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COMPRES 2006 Snowbird, Utah David Walker, Lamont-Doherty Earth Observatory, Columbia U.

Adventures at the ALS. With Simon Clark, Martin Kunz, Mike Walter and a COMPRES-supported cast of thousands. COMPRES 2006 Snowbird, Utah David Walker, Lamont-Doherty Earth Observatory, Columbia U. Why ever would the Earth’s core leak?. (NSF CSEDI+2 progress report).

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COMPRES 2006 Snowbird, Utah David Walker, Lamont-Doherty Earth Observatory, Columbia U.

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  1. Adventures at the ALS With Simon Clark, Martin Kunz, Mike Walter and a COMPRES-supported cast of thousands COMPRES 2006 Snowbird, Utah David Walker, Lamont-Doherty Earth Observatory, Columbia U. Why ever would the Earth’s core leak? (NSF CSEDI+2 progress report)

  2. Some plume basalts show correlated Os anomalies. Mauna Loa Loihi Koolau 0.119870 Evolution of OC Mauna Kea Kilauea Descending slab Hualalai 0.119860 Kohala Mixing Siberia Gorgona Os 0.119850 Pt 186Os/188Os 0.119840 0.119830 Chondritic Evolution 0.119820 0.100 0.120 0.140 187 188 Os/ Os Sr, O, Nd recycling signal Core- flavored plume Liquid metal outer core Inner core solid mantle 190Pt-driven atmosphere 187Re-driven Maybe Re? A.Brandon, R.J.Walker et al. (2003)

  3. Is the core really leaking? What could drive it? Manghnani and Yagi Yes, perhaps: Os isotopes Hawaiian plume Fe/Mn & Ni Perhaps not: radiogenic Sr/Os correlation

  4. Cooling drives changes in solubility Reorient for buoyant slag floating on the core

  5. Solubility extremely limited DAC limit O2 from Daresbury O’Neill et al. Rubie et al. Multi-anvil DVsolution = LiquidVFeO – CrystalVFeO What determines oxygen solubility(P)?

  6. But we still need to measure Oxygen solubility in Fe liquid at high P,T Thermal exsolution of a floating ‘slag’ (We know the Earth is cooling) Does it reach 2% or 20%? Manghnani and Yagi (A year in the lab can save you an hour in the library!)

  7. Laser melting X-ray absorption transmission imaging in situ Fe FeO X-ray beam 100 microns How to measure Oxygen solubility in molten Fe at a megabar? [Underway with COMPRES support for the ALS 12.2.2 team]

  8. Experiments at ALS/LBL With Mike Walter*, Simon Clark, Martin Kunz, and many others * http://xraysweb.lbl.gov/bl1222/home.htm

  9. Double-sided Laser heating X-rays in Remote and/or automated pneumatic P ramping LBL ALS Station 12.2.2

  10. Double-sided pyrometry X-rays in DAC gasket image High-resolution imaging FeO crystals in 100 hole Laser LBL ALS Station 12.2.2

  11. X-ray density for chemical analysis! Fe FeO CCD and optics Gasket Thin CdS phosphor In situ DAC X-Radiographic Imaging (XRI)

  12. FeO Itrans %O2 Liquid Fe Single in situ property (Itrans) needed to characterize chemistry along a binary join. Liq FeO Fe Absorption(ﻉ) &/or emission

  13. Liquid FeO Itrans %O2 Fe FeO Fe Peritectic possible to recognize when reactants are spatially resolved.

  14. Melting shows erosion 50 kilobars Fe Does this work? FeS Station 12.2.2 ALS

  15. 50 kilobars Fe FeS Melting shows erosion It seems to work! Topography convolved with chemistry -and- resolution limited by phosphor sharpness and sample preparation What about Fe-FeO?

  16. No erosion on melting! 550 kilobars FeO Fe Consistent with the DAC results of Takafuji et al. (2005) <6%

  17. XRI @ 120 kbar

  18. Lumpy D′′ probably not exsolved, floating slag on molten Fe of the outer core Oxygen solubility does not appear to be high enough to be interesting. Are there other solutions to the problem?

  19. Glatzmaier & Roberts 1995 Earth’s dynamo magnetic field

  20. Toroidal magnetic field in the outer core generates local anodic and cathodic areas at the CMB ~ 1 V Could this drive any electrochemical transfers across the CMB? mantle low [Fe] core (See Abby Kavner’s forthcoming paper in EPSL)

  21. N2+O2 Oxidized crust D” includes CMB magma chambers Contaminated plume source Oxidative corrosion of coremantle What does the presence of life do for us? Core signal generated by recycled oxidized crust.

  22. Iron meets oxygen! rusty surface Bright inner core When oxygen does not dissolve in iron.

  23. D" with magmatic titration chambers N2 + O2 Most effective and quick if oxygen solubility low Core- flavored plume Oxidized slab Os-Sr-Nd-O signal of recycled crust not a show stopper. It is the key to the delivery mechanism for the corrosive reaction. Liquid metal outer core Inner core solid mantle Revenge of the plants!

  24. Remaining questions: Does the biosphere-core feedback deserve to be taken seriously? Test: when does the Os signal start? [>2.8 Gy ago (Puchtel et al.)] Why not electrochemistry?

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