Hostname: page-component-cd9895bd7-gbm5v Total loading time: 0 Render date: 2024-12-25T14:32:13.614Z Has data issue: false hasContentIssue false
  • English
  • Français

Pressure-induced transformations in deep mantle and core minerals

Published online by Cambridge University Press:  05 July 2018

R. J. Hemley ,
H. K. Mao  and
S. A. Gramsch
R. J. Hemley*
Affiliation:
Geophysical Laboratory and Center for High-Pressure Research, Carnegie Institution of Washington, 5251 Broad Branch Road N.W., Washington D.C. 20015, USA
H. K. Mao
Affiliation:
Geophysical Laboratory and Center for High-Pressure Research, Carnegie Institution of Washington, 5251 Broad Branch Road N.W., Washington D.C. 20015, USA
S. A. Gramsch
Affiliation:
Geophysical Laboratory and Center for High-Pressure Research, Carnegie Institution of Washington, 5251 Broad Branch Road N.W., Washington D.C. 20015, USA
*
*E-mail: [email protected]
Get access Rights & Permissions [Opens in a new window]

Abstract

Recent experimental and theoretical studies provide new insight into the variety of high-pressure transformations in minerals that comprise the Earth’s deep mantle and core. Representative examples of reconstructive, displacive, electronic and magnetic transformations studied by new diamond-anvil cell techniques are examined. Despite reports for various transitions in (Mg,Fe)SiO3-perovskite, the stability field of the orthorhombic phase expands relative to magnesiowüstite + SiO2 with increasing pressure and temperature. The partitioning of Fe and Mg between Mg-rich silicate perovskite magnesiowüstite depends strongly on pressure, temperature, bulk Fe/Mg ratio, and ferric iron content. The soft-mode transition in SiO2 from the rutile- to CaCl2-type structure, originally documented by X-ray powder diffraction, Raman scattering, and first-principles theory has been explored in detail by single crystal diffraction, and transitions to higher-pressure forms have been examined. The effect of H on the transformations of various nominally anhydrous phases and transitions in dense hydrous Mg-silicates are also examined. New studies of the phase diagram of FeO include the transition to rhombohedral and higher-pressure NiAs polymorphs, and provide prototypical examples of coupled structural, electronic, and magnetic transitions. High-spin/low-spin transitions in FeO have been examined by high-resolution X-ray emission spectroscopy to 150 GPa, and the results are compared with similar studies of Fe2O3 and FeS. Finally, laser-heating studies to above 150 GPa and 2500K show that (hcp) ε-Fe has a large P-T stability field. Radial XRD measurements carried out at room temperature to 220 GPa have constrained the elasticity, rheology and sound velocities of ε-Fe at core pressures.

Keywords

high-pressurediamond cellperovskitestishoviteX-ray emission spectroscopyelastic contentsiron
Type
Research Article
Information
Mineralogical Magazine , Volume 64 , Issue 2 , April 2000 , pp. 157 - 184
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2000

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Alfè, D., Gillian, M.J. and Price, G.D. (1999) The melting curve of iron at the pressures of the earth’s core from ab initio calculations. Nature 401, 462–464.CrossRefGoogle Scholar
Andrault, D., Fiquet, G., Kunz, M., Visocekas, F. and Häusermann, D. (1997) The orthorhombic structure of iron: an in situ study at high temperature and high pressure. Science, 278, 831–4.CrossRefGoogle Scholar
Andrault, D., Fiquet, G., Guyot, F. and Hanfland, M. (1998) Pressure-induced Landau-type transition in stishovite. Science, 282, 720–4.CrossRefGoogle ScholarPubMed
Aoki, K., Yamawaki, H., Sakashita, M. and Fujihisa, H. (1996) Infrared absorption study of the hydrogenbond symmetrization in ice to 110 GPa. Phys. Rev. B, 54, 15673–7.CrossRefGoogle Scholar
