Batholith-volcano coupling in the metallogeny of porphyry copper deposits.

Abstract

The interior of a batholith is gravitationally unstable with respect to the more rapidly cooling upper part in contact with the country rock. The interior becomes buoyant and intrudes the upper part forming a broad dome intruded by later domes. Large-scale hydrothermal fluid transfer occurs, dominated by volcanic orifices constituting 'artesian vents'. These have isotopically dated lifetimes equal to those of stratovolcanoes, i.e. < approx 2.5 m.y. Ore components from the batholith and the country rock are distributed and precipitated in the variety of forms seen in porphyry systems.-R.E.S.