Carrying the Planet on their Backs: How Minerals Respond to Stress

Far from being passive building blocks, minerals govern how Earth evolves and deforms, from seismic wave propagation to rock deformation and plate motion. This article explores how pressure builds within Earth and how minerals’ elastic response to compression and seismic waves reveals its internal structure. At higher stresses, beyond their elastic limit, deformation in minerals becomes permanent through crystal plasticity created by crystal defects and strongly enhanced by temperature. Over geological time scales, aggregates of crystals behave effectively as highly viscous fluids, enabling mantle convection and plate dynamics. Understanding Earth’s large-scale behavior therefore requires linking rock rheology to the mechanics of minerals down to crystal defects. By integrating observations, experiments, and models, we uncover the hidden rules connecting atomic interactions to planetary dynamics.