Impact of Channeling on Fluid Mass Transport by Porosity Waves

Fluid migration across the lithosphere and mantle, involving aqueous fluids and melts, is crucial to geodynamic processes, including intra-plate volcanism and lithospheric metasomatism. In regions dominated by viscous deformation, porosity waves are a potential mechanism for fluid mass transport. For a constant compaction viscosity, porosity waves initiated by circular perturbations maintain a “blob-like” geometry. However, under decompaction weakening, where compaction viscosity decreases during dilation, these waves adopt a “channel-like” geometry, even when initiated with circular perturbations. While prior numerical studies established that blob-like porosity waves efficiently transport fluid mass, the efficiency of channel-like waves remains unclear. To address this, we present two-dimensional numerical simulations comparing fluid mass transport in blob-like and channel-like porosity waves. Our numerical model integrates tracer transport with varying distribution coefficients to quantify differences in transport efficiency. Preliminary results show that channel-like porosity waves significantly outperform blob-like waves in fluid mass transport. Furthermore, we apply our model to investigate lithospheric metasomatism driven by fluid migration, shedding light on processes underlying intra-plate volcanism, such as petit-spot volcanism.