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Evidence for Lateral Heterogeneity at the Core-Mantle Boundary from the Slowness of Diffracted S Profiles. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm046p0055] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Aspherical Structure of the Mantle, Tectonic Plate Motions, Nonhydrostatic Geoid, and Topography of the Core-Mantle Boundary. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm072p0135] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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3
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Christensen UR, Yuen DA. The interaction of a subducting lithospheric slab with a chemical or phase boundary. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb089ib06p04389] [Citation(s) in RCA: 310] [Impact Index Per Article: 25.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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4
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Bataille K, Flatté SM. Inhomogeneities near the core-mantle boundary inferred from short-period scatteredPKPwaves recorded at the Global Digital Seismograph Network. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb093ib12p15057] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Garfunkel Z, Anderson CA, Schubert G. Mantle circulation and the lateral migration of subducted slabs. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb091ib07p07205] [Citation(s) in RCA: 213] [Impact Index Per Article: 17.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Richter FM, McKenzie DP. On some consequences and possible causes of layered mantle convection. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb086ib07p06133] [Citation(s) in RCA: 153] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Spohn T, Schubert G. Modes of mantle convection and the removal of heat from the Earth's interior. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb087ib06p04682] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Heinz DL, Jeanloz R. Measurement of the melting curve of Mg0.9Fe0.1SiO3at lower mantle conditions and its geophysical implications. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb092ib11p11437] [Citation(s) in RCA: 160] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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O'Neill B, Jeanloz R. MgSiO3-FeSiO3-Al2O3in the Earth's lower mantle: Perovskite and garnet at 1200 km depth. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/94jb01752] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Boehler R. Adiabats of quartz, coesite, olivine, and magnesium oxide to 50 kbar and 1000 K, and the adiabatic gradient in the Earth's mantle. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb087ib07p05501] [Citation(s) in RCA: 103] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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11
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Roufosse MC, Jeanloz R. Thermal conductivity of minerals at high pressure: The effect of phase transitions. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb088ib09p07399] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Wright C, Muirhead KJ, Dixon AE. The P wave velocity structure near the base of the mantle. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb090ib01p00623] [Citation(s) in RCA: 77] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Watt JP, Ahrens TJ. The role of iron partitioning in mantle composition, evolution, and scale of convection. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb087ib07p05631] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Ivins ER, Sammis CG, Yoder CF. Deep mantle viscous structure with prior estimate and satellite constraint. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/92jb02728] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Revenaugh J, Jordan TH. Mantle layering fromScSreverberations: 4. The lower mantle and core-mantle boundary. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/91jb02163] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Choy GL, Cormier VF. Direct measurement of the mantle attenuation operator from broadbandPandSWaveforms. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb091ib07p07326] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Creager KC, Jordan TH. Slab penetration into the lower mantle beneath the Mariana and other island arcs of the northwest Pacific. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb091ib03p03573] [Citation(s) in RCA: 249] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mori J, Helmberger DV. Localized boundary layer below the mid-Pacific velocity anomaly identified from aPcPprecursor. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/95jb02243] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Richter FM. Focal mechanisms and seismic energy release of deep and intermediate earthquakes in the Tonga-Kermadec Region and their bearing on the depth extent of mantle flow. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb084ib12p06783] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Jeanloz R. Majorite: Vibrational and compressional properties of a high-pressure phase. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb086ib07p06171] [Citation(s) in RCA: 102] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sahagian DL, Holland SM. On the thermo-mechanical evolution of continental lithosphere. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/93jb00152] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Mula AHG. Amplitudes of diffracted long-periodPandSwaves and the velocities andQstructure at the base of the mantle. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb086ib06p04999] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Alvarez W. Geological evidence for the geographical pattern of mantle return flow and the driving mechanism of plate tectonics. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb087ib08p06697] [Citation(s) in RCA: 106] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Stixrude L. Mineralogy and elasticity of the oceanic upper mantle: Origin of the low-velocity zone. ACTA ACUST UNITED AC 2005. [DOI: 10.1029/2004jb002965] [Citation(s) in RCA: 212] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Panero WR, Jeanloz R. Temperature gradients in the laser-heated diamond anvil cell. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000jb900423] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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26
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Evidence for partial melt at the core–mantle boundary north of Tonga from the strong scattering of seismic waves. Nature 1998. [DOI: 10.1038/35601] [Citation(s) in RCA: 143] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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The temperature contrast across D″. ACTA ACUST UNITED AC 1998. [DOI: 10.1029/gd028p0073] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/30/2023]
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Forte AM, Woodward RL. Seismic-geodynamic constraints on three-dimensional structure, vertical flow, and heat transfer in the mantle. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/97jb01276] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Manga M, Jeanloz R. Thermal conductivity of corundum and periclase and implications for the lower mantle. ACTA ACUST UNITED AC 1997. [DOI: 10.1029/96jb02696] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
The observed density distribution of the lower mantle is compared with density measurements of the (M g,Fe)SiO
3
perovskite and (Mg,Fe)O magnesiowtistite highpressure phases as functions of pressure, tem perature and composition. We find that for plausible bounds on the composition of the upper mantle (ratio of magnesium to iron + magnesium components
x
M
g
^ 0.88) and the temperature in the lower mantle ( T ^ 2000 K), the high-pressure mineral assemblage of upper-mantle composition is at least 2 .6 ( ± 1 ) % less dense than the lower m antle over the depth range 1000-2000 km. Thus, we find that a model of uniform m antle composition is incompatible with the existing mineralogical and geophysical data. Instead, we expect that the mantle is stratified, with the upper and lower m antle convecting separately, and we estimate that the compositional density difference between these regions is about 5 ( + 2) %. The stratification may not be perfect (‘leaky layering’), but significant intermixing and homogenization of the upper and lower m antle over geological timescales are precluded.
