Thermal Convection Dynamics in Planetary Lithospheres

Thermal convection within planetary lithospheres governs the transfer of internal heat from a planet’s mantle to its surface and is fundamental to the evolution of tectonic regimes, magmatic activity and surface morphology. In rocky bodies such as Earth, Mars and Venus, heat generated by radioactive decay and primordial sources drives fluid-like mantle motions beneath the rigid lithospheric shell. Variations in temperature, pressure and composition give rise to strong viscosity contrasts that shape convective patterns, control the formation and mobility of tectonic plates, and influence the onset of subduction or stagnant lid regimes. Advances in numerical modelling have revealed that the geometry of computational domains, the parameterisation of temperature-dependent rheologies and the interplay between internal and basal heating critically affect predictions of cell scale, time-dependent behaviour and heat flux.

Planetary lithospheric convection not only determines long-term thermal evolution but also underpins magnetic field generation, crustal production and volatile cycling. In the context of exoplanets, understanding how convection scales with planetary mass, composition and heat production offers insight into potential habitability, surface renewal processes and tectonic modes beyond the Solar System. Empirical constraints from seismic imaging, gravity anomalies and surface geology provide benchmarks for simulations, while laboratory analogues and fluid-mechanical experiments help to validate theoretical scaling laws. Despite considerable progress, reconciling two-dimensional models with fully three-dimensional spherical shells remains a challenge, and quantifying the role of rheological complexity in subduction initiation demands further study.

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Thermal Convection Dynamics in Planetary Lithospheres publication trend

The graph below shows the total number of articles in thermal convection dynamics in planetary lithospheres across all publications each year (not limited to Nature Index journals).

Technical terms

Rayleigh number: Dimensionless measure of buoyancy-driven flow strength; higher values indicate vigorous convection.

Prandtl number: Ratio of momentum diffusivity to thermal diffusivity, governing the relative thickness of velocity and thermal boundary layers.

Nusselt number: Dimensionless ratio of total heat transport to conductive heat transport, used to quantify convective efficiency.

Rheology: Study of flow and deformation of mantle materials, often described by temperature- and pressure-dependent viscosity laws.

Lithosphere: Outermost rigid shell of a planet, comprising the crust and uppermost mantle, which responds elastically to stress over short timescales.

References

1. Assessing the Accuracy of 2‐D Planetary Evolution Models Against the 3‐D Sphere. Geochemistry Geophysics Geosystems (2024).
2. Horizontal length of finite-amplitude thermal convection cells with temperature-dependent viscosity. Physics of The Earth and Planetary Interiors (2023).
3. The fate of particles in a volumetrically heated convective fluid at high Prandtl number. Journal of Fluid Mechanics (2021).