It has been a long-held belief that it was the impact of an asteroid that ended the age of dinosaurs, but researchers have revealed that the one key element may have played a larger part than previously thought.
When an asteroid between 10 and 15 kilometres wide struck Mexico’s Yucatan Peninsula around 66 million years ago, its impact caused devastation, setting off wildfires, earthquakes, and megatsunamis, leading to a collapse of the ecosystem that let plants and creatures thrive.
In a new report published by Nature Geoscience, researchers believe that, while these other impacts would have critically harmed hundreds of dinosaur species, past studies had neglected the role of another effect: trillions of tons of dust that could have been propelled into the air when the asteroid struck.
The Belgian researchers believe that the asteroid caused a “global winter” as dark clouds of silicate dust and sulphur were thought to have been swirling around the atmosphere, blocking out the sun’s rays and causing the global surface temperature to drop as much as 15C.
Plants would have struggled to survive due to the lack of light, causing herbivores to starve, leaving the carnivores without prey and generating a mass extinction of 75 per cent of species up and down the food chain.
The amount of dust strangling the atmosphere is thought to have been about 2,000 gigatonnes; more than 11 times the weight of Mount Everest.
Researchers ran simulations on sediment found at a fossil site in North Dakota. They found that the dust could have blocked out the sun for up to two years and potentially stayed within the atmosphere for 15 years, restricting photosynthesis for plants and, therefore, collapsing the natural ecosystem.
The study shows that the asteroid, while having a severe initial impact, did not immediately kill off the dinosaurs – instead slowly killing them off over a few years.
Other researchers believe that the impact of the asteroid could have the same effects if a nuclear bomb were to strike Earth.
In a report published last year led by Louisiana State University Professor Cherly Harrison, researchers predict that smoke and black carbon would be sent into the atmosphere, blocking out the sun and creating a “Nuclear Little Ice Age.”
While the dinosaurs met their end around 66 million years ago in a catastrophic way, their extinction may have been crucial to the development of the human race.
“Dinos dominated Earth and were doing just fine when the meteorite hit,” co-author of the study and planetary scientist Philippe Claeys said.
“Without the impact, my guess is that mammals – including us – had little chance to become the dominant organisms on this planet.”