Criteria for Recognit

Rifting and Extension - CriticalVMS deposits form during episodic rifting ofoceanic and continental volcanic arcs, forearcs and in back-arc extensional regimesLong lived extension - crustal thinning– rifting– high heat flow- and extensive verticalpermeability (faults) are key to developingand sustaining ore forming VMShydrothermal systems – must be at shallowcrustal level (>10Km)Return to compressive environment results inuplift, a return to arc volcanism and potentialto form Epithermal and or Porphyry depositsSuperposition of ore deposit types andvolcanic products….(Allen et al., 2002)