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Mineral Physics: Modeling from the Atomic to the Global Scale

Mineral Physics: Modeling from the Atomic to the Global Scale. A Short Course Dipartimento di Scienze della Terra, Universit á degli Studi di Milano, February 19-23, 2007 Lars Stixrude University of Michigan. Outline. Composition and Structure of Earth’s Interior. Lars Stixrude

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Mineral Physics: Modeling from the Atomic to the Global Scale

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  1. Mineral Physics: Modeling from the Atomic to the Global Scale A Short Course Dipartimento di Scienze della Terra, Universitá degli Studi di Milano, February 19-23, 2007 Lars Stixrude University of Michigan

  2. Outline

  3. Composition and Structure of Earth’s Interior Lars Stixrude University of Michigan U. Milan Short Course

  4. Pressure, Temperature, Composition

  5. Earth’s interior Press & Siever

  6. Earth structure Seismology can tell us VP, VS, (r,,) What about Temperature and Composition? Dynamics, Differentiation, … Connection through mineralogical models Van Heijst, Ritsema, Woodhouse (1999)

  7. Earth history • Origin and early evolution • Thermal evolution • Formation of core and crust • How does it respond to changes in • Energy • Stress • Composition • Structure of planets • Capture with mineralogical model

  8. Upper Mantle Xenolith, Depth ~ 100 kmRed=garnet (gt); black=orthopyroxene (opx); green=clinopyroxene (cpx); yellow-green=olivine (ol)

  9. High pressure polymorphsMany found in meteoritesOriginally discovered in lab Purple ringwoodite, high pressure polymorph of olivine, in the Tenham chondrite (Spray, 1999)

  10. Mantle Phases Wadsleyite (wa); Ringwoodite (ri); akimotoite (ak); Mg-perovskite (mgpv); Ca-perovskite (capv); Ferropericlase (fp) Stixrude et al. (2007) EPSL

  11. Blue hydrous ringwoodite viewed in situ through the diamond anvil cell, transformed in laser-heated spots to perovskite+ferropericlase Jacobsen and Lin (2005) Elements

  12. Earth Structure Phase transformations Produce discontinuities Thermometers Tests of geophysical models Stixrude & Jeanloz (2007) Treatise

  13. Topography on mantle discontinuities Flanagan and Shearer (1998) JGR

  14. Deuss et al. (2006) Science

  15. Influence of phase transitions on mantle dynamics Christensen (1995) Annual Reviews

  16. Influence of phase transitions on mantle dynamics and chemistry Xie and Tackley (2004)

  17. Upper mantle ~ Geology + half-space cooling Lower mantle ~ Subduction history Transition zone? Ritsema et al. (2004)

  18. Mantle HeterogeneityPhase Stixrude et al. (2007) EPSL

  19. Origin of Lateral Heterogeneity Radioactivity Temperature Composition Differentiation Latent Heat Differentiation Entropy Chemical Potential Phase

  20. Samples of the Transition Zone? Haggerty and Sautter (1990) Cpx exsolution lamellae from garnet, Jagersfontein Kimberlite, South Africa Jeffrey W. Harris (2005) Ferropericlase inclusion in diamond Sao Luiz alluvial deposit, Brazil

  21. Magma from the Transition Zone? Spinfex texture, Komatiite, scale ~ 1 cm

  22. Mantle HeterogeneityComposition • Physical properties depend on composition • Phase proportions depend on composition • Major element heterogeneity is dynamically active

  23. 10-15-10-16 s-1 Long! Hofmann and Hart (1978) EPSL Allegré and Turcotte (1986) Nature Time scale of re-equilibration ol: Farber et al. (1994) Nature ri: Farber et al. (1994) Nature pv: Yamazaki et al. (2000) PEPI

  24. Where’s the water? Ohtani (2005) Elements

  25. Melt atop the 410? Revenaugh and Sipkin (1994) Science

  26. Deep Earthquakes? Green, Jung (2005)

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