Murray Rayner
Shown are polished colored diamonds from the Argyle diamond deposit. The now closed mine in Western Australia was the source of 90% of the world’s pink diamonds.
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Pink diamonds are extremely rare and sought after – a now closed mine in Australia was the source of 90% of the colored gems. Polished rose specimens of the highest quality may sell for tens of millions of dollars. But a discovery made in the same area may help uncover new gem deposits, scientists say.
Scientists studying the Argyle diamond deposit in Western Australia, where the mine was located, said they now have a better understanding of the geological conditions necessary for the formation of pink diamonds and other colored varieties, according to a study published Tuesday in the journal. The nature of communication.
Using lasers to analyze minerals and rocks extracted from the Argyle deposit, scientists have discovered that the pink diamond-rich site was formed during the breakup of an ancient supercontinent called Nuna about 1.3 billion years ago.
“While the continent that would become Australia did not break apart, the area where Argyle is located was stretched, including the scar, creating gaps in the Earth’s crust for magma to shoot to the surface, bringing the pink diamonds with it. Hugo Olierook, a researcher at the John de Laeter Center at Curtin University in Perth, Australia, said in a press release that study leader Dr. Hugo Olierook.
Murray Rayner
The Argyle Diamond Mine is located in the remote Kimberley region in the far north-east of Western Australia.
Most diamond deposits are located in the middle of ancient continents – in volcanic rocks that quickly transported diamonds from the depths of the Earth’s interior to the surface.
However, for the diamonds to turn pink or red, must be subjected to intense forces from colliding tectonic plates that twist and bend their crystal lattices. Most brown diamonds are also created this way.
At Argyle, this process occurred about 1.8 billion years ago, when Western Australia and Northern Australia collided, turning the once colorless diamonds pink hundreds of miles below the Earth’s crust.
But how did these colored diamonds get to the surface? The research team found that the Argyle deposits were 1.3 billion years old, from when the ancient supercontinent known as Nuna was breaking up into fragments.
Murray Rayner
Pink diamonds from the Argyle diamond mine were formed when an ancient supercontinent broke into fragments, according to a new study.
Supercontinents, which form when several continents merge into a single landmass, have appeared several times in Earth’s geological history.
“Using laser beams smaller than the width of a human hair on rocks supplied by Rio Tinto (the company that owned the mine), we found that Argyle is 1.3 billion years old, which is 100 million years older than previously thought. would probably have formed as a result of the breakup of an ancient supercontinent,” Olierook said.
The authors suggested that the breakup of Nuna may have reopened an old junction left behind by the colliding continents, allowing diamond-bearing rocks to travel through the area to form a large diamond deposit.
This chain of events, according to the study, suggests that the intersections of ancient continents may be important for finding pink diamonds — and may lead to the exploration of other deposits.
“Most diamond deposits have been found in the middle of ancient continents because their host volcanoes tend to be exposed on the surface for explorers to find,” Olierook said.
“Argyle is on the landmass of two of these ancient continents, and these edges are often covered with sand and soil, so there is a possibility that similar pink diamond-bearing volcanoes still lie undiscovered, including in Australia.”
