Researchers discover rare glass field in South Australia, evidence of previously unidentified powerful collision
An extraordinary field of glass
Researchers from Curtin University in Australia, in collaboration with the University of Aix-Marseille in France, have uncovered evidence of a large asteroid impact that occurred about 11 million years ago. Unlike familiar cases where impact remnants are recorded in craters, here the only evidence is a new field of tektites – natural glasses formed by the melting of surface rocks during an asteroid impact.
The tektites discovered in South Australia exhibit unique chemistry and are different from any other tektite known to date. “These are like tiny time capsules from Earth’s geological past,” says Professor Fred Jourdan from Curtin University’s School of Earth and Planetary Sciences.
What are tactites??
Tektites – or, as they are poetically called, “cosmic glasses” – are formed when the energy of an asteroid impact melts the Earth’s surface, and the molten material is thrown up to enormous heights before resolidifying as glass. This process disperses the tektites hundreds or even thousands of kilometers from the impact site.
Four major tektite fields have been identified in the past: the Australasian (the largest, 780 years ago), the North American, the West African, and the Czechoslovakian. Now a fifth field has been added – unique to Australia, and formed in a collision that has not yet been identified.
Riddle: Where is the crater??
The finding raises a disturbing question: If this was indeed an asteroid impact of such a powerful magnitude, why was no crater found? Prof. Jourdan notes that the crater may have been covered over time by layers of sediment or eroded by geological activity. Another possibility is that it was an impact along an ancient volcanic arc, so that the original structure was hidden by tectonic activity.
“The very existence of unique tactites clearly points to an event that we had not previously known about,” says lead researcher Anna Musolino, a doctoral student at the University of Aix-Marseille. “Their unusual chemistry, combined with their age – 11 million years – sets them apart from any known group of tactites.”
The new taktites are different from the famous Australasian Field, which formed about 780 years ago and spanned half of the Earth. While the Australasian Field is well known and studied in depth, the new field points to a completely separate collision – earlier, and probably also devastating on a regional scale.
Extraordinary chemistry
The study, published in the journal Earth and Planetary Science Letters, indicates that the taktites contain chemical signatures that have not been observed before – indicating a different geological origin and particularly extreme conditions at the time of impact. “They tell us a new story about the history of the Earth,” emphasizes Prof. Jourdan.
Studying asteroid impacts is not just a matter of planetary archaeology. It is also essential for understanding the risks to humanity's future. Giant impacts have occurred many times throughout Earth's history—the most famous of which is the Chicxulub impact in Mexico 66 million years ago, which contributed to the extinction of the dinosaurs.
“The better we understand the history of impacts, the better we can assess future risks,” says Mussolino. “Such events may be rare on the scale of a human lifetime, but over millions of years – they are part of the routine of the solar system.”
This discovery, she said, “opens a new chapter in the dramatic history of the Earth.” It suggests that there may be other major impacts that have not yet been detected, hidden beneath the surface or lost in the tangle of ancient geology.
The study was published on August 29, 2025:
"A new tektite strewn field in Australia ejected from a volcanic arc impact crater 11 Myr ago"
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One response
Why not in one of the oceans?