Lattice and radiative thermal conductivity variations through high p, T polymorphic structure transitions and melting points

Macpherson, W. R.; Schloessin, H. H.

doi:10.1016/0031-9201(82)90138-8

Cited by 23 publications

(10 citation statements)

References 21 publications

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“…The Inset of the Fig. 3 shows the calculated κðPÞ∕κðP ¼ 0Þ ratio at 300 K (Solid Line) that falls in the scattered experimental high pressure measurements (19)(20)(21)(22). The LDA-calculated isothermal pressure coefficient (d lnðκ MgO Þ∕dP) is about 3.90% GPa −1 at T ¼ 300 K near ambient pressure, which is in good agreement with the measured value of 4% GPa −1 (20, 33) and 4.9% GPa −1 (21).…”

Section: Discussionsupporting

confidence: 69%

“…The adopted units for κ, T , and ρ are W∕K-m, K, and g∕cm 3 , resp. (19)(20)(21)(22) as a function of pressure (up to 6 GPa) at room temperature. lower-mantle conditions (Fig.…”

Section: Discussionmentioning

confidence: 99%

“…Hence, studying its thermal conductivity provides a useful approach to constraining the thermal conductivity of the lower mantle. Though efforts have been devoted to measuring the thermal conductivity of MgO (κ MgO ) at both high pressures and temperatures (16)(17)(18)(19)(20)(21)(22)(23)(24), most of those measurements have been limited to below 7 GPa. First, nonempirical calculations of lattice thermal conductivity (25) of MgO at high pressure were performed based on molecular dynamics simulations and Green-Kubo theory (26).…”

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confidence: 99%

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Lattice thermal conductivity of MgO at conditions of Earth’s interior

Tang

Dong

2010

Proc. Natl. Acad. Sci. U.S.A.

150

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Thermal conductivity of the Earth's lower mantle greatly impacts the mantle convection style and affects the heat conduction from the core to the mantle. Direct laboratory measurement of thermal conductivity of mantle minerals remains a technical challenge at the pressure-temperature (P-T) conditions relevant to the lower mantle, and previously estimated values are extrapolated from low P-T data based on simple empirical thermal transport models. By using a numerical technique that combines first-principles electronic structure theory and Peierls-Boltzmann transport theory, we predict the lattice thermal conductivity of MgO, previously used to estimate the thermal conductivity in the Earth, at conditions from ambient to the core-mantle boundary (CMB). We show that our first-principles technique provides a realistic model for the P-T dependence of lattice thermal conductivity of MgO at conditions from ambient to the CMB, and we propose thermal conductivity profiles of MgO in the lower mantle based on geotherm models. The calculated conductivity increases from 15 -20 W∕K-m at the 670 km seismic discontinuity to 40 -50 W∕K-m at the CMB. This large depth variation in calculated thermal conductivity should be included in models of mantle convection, which has been traditionally studied based on the assumption of constant conductivity.first-principles | phonon transport theory | phonon lifetime | high pressure | Lower Mantle T hermal conductivity (κ) is one of the most important mineral properties in determining the heat budget of the Earth. Heat in the Earth's interior is transferred by convection in the mantle and core and regulated by conduction at thermal boundary layers. As defined by Fourier's law of heat conduction J Q ¼ −κ · ∇T, determines the conducting heat flow density (J Q ) in the presence of a temperature gradient ∇T. κ also appears in the Rayleigh number, which measures the convective vigor of a system. Thus, the thermal conductivity of the lower mantle affects the structure, thickness, and dynamics of the CMB (1, 2), the style and structure of mantle convection (3-5), and the amount of heat conducted from the core to the mantle (6) that in turn influences the generation of the Earth's magnetic field (7).Despite its importance, thermal conductivity remains as one of the least constrained physical properties of minerals, especially at lower-mantle pressures (P) and temperatures (T) and approximately 1,900-4,000 K (9-12). Experimental data at deep mantle conditions are scarce due to the technical difficulty of measuring thermal conductivity at these extremes. Thermal conductivity of lower-mantle minerals is often estimated either by extrapolating data from lower P-T conditions and/or employing theoretical models with parameters fitted with lower P-T data (1, 13). However, direct extrapolation to deep mantle conditions can be unreliable beyond the P-Trange of the measurements, and empirical models are often based on untested assumptions. For example, the sound velocities are used to approximate phonon vel...

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Section: Discussionsupporting

confidence: 69%

“…The adopted units for κ, T , and ρ are W∕K-m, K, and g∕cm 3 , resp. (19)(20)(21)(22) as a function of pressure (up to 6 GPa) at room temperature. lower-mantle conditions (Fig.…”

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Lattice thermal conductivity of MgO at conditions of Earth’s interior

Tang

Dong

2010

Proc. Natl. Acad. Sci. U.S.A.

