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

2. Mauna Loa Loihi Koolau Mauna Kea Kilauea Hualalai Kohala Siberia Gorgona solidmantle Innercore Liquid metal outer core Core-flavoredplume atmosphere A.Brandon, R.J.Walker et al. (2003) Some plume basalts show correlated Os anomalies. Os Pt Descendingslab Sr, O, Nd recycling signal 187 Re-driven 190 Pt-driven Maybe Re?

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

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

5. DAC limit O 2 from Daresbury O’Neill et al. Rubie et al. Multi-anvil  V solution = Liquid V FeO – Crystal V FeO What determines oxygen solubility(P)? Solubilityextremelylimited

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

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

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

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

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

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

12. Fe FeO Liq I trans Fe FeO Liquid %O 2 Single in situ property (I trans ) needed to characterize chemistry along a binary join. Absorption(ﻉ) &/or emission

13. I trans Fe FeO Liquid %O 2 Peritectic possible to recognize when reactants are spatially resolved. Fe FeO

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

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

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

17. XRI @ 120 kbar

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

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

20. mantle core low [Fe] 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? (See Abby Kavner’s forthcoming paper in EPSL)

21. What does the presence of life do for us? Oxidative corrosion of core  mantle Core signal generated by recycled oxidized crust. Contaminated plume source D” includes CMB magma chambers N2 + O2N2 + O2 Oxidized crust

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

23. solidmantle Innercore Liquid metal outer core Core-flavoredplume N 2 + O 2 D" with magmatic titration chambers Most effective and quick if oxygen solubility low Revenge of the plants! Oxidizedslab Os-Sr-Nd-O signal of recycled crust not a show stopper. It is the key to the delivery mechanism for the corrosive reaction.

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