Electrical Conductivity Properties of Mantle Materials

The electrical conductivity of Earth’s mantle is a key parameter for understanding planetary dynamics, thermal structure and volatile distribution in the deep interior. Conductivity in mantle materials varies strongly with mineral composition, temperature, pressure, water content and the presence of partial melt. In peridotitic regions, conductivity anomalies often signal elevated temperatures, enhanced water solubility in nominally anhydrous minerals or small melt fractions. Across the mantle transition zone and into the lower mantle, phase transformations and mineralogical heterogeneity exert a further control on the electrical structure. Geophysical imaging techniques that exploit natural electromagnetic sources or controlled signals combine laboratory measurements with three-dimensional inversion schemes to produce conductivity profiles at scales from tens to thousands of kilometres. Such profiles inform models of mantle convection, plume dynamics and the global water cycle. In practical terms, accurate conductivity models support assessments of geomagnetically induced currents, resource exploration and hazard forecasting, as well as comparative studies of other terrestrial planets.

Research from Nature Portfolio

Seminal laboratory experiments have measured hydrogen self-diffusion in single-crystal olivine under upper-mantle pressures and temperatures, revealing highly anisotropic diffusion rates along crystallographic axes. By applying the Nernst–Einstein relation, these results have quantified the contribution of dissolved water to the electrical conductivity of olivine, demonstrating that realistic H₂O concentrations (up to a few hundred ppm) can account for high conductivity values observed in the asthenosphere. The new diffusivity constraints have refined conductivity models of the upper mantle and strengthened interpretations of conductivity anomalies in terms of water content and mineral chemistry.

Electrical Conductivity Properties of Mantle Materials publication trend

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

Technical terms

Electrical conductivity: The measure of a material’s ability to transmit electric current, governed by charge carriers such as ions, electrons or defects.

Magnetotellurics (MT): A passive geophysical method that uses natural variations in the Earth’s magnetic and electric fields to image subsurface conductivity structures.

Mantle transition zone (MTZ): The depth interval between approximately 410 km and 660 km in the mantle where mineral phase changes create seismic and conductivity discontinuities.

Nernst–Einstein relation: An equation linking the diffusion coefficient of charged species to the electrical conductivity in ionic solids.

Nominally anhydrous minerals: Minerals that contain negligible free fluid but can incorporate trace amounts of water within their crystal lattice.

Anisotropy: The directional dependence of a physical property, such as electrical conductivity or diffusion, within a crystalline material.

References

1. Unravelling the Electrical Conductivity of Earth and Planets. Surveys in Geophysics (2024).
2. Hydrogen self-diffusion in single crystal olivine and electrical conductivity of the Earth’s mantle. Scientific Reports (2017).
3. Electrical Conductivity of Mantle Transition Zone and Water Content Revealed by the Magnetic Data of China Seismo-Electromagnetic Satellite. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing (2024).
4. Probing 3-D electrical conductivity of the mantle using 6 years of Swarm, CryoSat-2 and observatory magnetic data and exploiting matrix Q-responses approach. Earth, Planets and Space (2021).