The Chicxulub asteroid impact triggered an impact winter and may have later overheated Earth, with fine dust and reentering debris fueling extreme heat and global wildfires during the dinosaur extinction, according to new research from Purdue University and the University of Colorado Boulder.
Approximately 66 million years ago, during the Cretaceous period, a massive asteroid struck Earth near the present-day town of Chicxulub on Mexico’s Yucatan Peninsula.
The Chicxulub impact released an estimated 1023 joules of energy—enough to trigger powerful earthquakes, generate mega-tsunamis, and excavate a crater measuring approximately 180-200 km in diameter.
The catastrophic asteroid collision caused the extinction of roughly 75% of Earth’s plant and animal species, including non-avian dinosaurs and ammonites.
Scientists have long studied how the Chicxulub impact caused the Cretaceous-Paleogene, or K-Pg, mass extinction.
In a new study, Purdue University planetary scientist Brandon Johnson and his colleagues revisited the possibility that extreme heat and widespread wildfires were among the most deadly consequences of the asteroid impact for life on land.
“We’re in the realm where we might be essentially killing off everything within that first hour or two,” Dr. Johnson said.
“This result reinvigorates the decades-long debate around whether it was the asteroid impact or another after effect that killed the dinosaurs.”
According to the researchers, material blasted into space by the Chicxulub asteroid impact traveled around the planet before reentering Earth’s atmosphere.
During this process, molten droplets called spherules separated from vaporized rock produced by the impact.
Geological evidence suggests that the hot vapor eventually cooled and formed enormous quantities of fine dust that remained suspended in the atmosphere.
As the spherules reentered the atmosphere, friction generated intense heat across the planet.
The fine dust may have intensified this heating by trapping additional thermal energy near Earth’s surface.
Together, the reentering debris and atmospheric dust could have scorched terrestrial environments and sparked widespread wildfires. The findings suggest that extreme heat may have played a major role in the extinction of land-dwelling plants and animals during the K-Pg mass extinction.
“It probably looked more like hell than like Venus,” Dr. Johnson said.
“The clouds would have blocked daylight, so to any animal, like humans, that don’t see far into the infrared, the surface would have probably looked dark.”
“You would only have been able to see a reddish glow from the wildfires. But there really wouldn’t be anything alive to do the seeing anyway, except for any animal that was able to burrow or swim or shelter in some way, to find a way to survive. It would have been terrible.”
The results were published July 28 in the Journal of Geophysical Research: Biogeosciences.
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Brandon C. Johnson et al. 2026. Heat and Wildfires during the K-Pg Mass Extinction Enhanced by Fine Dust. Journal of Geophysical Research: Biogeosciences 131 (7): e2026JG009837; doi: 10.1029/2026JG009837
Source: www.sci.news