Phys.org September 23, 2023
An international team of researchers (Switzerland, France, Germany) studied (de)hydration reactions where associated solid density changes were predominantly balanced by porosity changes, with solid rock deformation playing a minor role and proposed a hypothesis for three scenarios of (de)hydration front propagation and test it. The models coupled porous fluid flow, solid rock volumetric deformation, and (de)hydration reactions. Their model validated the hypothesized scenarios and showed that the change in solid density across the reaction boundary dictates whether hydration or dehydration fronts propagate. The models demonstrated that reactions could drive the propagation of (de)hydration fronts, characterized by sharp porosity fronts, into a viscous medium with zero porosity and permeability; such propagation was impossible without reactions, as porosity fronts become trapped. They applied their model to serpentinite dehydration reactions and used the results of systematic numerical simulations to derive a new equation that allowed estimating the transient, reaction-induced permeability of natural (de)hydration zones… read more. Open Access TECHNICAL ARTICLEÂ
Photographs of natural rocks showing (a) hydration and (b) dehydration features. Credit: AGU Geochemistry, Geophysics, Geosystems, 07 September 2024