Formation of massive sulfide ore deposits on the seafloor-constraints from numerical heat and fluid flow modeling

Numerical simulations of seafloor hydrothermal systems based on the Lau back-arc basin were carried out to investigate conditions that lead to the formation of economic massive sulfide ore deposits in seafloor environments. Fluid discharge behavior, fluid exit temperatures and fluid velocities depend primarily on rock and fault properties and to a lesser degree on fault distribution and surface/basement topography. Ideal conditions promoting vigorous hydrothermal convection and effective leaching of base metals are found in highly permeable fresh rocks with an effective fault system. High-temperature (350-400 °C), high-velocity (>5 × 10^-7 m/s) hydrothermal fluids capable of forming significant massive sulfide ore bodies occur near topographic highs on the flanks of the basin structure and significant base metal ore bodies (>1 Mt ore-grade material) can be formed in 700-3000 years with fluids containing 10 ppm combined base metals and a 10% deposition efficiency.