150

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“…Conductivities in the mantle probably increase with increasing depth and temperature, since above about 500°C, radiative, or photon, conductivity that has a positive temperature coefficient becomes the dominant parameter controlling the conductive gradient (Birch and Clark, 1940;Clark, 1957;Fujisawa and others, 1968;Kanamori and others, 1968;Schatz and Simmons, 1972;MacPherson and Schloessin, 1982). For relatively cool geotherms, typical of stable regions, it is possible to choose mean conductivities for the crust and mantle that predict geotherms not significantly different from those predicted using temperaturedependent conductivity models (Morgan, 1984).…”

Section: Crustal Factorsmentioning

confidence: 99%

Chapter 23: Heat flow and thermal regimes in the continental United States

Morgan

Gosnold²

1989

Geological Society of America Memoirs

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Heat flow and associated lithospheric thermal regimes in the continental UnitedStates are intricately related to the tectonic evolution and physical properties of the continental lithosphere. More than 2,000 published heat-flow values are now available for the United States, although the distribution of these data is very uneven, with most data sites in the western United States. The data define a single basic thermal regime in all provinces east of the Rocky Mountains and variable thermal regimes in provinces in the western United States. "Normal" heat flow east of the Rockies is interpreted to reflect a stable thermal regime with regional variations associated with redistribution of heat by ground-water convection and heterogeneity in upper crustal heat production. With the exception of Lake Superior in the Canadian Shield, there is a general trend of increasing surface heat flow with increasing crustal thickness in this stable region. Heat flow in the western United States is generally high, and the surface heat-flow pattern is not everywhere controlled by province boundaries. Calculated geotherms for much of the region suggest temperatures near the solidus close to the Moho for much of the region, with major crustal melting predicted by steady-state geotherm calculations for hot thermal subprovinces. In the Basin and Range province, extension may have been an important factor in producing or maintaining the high heat flow, but elsewhere-and perhaps in the Basin and Range also-convection of heat into the crust by mantlederived melts not simply related to extension appears to be the primary heat source. These melts are probably related to subduction, but the exact mechanism of their origin is unclear. Low heat flow in the eastern Snake River Plain and the "Eureka Low" appears to result from downward convection by ground-water recharge. Low heat flow in the Sierra Nevada and Northwest Pacific coastal provinces appears to be related to subduction. Relatively normal heat flow in the Colorado Plateau is inconsistent with the elevation of the plateau, and an increase in heat flow with depth is predicted beneath this province. High heat flow in the California Coast Ranges is related to growth of the San Andreas fault zone and local segments of extension along its length. These thermal regimes are directly related to variations in lithospheric thickness across the United States, and regional elevation differences are associated with both crustal thickness and geotherm variations. Increased understanding of these thermal regimes and their evolution is leading to a better understanding of the tectonic evolution, physical properties, and lithospheric structure of the continental United States.

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“…Conductive heat transfer is believed to be a dominant heat transfer mechanism in subducting slabs so that the measurements of thermal diffusivity and conductivity are fundamental to the comprehension of geophysical processes associated with subduction. So far, high pressure measurements of these heat transfer properties have been made at pressures up to 6 GPa (Fujisawa et al 1968;Yukutake 1974;Kieffer et al 1976;MacPherson and Schloessin 1982;Horai and Susaki 1989). These studies demonstrate that the pressure effects on the heat transfer properties of minerals are relatively large, suggesting that these properties must be measured under high P-T conditions appropriate to the upper mantle.…”

Section: Introductionmentioning

confidence: 99%

Thermal diffusivity of silica glass at pressures up to 9 GPa

Katsura

1993

Phys Chem Minerals

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Abstract. The thermal diffusivity of silica glass was measured at pressures up to 9 GPa and temperatures up to 1200 K. The measurements involve adopting the ~ngstr6m method to a cylindrical geometry in a uniaxial split-sphere apparatus. This method can be used to determine thermal diffusivity in samples with dominant conductive heat transfer. The thermal diffusivity of silica glass has a negative first pressure derivative but a positive second pressure derivative. Although the elastic moduli have minima near 3 GPa, the thermal diffusivity does not has minimum up to 9 GPa, which cannot be explained by the model of Kittel (1949). The negative pressure derivative of thermal diffusivity is a feature probably unique in silica glass, and its magnitude should decrease with the addition of Na20.

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Lattice and radiative thermal conductivity variations through high p, T polymorphic structure transitions and melting points

Cited by 23 publications

References 21 publications

Lattice thermal conductivity of MgO at conditions of Earth’s interior

Lattice thermal conductivity of MgO at conditions of Earth’s interior

Chapter 23: Heat flow and thermal regimes in the continental United States

Thermal diffusivity of silica glass at pressures up to 9 GPa

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