Badro, J., Struzhkin, V.V., Shu, J., Hemley, R.J., Mao, H.K., Kao, C.C., Rueff, J.P. and Shen, G. (1999) Magnetism in FeO at megabar pressures from X-ray emission spectroscopy. Phys. Rev. Lett., 83, 4101–4.CrossRefGoogle Scholar
Bina, C.R. (1998) Lower mantle mineralogy and the geophysical perspective. Pp. 205–39 in: Ultrahigh Pressure Mineralogy (Hemley, R.J., editor). Reviews in Mineralogy, 37. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Bocquet, A., Mizokawa, T., Saitoh, T., Namatame, H. and Fujimori, A. (1992) Electronic structure of 3d transition-metal oxides by analysis of the 2p core level photoemission spectra. Phys. Rev. B, 46, 3771–84.CrossRefGoogle Scholar
Boehler, R. (1993) Temperatures in the Earth’s core from melting-point measurements of iron at high static pressures. Nature, 363, 534–6.CrossRefGoogle Scholar
Boehler, R., von Bergen, N. and Chopelas, A. (1990) Melting, thermal expansion and phase transitions of iron at high pressures. J. Geophys. Res., 95, 21731–6.CrossRefGoogle Scholar
Brown, J.M. and McQueen, R.G. (1986) Phase transitions, Gruneisen parameter and elasticity for shocked iron between 77 GPa and 400 GPa. J. Geophys. Res., 91, 7485–94.CrossRefGoogle Scholar
Carpenter, M.A., Hemley, R.J. and Mao, H.K. (2000) High-pressure elasticity of stishovite and the P42/mnm → Pnnm phase transition. J. Geophys. Res., in press.CrossRefGoogle Scholar
Cavazzoni, C., Chiarotti, G., Scandolo, S., Tosatti, E., Bernasconi, M. and Parrinello, M. (1999) Behavior of ammonia and water at high pressure and temperature: implications for planetary physics. Science, 283, 44–7.CrossRefGoogle Scholar
Cohen, R.E. (1992) First-principles predictions of elasticity and phase transitions in high pressure SiO2 and geophysical implications. Pp. 425–31 in: High-Pressure Research: Application to Earth and Planetary Sciences (Syono, Y. and Manghnani, M.H., editors). Terra Scientific, Tokyo and A.G.U., Washington, D.C. Google Scholar
Cohen, R.E. (1994) First-principles theory of crystalline SiO2 . Pp. 369–402 in: Silica – Physical Behavior, Geochemis try and Materials Applications (Heaney, P., Gibbs, G.V. and Prewitt, C.T., editors). Reviews in Mineralogy, 29. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Cohen, R.E., Mazin, I.I. and Isaak, D.G. (1997) Magnetic collapse in transition metal oxides at high pressure: implications for the Earth. Science, 275, 654–7.CrossRefGoogle ScholarPubMed
Cohen, R.E., Fei, Y., Downs, R., Mazin, I.I. and Isaak, D.G. (1998) Magnetic collapse and the behavior of transition metal oxides: FeO at high pressures. Pp. 27–37 in: High-Pressure Materials Research. Proc. Fall 1997 Materials Research Soc. Meet. (Wentzcovitch, R., Hemley, R.J., Nellis, W.J. and Yu, P., editors) Materials Research Society, Pittsburgh, PA.Google Scholar
Dubrovinsky, L.S., Saxena, S.K., Lazor, P., Ahuja, R., Eriksson, O., Wills, J.M. and Johansson, B. (1997) Experimental and theoretical identification of a new high-pressure phase of silica. Nature, 388, 363–5.CrossRefGoogle Scholar
Duffy, T.S., Hemley, R.J. and Mao, H.K. (1995 a) Equation of state and shear strength at multimegabar pressures: Magnesium oxide to 227 GPa. Phys. Rev. Lett., 74, 1371–4.CrossRefGoogle ScholarPubMed
Duffy, T.S., Meade, C., Fei, Y., Mao, H.K. and Hemley, R.J. (1995 b) High-pressure phase transition in brucite, Mg(OH)2. Amer. Mineral., 80, 222–30.CrossRefGoogle Scholar
Fang, Z., Solovyev, I.V., Sawada, H. and Terakura, K. (1999) First-principles study on electronic structures and phase stability of MnO and FeO under high pressure. Phys. Rev. B, 59, 762–74.CrossRefGoogle Scholar
Faust, J. and Williams, Q. (1996) Infrared spectra of phase B at high pressures: hydroxyl bonding under compression. Geophys. Res. Lett., 23, 427–30.CrossRefGoogle Scholar
