Pacific ‘ring of fire’
Recent research has also found why changes to Earth’s magnetic field are weaker over the Pacific.
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Earth’s mantle is currently classified into two main domains, African and Pacific.
However, little is known about their formation and history, and they are commonly assumed to be chemically the same, says Tech Explorist.
In a new study by Curtin University, scientists studied chemical and isotopic “make-up” of rocks sourced from thousands of kilometers below the surface.
They wanted to understand how the Earth’s mantle responds to plate movements that occur near its surface.
Their study has uncovered how rocks sourced from the Earth’s mantle are linked to the formation and breakup of supercontinents and super oceans over the past 700 million years, suggesting that the Earth is made up of two distinct “faces.”
Lead author Dr. Luc-Serge Doucet, from the Earth Dynamics Research Group in Curtin’s School of Earth and Planetary Sciences, said:
“Our team used trace metals such as lead, strontium, and neodymium, from hotspot volcanic islands including the Hawaiian islands in the Pacific Ocean and the La Reunion island in the Indian Ocean, to examine whether these two domains have the same chemical ‘make-up.”
“We found that the African domain was ‘enriched’ by subducted continental materials, which was linked to the assembly and breakup of the supercontinent Pangaea, whereas no such feature was found in the Pacific domain.”
Scientists found that the contents of the two mantle domains are not the same as previously thought.
Instead, it appears that the Earth has two chemically distinct hemispheric “faces,” with the Pacific ring of fire being the surface expression of the boundary between the two.
Full article here.
via Tallbloke’s Talkshop
July 2, 2020 at 08:03AM
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