IGNEOUS SERIES AND EPITHERMAL PORPHYRY Cu-Au-Ag MINERALIZATION SYSTEM IN THE ZIJINGSHAN ORE FIELD,FUJIAN PROVINCE

The rocks in the Zijingshang ore field are from the surface to depth as follows: Lower Cretaceous intermediate-acid volcanic rocks, subvolcanic dacite-porphyry, hypabyssal granodiorite-porphyry and middle- and deep-level porphyritic granodiorite, forming an intermediate-acid volcanic-intrusive sequence. Strong alteration-mineralization occur around the Zijinshan volcanic edifice, forming high-sulfur epithermal Cu-Au deposits, low-sulfur epithermal Ag-Au deposits and porphyry Cu (Mo) deposits. In the ore field, various types of Cu-Au-Ag deposit have close temporal-spatial and material source relations. They evolved continuously in terms of time and space and are products of consanguineous ore-bearing intermediate-acid magmas in the same background of mineralization but in different stages of evolution. The occurrence of different types of ore deposit in diverse geological positions depended on the physico-chemical properties and temporal-spatial migration of ore fluids, thus forming an epithermal porphyry Cu-Au-Ag mineralization system related to intermediate-acid subvolcanic rocks and porphyry.