Figure 7
From: Formation of giant iron oxide-copper-gold deposits by superimposed episodic hydrothermal pulses
Schematic model for the Candelaria IOCG district. (A) Slow cooling of a dioritic intrusion and separation of a fluid phase, coalescence of the fluid phase, and encapsulation of magnetite microlites to form a magnetite-fluid suspension accumulation under overpressure conditions that scavenges Fe, Cu, Au, S and Cl56,57. (B) The accumulated fluid is sporadically “tapped” by active deep crustal sinistral strike-slip faults initially associated with the formation of the sedimentary basin. Fault movement allowed the ascent of high-temperature Fe-rich fluid. (C) Further fault movement would allow the ascent a (Cu, Fe)-rich fluid, Cu increases due to increase solubility of CuCl. (D) Further fluid cooling of the ascending hydrothermal fluids by convection causes Cu precipitation. At the final stages of the hydrothermal system hydrothermal fluids would have interacted with external, basin derived fluids which would have added reduces sulfur into the system in the form of pyrite but no significant Cu mineralization20. *Depth estimated from Pollard67 for similar hydrothermal conditions.
