 times the weight of Mount Everest - and stayed in the Earth's atmosphere for up to 15 years.
A chain reaction of events soon followed, including a drop in surface temperatures of about 15C degrees. Eventually, as the plants died off so did all the herbivores and carnivores that roamed the Earth.
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The research, published in Nature Geoscience, based its findings on the Tanis fossil site in North Dakota and suggested that the dust in the air caused a global winter. Researchers said the dust particles were around 0.8 to 8.0 micrometres, making them the right size to linger for around 15 years.
Using this information, the team concluded that the debris played a much bigger role in the extinction of dinosaurs than previously thought. This hypothesis rebuffs the idea that the asteroid itself directly killed them off.
The study's co-author Philippe Claeys said: "It was cold and dark for years." While fellow researcher Ozgur Karatekin added: “Biotic groups that were not adapted to survive dark, cold and food-deprived conditions for almost two years would have experienced massive extinctions."
Sean Gulick, a geophysicist at the University of Texas at Austin, told AFP that the new study contributed to the 'hot question' of what drove the impact of winter but did not provide a conclusive answer. Gulick, who was not involved in the research, said: "Maybe we can better predict our own mass extinction that we're probably in the middle of."