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Some Observations on Translation Gliding and Kinking in Experimentally Deformed Calcite and Dolomite. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm016p0095] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2023]
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Green HW, Radcliffe SV. Deformation Processes in the Upper Mantle. FLOW AND FRACTURE OF ROCKS 2013. [DOI: 10.1029/gm016p0139] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Hobbs BE, McLaren AC, Paterson MS. Plasticity of Single Crystals of Synthetic Quartz. FLOW AND FRACTURE OF ROCKS 2013. [DOI: 10.1029/gm016p0029] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
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Baker DW, Carter NL. Seismic Velocity Anisotropy Calculated for Ultramafic Minerals and Aggregates. FLOW AND FRACTURE OF ROCKS 2013. [DOI: 10.1029/gm016p0157] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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Transmission Electron Microscopy of Experimentally Deformed Olivine Crystals. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm016p0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Seismic Anisotropy, Flow, and Constitution of the Upper Mantle. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm016p0167] [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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Oscillating Disk Dynamo and Geomagnetism. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm016p0325] [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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Transmission Electron Microscope Investigation of Some Naturally Deformed Quartzites. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm016p0055] [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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Steady-State Flow in Polycrystalline Halite at Pressure of 2 Kilobars. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm016p0191] [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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Experimental Recrystallization of Ice Under Stress. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm016p0211] [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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Model for Aftershock Occurrence. ACTA ACUST UNITED AC 2013. [DOI: 10.1029/gm016p0259] [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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Tullis J, Tullis T. Preferred Orientation of Quartz Produced by Mechanical Dauphiné Twinning: Thermodynamics and Axial Experiments. FLOW AND FRACTURE OF ROCKS 2013. [DOI: 10.1029/gm016p0067] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Raleigh CB, Healy JH, Bredehoeft JD. Faulting and Crustal Stress at Rangely, Colorado. FLOW AND FRACTURE OF ROCKS 2013. [DOI: 10.1029/gm016p0275] [Citation(s) in RCA: 101] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Forsyth DW, Press F. Geophysical tests of petrological models of the spreading lithosphere. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb076i032p07963] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Jacob KH. Global tectonic implications of anomalous seismicPtraveltimes from the nuclear explosion longshot. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb077i014p02556] [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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Mao NH. Velocity-density systematics and its implications for the iron content of the mantle. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb079i035p05447] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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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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Gaffney ES, Anderson DL. Effect of low-spin Fe2+on the composition of the lower mantle. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb078i029p07005] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Sammis CG, Smith JC, Schubert G, Yuen DA. Viscosity-depth profile of the Earth's mantle: Effects of polymorphic phase transitions. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb082i026p03747] [Citation(s) in RCA: 112] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Mizutani H, Hamano Y, Akimoto SI. Elastic-wave velocities of polycrystalline stishovite. ACTA ACUST UNITED AC 2012. [DOI: 10.1029/jb077i020p03744] [Citation(s) in RCA: 113] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Abstract
Shock wave techniques have been used to investigate the pressuredensity relations of metals, silicates, and oxides over the entire range of pressures present in the earth (3.7 x 10(6) bars at the center). In many materials of geophysical interest, such as iron, wüstite, calcium oxide, and forsterite, major shock-induced phase changes dominate the compression behavior below pressures of 10(6) bars. The shock wave data for the high-pressure phases of these minerals lead to important inferences about the composition of the lower mantle and outer, liquid core of the earth. The lower mantle of the earth appears to have a slightly higher density than is inferred to correspond to the behavior of an olivine-rich assembiage of the same composition as the upper mantle. The core has a density some 10 percent less than that of pure iron and may have 9 to 12 percent sulfur or about 8 percent oxygen by weight.
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Abstract
Seismology is providing a more sharply focused picture of the Earth's internal structure that should lead to improved models of mantle dynamics. Lateral variations in seismic wave speeds have been documented in all major layers of the Earth external to its core, with horizontal scale lengths ranging from 10 to 10(4) km. These variations can be described in terms of three types of heterogeneity: compositional, aeolotropic, and thermobaric. All three types are represented in the lithosphere, but the properties of the deeper inhomogeneities remain hypothetical. It is argued that sublithospheric continental root structures are likely to involve compositional as well as thermobaric heterogeneities. The high-velocity anomalies characteristic of subduction zones-seismic evidence for detached and sinking thermal boundary layers-in some areas appear to extend below the seismicity cutoff and into the lower mantle or mesosphere. Mass exchange between the upper and lower mantles is implied, but the magnitude of the flux relative to the total mass flux involved in plate circulations is as yet unknown. Other observations, such as the vertical travel time anomalies seen in the western Pacific, may yield additional constraints on the flow geometries, but further documentation is necessary. Thermobaric heterogeneities associated with a thermal boundary layer at the base of the mantle could provide the explanation for some of the observations of heterogeneities in the deep mantle. The evidence for very small scale inhomogeneities (<50 km) in region D'' and for topography on the core-mantle interface motivate the speculation that there is a chemical boundary layer at this interface, as well as a thermal one.
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Affiliation(s)
- T H Jordan
- Geological Research Division, Scripps Institution of Oceanography, La Jolla, California 92093
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Liebermann RC. Elasticity of Olivine (α), Beta(β), and Spinel (γ) Polymorphs of Germanates and Silicates. ACTA ACUST UNITED AC 2007. [DOI: 10.1111/j.1365-246x.1975.tb06458.x] [Citation(s) in RCA: 103] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Affiliation(s)
- Don L Anderson
- Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, USA.
