New research may provide a clue to the hunt for rare pink diamonds

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Pink diamonds are extremely rare and desirable, and a now-closed mine in Australia was the source of 90% of the colored gemstones. Polished pink specimens can be sold at the highest levels Tens of millions of dollars. But researchers say that the discovery made in the same area may help uncover new deposits of jewelry.

Scientists studying Argyle diamond deposits in Western Australia, where the mine is located, said they now have a better understanding of the geological conditions needed to form pink diamonds and other color types, according to a study published Tuesday in the journal. Nature Communications.

Using lasers to analyze minerals and rocks extracted from the Argyle deposits, the researchers found that the pink diamond-rich site formed during the break-up of an ancient supercontinent called Nuna, about 1.3 billion years ago.

“Although the continent that later became Australia did not break up, the area where Argyll lies expanded, including along the scar, creating gaps in the Earth’s crust for magma to escape to the surface, bringing with it the pink diamonds.” Lead study author Dr. Hugo Ollerock, a research fellow at the John D. Laitre Center at Curtin University in Perth, Australia, said in a press release.

Most diamond deposits are found in the middle of ancient continents, within volcanic rocks that quickly transported diamonds from deep within the Earth to the surface.

However, in order to turn diamond Pink color Or red, they must be exposed to intense forces from the collision of tectonic plates, which bend and bend their crystal lattices. Most Brown diamond It is also formed in this way.

At Argyle, this process occurred about 1.8 billion years ago when Western Australia and Northern Australia collided, turning colorless diamonds pink hundreds of miles below the Earth’s crust.

But how did these colorful diamonds make their way to the surface? The research team found that Argyle’s deposits are 1.3 billion years old, from when an ancient supercontinent, known as Nuna, split into parts.

Supercontinents, which form when several continents come together to form a single landmass, have appeared several times in Earth’s geological history.

“Using lasers smaller than the width of a human hair on rocks provided by Rio Tinto (the company that owns the mine), we found that Argyle is 1.3 billion years old, which is 100 million years older than previously thought, meaning that it is… “It was likely formed as a result of the breakup of an ancient supercontinent.”

The authors suggested that the breakup of Nuna may have reopened an ancient bend left behind by the colliding continents, allowing diamond-bearing rocks to travel through this region to form large diamond deposits.

This chain of events, according to the study, suggests that ancient continental junctures may be important for finding pink diamonds, and may guide exploration for other deposits.

“Most diamond deposits are found in the middle of ancient continents because their host volcanoes tend to be exposed on the surface for explorers to find,” Ollerok said.

“Argyle lies at the junction of two of these ancient continents, and these edges are often covered in sand and soil, leaving the possibility that similar pink diamond-bearing volcanoes remain undiscovered, including in Australia.”