Fireball turned kilometers of the Atacama desert into glass

(CNN) – The Atacama desert In Chile, it has been used to simulate extraterrestrial environments, such as Mars, on Earth. Now, researchers believe that a comet here exploded with enough force to form giant slabs of silicate glass, according to a new study.

The research was published Tuesday in the journal geology.

About 12,000 years ago, intense heat transformed the Atacama sandy soil into vast expanses of glass that stretched for 75 kilometers, but researchers weren’t sure what caused this drastic change.

The Atacama Desert is the driest region on Earth, with an extremely low level of humidity and precipitation. Fragmented desert glass contains minute metal fragments commonly found in meteorites that reach Earth.

The minerals in this glass match particles collected by NASA’s Stardust mission, which sampled from a comet known as Wild 2. Researchers are certain that the minerals they found in the Chilean desert are what remains after a comet similar to Comet Wild 2 that has exploded in sand. and melted it.

“This is the first time we have clear evidence of glass on Earth that was caused by thermal radiation and winds from a fireball that exploded just above the surface,” study author Pete Schultz said in a statement. Brown University and Research Professor in the Department of Earth, Environmental and Planetary Sciences at Brown University. “In order to make such a massive impact over such a large area, this was a really massive explosion,” he explained. “Many of us have seen fireballs (bright meteors) twinkling across the sky, but these are small flashes compared to this.”

How amazing are the glass fields of the Atacama

Spectacular glass fields, having a dark green or black appearance, stretch across an area to the east of the Pampa del Tamarogal plateau, located between the Andes mountain range and the Chilean coast mountain range. Although volcanic activity can produce this type of glass, there is no evidence that Atacama glass formed in this way.

Investigators had previously indicated that the fires were the cause. The area was once home to wetlands derived from rivers. If those ancient herbs had burned in wildfires on a large scale, some believe they could have made glass.

However, the glass itself is more complex. Up close, the pieces of glass appear to have been bent, bent, twisted, and thrown while still molten. This, according to the researchers, would only be possible with an atmospheric blast that could unleash winds that compete with those of hurricanes.

A chemical analysis of the glass revealed the presence of zircon, minerals that thermally decompose to form badelite crystals. This change can only happen when the temperature rises above 1,600 degrees Celsius, which will certainly exceed the heat generated by the fires.

The analysis also showed minerals such as cupanite and troelite, both of which are found in Comet Wild 2 and in meteorites.

“It’s these minerals that tell us that this object bears all the signs of a comet,” Scott Harris, one of the study authors and a planetary geologist at Fairbank Science Center in Georgia, said in a statement. “Having the same minerals that we’ve seen in the (mission) Stardust samples on these glasses is really strong evidence that what we’re seeing is the result of a comet airburst.”

The investigation is continuing

The researchers want to focus on dating the glass to determine its exact age, as well as the possible size of the comet, but their current prediction that the impact occurred 12,000 years ago corresponds to a time when large mammals disappeared from the area.

“It’s too early to say whether or not there is a causal relationship, but what we can say is that this event occurred at the same time that we think the megafauna disappeared, which is interesting,” Schultz said. “There is also a possibility that this may have been witnessed by the first residents, who had just arrived in the area. It would have been a wonderful sight.”