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The Bakerian Lecture, 1983 - The Earth’s core: its composition, formation and bearing upon the origin of the Earth. ACTA ACUST UNITED AC 1997. [DOI: 10.1098/rspa.1984.0088] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The density of the outer core is about 3 % smaller than pure iron, which implies that the core contains a substantial amount of one or more low atomic mass elements. Candidates which have been suggested on various grounds include S, H, C, O, Si, and Mg. Plausible models of accretion of the Earth encounter difficulties in trapping sufficient S, H and C to explain the density deficit. On the other hand, entry of Si and Mg is not favoured by thermodynamic arguments. Oxygen is the most abundant element in the Earth and would be a prime candidate if it could be shown to be extensively soluble in molten iron at core temperatures and pressures. New experimental data on the solubility of FeO in molten iron are reviewed. They demonstrate that at atmospheric pressure, FeO is extensively soluble in iron at 2500 °C and that complete miscibility probably occurs above 2800 °C. Moreover, liquid iron in equilibrium with magnesiowüstite (Mg
0.8
Fe
0.2
)O also dissolves large quantities of FeO above 2800 °C. The solubility of FeO in molten iron is considerably increased by high pressures, because of the small partial molar volume of FeO in the Fe─FeO melt. If the core formed by segregation of metal originally dispersed throughout the Earth, it seems inevitable that it would have dissolved large amounts of FeO. The density of the outer core can be matched if it contains about 35 mol % FeO, a quantity that is readily explained by the new experimental data. Solution of FeO in iron causes the melting point of the metal phase to be depressed below the solidus temperature of the silicate phase assemblages in the mantle. A model for the formation of the core is described, based upon Fe-FeO phase relations at high temperatures and pressures. The model implies the presence of a high content of FeO in the Bulk Earth. This can be explained if the Earth accreted from a mixture of two components: A, a highly reduced, metal-rich devolatilized assemblage and B, a highly oxidized, volatile-rich assemblage similar to C1 chondrites. The formation of these components in the solar nebula is discussed. The large amount of FeO now inferred to be present in the Earth was mainly produced during accretion by oxidation of metallic iron from component A by water from component B. This two-component mixing model also provides an attractive explanation of some aspects of the chemistry of the Earth’s mantle including the abundances of siderophile and volatile elements.
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Abstract
The three-dimensional maps of the earth's interior now span regions from the bottom of the crust to the inner core of the earth. Although a wealth of new information on the dynamics of the earth has been discovered, the inner core offers the greatest surprise: it appears to be anisotropic with the axis of symmetry aligned with the axis of rotation.
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Abstract
A major component of the Inter-Union Commission on Geodynamics Project, labeled "Internal Properties and Processes," included certain experimental and theoretical research in tectonophysics, seismology, geochemistry, petrology, volcanology, and planetology. This review focuses on a few research areas in which there have been surprises and reversals. In particular, attention is given to the attempts to quantify the thermal profile in the earth's interior and the material properties of the earth's interior.
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Jeanloz R, Ahrens TJ, Mao HK, Bell PM. B1-B2 Transition in Calcium Oxide from Shock-Wave and Diamond-Cell Experiments. Science 1979; 206:829-30. [PMID: 17820761 DOI: 10.1126/science.206.4420.829] [Citation(s) in RCA: 170] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Volume and structural data obtained by shock-wave and diamond-cell techniques demonstrate that calcium oxide transforms from the B1 (sodium chloride type) to the B2 (cesium chloride type) structure at 60 to 70 gigapascals (0.6 to 0.7 megabar) with a volume decrease of 11 percent. The agreement between the shockwave and diamond-cell results independently confirms the ruby-fluorescence pressure scale to about 65 gigapascals. The shock-wave data agree closely with ultrasonic measurements on the B1 phase and also agree satisfactorily with equations of state derived from ab initio calculations. The discovery of this B1-B2 transition is significant in that it allows considerable enrichment of calcium components in the earth's lower mantle, which is consistent with inhomogeneous accretion theories.
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Ming LC, Manghnani MH. Isothermal compression of TiO2(Rutile) under hydrostatic pressure to 106 kbar. ACTA ACUST UNITED AC 1979. [DOI: 10.1029/jb084ib09p04777] [Citation(s) in RCA: 47] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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LIEBERMANN ROBERTC. Elastic Properties of Germanate Analogues of Olivine, Spinel and β Polymorphs of (Mg,Fe)2SiO4. ACTA ACUST UNITED AC 1973. [DOI: 10.1038/physci244105a0] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Ganapathy R, Laul JC, Morgan JW, Anders E. Moon: Possible Nature of the Body That Produced the Imbrian Basin, from the Composition of Apollo 14 Samples. Science 1972; 175:55-9. [PMID: 17833980 DOI: 10.1126/science.175.4017.55] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Soils from the Apollo 14 site contain nearly three times as much meteoritic material as soils from the Apollo 11, Apollo 12, and Luna 16 sites. Part of this material consists of the ubiquitous micrometeorite component, of primitive (carbonaceous-chondrite-like) composition. The remainder, seen most conspicuously in coarse glass and norite fragments, has a decidedly fractionated composition, with volatile elements less than one-tenth as abundant as siderophiles. This material seems to be debris of the Cyprus-sized planetesimal that produced the Imbrian basin. Compositionally this planetesimal has no exact counterpart among known meteorite classes, though group IVA irons come close. It also resembles the initial composition of the earth as postulated by the two-component model. Apparently the Imbrian planetesimal was an Earth satellite swept up by the moon during tidal recession or capture, or an asteroid deflected by Mars into terrestrial space.
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