Australian scientists from Curtin University together with Chinese colleagues from Laoshan Laboratory in Qingdao have concluded that the Earth’s mantle has split into two parts. This process reflects the creation and destruction of the supercontinent Pangaea. The study was published in the scientific journal Nature Geoscience (NatGeo).
According to experts, the mantle consists of the African and Pacific domains. The African domain extends from the east coast of Asia and Australia through Europe, Africa and the Atlantic. The Pacific domain, in keeping with its name, encompasses the Pacific Ocean. The domains are separated by the Pacific Ring of Fire fault.
The mantle beneath the African domain is full of isotopes of many elements, whose set is much more diverse compared to the Pacific domain, the scientists noted.
According to the authors of the discovery, this pattern reflects the last two cycles of supercontinents. About 1.2 billion years ago, the supercontinent Rodinia formed and broke up about 750 million years ago. This was followed about 335 million years ago by the formation of the supercontinent Pangaea, which ceased to exist 200 million years ago.
After Pangaea disintegrated, various elements and their isotopes remained in both the deep and surface layers of the mantle. They got there through the process of subduction – the sliding of one lithospheric plate over another.
The findings shed more light on the processes linking the mantle and the surface. The cause of the breakup of supercontinents is not fully understood, but it is thought to be due to the rise of hot mantle material from deep regions of the mantle called mantle ‘clots’.
Understanding these processes can help geologists determine where useful mantle materials, particularly rare earth elements, may be concentrated.
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