Fei, Y. and Mao, H.K. (1994) In situ determination of the NiAs phase of FeO at high pressure and high temperature. Science, 266, 1678–80.CrossRefGoogle Scholar
Fei, Y., Virgo, D., Mysen, B.O., Wang, Y. and Mao, H.K. (1994) Temperature-dependent electron delocalization in (Mg,Fe)SiO3 perovskite. Amer. Mineral., 79, 826–37.Google Scholar
Fei, Y., Finger, L.W. and Wang, Y. (1996) Maximum solubility of FeO in (Mg,Fe)SiO3–perovskite as a function of temperature at 26 GPa: implications for FeO in the lower mantle. J. Geophys. Res., 101, 11525–30.CrossRefGoogle Scholar
Fei, Y., Prewitt, C.T., Frost, D.J., Parise, J.B. and Brister, K. (1998) Structures of FeS polymorphs at high pressures and temperatures. Pp. 55–8 in: Review of High-Pressure Science and Technology, 7 (Nakahara, M., editor). Japan Society of High-Pressure Science and Technology, Kyoto.Google Scholar
Fiquet, G., Andrault, D., Dewaele, A., Charpin, T., Kunz, M. and Häusermann, D. (1998) P-V-T equation of state of MgSiO3 perovskite. Phys. Earth Planet. Inter., 105, 21–31.CrossRefGoogle Scholar
Frost, D.J. (1999) The stability of dense hydrous magnesium silicate's in Earth’s transition zone and lower mantle. Pp. 283–96 in: Mantle Petrology: Field Observations and High Pressure Experimentation: A Tribute to Francis (Joe) Boyd (Fei, Y., Bertka, C.M. and Mysen, B.O., editors). Geochemical Society, Houston, TX.Google Scholar
Frost, D.J. and Fei, Y. (1998) Stability of phase D at high pressure and high temperature. J. Geophys. Res., 103, 7463–74.CrossRefGoogle Scholar
Frost, D.J. and Fei, Y. (1999) Static compression of the hydrous magnesium silicate phase D to 30 GPa at room temperature. Phys. Chem. Min., 26, 415–8.CrossRefGoogle Scholar
Funamori, N. and Yagi, T. (1993) High pressure and high temperature in situ X-ray observation of MgSiO3 perovskite under lower mantle conditions. Geophys. Res. Lett., 20, 387–90.CrossRefGoogle Scholar
Funamori, N., Yagi, T., Utsumi, W., Kondo, T. and Uchida, T. (1996) Thermoelastic properties of MgSiO3 perovskite determined by in situ X-ray observations up to 30 GPa and 2000 K. J. Geophys. Res., 101, 8257–69.CrossRefGoogle Scholar
Gasparik, T. (1993) The role of volatiles in the transition zone. J. Geophys. Res., 98, 4287–99.CrossRefGoogle Scholar
German, V.N., Podurets, M.A. and Trunin, R.F. (1973) Synthesis of a high-density phase of silicon dioxide in shock waves. Sov. Phys.- JETP, 37, 107–8.Google Scholar
Goarant, F., Guyot, F., Peyronneau, J. and Poirier, J.-P. (1992) High-pressure and high-temperature reactions between silicates and liquid iron alloys, in the diamond-anvil cell, studied by analytical electron microscopy. J. Geophys. Res., 97, 4477–87.CrossRefGoogle Scholar
Goncharov, A.F., Struzhkin, V.V., Somayazulu, M., Hemley, R.J. and Mao, H.K. (1996) Compression of H2O ice to 210 GPa: Evidence for a symmetric hydrogen-bonded phase. Science, 273, 218–20.CrossRefGoogle Scholar
Goresy, A.E., Dubrovinsky, L., Saxena, S. and Sharp, T.G. (1998) A new post-stishovite polymorph with the the baddelyite structure (zirconium oxide) in the SNC meteorite Shergotty: evidence for extreme shock pressure. Meteor. Planet. Sci. (Supp. 4), 33, A145.Google Scholar
Hemley, R.J. and Cohen, R.E. (1992) Silicate perovskite. Ann. Rev. Earth Planet. Sci., 20, 553–600.CrossRefGoogle Scholar
Hemley, R.J. and Cohen, R.E. (1996) Structure and bonding in the deep mantle and core. Phil. Trans. Roy Soc. Lond. A, 354, 1461–79.Google Scholar
Hemley, R.J., Prewitt, C.T. and Kingma, K.J. (1994) High-pressure behavior of silica. Pp. 41–81 in: Silica – Physical Behavior, Geochemistry and Materials Applications(Heaney, P.J., Gibbs, G.V. and Prewitt, C.T., editors). Reviews in Mineralogy, 29. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Hemley, R.J., Mao, H.K., Shen, G., Badro, J., Gillet, P., Hanfland, M. and Häusermann, D. (1997) X-ray imaging of stress and strain of diamond, iron and tungsten at megabar pressures. Science, 276, 1242–5.CrossRefGoogle Scholar
