Mother nature recycles trash to create diamonds

A 213-carat diamond recovered from Lucapa’s Mothae mine.

New research from Curtin University has provided a model that explains the formation and locations of all three major types of diamonds, which could impact the way the gems are mined.

The earth’s deepest diamonds are commonly created by the recycling of former living organisms hundreds of kilometres beneath the surface, new research from Curtin University shows.

Similarities were found between diamonds found in oceanic rocks and super-deep continental diamonds, and the origins of recycled organic carbon deep within the earth’s mantle.

Co-lead author John Curtin Distinguished Professor Zheng-Xiang Li, the Head of the Earth Dynamics Research Group, said the research provided a model that explains the formation and locations of all three major types of diamonds.

“This is the first time that all three major types of diamonds have been linked to mantle plumes, ballooning hot rocks driven by plate tectonics and the supercontinent cycle from deeper Earth,”  Li said.

“This research not only helps to understand Earth’s carbon cycle, but also has the potential to unlock more secrets of the Earth’s dynamic history through tracking the past locations of mantle plumes and superplumes. This can be achieved by mapping out the distribution of both continental and oceanic diamonds.”

Lead author Dr Luc Doucet said the findings offered a fascinating insight into regeneration and the power of mother nature.

“Bringing new meaning to the old trash to treasure adage, this research discovered that the earth’s engine actually turns organic carbon into diamonds many hundreds of kilometres below the surface,” Doucet said.

“Ballooning rocks from the earth’s deeper mantle, called mantle plumes, then carry the diamonds back up to the earth’s surface via volcanic eruptions for humans to enjoy as sought-after gemstones.

“While recycling is becoming a modern-day necessity for our sustainable survival, we were particularly surprised to learn, through this research, that mother nature has been showing us how to recycle with style for billions of years.”

While Rio Tinto’s Argyle diamond mine stopped production in November 2020 after 37 years of operation, Lucapa Diamond Company is in the process of acquiring the Merlin Mine in the Northern Territory.

Known for producing Australia’s largest diamond on record – a 104-carat type-2A diamond, as part of Lucapa’s JORC assessments, Merlin holds approximately four million carats in reserves.

Beyond the NT, Lucapa is also running a primary resource exploration program in the West Kimberley region of Western Australia in search of Australia’s next diamond mine.

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