Dinosaurs likely brought down by dust, not asteroid, researchers say
A study published in Nature Geoscience on Monday suggests that finely ground dust, resulting from the impact of The Chicxulub asteroid, which was ejected into Earth's atmosphere, may have had a more substantial impact than the impact event itself.
The asteroid's impact not only released plumes of sulfur-based gases into the atmosphere but, according to researchers, the resulting dust also significantly blocked out the sun, disrupting plant photosynthesis for years.
"It had been long assumed that the main killing mechanism was extreme cold following the Chicxulub impact, but of course the cessation of photosynthesis after impact is a mechanism itself," Cem Berk Senel, lead study author and planetary scientist, told CNN.
"Within a few weeks, months (of the impact), the planet underwent a global shutdown in photosynthesis, which continued for almost two years during which photosynthesis is completely gone," said Senel, of the Royal Observatory of Belgium.
Researchers reached this conclusion through collecting data from rock samples in North Dakota. Utilizing a new computer model, they were able to determine the fine dust remained suspended in the atmosphere for a 15 years.
During this period, researchers said, the dust had a profound cooling effect on the planet, causing the average temperature to plummet by as much as 15 degrees Celsius. The cooling not only altered the climate, but also disrupted the Earth's ecosystems, the study suggests.
The impact event also led to widespread wildfires that released additional agents into the atmosphere, such as soot and sulfur.
When combined with the prolonged dust cloud, researchers said, the chemicals had a catastrophic impact on plant and algae growth.
It's unclear if this new research supports the theory that multiple asteroids may have struck Earth, contributing to the extinction of the dinosaurs.
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