Earth’s 12,000-year-old glass found in South American country, mystery of origin solved

In the past, paper mache windows were used in ancient China and glass windows are only modern, making the glass walls of cities a magnificent sight, but tens of thousands of years old glass has also been found on earth, right in a 75 kilometre corridor in the Atacama Desert in the northern South American country of Chile. Deposits of dark silicate glass are scattered in the area and have been tested to show that they have been there 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 very hot combustion would have burnt the sandy soil to silicate crystals, leading some to suggest that “hell fires” once took place 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 surface, according to a Yahoo News report on 5 November. In other words, the mystery of the origin of the ancient glass has been solved.

In the Brown University study, recently published in the journal Geology, researchers say that 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 concluded, in conjunction with other studies, that these mineral assemblages are likely to be the result of a comet with a composition similar to Wild 2 exploding at a location close to Earth, with parts falling rapidly 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 bounded by the Andes to the east and the Chilean Coastal Mountains to the west. In the absence of any evidence for violent volcanic eruptions, the genesis of the glass has always attracted the geological and geophysical community to the area for related investigations.