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Lenardic A, Kaula WM. Tectonic plates, D″ thermal structure, and the nature of mantle plumes. ACTA ACUST UNITED AC 1994. [DOI: 10.1029/94jb00466] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Gaherty JB, Lay T. Investigation of laterally heterogeneous shear velocity structure in D″ beneath Eurasia. ACTA ACUST UNITED AC 1992. [DOI: 10.1029/91jb02347] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Ita J, Stixrude L. Petrology, elasticity, and composition of the mantle transition zone. ACTA ACUST UNITED AC 1992. [DOI: 10.1029/92jb00068] [Citation(s) in RCA: 341] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Knittle E, Jeanloz R. Earth's Core-Mantle Boundary: Results of Experiments at High Pressures and Temperatures. Science 1991; 251:1438-43. [PMID: 17779437 DOI: 10.1126/science.251.5000.1438] [Citation(s) in RCA: 317] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Laboratory experiments document that liquid iron reacts chemically with silicates at high pressures (>/=2.4 x 10(10) Pascals) and temperatures. In particular, (Mg,Fe)SiO(3) perovskite, the most abundant mineral of Earth's lower mantle, is expected to react with liquid iron to produce metallic alloys (FeO and FeSi) and nonmetallic silicates (SiO(2) stishovite and MgSiO(3) perovskite) at the pressures of the core-mantle boundary, 14 x 10(10) Pascals. The experimental observations, in conjunction with seismological data, suggest that the lowermost 200 to 300 kilometers of Earth's mantle, the D" layer, may be an extremely heterogeneous region as a result of chemical reactions between the silicate mantle and the liquid iron alloy of Earth's core. The combined thermal-chemical-electrical boundary layer resulting from such reactions offers a plausible explanation for the complex behavior of seismic waves near the core-mantle boundary and could influence Earth's magnetic field observed at the surface.
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Miller GH, Stolper EM, Ahrens TJ. The equation of state of a molten komatiite: 2. Application to komatiite petrogenesis and the Hadean Mantle. ACTA ACUST UNITED AC 1991. [DOI: 10.1029/91jb01203] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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39
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Knittle E, Jeanloz R. The high-pressure phase diagram of Fe0.94O: A possible constituent of the Earth's core. ACTA ACUST UNITED AC 1991. [DOI: 10.1029/90jb00653] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Young CJ, Lay T. Multiple phase analysis of the shear velocity structure in the D″ region beneath Alaska. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/jb095ib11p17385] [Citation(s) in RCA: 117] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Williams Q, Jeanloz R. Melting relations in the iron-sulfur system at ultra-high pressures: Implications for the thermal state of the Earth. ACTA ACUST UNITED AC 1990. [DOI: 10.1029/jb095ib12p19299] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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43
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Gould A, Frieman JA, Freese K. Probing the Earth with weakly interacting massive particles. PHYSICAL REVIEW. D, PARTICLES AND FIELDS 1989; 39:1029-1045. [PMID: 9959739 DOI: 10.1103/physrevd.39.1029] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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44
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Schmitt DR, Ahrens TJ. Shock temperatures in silica glass: Implications for modes of shock-induced deformation, phase transformation, and melting with pressure. ACTA ACUST UNITED AC 1989. [DOI: 10.1029/jb094ib05p05851] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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45
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46
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Sleep NH, Richards MA, Hager BH. Onset of mantle plumes in the presence of preexisting convection. ACTA ACUST UNITED AC 1988. [DOI: 10.1029/jb093ib07p07672] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
True polar wander, the shifting of the entire mantle relative to the earth's spin axis, has been reanalyzed. Over the last 200 million years, true polar wander has been fast (approximately 5 centimeters per year) most of the time, except for a remarkable standstill from 170 to 110 million years ago. This standstill correlates with a decrease in the reversal frequency of the geomagnetic field and episodes of continental breakup. Conversely, true polar wander is high when reversal frequency increases. It is proposed that intermittent convection modulates the thickness of a thermal boundary layer at the base of the mantle and consequently the core-to-mantle heat flux. Emission of hot thermals from the boundary layer leads to increases in mantle convection and true polar wander. In conjunction, cold thermals released from a boundary layer at the top of the liquid core eventually lead to reversals. Changes in the locations of subduction zones may also affect true polar wander. Exceptional volcanism and mass extinctions at the Cretaceous-Tertiary and Permo-Triassic boundaries may be related to thermals released after two unusually long periods with no magnetic reversals. These environmental catastrophes may therefore be a consequence of thermal and chemical couplings in the earth's multilayer heat engine rather than have an extraterrestrial cause.
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Williams Q, Jeanloz R, Bass J, Svendsen B, Ahrens TJ. The Melting Curve of Iron to 250 Gigapascals: A Constraint on the Temperature at Earth's Center. Science 1987; 236:181-2. [PMID: 17789782 DOI: 10.1126/science.236.4798.181] [Citation(s) in RCA: 305] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The melting curve of iron, the primary constituent of Earth's core, has been measured to pressures of 250 gigapascals with a combination of static and dynamic techniques. The melting temperature of iron at the pressure of the core-mantle boundary (136 gigapascals) is 4800 +/- 200 K. whereas at the inner core-outer core boundary (330 gigapascals), it is 7600 +/- 500 K. Corrected for melting point depression resulting from the presence of impurities, a melting temperature for iron-rich alloy of 6600 K at the inner core-outer core boundary and a maximum temperature of 6900 K at Earth's center are inferred. This latter value is the first experimental upper bound on the temperature at Earth's center, and these results imply that the temperature of the lower mantle is significantly less than that of the outer core.
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