Abstract:

We reviewed the characteristics of ore forming fluids of quartzvein tungsten deposits associated with S type granites and porphyry copper deposits associated with Itype (some associated with Atype) granitic rocks.  The two fluid systems are similar in that both of them are derived from magmatic evolution, with involvement of meteoric water in the late stage. On the other hand, they are different in the following  aspects: (1) the ore forming fluids of quartzvein tungsten deposits belong to the H2ONaCl±CO2 system with moderatehigh temperature and moderatelow salinity, whereas those associated with porphyry copper deposits belong to the H2ONaClKCl±CO2 system with high temperature and high salinity; (2) boiling and phaseseparation are common in porphyry copper deposits and may have played important roles for the transport and deposition of Cu, but are uncommon in quartzvein tungsten deposits, in which fluid mixing may have played a more important role; (3) W is more associated with O and Na in fluid systems while Cu is with Cl and S, so the formation and the type of deposits depend in part on availability of these elements in the fluids.

Key words:  granitic rocks, ore forming fluids, porphyry copper deposits, quartzvein tungsten deposits