Nature of electrical charge carriers in the Earth's lower mantle from laboratory measurements (Paper 94GL01934) 2183

Thermoelectric power measurements on a silicate-perovskite and magnesiowustite assemblage at lower-mantle conditions [(Mg0.89Fe0.11)2SiO4 bulk composition at 48 GPa and temperatures up to 2500 K] yield a positive Seebeck coefficient, thus implying that the dominant charge carriers are positive and that electrons in the conduction band (intrinsic carriers) contribute little to the electrical conductivity. The present results suggest that electrical transport is likely dominated by extrinsic charge carriers throughout the entire mantle and, hence, the electrical conductivity can be a powerful tool for characterizing minor phases, impurities and defect states of the Earth's deep interior.

[1]  H. Mao,et al.  Solid carbon at high pressure: Electrical resistivity and phase transition , 1994 .

[2]  J. S. Sweeney,et al.  High-Pressure Melting of (Mg,Fe)SiO3-Perovskite. , 1994, Science.

[3]  A. Schultz,et al.  Conductivity discontinuities in the upper mantle beneath a stable craton , 1993 .

[4]  R. Jeanloz,et al.  Pressure dependence of the electrical conductivity of (Mg0.9Fe0.1)SiO3 perovskite , 1993 .

[5]  R. Jeanloz,et al.  The high‐pressure phase diagram of Fe0.94O: A possible constituent of the Earth's core , 1991 .

[6]  L. M. Hirsch,et al.  Point defects in (Mg,Fe)SiO3 perovskite , 1991 .

[7]  B. Wood,et al.  High-temperature electrical conductivity of the lower-mantle phase (Mg, Fe)O , 1991, Nature.

[8]  R. Jeanloz,et al.  Effect of iron content on the electrical conductivity of Perovskite and Magnesiowüstite assemblages at lower mantle conditions , 1991 .

[9]  R. Jeanloz,et al.  Phases and electrical conductivity of a hydrous silicate assemblage at lower-mantle conditions , 1991, Nature.

[10]  R. Jeanloz,et al.  High pressure-temperature electrical conductivity of magnesiowustite as a function of iron oxide concentration , 1990 .

[11]  A. Schultz.  On the vertical gradient and associated heterogeneity in mantle electrical conductivity , 1990 .

[12]  R. Jeanloz,et al.  Ultrahigh-Pressure Melting of Lead: A Multidisciplinary Study , 1990, Science.

[13]  R. Jeanloz,et al.  Laboratory studies of the electrical conductivity of silicate perovskites at high pressures and temperatures , 1990 .

[14]  W. D. Parkinson,et al.  The electrical conductivity of the Earth. , 1989 .

[15]  G. Rossman.  Chapter 7. OPTICAL SPECTROSCOPY , 1988 .

[16]  C. R. A. Catlow,et al.  Point Defects in Materials , 1988 .

[17]  R. Jeanloz,et al.  Electrical conductivity of (Mg,Fe)SiO3 perovskite and a perovskite-dominated assemblage at lower man , 1987 .

[18]  R. Jeanloz,et al.  Temperature Measurements in the Laser‐Heated Diamond Cell , 1987 .

[19]  P. A. Cox.  The Electronic Structure And Chemistry Of Solids , 1987 .

[20]  R. Jeanloz,et al.  High-pressure electrical resistivity measurements of Fe2O3: comparison of static-compression and shock-wave experiments to 61 GPa , 1986 .

[21]  D. Greig,et al.  Thermoelectric Power of Metals , 1976 .

[22]  S. Wisniewski,et al.  Thermodynamics of Nonequilibrium Processes , 1976 .

[23]  A. Hughes.  Optical Techniques and an Introduction to the Symmetry Properties of Point Defects , 1976 .

[24]  A. Lundén,et al.  On the pressure dependence of the electrical conductivity of silver iodide , 1975 .

[25]  T. Shankland.  Electrical conduction in rocks and minerals: Parameters for interpretation , 1975 .

[26]  J. S. Anderson,et al.  Solid State Chemistry , 1973, Nature.

[27]  M. Bott,et al.  The interior of the earth , 1971 .

[28]  G. Kennedy,et al.  Effect of Pressure on the emf of Chromel‐Alumel and Platinum‐Platinum 10% Rhodium Thermocouples , 1970 .

[29]  T. Shankland.  Band Gap of Forsterite , 1968, Science.

[30]  F. Bundy.  Effect of Pressure on emf of Thermocouples , 1961 .

[31]  D. Tozer.  The electrical properties of the earth's interior , 1959 .