There are two faces of the Earth: study

Posted: July 2, 2020 by oldbrew in Geology, History, research

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.

Comments
  1. Curious George says:

    “the Pacific ring of fire being the surface expression of the boundary between the two.” When you rotate your globe so that it shows no continents at all, you are viewing the Pacific domain. In Pangaean times you could have rotated your globe so that it would show mostly dry land. It has scattered since. And the two regions have now been shown different?

  2. spetzer86 says:

    A reinforcement of the rouge planet slamming into early Earth and generating the Earth/Moon theory? The Ring of Fire is the continuing battle of the two planetary bodies? Would the Moon be similarly differentiated at some point?

  3. hunterson7 says:

    Further evidence of the ancient cataclysm that made Earth habitable.

  4. ichor0 says:

    something to do with “the Pacific Triangle”?

    “The triangle is formed by lines of equal age in the ocean floor derived from bands of alternating magnetism as the earth’s pole flipped. It is one of the great mysteries discussed previously. The ocean floor gets progressively older from all three sides towards a small triangle in the middle. ”
    https://geosciencebigpicture.com/2013/11/24/the-pacific-triangle/

    in another post, with a great picture,
    “Essentially, the Pacific Triangle IS the Pacific Plate. Unless you wish to consider it a sinkhole, a point subduction zone, all that we know as the Pacific Plate has grown out of this spot in the last 175 million years”

    in another
    “It just seems so outrageous that three spreading ridges would suddenly emerge from a single point in the Panthalassic Ocean 170 million years ago and begin migrating away in three directions.”

  5. oldbrew says:

    Mount Everest would fit in the Mariana Trench (centre left, above) with 2km. to spare.

    https://en.wikipedia.org/wiki/Mariana_Trench

  6. ivan says:

    Did they include all those under water volcanoes round Antarctica?

  7. tallbloke says:

    According to this map of relative plate movement speeds and subduction zones, all the action is in the Pacific where the deep tranches are. No subduction around Africa or Europe or the eastern seabord of the Americas, or the indian ocean.

    Global map illustrating the major subduction zones on Earth for which the trench-normal subducting plate velocity (v SP? ) and the trench-normal trench migration velocity (v T? ) have been plotted. Blue vectors illustrate v SP? , red vectors illustrate v T? , while large white vectors with green outline illustrate plate velocity (v P ) for the major plates and some microplates. Velocities were calculated in the IndoAtlantic hot spot reference frame from O’Neill et al. [2005] using the geophysical relative plate motion model from DeMets et al. [1994] for motion of the major plates and using numerous microplate motions and backarc/arc/fore-arc deformation rates from other sources as summarized by Schellart et al. [2008, Tables 1 and 3] and Schellart [2008c, Tables S1 and S2].

  8. Gamecock says:

    ‘rocks sourced from thousands of kilometers below the surface’

    Wut?

    We don’t have access to rocks from ‘thousands of kilometers below the surface.’

    ‘Our team used trace metals such as lead, strontium, and neodymium, from hotspot volcanic islands including the Hawaiian islands in the Pacific Ocean’

    Rocks are solid; magma is liquid.

    Islands are not ‘thousands of kilometers below the surface.’

    They sourced the rocks from the surface.

    I think their research is useful. I just find the description oddly incorrect. Luc Doucet is French, so maybe it’s due to an English-as-a-second-language writer.

    Why wouldn’t peer review have fixed it? Why would Nature Geoscience and Nature publish without asking for correction? Are they brain dead?

  9. It’s CO2 causing climate change and affecting the magnetic poles, at least that is what I was told when I investigated the link between climate change and the drift of the magnetic poles

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