The missing ingredient was the volcanic event that sent the diamonds to the Earth’s surface, where humans could reach them with their hands.
In the 1980s, it was estimated that argyle diamonds appeared 1.2 billion years ago. But there was no “trigger” for the surge in rare diamonds at the time, Ollerok said, so investigators sought to establish a more precise timeline.
They used a laser thinner than a human hair to examine tiny crystals in a sample of argyle rock provided by the mine owner, Anglo-Australian mining giant Rio Tinto.
By measuring the age of the elements in the crystals, the researchers determined that the age of Argyle was 1.3 billion years, meaning that diamonds appeared 100 million years later than previously thought.
This fact is consistent with the breakup of the world’s first supercontinent, known as Nona or Colombia.
At Nona, “almost all of Earth’s land masses have been compressed,” explains Ollerok.
The enormous pressure that gave diamonds their color – the second component – occurred during collisions between Western Australia and Northern Australia 1.8 billion years ago.
When Nuna began to disintegrate 500 million years later, it worsened the “scar” from that event, Ollerok said.
He added that the magma penetrated this ancient scar “like popping a champagne cork,” taking the diamonds with it.
Such a “colossal explosion” — which sent diamonds traveling at almost the speed of sound — had never occurred in recorded human history, said Luc Doucet, co-author of the study.
