Ultimately, it was the dust that caused the extinction of the dinosaurs. This conclusion was reached through computer simulations of the effects of the asteroid impact that dramatically altered the Earth’s ecosystem 66 million years ago.

The catastrophic collision that occurred in present-day Chicxulub on the Yucatán peninsula in Mexico resulted in the extinction of 75% of all species on our planet, including non-avian dinosaurs. However, the exact details of this devastating event have been a topic of research for many years, with theories ranging from wildfires emitting soot, to volcanic eruptions, to large amounts of sulfur being potential causes.

In a publication in Nature Geoscience, a team of scientists from Belgium state that the precise mechanisms of destruction caused by the impact are still not well understood. They also point out that the significant amount of dust, possibly trillions of tonnes, produced by the impact has not received enough attention.

For many years, soot, sulphur, and dust have been circling in the atmosphere. These substances are capable of obstructing the sun and causing a worldwide winter. This can lead to the failure of vegetation and have severe consequences for the animals that rely on it.

To further explore the impact of various factors, the researchers conducted simulations of the past climate by incorporating data on fine particles found at a site in North Dakota. These particles were generated by the Chicxulub impact and settled as a layer of dust.

Based on the simulations, particles of dust similar to those found in Dakota could have lingered in the air for a maximum of 15 years after being propelled into the sky. This amount of dust, estimated at 2,000 billion tonnes, could have obstructed the sun’s rays and potentially disrupted photosynthesis for a period of about two years, resulting in a cooling of the Earth’s temperature by as much as 15 degrees Celsius.

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.

According to Philippe Claeys, a geologist and planetary scientist at the Free University of Brussels and co-author of the study, the simulations showed that silicate dust is the most effective at blocking photosynthesis. This is because it makes the atmosphere less transparent to sunlight, which hinders the process of photosynthesis in plants.

Based on the computer simulations, it would have required a period of two years for photosynthesis to restart.

According to Steve Brusatte, a professor at the University of Edinburgh who was not part of the research team, the asteroid that caused the extinction of dinosaurs was described as “apocalyptic”.

According to him, the asteroid that hit Earth was the biggest one in the past 500 million years. It exploded with the impact of more than a billion nuclear bombs combined. However, this event was not the main cause of extinction for the dinosaurs and 75% of other species.

The downfall of the dinosaurs was ultimately caused by the aftermath of an asteroid impact. The debris and dirt from the impact rose into the atmosphere, blocking out the sun and causing the Earth to become dark and cold for several years. The asteroid did not immediately wipe out all the dinosaurs, but rather acted as a silent killer, leading to a gradual decline that resulted in the extinction of three out of every four species.

Source: theguardian.com