Porphyry metallogenic system of Geza arc in the Sanjiang region, southwestern China
西南“三江”格咱岛弧斑岩成矿系统

Gaza arc is an important tectonic unit formed by evolution of Tethys in the Sanjiang region, Southwest China. The island arc has complex tectonic structures, strong magmatisms, active ore forming fluids, complicated and multiple metallogenics which formed a number of large-super large scale deposits with complete deposit types. Pervasive traces of multi-episode tectonic-magmatic-hydrothermal activities make the island arc a natural laboratory for studies of tectonic evolution and multi-episode metallogenics since Tethys period in the Sanjiang region. Based on discoveries of large-super large scale deposits in this area and achievements on systematic studies of magmatisms and metallogenics since Indosinian, the authors divided the Gaza island arc metallogenics into three metallogenic systems based on three-stage magmatisms: Indosinian porphyry Cu-polymetallic metallogenic system, Yanshanian porphyry Mo-Cu-polymetallic metallogenic system and Himalayan alkali-rich porphyry Au-Mo-Cu polymetallic metallogenic system. This paper discussed and concluded the mineralization ages, source of ore-forming materials, ore-forming fluid systems and metallogenic dynamics backgrounds of the three-stage porphyry metallogenic systems of Gaza island metallogenic system.