Hemley, R.J., Goncharov, A.F., Lu, R., Li, M., Struzhkin, V.V. and Mao, H.K. (1998 a) High-pressure synchrotron infrared spectroscopy at the National Synchrotron Light Source. II Nuovo Cimento D, 20, 539–51.CrossRefGoogle Scholar
Hemley, R.J., Mao, H.K. and Cohen, R.E. (1998 b) High-pressure electronic and magnetic properties of minerals. Pp. 591–638 in: Ultrahigh-Pressure Mineralogy (Hemley, R.J., editor), Reviews in Mineralogy, 37. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Hemley, R.J., Shu, J, Carpenter, M.A., Hu, J., Mao, H.K. and Kingma, K.J. (2000) Strain/order parameter coupling in the ferroelastic transition in dense SiO2. Phys. Rev. Lett., Solid State Commun., in press.CrossRefGoogle Scholar
Hirose, K., Fei, Y., Ma, Y. and Mao, H.K. (1999) Fate of subducted basaltic crust in the lower mantle. Nature, 397, 53– 6.CrossRefGoogle Scholar
Jeanloz, R. and Ahrens, T.J. (1980) Equations of state of FeO and CaO. Geophys. J. R. Astr. Soc., 62, 505–28.CrossRefGoogle Scholar
Jeanloz, R. and Williams, Q. (1998) The core-mantle boundary region. Pp. 241–59 in: Ultrahigh-Pressure Mineralogy (Hemley, R.J., editor). Reviews in Mineralogy, 37. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Jephcoat, A.P., Mao, H.K. and Bell, P.M. (1986) The static compression of iron to 78 GPa with rare-gas solids as pressure-transmitting medium. J. Geophys. Res. B, 91, 4677–84.CrossRefGoogle Scholar
Jephcoat, A.P., Hriljac, J.A., McCammon, C.A., St. C.O’Neill, H., Rubie, D.C. and Finger, L.W. (1999) High-resolution synchrotron X-ray powder diffraction and Rietveld structure refinement of two (Mg0.95 Fe0.95)SiO3 perovskite samples synthesized under different oxygen fugacities. Amer. Mineral., 84, 214–20.CrossRefGoogle Scholar
Kagi, H., Inoue, T., Weidner, D.J., Lu, R. and Rossman, G.R. (1997) Speciation of hydroxides in hydrous ringwoodite. Eos Trans. Amer. Geophys. Union, 78, S312.Google Scholar
Karki, B.B., Warren, M.C., Stixrude, L., Ackland, G.J. and Crain, J. (1997) Ab initio studies of high-pressure structural transformations in silica. Phys. Rev. B, 55, 3465–3471.CrossRefGoogle Scholar
Katsura, T., Sato, K. and Ito, E. (1998) Electrical conductivity of silicate perovskite at lower-mantle conditions. Nature, 395, 493–5.CrossRefGoogle Scholar
Kellogg, L., Hager, B.H. and van der Hilst, R.D. (1999) Compositional strati. cation in the deep mantle. Science, 283, 1881–4.CrossRefGoogle Scholar
Kesson, S.E., FitzGerald, J.D. and Shelley, M.G. (1994) Mineral chemistry and density of subducted basaltic crust at lower-mantle pressures. Nature, 372, 767–9.CrossRefGoogle Scholar
King, H., Virgo, D. and Mao, H.K. (1978) High-pressure phase transitions in FeS, using 57Fe Mössbauer spectroscopy. Carnegie Inst. Washington Yearb., 77, 830–5.Google Scholar
Kingma, K.J., Cohen, R.E., Hemley, R.J. and Mao, H.K. (1995) Transformation of stishovite to a denser phase at lower-mantle pressures. Nature, 374, 243–5.CrossRefGoogle Scholar
Kingma, K.J., Mao, H.K. and Hemley, R.J. (1996) Synchrotron diffraction of SiO2 to multimegabar pressures. High Press. Res., 14, 363–74.CrossRefGoogle Scholar
Knittle, E. and Jeanloz, R. (1986) High-pressure metallization of FeO and implications for the Earth’s core. Geophys. Res. Lett., 13, 1541–4.CrossRefGoogle Scholar
Knittle, E. and Jeanloz, R. (1991) Earth’s core-mantle boundary: Results of experiments at high pressures and temperatures. Science, 251, 1438–43.CrossRefGoogle ScholarPubMed
Kusaba, K., Syono, Y., Kikegawa, T. and Shimomura, O. (1997) Structure of FeS under high pressure. J. Phys. Chem. Solids, 58, 241–6.CrossRefGoogle Scholar
