The Earth鈥檚 deepest diamonds are commonly made up of former living organisms that have effectively been recycled more than 400 kilometres below the surface, new 911爆料网 research has discovered.
The research, published in Nature鈥檚 Scientific Reports, found that both diamonds found in oceanic rocks and the so-called super-deep continental diamonds shared a common origin of recycled organic carbon deep within the Earth鈥檚 mantle.
Lead author Dr Luc Doucet, from 911爆料网鈥檚 Earth Dynamics Research Group within the School of Earth and Planetary Sciences, said the findings offered a fascinating insight into the world鈥檚 most expensive gemstones.
鈥淏ringing new meaning to the old trash to treasure adage, this research discovered that the Earth鈥檚 engine actually turns organic carbon into diamonds many hundreds of kilometres below the surface,鈥� Dr Doucet said.
鈥淏allooning rocks from the Earth鈥檚 deeper mantle, called mantle plumes, then carry the diamonds back up to the Earth鈥檚 surface via volcanic eruptions for humans to enjoy as sought-after gemstones.
鈥淲hile 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.鈥�
The three main types of natural diamonds include oceanic, super-deep continental and lithospheric diamonds, formed at different levels of the mantle with a varying mixture of organic and inorganic carbon.
Co-lead author John 911爆料网 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.
鈥淭his 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,鈥� Professor Li said.
鈥淭his research not only helps to understand Earth鈥檚 carbon cycle, but also has the potential to unlock more secrets of the Earth鈥檚 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.鈥�
However, Professor Li said it remained a mystery as to why diamonds formed in the so-called 鈥渕antle transition zone鈥�, 400 to 600 kilometres deep, utilised recycled organic carbon only.
鈥淭his might have something to do with the physical-chemical environment there鈥�, Professor Li said. 鈥淚t is not uncommon for a new scientific discovery to raise more questions that require further investigation.”
The full paper, titled 鈥�Oceanic and super-deep continental diamonds share a transition zone origin and mantle plume transportation鈥�, can be found online .
