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synchrotron XRD

synchrotron XRD. chemical analysis by TEM. olivine. Discovery of post-perovskite phase transition. Determination of crystal structure by MD simulations. “Si” CN=6 x 6 8 x 2. “Mg” CN=6 x 2 8 x 6. exchanged. (1) Compositional effect on

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synchrotron XRD

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  1. synchrotron XRD chemical analysis by TEM

  2. olivine

  3. Discovery of post-perovskite phase transition

  4. Determination of crystal structure by MD simulations “Si” CN=6 x 6 8 x 2 “Mg” CN=6 x 2 8 x 6 exchanged

  5. (1) Compositional effect on post-perovskite phase transition

  6. Post-perovskite phase transition in: pure MgSiO3 Pyrolite (8% FeO* 4%Al2O3) MORB (10% FeO* 16%Al2O3) all occur at 110 to 115GPa @ 2500K based on gold scale Compositional effect is small!

  7. Mg-Fe partitioning between PPv, Pv & Mw PPv & CaPv Mw 110GPa & 2550K

  8. Murakami, Hirose, Sata, Ohishi, 2005 GRL Pv should be more Fe-rich than PP

  9. Core-mantle chemical reaction

  10. (2) Light elements in the core?

  11. S in the core? Only 1.2-1.7 wt% S in the core 8 wt% S is necessary to account for the 7% core density deficit

  12. Larger simultaneous solubilities of Si & O at high pressures?

  13. O Mg Si

  14. (3) What is going on at CMB?

  15. Any reaction products?

  16. No reaction products!

  17. in pv

  18. What is the chemical composition of the mantle in contact with the core?Core liquid should be in equilibrium,at least with the base of the mantle.

  19. (Fe-depleted)

  20. How has chemical reaction at CMB changed the core composition over the geological time?

  21. Core can dissolve more Si & O when the Fe-depleted bottom of the mantle is replaced by the normal mantle

  22. Core is not saturated in Si & O Si & O contents in the core may have increased with time! Dissolution of Si & O into the core from partially molten layer in D”?

  23. Thank you.

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