Thermal Conductivity of Rocks and Minerals
01 Mar 2013-pp 105-126
TL;DR: In this paper, if the hydraulic permeability of crustal material is sufficiently high, convection driven advection of heat can be an equally or even much more efficient transfer mechanism, provided sufficiently strong driving forces are supplied by forced or free convection systems.
Abstract: (1) If the hydraulic permeability of crustal material is sufficiently high, convection driven advection of heat can be an equally or even much more efficient transfer mechanism, provided sufficiently strong driving forces are supplied by forced or free convection systems. This is often the case in sedimentary basins. However, fluid driven heat advection can be important also in crystalline rocks and on a crustal scale (Etheridge et al., 1983, Torgersen, 1990, Clauser, 1992).
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TL;DR: The Community Land Model (CLM) as discussed by the authors is the land component of the Community Climate System Model (CCSM) and has been extended with a carbon-nitrogen (CN) biogeochemical model that is prognostic with respect to vegetation, litter, and soil carbon and nitrogen states.
Abstract: [1] The Community Land Model is the land component of the Community Climate System Model. Here, we describe a broad set of model improvements and additions that have been provided through the CLM development community to create CLM4. The model is extended with a carbon-nitrogen (CN) biogeochemical model that is prognostic with respect to vegetation, litter, and soil carbon and nitrogen states and vegetation phenology. An urban canyon model is added and a transient land cover and land use change (LCLUC) capability, including wood harvest, is introduced, enabling study of historic and future LCLUC on energy, water, momentum, carbon, and nitrogen fluxes. The hydrology scheme is modified with a revised numerical solution of the Richards equation and a revised ground evaporation parameterization that accounts for litter and within-canopy stability. The new snow model incorporates the SNow and Ice Aerosol Radiation model (SNICAR) - which includes aerosol deposition, grain-size dependent snow aging, and vertically-resolved snowpack heating – as well as new snow cover and snow burial fraction parameterizations. The thermal and hydrologic properties of organic soil are accounted for and the ground column is extended to ∼50-m depth. Several other minor modifications to the land surface types dataset, grass and crop optical properties, surface layer thickness, roughness length and displacement height, and the disposition of snow-capped runoff are also incorporated. The new model exhibits higher snow cover, cooler soil temperatures in organic-rich soils, greater global river discharge, and lower albedos over forests and grasslands, all of which are improvements compared to CLM3.5. When CLM4 is run with CN, the mean biogeophysical simulation is degraded because the vegetation structure is prognostic rather than prescribed, though running in this mode also allows more complex terrestrial interactions with climate and climate change.
1,295 citations
DOI•
01 Jan 2013
858 citations
Cites background from "Thermal Conductivity of Rocks and M..."
...3 bedrock λ = W m -1 K is the thermal conductivity assumed for the deep ground layers (typical of saturated granitic rock; Clauser and Huenges, 1995)....
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TL;DR: Permafrost degradation in steep bedrock can be strongly affected by percolating water in fractures and can lead to quick and deep development of thaw corridors along permafrost and potentially destabilize much greater volumes of rock than conduction would as discussed by the authors.
Abstract: Permafrost in steep bedrock is abundant in many cold-mountain areas, and its degradation can cause slope instability that is unexpected and unprecedented in location, magnitude, frequency, and timing. These phenomena bear consequences for the understanding of landscape evolution, natural hazards, and the safe and sustainable
operation of high-mountain infrastructure. Permafrost in steep bedrock is an emerging field of research. Knowledge of rock temperatures, ice content, mechanisms of degradation, and the processes that link warming and destabilization is often fragmental.
In this article we provide a review and discussion of existing literature and pinpoint important questions. Ice-filled joints are common in bedrock permafrost and possibly actively widened by ice segregation. Broad evidence of destabilization by warming permafrost exists despite problems of attributing individual events to this phenomenon
with certainty. Convex topography such as ridges, spurs, and peaks is often subject to faster and deeper thaw than other areas. Permafrost degradation in steep bedrock can be
strongly affected by percolating water in fractures. This degradation by advection is difficult to predict and can lead to quick and deepdevelopment of thaw corridors along
fractures in permafrost and potentially destabilize much greater volumes of rock than conduction would. Although most research on steep bedrock permafrost originates from the Alps, it will likely gain importance in other geographic regions with mountain permafrost.
557 citations
TL;DR: In this paper, the authors numerically modeled this parodoxically interesting geological phenomenon, in which rising diapiric structures, colder than the asthenosphere by 300-400°C, are driven upward by compositional buoyancy, with a high-resolution two-dimensional regional model.
