C09 - Dynamics of rock dehydration on multiple scales
Head(s): Prof. Dr. Timm John (FU Berlin), Dr. Marita Thomas (FU Berlin)
Project member(s): Konstantin Huber, Lisa Kaatz, Dr. Johannes Vrijmoed, Andrea Zafferi (WIAS)
Participating institution(s): FU Berlin
This project seeks to understand the dynamic formation of dehydration-induced fluid flow structures in rocks. The goal is to investigate their initial growth by fluid release during dehydration reactions, the intermediate stages of fluid pooling and vein network formation, and the final stages of fluid release from the dehydrating system. In the current funding phase, we are concerned with the development of a continuum mechanical multiphysics porous media model that includes all relevant quantities and processes. Special attention is given to the modeling of reactive flow considering the chemical composition of the fluid phase, to the transport of chemical species with the fluid, and to the mechanics of the solid rock matrix including crack propagation.
In the next phase, we pursue two objectives: First, building on our results from phase 2, to rigorously verify this porous media model by upscaling of a suitable grain-scale fluid-structure interaction model by means of mathematical homogenization. Second, to extend the porous media model with regard to mechanical and chemical effects relevant on km-scales. The latter goal is motivated by the observation that slab dehydration causes two characteristic features of
subduction zones. The first is related to reactive flow leading to mobilization and transport of elements, resulting in the characteristic global chemical signature of arc volcanism, while the second is related to hydraulic fracturing, which often leads to seismicity. We aim to investigate the mechanisms behind fluid channeling that control the occurrence of these two features. This will be done via mathematical analysis, numerical experiments, and subsequent comparison of the simulations with field observations.