LeStunff, Y., Wicks, C.W. and Romanowicz, B. (1995) P′P′ precursors under Africa: Evidence for midmantle reflectors. Science, 270, 74–7.CrossRefGoogle Scholar
Li, X. and Jeanloz, R. (1991) Phases and electrical conductivity of a hydrous silicate assemblage at lower-mantle conditions. Nature, 350, 332–4.CrossRefGoogle Scholar
Laio, A., Bernard, S., Chiarotti, G.L., Scandolo, S. and Tosatti, E. (2000) Physics of iron at Earth’s core conditions. Science, 287, 1027–30.CrossRefGoogle ScholarPubMed
Lu, R., Hemley, R.J., Mao, H.K., Carr, G.L. and Williams, G.P. (1996) Synchrotron micro-infrared spectroscopy: Applications to hydrous mantle minerals. Eos Trans. Amer. Geophys., 77, F661.Google Scholar
Ma, Y., Mao, H.K. and Hemley, R. J. (1999) High P, T phase diagram of Fe2O33. Bull. Amer. Phys. Soc., 44, 1598.Google Scholar
Mao, H.K. and Hemley, R.J. (1996) Energy dispersive X-ray diffraction of micro-crystals at ultrahigh pressures. High Press. Res., 14, 257–67.CrossRefGoogle Scholar
Mao, H.K. and Hemley, R.J. (1998) New windows on the Earth’s deep interior. Pp. 1–32 in Ultrahigh-Pressure Mineralogy. (Hemley, R.J., editor). Reviews in Mineralogy, 37. Mineralogical Society of America, Washington, D.C. Google Scholar
Mao, H.K., Wu, Y., Chen, L.C., Shu, J.F. and Jephcoat, A.P. (1990) Static compression of iron to 300 GPa and Fe0.8Ni0.2 alloy to 260 GPa: Implications for composition of the core. J. Geophys. Res., 95, 21737–42.CrossRefGoogle Scholar
Mao, H.K., Shu, J., Fei, Y., Hu, J. and Hemley, R.J. (1996) The wüstite enigma. Phys. Earth Planet. Inter., 96, 135–45.CrossRefGoogle Scholar
Mao, H.K., Hemley, R.J. and Mao, A.L. (1997 a) Diamond-cell research with synchrotron radiation. Pp. 12–19 in: Advances in High Pressure Research in Condensed Matter (Sikka, S.K., editor). NISCOM, New Delhi, India.Google Scholar
Mao, H.K., Shen, G. and Hemley, R.J. (1997 b) Multivariable dependence of Fe/Mg partitioning in the lower mantle. Science, 278, 2098–100.CrossRefGoogle Scholar
Mao, H.K., Shen, G., Hemley, R.J. and Duffy, T.S. (1998 a) X-ray diffraction with a double hot plate laser-heated diamond cell. Pp. 27–34 in: Properties of Earth and Planetary Materials at High Pressure and Temperature (Manghnani, M.H. and Yagi, T., editors ). American Geophycsical Union, Washington, D.C. CrossRefGoogle Scholar
Mao, H.K., Shu, J., Shen, G., Hemley, R.J., Li, B. and Singh, A.K. (1998 b) Elasticity and rheology of iron above 220 GPa and the nature of the Earth’s inner core. Nature, 396, 741–3. Correction (1999) 399, 280.CrossRefGoogle Scholar
Mazin, I.I., Fei, Y., Downs, R. and Cohen, R. (1998) Possible polytypism in FeO at high pressures. Amer. Mineral., 83, 451–7.CrossRefGoogle Scholar
McCammon, C.A. (1992) Magnetic properties of FexO (x>0.95) variation of Neél temperature. J. Magn. Mater., 104–107, 1937–8.CrossRefGoogle Scholar
McCammon, C.A. (1998) The crystal chemistry of ferric iron in Fe0.05Mg0.95SiO3 perovskite as determined byMössbauer spectroscopy in the temperature range 80–293 K. Phys. Chem. Min., 25, 292–300.CrossRefGoogle Scholar
Meade, C., Mao, H.K. and Hu, J. (1995) High-temperature phase transition and dissociation of (Mg,Fe)SiO3 perovskite at lower mantle pressures. Science, 268, 1743–5.CrossRefGoogle ScholarPubMed
Nakamoto, K., Margoshes, M. and Rundle, R.E. (1955) Stretching frequencies as a function of distances in hydrogen bonds. J. Amer. Chem. Soc., 77, 6480–6.CrossRefGoogle Scholar
Nelmes, R.J., McMahon, M.I., Belmonte, S.A., Allan, D.R., Gibbs, M.R. and Parise, J.B. (1998) High pressure structures of iron sulphide. Pp. 202–4 in: Review of High-Pressure Science and Technology, 7. (Nakahara, M., editor). Japanese Society High Pressure Science and Technology, Kyoto.Google Scholar
Nguyen, J. and Holmes, N.C. (1998) Iron sound velocities in shock wave experimen ts up to 400 GPa. Eos Trans. Amer. Geophys. Union, 79, F846.Google Scholar
