Modelling of zinc mobilization by magmatic-hydrothermal circulation in the sub-seafloor

Abstract

We present simulations of hydrothermal circulation triggered by the emplacement of magmatic intrusions in the sub-seafloor, we aim to understand and evaluate the processes controlling metal leaching from the host rock and transport to the seafloor. The simulations are conducted using a transport simulator allowing us to explicitly represent magmatic intrusions up to temperatures of 1000 degrees C. We use water-NaCl as a proxy for the fluid chemical composition. To gain insights into metal mobilization, a basic zinc solubility model is added to the transport simulator, which considers the dissolution reactions of sphalerite. We present two sets of simulations, one with simplified setups and one with the real, albeit simplified topography of the seafloor resembling the TAG area of the mid-Atlantic oceanic ridge. The results show that the size and depth of the intrusion, as well as the depth of the seafloor, play a significant role in controlling the metal mobilization potential of hydrothermal fluxes. The simulations also highlighted the importance of understanding the complex interplay of structural and magmatic controls to better estimate the size and grades of seafloor resources.