Worlds oldest diamonds dating 4.25 bln years discovered Down Under

Scientists have found the worlds oldest known diamond encased in a crystal in Western Australia.

Washington, Aug 23 : Scientists have found the world's oldest known diamond encased in a crystal in Western Australia.

Geologists say the minuscule gemstones are 4.25 billion years old and could provide a rare glimpse into Earth's distant geologic past.

"No one would have really predicted that diamonds were in there," said Simon Wilde, a geologist at Curtin University of Technology in Perth and a member of the team that made the find.

He said the discovery provided evidence that seas of molten lava that covered primordial Earth had cooled down faster than had previously been thought.

The find also suggested that plate tectonics, the process by which large shelves of Earth's crust move to create geologic activity might have already been underway, he said.

"A diamond would never form in a magma ocean," said Thorsten Geisler, a geologist at Westfalische Wilhelms-Universitaet in Munster, Germany, and a member of the team.

Geisler said the discovery was a shocker to the researchers, as many of them believed that the molten lava and volcanic activity persisted on Earth's surface for at least 500 million years after our planet formed some 4.5 billion years ago.

According to National Geographic, the tiny diamonds were found trapped in zircon, a rare and exceptionally stable mineral that forms under temperatures between 1,112 and 1, 652 Fahrenheit.

Once zircon is crystallized, geological processes sometimes move it around, but its chemical makeup and structure doesn't change, which makes its age easy to pinpoint.

Wilde said as zircon crystals represent the only record of the first 400 million to 500 million years of Earth's history, hence, by analysing a crystal's trace minerals and structure, it becomes possible to deduce the conditions under which it formed.

John Valley, a geologist at University of Wisconsin in Madison who was not involved in this study, said there are four known "recipes" that create diamonds, but the 4.25-billion-year-old diamonds "suggest the additional possibility that the diamonds have formed by some process that is not yet understood".

The study by Martina Menneken, a master's student at the Westfaelische Wilhelms-Universitaet, appears in this week's issue of the journal Nature.

ANI