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Featured Rethinking the Earth's core

  1. Jan 9, 2017 #1

    1oldman2

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    The missing element mystery in the earths core may have been solved.
    http://www.bbc.com/news/science-environment-38561076
    Lead researcher Eiji Ohtani from the University of Tokyo told BBC News: "We believe that silicon is a major element - about 5% [of the Earth's inner core] by weight could be silicon dissolved into the iron-nickel alloys."
     
  2. jcsd
  3. Jan 9, 2017 #2
    I would have expected heavy elements like Gold and Lead would sink into the core of early Earth more so than relatively light Silicon.
     
  4. Jan 9, 2017 #3

    1oldman2

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    Same here, thus the thread title. I'm still trying to figure out if it's because the silicone is trapped in suspension with the Iron/Nickle or if I'm missing something really strange.
     
  5. Jan 9, 2017 #4

    Baluncore

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    A really interesting model.
    But I do not think there needs to be a single element to satisfy that requirement. I would expect roughly equal amounts of both silicon and aluminium to be held in the matrix of the solid inner core. Any Si and Al in the liquid Fe-Ni outer core should have floated up into the Si-Al mantle long ago.
     
  6. Jan 10, 2017 #5

    davenn

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    interesting, I will have to do some reading :smile:

    silicone is a man made substance .... sealers, fake chest mounds etc

    stick with the silicon (no "e") :wink::biggrin:

    Dave
     
  7. Jan 10, 2017 #6

    1oldman2

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    :doh:This problem originates from a life in construction vs. a life in general.
     
  8. Jan 11, 2017 #7
    The composition of core, mantle and crust, while partly determined by density are also strongly influenced by chemical affinity. Likewise, we would expect that the speed of the iron catastrophe (core formation) would have inhibited complete unmixing of the silicon component.

    My curiosity centres on what the silicon is bound to .

    Edit: From the paper abstract here it appears they postulate the silicon is alloyed with the iron, or iron-nickel. Not an obvious alloy under crustal conditions, but that's the core for you.
     
  9. Jan 11, 2017 #8

    1oldman2

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  10. Feb 10, 2017 #9

    1oldman2

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  11. Feb 17, 2017 at 3:00 PM #10

    1oldman2

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    I've heard of "Zealandia" before, this on the other hand caught me by surprise. I'm curious to hear what Dave makes of it. (Could NZ actually have its own Craton? o_O)
    http://www.geosociety.org/gsatoday/archive/27/3/abstract/GSATG321A.1.htm
    A 4.9 Mkm2 region of the southwest Pacific Ocean is made up of continental crust. The region has elevated bathymetry relative to surrounding oceanic crust, diverse and silica-rich rocks, and relatively thick and low-velocity crustal structure. Its isolation from Australia and large area support its definition as a continent—Zealandia. Zealandia was formerly part of Gondwana. Today it is 94% submerged, mainly as a result of widespread Late Cretaceous crustal thinning preceding supercontinent breakup and consequent isostatic balance. The identification of Zealandia as a geological continent, rather than a collection of continental islands, fragments, and slices, more correctly represents the geology of this part of Earth. Zealandia provides a fresh context in which to investigate processes of continental rifting, thinning, and breakup.
    https://phys.org/news/2017-02-zeala...e=menu&utm_medium=link&utm_campaign=item-menu
    http://www.bbc.com/news/world-asia-39000936
     
    Last edited: Feb 17, 2017 at 3:29 PM
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