Study Finds Asteroid Dust Responsible for Mass Extinction of Dinosaurs

Approximately 66 million years ago, a colossal asteroid collided with Earth, surpassing the size of Mount Everest, resulting in the extinction of 75% of all species inhabiting the planet, including the dinosaurs.

This much we know.

But how exactly the impact of the Chicxulub asteroid caused all of these animals to become extinct is still a matter of debate.

Recently, the most common theory has been that sulfur from the asteroid impact – or soot from the wildfires it ignited – blanketed the sky and plunged the world into a long, dark winter, killing all but the lucky few.

However, a study published on Monday, based on particles found at a key fossil site, confirmed an earlier hypothesis: the impact winter was caused by dust kicked up by an asteroid.

The fine-grained silicate dust from the fine-grained rock would have remained in the atmosphere for 15 years and lowered the Earth’s temperature by up to 15 degrees Celsius, the researchers said in a study published in the journal Nature Geoscience.

In 1980, father and son scientists Luis and Walter Alvarez first proposed that the dinosaurs were killed by an asteroid impact that covered the world in dust.

Their claim was met with some skepticism at first – until ten years later the massive crater of Chicxulub was discovered on what is now the Yucatan Peninsula in the Gulf of Mexico.

Now scientists largely agree that Chicxulub was to blame.

But the idea that sulfur, and not dust, caused the winter effect has become “very popular” in recent years, researcher Ozgur Karatekin of the Royal Observatory of Belgium told AFP.

Karatekin, the study’s co-author, said this was because the dust from the impact was thought to be the wrong size to stay in the atmosphere long enough.

For the study, an international team of researchers was able to measure dust particles believed to have originated immediately after the asteroid hit.

– “Catastrophic Collapse” –

The particles were found at the Tanis fossil site in the US state of North Dakota.

Although the site is 3,000 kilometers (1,865 mi) away from the crater, several significant finds have been preserved there, which are believed to date from immediately after the asteroid impact in the sedimentary layers of an ancient lake.

The dust particles were about 0.8 to 8.0 micrometers — just the right size to stay in the atmosphere for up to 15 years, the researchers said.

By feeding this data into climate models similar to those on Earth today, the researchers concluded that dust likely played a much greater role in the mass extinction than previously thought.

Of all the material that the asteroid shot into the atmosphere, they estimate that it was 75 percent dust, 24 percent sulfur, and one percent soot.

The dust particles “completely shut down photosynthesis” in plants for at least a year, causing a “catastrophic collapse” of life, Karatekin said.

Sean Gulick, a geophysicist at the University of Texas at Austin and not involved in the study, told AFP the study was another interesting attempt to answer a “hot question” – what affected winter – but did not provide a definitive answer. answer.

He emphasized that finding out what happened during the world’s last mass extinction event was important not only for understanding the past, but also for the future.

“Maybe we can better predict our own mass extinction, which we’re probably in the middle of,” Gulick said.