Thermal Transport Properties of Earth Materials

Thermal transport in Earth materials underpins our understanding of planetary heat budgets, mantle convection and lithospheric stability. Two fundamental parameters govern this process: thermal conductivity, which quantifies the rate of heat flow through a material under a temperature gradient, and thermal diffusivity, which describes the speed at which a temperature perturbation spreads. In crystalline minerals, lattice vibrations dominate heat transport, but point defects, grain boundaries and fluid inclusions introduce scattering that reduces both conductivity and diffusivity. Temperature and pressure exert opposing influences: rising temperature generally enhances phonon scattering and lowers transport coefficients, while increasing pressure tends to stiffen lattices and raise conductivity. Composition and crystal structure further modulate these trends; for example, iron substitution in silicates can lead to pronounced declines in thermal transport. At the rock scale, advection of fluids, pore connectivity and anisotropy arising from preferred mineral orientation may enhance or impede heat transfer. Experimental advances—such as laser-flash methods, transient plane-source techniques and in situ high-pressure cells—have refined our capacity to measure transport properties from cold crustal conditions to deep‐mantle environments. These data feed inversions of geophysical observations to constrain subsurface temperature profiles and drive models of mantle circulation, melt generation and continental evolution. On a practical level, accurate transport parameters inform geothermal resource assessment, geothermal reservoir engineering and the appraisal of heat-driven processes at plate boundaries. Together, laboratory measurements, petrophysical modelling and geodynamic simulations assemble a coherent picture of how Earth materials conduct and diffuse heat, connecting mineral-scale physics to global thermal regimes.

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Thermal Transport Properties of Earth Materials publication trend

The graph below shows the total number of articles in thermal transport properties of earth materials across all publications each year (not limited to Nature Index journals).

Technical terms

Thermal conductivity: The rate at which heat passes through a material under a given temperature gradient.

Thermal diffusivity: The speed at which a temperature disturbance propagates through a material, defined as conductivity divided by volumetric heat capacity.

Anisotropy: Variation of a physical property, such as thermal diffusivity, depending on crystallographic direction.

Phase transition: A change in crystal structure or state (e.g. α- to β-quartz) that alters thermal transport mechanisms.

Geotherm: The temperature profile of Earth’s interior as a function of depth, informed by transport properties and heat sources.

References

1. Effect of Iron Content on the Thermal Conductivity and Thermal Diffusivity of Orthopyroxene. Geochemistry Geophysics Geosystems (2024).
2. Anisotropic thermal transport properties of quartz: from -120 ∘C through the α–β phase transition. European Journal of Mineralogy (2021).
3. Lower mantle geotherms, flux, and power from incorporating new experimental and theoretical constraints on heat transport properties in an inverse model. European Journal of Mineralogy (2022).