Constraining the interplay of magmatic and hydrothermal processes during ore formation with numerical models

Magmatic-hydrothermal ore deposits form our largest resources of Cu, Mo, Sn and W and are formed by fluids released from magmatic intrusions into a hydrothermal system within the country rock. The potential to form world-class deposits critically depends on cross-boundary fluid fluxes at this magmatic-hydrothermal interface, which is one of the key unknowns in our current understanding of these deposits. Capturing the dynamics of these interface processes with numerical models requires to resolve mass and energy fluxes as a continuum that extends beyond the roots of hydrothermal systems and bridges the gaps between fluid flow and magma dynamics. Magma is mobile during intrusion events and can convect until it reaches a crystal lockup due to cooling and crystallization. During this process, the magma reservoir reaches fluid saturation and exsolves metal-bearing magmatic volatiles to the host rock. This magma solidification behavior depends on its chemical composition, which can be constrained by geochemical analyses of field samples. We have developed a consistent formulation for fluid generation and transport in a coupled model for viscous flow according to the Navier-Stokes Equations and porous flow with Darcy’s Law. Our simulation results suggest that the interplay of magma emplacement, magma convection and fluid release during crystallization exerts a strong control on the ore-forming potential. This contribution will present preliminary results from our coupled magmatic-hydrothermal model.