"In the end it was the dust that did it for the dinosaurs. At least that is the
finding of computer simulations of the aftermath of the asteroid impact that
reshaped life on Earth 66m years ago.
The cataclysmic impact in what is now Chicxulub on Mexico’s Yucatán peninsula
wiped out 75% of species on Earth, including non-avian dinosaurs. But the
precise nature of the deadly blow has kept scientists busy for decades, with
soot-spewing wildfires, volcanic eruptions and vast quantities of sulphur all
Writing in Nature Geoscience
, researchers in Belgium argue that the “exact
killing mechanisms” set in train by the impact remain poorly understood and
that too little attention has been paid to the role of potentially trillions of
tonnes of dust kicked up by the violent event.
Swirling around in the atmosphere for years, soot, sulphur and dust all have
the capacity to block out the sun and contribute to a global winter where
vegetation fails, with devastating knock-on effects for the animals it
To delve deeper into the role of the different factors, the scientists ran
simulations of the ancient climate that took into account measurements of fine
particles recovered from a site in North Dakota where a layer of dust generated
by the Chicxulub impact settled.
According to the simulations, dust of the size found in Dakota could have
remained in the atmosphere for up to 15 years after being blasted into the sky.
By blocking out the sun’s rays, up to 2,000bn tonnes of it could have shut down
photosynthesis for nearly two years and cooled the planet by up to 15C.
Created from pulverised granite and other rock at the impact site, the dust
“most likely drove the last mass extinction event through the disruption of
photosynthetic activity,” said Cem Berk Senel, a researcher on the study at the
Royal Observatory of Belgium in Brussels."
*** Xanni ***
Chief Scientist, Xanadu
Partner, Glass Wings
Manager, Serious Cybernetics