Libyan desert glass has remained a mystery for centuries
Shane Reynolds / Youtube
A meteorite which smashed into earth 29m years ago may be behind a strange yellow glass found in a certain part of the desert in southeast Libya and southwestern Egypt, according to researchers.
The Great Sand Sea Desert stretches over about 72,000 square kilometres across the two countries, and is the only place where the mysterious yellow material is found on Earth.
Researchers first described it in a 1933 scientific paper, calling it Libyan desert glass. Mineral collectors have long valued it for its beauty and mysterious qualities – and it was even found in a pendant in Egyptian pharaoh Tutankhamun’s tomb.
The origin of the glass has been a mystery for centuries, but researchers writing in the journal De Gruyter used new advanced microscopy technology to get answers.
Elizaveta Kovaleva, a lecturer at the University of the Western Cape, wrote that the glass was caused by “the impact of a meteorite on the Earth's surface”.
Writing in The Conversation, she said: “Space collisions are a primary process in the solar system, as planets and their natural satellites accreted via the asteroids and planet embryos (also called planetesimals) colliding with each other. These impacts helped our planet to assemble, too.”
She said: “We studied the samples with a state-of-the-art transmission electron microscopy technique, which allows us to see tiny particles of material – 20,000 times smaller than the thickness of a paper sheet.
\ud83d\udc9b\ud83e\udd0d\ud83d\udc9b Libyan Desert glass or Great Sand Sea glass is an impactite, made mostly of lechatelierite, found in areas in the eastern Sahara, in the deserts of eastern Libya and western Egypt. Fragments of desert glass can be found over areas of tens of square kilometers.\ud83d\udc9b
“Using this super-high magnification technique, we found small minerals in this glass: different types of zirconium oxide (ZrO₂).”
One of the types of this mineral found in the glass can only form at temperatures between 2,250 celsius and 2,700 celsius. Toasty.
Kovaleva said: “Such conditions can only be obtained in the Earth's crust by a meteorite impact or the explosion of an atomic bomb.”
However, she wrote, there are just as many questions as there are answers.
The nearest known meteorite craters are too far away and too small to be the cause of that much glass all concentrated in one part of the world.
“So, while we've solved part of the mystery, more questions remain. Where is the parental crater? How big is it – and where is it? Could it have been eroded, deformed or covered by sand?”
Safe to say, the scientists will keep on looking until they have the answers.