Killer asteroid that wiped out dinosaurs stopped a key process for life on Earth - scientists

Mankind has long known that a giant asteroid that hit the Earth 66 million years ago was responsible for the extinction of the dinosaurs, but the process that led to the mass extinction of species has remained a mystery and has kept scientists arguing. The latest work of researchers suggests that the dust that flew into the sky after the fall of the celestial body stopped photosynthesis and started a chain reaction of extinction.

The results of the study were published in the journal Nature Geoscience. Previously, it was believed that the global winter and rapid temperature decline were caused by sulfur released during the impact that left a 180-kilometer-wide crater, and soot from forest fires.

To understand the nature of the fatal global winter, a team of geologists led by Jem Burke Senel from the Royal Observatory of Belgium in Brussels investigated the effects of the collision that created Mexico's Chicxulub crater.

They studied a well-preserved sample of rock formed during an extinction event in what is now North Dakota (USA). Such rocks contain traces that geologists use to mark the change from the Cretaceous to the Paleogene period in the history of the Earth.

During the study, they analyzed the amount of sulfur, soot, and silicates, and found that the sample contained much more than expected small, fine silicate dust particles - with diameters ranging from 0.8 to 8.0 micrometers.

Senel's team speculates that the asteroid impact kicked up clouds of these tiny particles, resulting in dust clouds that blocked the sun and halted plant photosynthesis for about two years, a biological process that is critical to life.

As a result, all vegetation died out and provoked starvation among many herbivorous species, including some dinosaurs. This could eventually lead to a catastrophic mass extinction of 75% of species.

"It (the cessation of photosynthesis - Ed.) destroyed the food web, creating a chain reaction of extinction," Senel said.

The researchers' modeling showed that the dust could have remained in the atmosphere for up to 15 years, causing a 15°C drop in temperature.

Senel notes that his team is the first to conduct paleoclimatic modeling that has indicated a 2-year suppression of photosynthetic activity and a 15-20-year winter that was caused by dust.

"For a long time, it was thought that the main killing mechanism was the extreme cold after the Chicxulub impact, but of course the cessation of photosynthesis after the impact is a mechanism in itself," the researcher said.

Earlier, OBOZ.UA reported that dinosaurs existed on Earth, but in a completely different part of the galaxy.

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