The evolution of economic precious metal and copper-gold deposits in high-level igneous terranes is dependent on very
efficient fluid focussing. This is most readily achieved by contemporaneous deformation, igneous intrusion and
hydrothermal activity. Mineralisation in these environments generally occurs in fault and fault-vein arrays developed in the
cover sedimentary and volcanics sequences above older regional scale fault systems. Such reactivated fault systems an
particularly prone to developing the complex fracture arrays, extreme local dilation and dramatic increases in permcahilit}
that are necessary to efficiently focus hydrothermal fluid and produce large mineral deposits.