The Atacama Desert in Chile has been used to simulate and study life in extraterrestrial environments, such as in Mars. Now, a recent study has revealed that researchers believe the desert was the site of an ancient comet explosion, intense enough to create giant slabs of silicate glass.
The research was published on Tuesday (2) in the journal “geology”.
About 12,000 years ago, intense heat transformed the sandy Atacama soil into vast expanses of glass stretching for 75 kilometers. Until now, scientists were not sure what caused this dramatic shift.
The Atacama Desert is the driest desert region on Earth, with extremely low humidity or precipitation. Fragmented desert glass contains tiny metallic particles that are often found in meteorites that land on Earth.
The minerals in the glass combined with particles collected by NASA’s Stardust mission, which it took from a comet known as Wild 2. Researchers are confident that the Chilean desert minerals are what’s left after a comet explodes similar to Wild 2. It melted.
said Pete Schultz, study author and emeritus professor of geosciences at Brown University and research professor in the Department of Earth, Environmental and Planetary Sciences at Brown University. “To have such a dramatic effect over such a large area, this was a truly massive explosion. Many of us had seen polyide fireballs (a brilliant meteor) seep through the sky, but they are small specks compared to this.”
Stunning glass fields, dark green or black, stretch across the eastern Pampa del Tamarogal plateau, located between the Andes and the mountains of the South Pacific coast. And although volcanic activity can produce this type of glass, there is no evidence to prove that the Atacama glass is formed by volcanoes.
In the past, researchers have suggested ancient fires were the cause. The area once hosted wetlands with herbs drawn from rivers. If that ancient forest had been burned in widespread wildfires, it could prove that the fire created the glass.
However, the glass itself is more complex than the glass from common fires. Up close, it appears that the pieces of glass were twisted, bent, twisted and thrown while they were still melting. For the researchers, this would only be possible with an atmospheric explosion that could release strong winds like hurricanes.
A chemical analysis of the glass revealed the presence of zircon, a mineral that thermally decomposes to form stick crystals. This change can only occur when the temperature reaches a peak above 1,600 degrees Celsius, which will certainly exceed the heat generated by the grass fires.
The analysis also showed minerals such as cupanite and troelite, both of which are found in comet Wild 2 and meteorites.
“These minerals tell us that this object bears all the signs of a comet,” study co-author Scott Harris, a planetary geologist at Fernbank Science Center in Georgia, said in a statement. “The presence of the same minerals that we saw in the stellar dust samples that are in these glasses is really strong evidence that what we’re seeing is the result of a comet airburst.”
The researchers want to date the glass to determine its exact age as well as the likely size of the comet, but their current prediction that the impact occurred 12,000 years ago is in line with the time when large mammals disappeared from the area.
“It’s too early to say if there is a causal relationship or not, but what we can say is that this event occurred at the same time that the megafauna is thought to have disappeared, which is interesting,” Schultz noted. “There is also a possibility that this may have been witnessed by the first residents who had just arrived in the area. It must have been an enormous sight.”
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