505 citations
TL;DR: In this article, a 2D thermal-mechanical code incorporating both a Lagrangian marker-in-cell method and conservative finite-difference (FD) schemes was designed for the accurate portrayal of very fine thermal structures.
455 citations
References
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Book•
01 Jan 1986
TL;DR: In this paper, the authors consider the thermal properties of harmonic lattice vibrations in real crystals and atomic vibrations in defect lattices, as well as the properties of anisotropic and polycrystalline materials.
Abstract: Preface. Chapter 1. Bonding characteristics. 2. Crystal defects. 3. Elasticity. Basic relations. 4. What values do the elastic constants take? 5. Sound waves. 6. The phonon spectrum. 7. Thermal properties of harmonic lattice vibrations. 8. Phonons in real crystals: anharmonic effects. 9. Atomic vibrations in defect lattices. 10. Thermodynamic properties of conduction electrons. 11. Thermal properties of few-level systems and spin waves. 12. Melting and liquids. 13. Equation of state and thermal expansion: macroscopic relations. 14. Thermal expansion: microscopic aspects. 15. Electrical conductivity of metals and alloys. 16. Thermal conductivity. 17. Transport, elastic and thermal expansion parameters of composite materials. 18. Anisotropic and polycrystalline materials. 19. Estimations and correlations. Appendices. Author index. Subject index. Materials index.
1,114 citations
TL;DR: In this paper, the problem of determining the effective thermal conductivity of a two-phase system, given the conductivities and volume fractions of the components, is examined, and an equation based on a three-element resistor model is proposed.
Abstract: The problem of determining the effective thermal conductivity of a two‐phase system, given the conductivities and volume fractions of the components, is examined. Equations are described which have been proposed as solutions to this problem, including those of Maxwell, de Vries, and Kunii and Smith, the weighted geometric mean equation, and an equation based on a three‐element resistor model found applicable to the analogous electrical conductivity problem. Experimental results are presented for five unconsolidated samples: three quartz sand packs, a glass bead pack, and a lead shot pack. The method of conductivity measurement using the transient line heat source (thermal conductivity probe) is described. Data are reported showing the variation of effective thermal conductivity with porosity, solid particle conductivity, saturating fluid conductivity, and the pressure of the saturating gas. From considerations based on the kinetic theory of gases, it is shown that the characteristic dimension of the pore ...
818 citations
TL;DR: In this paper, a Rayleigh-Darcy modeling of a uniformly permeable, crustal slab is used to show that convective instability of metamorphic fluid is expected at the permeabilities suggested for the high Pf conditions, and that large scale convective cells operating in overpressured, but capped systems may provide a satisfactory explanation for the large fluid/rock ratios and extensive mass transport demonstrated for many low and medium-grade metamorphin-ments.
Abstract: Evidence from rock microstructures, mass transfer and isotopic exchange indicates that substantial quantities of aqueous fluids are involved in low- and medium-grade regional metamorphism. Similar conclusions are drawn from many retrograde environments, whereas high-grade metamorphic fluids may be melt dominated. The mobile fluids play essential roles in metamorphic reactions, mass transport and deformation processes. These processes are linked by the mechanical consequences of meta- morphic fluid pressures (Pr) generally being greater than or equal to the minimum principal compressive stress. Under such conditions meta- morphic porosity comprises grain boundary tubules and bubbles together with continuously generated (and healed) microfractures. Deform- ation results in significant interconnected porosity and hence enhanced permeability. Lithologically and structurally controlled perme- ability variations may cause effective fluid channelling. Simple Rayleigh-Darcy modelling of a uniformly permeable, crustal slab shows that convective instability of metamorphic fluid is expected at the permeabilities suggested for the high Pf metamorphic conditions. Complex, large- scale convective cells operating in overpressured, but capped systems may provide a satisfactory explanation for the large fluid/rock ratios and extensive mass transport demonstrated for many low- and medium-grade metamorphic environ- ments. Such large-scale fluid circulation may have important consequences for heat transfer in and the thermal evolution of metamorphic
518 citations
TL;DR: The thermal conductivities /K/ of rock forming minerals reveal K as linear function of density for constant mean atomic weight as discussed by the authors, where k is the number of atoms in a given sample.
Abstract: Thermal conductivities /K/ of rock forming minerals reveals K as linear function of density for constant mean atomic weight
494 citations
438 citations