Full 3-D numerical simulation of hydrothermal fluid flow in faulted sedimentary basins: Example of the McArthur Basin, Northern Australia

Abstract

This paper presents the first fully 3-D numerical modeling of fluid flow and heat transport in the McArthur Basin, and reveals that fluid flow tends to circulate within more permeable fault zones and form a series of planar convection cells over the fault plane rather than in less permeable host rocks. Localized, subvertical columns of enhanced permeability, related to the intersection of the primary major faults with a secondary cross fault, are essential to developing 3-D ‘mushroom-shaped’ hydrothermal convection cells that allow significant amount of fluids to circulate through the host rocks and hence leach sufficient metal content to form ore deposits. Therefore, field exploration should concentrate on defining these localized high-permeability zones. Such zones are likely to be controlled by the intersection of secondary cross faults with the main faults, the changes in fault orientation, or the intersection of the faults with a particular host rock unit.