The world may owe its supply of pink diamonds to the breakup of the planet’s first supercontinent. The publication writes about this Nature. The Argyle Formation in Western Australia is the source of 90% of the Earth’s pink diamonds. It’s a strange place for diamonds: It’s on the edge of the continent, not in the center where most diamond mines are located, and in rock that’s slightly different from the rocks that usually contain diamonds.

New research suggests that the strange color and strange geology probably come from a similar origin, namely the planet’s plate tectonics about 1.3 billion years ago. Recent work by other researchers suggests that these large-scale continental movements are also important in bringing other colored diamonds to the surface.

“The breakup of these continents is fundamental to the recovery of these diamonds from these deep depths,” said Hugo Oliruk, a researcher at Curtin University in Australia and lead author of a new study on the origin of pink diamonds.

Pink diamonds are different from blue or yellow diamonds, which get their color from impurities such as nitrogen and boron. In contrast, pink diamonds are colored only because their crystal structure is bent. Argyle also contains many brown diamonds that acquire their color as a result of further deformation of the crystal structure.

Argyle diamond mine closed in 2020. Research conducted in the 1980s, shortly after the discovery of the deposit, revealed that the age of the rocks was approximately 1.2 billion years. But even the scientists who conducted this original study were unsure of such a number,” Olieruk said.

He and his colleagues decided to double-check using modern equipment, including laser ablation technology, which allowed them to carefully identify individual crystals in the rock they had dated.

These new results showed that Argyle, which contains pink diamonds, is 100 million years older than previously thought, or 1.3 billion years. This explains its origin at the beginning of the breakup of the supercontinent Noon.

“This paints a new picture of how Argyle’s pink diamonds came to be,” Oliruk said.

“First, about 1.8 billion years ago, two parts of the continental crust crashed into each other during the formation of Nuna. It was at this junction that what would eventually become the Argyle formation. “Probably due to the influence of the earth’s crust, the diamonds bent and turned pink.”

It was the breakup of Nuna 500 million years later that brought the diamonds to the surface. The continent did not break up directly near Argyll, but the resulting stretching probably weakened the “old wound” of the continental collision in which the formation was located. This weakening led to an eruption that occurred within days or weeks of the deep rock bearing the rare pink diamonds.

“I think we’re seeing a general destabilization of the mantle as supercontinents are breaking up,” Oliruk said. said. “This rifting process not only works at the edges, it also seems to work in the middle of the continents, and in many cases that’s probably what makes diamonds appear at their centres,” he said.

“Tracking the paths of diamonds from the depths to the surface is useful for understanding how carbon moves in and out of the planet’s interior,” Oliruk said. said. After all, diamonds consist mostly of pure carbon.

According to the scientist, Argyle is a rather unique place, but there is a possibility that pink diamonds can be found elsewhere on Earth.

“I really think we’ll find another Argyle, another trove of pink diamonds,” he said, “but it’s going to take a lot of luck.” Source