Rare Australian pink diamonds emerged when a supercontinent broke up

Coloured diamonds from the Argyle mine in Australia

Colored diamonds from the Argyle Diamond Mine in Western Australia

Murray Rayner

Western Australia’s pink diamonds had been delivered to the floor from deep underground round 1.3 billion years in the past when the previous supercontinent Nuna broke up.

Pink diamonds are extraordinarily uncommon and prized. Greater than 90 per cent of these discovered to this point have come from the Argyle Diamond Mine within the Kimberley area of Western Australia.

Like different diamonds, Argyle pink diamonds initially shaped no less than 150 kilometres underground throughout Earth‘s historic previous and began out colourless.

Then, round 1.85 billion years in the past, they’re believed to have turned pink when two former continents – which now type northern and western sections of Australia – smashed collectively to change into a part of a supercontinent known as Nuna that after included 90 per cent of Earth’s land mass.

The collision deformed the crystal buildings of diamonds caught within the center and prompted them to replicate mild otherwise, changing into pink, says Hugo Olierook at Curtin College in Western Australia.

To learn how and when the pink diamonds later got here to the floor, Olierook and his colleagues analysed samples of diamond-containing rock from the Argyle Diamond Mine.

They decided that the diamonds settled on the floor between 1.31 and 1.25 billion years in the past by courting the encompassing rock utilizing radiometric strategies. This coincides with when Nuna began to interrupt into smaller continents, suggesting the 2 are linked, says Olierook.

The northern and western sections of Australia held collectively at the moment, however they had been stretched aside sufficient for diamond-containing magma to properly up between the previous continents. “It’s like if you happen to had been to yank a sutured pores and skin wound open, the stitches might maintain, however a bit little bit of blood may trickle out,” says Olierook.

Up to now, most diamonds have been discovered in the course of historic continents, the place they’ve shaped on the base of the thick crust and later been shot up by volcanic exercise. Nevertheless, the bizarre placement of the Argyle deposit suggests there could also be extra riches to be found on the edges of historic continents, says Olierook, which have historically been ignored.

The Argyle Diamond Mine closed in 2020 in any case its pink and different diamonds had been extracted over a 37-year interval, which means the search is now on for brand new deposits.