Reactive transport model for chemically driven rock (de)hydration in the Lithosphere

Reactive fluid transport through deformable porous rocks drives key geodynamic processes, including flux melting, subduction zone dehydration, and lithospheric melt migration. These thermo-hydro-mechanical-chemical (THMC) processes involve complex couplings that remain poorly understood.

We present a THMC model and numerical algorithm for multicomponent reactive transport in deformable, two-phase porous media. The model captures heat transfer, fluid-rock reactions, viscoelastic deformation, and porosity changes driven by reactions and deformation. Thermodynamic admissibility ensures consistency across poroelastic and poroviscous regimes. Conservative discretization enables resolving sharp reaction fronts, such as magma crystallization or rock hydration.

Validation against analytical solutions highlights robustness, with applications to melting, (de)hydration in the antigorite–olivine system, and feldspar-rich reactive transport involving 5 neutral and 50 charged species. This open-access tool advances the study of  THMC processes in Earth's lithosphere.