Zircon U-Pb age of Disuga metallogenic porphyries in Geza island arc, Yunnan Province, and its geological significance

Using LA-ICP-MS zircon U-Pb dating method, the authors made geochronologic studies of the barren and ore-bearing quartz diorite porphyries in Disuga ore-forming intrusion of central Geza island arc. The age of barren quartz diorite porphyry is 203.03Ma±0.54Ma, whereas the ages of ore-bearing porphyries can be divided into two groups, i.e., 217.25Ma±0.89Ma and 208.5Ma±1.0Ma, which constrain the magmatic intrusion time to 217~203Ma; nevertheless, the hydrothermal events associated with mineralization mainly occurred in 208Ma. Studies have shown that the rock-forming and metallogenic events occurred in the late Triassic, magmatism and mineralization were basically consistent with each other，but the time of the magmatism was close to the Yanshanian movement. All these data are of very important significance in investigating the island arc magmatic evolution and rock-forming and ore-forming activities.