In the past, paper mache windows were used in ancient China, and glass windows are only available in modern times, making glass curtain walls in cities a magnificent sight, but tens of thousands of years old glass has also been found on earth, right in a 75-kilometer corridor of the Atacama Desert in the northern part of the South American country of Chile. Deposits of dark silicate glass are scattered locally, and they have been tested to be here for 12,000 years, well before humans invented glass-making technology. There has been speculation as to where these glassy objects came from, as only extremely high heat combustion would have burned the sandy soil to silicate crystals, so some say “hellfire” once occurred here. A recent study led by Brown University’s Department of Earth, Environmental and Planetary Sciences suggests that the glass may have been formed by the instantaneous heat of an ancient comet that exploded above the Earth’s surface, according to a Nov. 5 Yahoo News report. In other words, the mystery of the origin of these ancient glasses has been solved.
In the Brown University study, recently published in the journal Geology, researchers say samples of desert glass contain tiny fragments that are not currently found on Earth. And the minerals closely match the composition of material brought back to Earth by NASA’s Stardust mission, which collected particles from a comet called Wild 2. The team combined with other studies to conclude that these mineral assemblages are likely the result of a comet with a composition similar to Wild 2 that exploded at a location closer to Earth and partially and rapidly fell into the Atacama Desert, instantly generating extremely high temperatures and melting the sandy surface, while leaving behind some of its own material.
These glassy bodies are concentrated on the Atacama Desert east of Chile, a plateau in northern Chile bordered by the Andes to the east and the Chilean Coastal Range to the west. Since there is no evidence of violent volcanic eruptions here, the genesis of the glass has always attracted the geological and geophysical community to make relevant local investigations.
These glassy objects contain a zircon component, which in turn thermally decomposes to form baddeleyite, a mineral transformation that requires reaching temperatures above 1600 degrees, which is indeed no earthly fire. And this time the Brown University study has further identified peculiar combinations of minerals found only in meteorites and other extraterrestrial rocks, such as calcite, meteoric iron sulfide and calcium-aluminum-rich inclusions, matching the mineralogical signature of comet samples taken from NASA’s Stardust mission. This led to the present conclusion.
Post time: Nov-16-2021