The authors present detailed petrographic observations of primary igneous features,  combined with silicate-melt and fluid inclusion studies, and find physical models of exsolution. Metallic elements are preferentially partitioned into the associated magmatic volatile phase. As the volatile concentration increases, the vapor pressure leads to sudden failure of the carapace and adjacent wall rock-this occurs once the vapor pressure is greater than the confining pressure. Magmatic fluids escape as the cracking of the wall rock continues; these fluids then hydrothermally alter the rock which they pass through. At the same time, caused by the rapid decreasing pressure, the hypersaline fluid boils again. This causes Cu-Mo sulfides to deposit from the fluid.