Nguyen, J.H., Kruger, M.B. and Jeanloz, R. (1997) Evidence for ‘partial’ (sublattice) amorphization in Co(OH)2 . Phys. Rev. Lett., 78, 1836–9.CrossRefGoogle Scholar
Novak, A. (1974) Hydrogen bonding in solids. Correlation of spectroscopic and crystallographic data. Structure and Bonding, 18, 177–216.CrossRefGoogle Scholar
Ohtani, E., Kudoh, Y., Naito, H. and Arashi, H. (1998) Stability of dense hydrous magnesium silicate phase G in the transition zone and the lower mantle. Mineral. J., 20, 163–9.CrossRefGoogle Scholar
Parise, J.B., Theroux, B., Li, R., Loveday, J.S., Marshall, W.G. and Klotz, S. (1998) Pressure dependence of hydrogen bonding in metal deuteroxides: a neutron powder diffraction study of Mn(OD)2 and β-Co(OD)2 . Phys. Chem. Min., 25, 130–7.CrossRefGoogle Scholar
Pasternak, M.P., Taylor, R.D., Jeanloz, R., Xu, L., Nguyen, J.H. and McCammon, C.A. (1997) High pressure collapse of magnetism in Fe0.94O: Mössbauer spectroscopy beyond 100 GPa. Phys. Rev. Lett., 79, 5046–9.CrossRefGoogle Scholar
Pasternak, M.P., Rozenberg, G.K., Machavariani, G.Y., Naaman, O., Taylor, R.D. and Jeanloz, R. (1999) Breakdown of the Mott-Hubbard state in Fe2O3: a first-order insulator-metal transition with collapse of magnetism at 50 GPa. Phys. Rev. Lett., 82, 4663–6.CrossRefGoogle Scholar
Peng, G., Wang, X., Randall, C.R. and Cramer, S.P. (1994) Spin selective X-ray absorption spectroscopy: demonstration using high-resolution Fe Kβ fluorescence. Appl. Phys. Lett., 65, 2527–9.CrossRefGoogle Scholar
Peyronneau, J. and Poirier, J.P. (1998) Experimental determination of the electrical conductivity of the material of the Earth’s lower mantle. Pp. 77–87 in: Properties of Earth and Planetary Materials at High Pressure and Temperature (Manghnani, M.H. and Yagi, T., editors). American Geophysical Union, Washington, D.C. Google Scholar
Price, G.D., Vocaldo, L., Alfè, D., Brodholt, J. and Gillan, M.J. (1999) The ab initio calculation of the structure and stability of iron. P. 99 in: Int. Union Crystallogr. 15th Cong Gen. Assem., Glasgow, Scotland. Abstracts.Google Scholar
Rossman, G.R. (1996) Studies of OH in nominally anhydrou s minerals, Phys. Chem. Min., 23, 299–304.CrossRefGoogle Scholar
Rueff, J.P., Kao, C.C., Struzhkin, V.V., Badro, J., Shu, J.F., Hemley, R.J. and Mao, H.K. (1999) Pressureinduced high-spin to low-spin transition in FeS evidenced by X-ray emission spectroscopy. Phys. Rev. Lett., 82, 3284–7.CrossRefGoogle Scholar
Saitoh, T., Bocquet, A., Mizokawa, T. and Fujimori, A. (1999) Systematic variation of the electronic structures of 3d transition metal oxides. Phys. Rev. B, 52, 7934–8.CrossRefGoogle Scholar
Saxena, S.K., Dubrovinsky, L.S., Häggkvist, P., Cerenius, Y., Shen, G. and Mao, H.K. (1995) Synchrotron X-ray study of iron at high pressure and temperature. Science, 269, 1703–4.CrossRefGoogle ScholarPubMed
Saxena, S.K., Dubrovinsky, L.S., Lazor, P., Cerenius, Y., Häggkvist, P., Hanfland, M. and Hu, J. (1996) Stability of perovskite (MgSiO3) in the Earth’s mantle. Science, 274, 1357–9.CrossRefGoogle ScholarPubMed
Saxena, S.K., Dubrovinsky, L.S., Lazor, P. and Hu, J. (1998) In situ X-ray study of perovskite (MgSiO3) Phase transition and dissociation at mantle conditions. Eur. J. Mineral., 10, 1275–81.CrossRefGoogle Scholar
Serghiou, G., Zerr, A. and Boehler, R. (1998) (Mg,Fe)SiO3-perovskite stability under lower mantle conditions. Science, 280, 2093–5.CrossRefGoogle ScholarPubMed
Sharp, T.G., El Goresy, A., Dubrovinsky, L. and Chen, M. (1998) Microstructures of shocked silicon dioxide in Shergotty: evidence for multiple poststishovite silicon dioxide polymorphs at extreme shock pressures. Meteor. Planet. Sci. (Supp. 4), 33, A144.Google Scholar
