The age of the dinosaurs came to an end nearly 66 million years ago, after a colossal asteroid collided with a shallow sea near what we now call Mexico, forming a city-sized crater. However, the precise sequence of events leading to the mass extinction of 75 per cent of Earth's species in the years following this catastrophic impact has remained shrouded in mystery.
Previous studies had proposed that the release of sulfur during the impact, coupled with soot from widespread wildfires, ushered in a global winter as temperatures plummeted. But a new research, released on Monday and published in the journal Nature Geoscience, posits that the primary culprit may have been fine dust, formed from the pulverised rock that was flung high into Earth's atmosphere in the aftermath of the impact.
This fine dust, to a significant degree, eclipsed the sun's rays, preventing plants from carrying out photosynthesis, a vital biological process for sustaining life, for nearly two years following the cataclysmic event, said the study.
"Photosynthesis shutting down for almost two years after impact caused severe challenges (for life). It collapsed the food web, creating a chain reaction of extinctions," lead author and planetary scientist Cem Berk Senel, a postdoctoral researcher at the Royal Observatory of Belgium, was quoted as saying by CNN.
Scientists used the power of technology to do some number-crunching. They developed a new computer model to simulate global climate after the asteroid strike. The computer model was created on the basis of published information on Earth's climate at that point of time, as well as new data from sediment samples taken from the Tanis fossil site in North Dakota that captured a 20-year period during the aftermath of the strike.
In the new study, the scientists also analysed the data from the samples of silicate dust particles that were thrust into the atmosphere in a plume before returning to Earth.
It took the dust particles 15 years to finally settle on the surface of the Earth. The researchers suggested that global climate may have cooled by as much as 15 degrees Celsius during this period.
