Porphyry deposits

  • Bulk tonnage low grade metal
  • Intrusion rocks with porphyritic texture
  • Quartz-sulphide stockwork (sheeted) veins
  • Characteristic alteration & mineralisation zoned in time and space

Porphyry localisation

  • Subduction-related magmatic arcs
  • Root zones of andesitic stratovolcanoes
  • Dilatant sites on major structures
    • Arc parallel structures including sutures
    • Transfer structures
    • Conjugate fractures
  • Change of convergence as a trigger
  • Space problem