Sharp, T.G., El Goresy, A., Wopenka, B. and Chen, M. (1999) A post-stishovite SiO2 polymorph in the meteorite Shergotty: implications for impact events. Science, 284, 1511–3.CrossRefGoogle ScholarPubMed
Shen, G., Mao, H.K., Hemley, R.J., Duffy, T.S. and Rivers, M.L. (1998) Melting and crystal structure of iron at high pressures and temperatures. Geophys. Res. Lett., 25, 373–6.CrossRefGoogle Scholar
Shieh, S., Ming, L.C., Mao, H.K. and Hemley, R.J. (1998) Decomposition of phase D in the lower mantle and the fate of dense hydrous silicates in subducting slabs. Earth Planet. Sci. Lett., 159, 13–23.CrossRefGoogle Scholar
Shieh, S., Mao, H.K., Hemley, R.J. and Ming, L.C. (2000) In situ X-ray diffraction studies of dense hydrous magnesium silicates at mantle conditions. Submitted.CrossRefGoogle Scholar
Shu, J., Mao, H.K., Hu, J., Fei, Y. and Hemley, R.J. (1998) Single-crystal X-ray diffraction of wüstite to 30 GPa hydrostatic pressure. Neues Jahrb. Mineral. Abh., 172, 309–23.Google Scholar
Singh, A.K., Balasingh, A., Mao, H.K., Hemley, R.J. and Shu, J. (1998 a) Analysis of lattice strains measured under non-hydrostatic pressure. J. Appl. Phys., 83, 7567–75.CrossRefGoogle Scholar
Singh, A.K., Mao, H.K., Shu, J.F. and Hemley, R.J. (1998 b) Estimation of single-crystal elastic moduli from polycrystalline X-ray diffraction at high pressure: Application to FeO and iron. Phys. Rev. Lett., 80,2157-60.CrossRefGoogle Scholar
Sinogeiken, S.V. and Bass, J.D. (1999) Single-crystal elasticity of MgO at high pressure. Phys. Rev. B, 59, R14141–R12144.CrossRefGoogle Scholar
Song, X.D. and Helmberger, D.V. (1993) Anisotropy of Earth’s inner core. Geophys. Res. Lett., 20, 2591–4.CrossRefGoogle Scholar
Song, X.D. and Richards, P.G. (1996) Observational evidence for differential rotation of the Earth’s inner core. Nature, 382, 221–4.CrossRefGoogle Scholar
Stenle-Neumann, G., Stixrude, L. and Cohen, R.E. (1999) First-principles elastic constants for the hcp transition metals Fe, Co and Re at high pressure. Phys. Rev. B, 60, 791–9.CrossRefGoogle Scholar
Stixrude, L. and Brown, J.M. (1998) The Earth’s core. Pp. 261–82 in: Ultrahigh-Pressure Mineralogy. (Hemley, R.J., editor). Reviews in Mineralogy, 37. Mineralogical Society of America, Washington, D.C. CrossRefGoogle Scholar
Stixrude, L. and Cohen, R.E. (1993) Stability of orthorhombic MgSiO3 perovskite in the Earth’s lower mantle. Nature, 364, 613–6.CrossRefGoogle Scholar
Stixrude, L. and Cohen, R.E. (1995) High pressure elasticity of iron and anisotropy of Earth’s inner core. Science, 267, 1972–5.CrossRefGoogle ScholarPubMed
Stixrude, L., Cohen, R.E., Yu, R. and Krakauer, H. (1996) Prediction of phase transition in CaSiO3 perovskite and implications for lower mantle structure. Amer. Mineral., 81, 1293–6.Google Scholar
Stixrude, L., Wasserman, E. and Cohen, R.E. (1997) Composition and temperature of Earth’s inner core. J. Geophys. Res., 102, 24729–39.CrossRefGoogle Scholar
Su, W., Dziewonski, A.M. and Jeanloz, R. (1996) Planet within a planet: rotation of the inner core of the Earth. Science, 274, 1883–7.CrossRefGoogle Scholar
Syono, Y., Noguchi, Y., Fukuoka, K., Kusaba, K. and Atou, T. (1998) Shock-induced phase transition of MnO and several other transition metal oxides. Pp. 151–4 in: Shock Compression of Condensed Matter – 1997 (Schmidt, S.C. et al., editors). American Institute of Physics, New York.Google Scholar
Taguchi, M., Uozumi, T. and Kotani, A. (1997) Theory of X-ray photoemission and X-ray emission spectra in Mn compounds. J. Phys. Soc. Jpn., 66, 247–56.CrossRefGoogle Scholar
Takele, S. and Hearne, G.R. (1999) Electrical transport, magnetism and spin-state configuration of high-pressure phases of FeS. Phys. Rev. B, 60, 4401–3.CrossRefGoogle Scholar
Teter, D.M., Hemley, R.J., Kresse, G. and Hafner, J. (1998) High pressure polymorphism in silica. Phys. Rev. Lett., 80, 2145–8.CrossRefGoogle Scholar
Tschanuer, O., Zerr, A., Sprecht, S., Rocholl, A., Boehler, R. and Palme, H. (1999) Partitioning of nickel and cobalt between silicate perovskite at pressures up to 80 GPa. Nature, 398, 604–7.CrossRefGoogle Scholar
Tse, J.S., Klug, D.D. and Page, Y.L. (1992) Novel highpressure phase of silica. Phys. Rev. Lett., 69, 3647–50.CrossRefGoogle Scholar
Tsuchida, Y. and Yagi, T. (1989) A new, post-stishovite, high-pressure polymorph of silica. Nature, 340, 217–20.CrossRefGoogle Scholar
Tsutsumi, K., Nakamori, H. and Ichikawa, K. (1976) X-ray Kβ emission spectra of manganese oxides and manganates. Phys. Rev. B, 13, 929–33.CrossRefGoogle Scholar
Van der Hilst, R.D., Widiyantoro, S. and Engdahl, E.R. (1997) Evidence for deep mantle circulation from global tomography. Nature, 386, 578–84.CrossRefGoogle Scholar
Van der Hilst, R.D. and Karason, H. (1999) Compositional heterogeneity in the bottom 1000 kilometers of Earth’s mantle: toward a hybrid convective model. Science, 283, 1885–8.CrossRefGoogle Scholar
Vocaldo, L., Brodholt, J., Alfè, D., Price, G.D. and Gillan, M.J. (1999) The structure of iron under the conditions of the Earth’s inner core. Geophys. Res. Lett., 1231–4.Google Scholar
Wang, Y., Guyot, F., Yeganeh-Haeri, A. and Liebermann, R.C. (1990) Twinning in MgSiO3 perovskite. Science, 248, 468–71.CrossRefGoogle ScholarPubMed
Warren, M.C. and Ackland, G.J. (1996) Ab initio studies of structural instabilities in silicate perovskites. Phys. Chem. Min., 23, 107–18.CrossRefGoogle Scholar
Warren, M.C., Ackland, G.J., Karki, B.B. and Clark, S.J. (1998) Phase transitions in silicate perovskites from first principles. Mineral. Mag., 62, 585–98.CrossRefGoogle Scholar
Wentzcovitch, R.M., Ross, N.L. and Price, G.D. (1995) Ab initio study of MgSiO3 and CaSiO3 perovskites at lower-mantle pressures. Phys. Earth Planet. Inter., 90, 101–12.CrossRefGoogle Scholar
Williams, Q., Jeanloz, R., Bass, J., Svendsen, B. and Ahrens, T.J. (1987) The melting curve of iron to 250 gigapascals: a constraint on the temperature at Earth’s center. Science, 236, 181–2.CrossRefGoogle ScholarPubMed
Williams, Q., Revenaugh, J. and Garnero, E. (1998) A correlation between ultra-low basal velocities in the mantle and hot spots. Science, 281, 546–9.CrossRefGoogle ScholarPubMed
Yagi, T., Kondo, T. and Syono, Y. (1998) High pressure in situ X-ray diffraction study of MnO to 137 GPa and comparison with shock compression experiment: Pp. 159–62 in: Shock Compression of Condensed Matter – 1997 (Schmidt, S.C. et al., editors). American Institute of Physics, New York.Google Scholar
Yang, H., Prewitt, C.T. and Frost, D.J. (1997) Crystal structure of the dense hydrous magnesium silicate, phase D. Amer. Mineral., 82, 651–4.CrossRefGoogle Scholar
Yoo, C.S., Holmes, N.C., Ross, M., Webb, D.J. and Pike, C. (1993) Shock temperatures and melting of iron at Earth’s core conditions. Phys. Rev. Lett., 70, 3931–4.CrossRefGoogle Scholar
Zaanen, J., Sawatzky, G. and Allen, J. (1985) Band gaps and electronic structure in transition-metal compounds. Phys. Rev. Lett., 55, 418–21.CrossRefGoogle ScholarPubMed
Zha, C.S., Hemley, R.J., Mao, H.K. and Duffy, T.S. (1997) Elasticity measurement and equation of state from MgO to 60 GPa. Eos Trans. Amer. Geophys. Union, 78, F752.Google Scholar
Zhang, L. (1997) High pressure Mössbauer spectroscopy using synchrotron radiation on earth materials. In: Crystal lography at High Pressure Using Synchrotron Radiation: The Next Steps. ESRF, Grenoble, France.Google Scholar
Zhang, L., Stanek, J., Hafner, S.S., Ahsbahs, H., Grünstudel, H.F., Metge, J. and Rüffer, R. (1999) 57Fe nuclear forward scattering of synchrotron radiation in hedenbergite CaFeSi2O6 at hydrostatic pressures up to 68 GPa. Amer. Mineral., 84, 447–53.CrossRefGoogle Scholar