LA-ICP-MS zircon U-Pb ages of two types of ore-bearing dykes in the Tuokuzibayi gold ore district in Habahe area of Xinjiang and their geological significance

The Tuokuzibayi orogenic-type gold ore belt was formed by multi-stage evolution, which included complete forearc-arc-backarc system, collisional orogeny and post-collisional extensional tectonic activities. The Tuokuzibayi dykes include two intrusive phases, i.e., the granite-porphyry dyke phase and the diorite dyke phase, both of which are associated with Au mineralization. LA-ICP-MS U-Pb zircon analyses suggest that the granite-porphyry dykes were formed at 384.1±1.5 Ma and 384.7±1.2 Ma, suggesting their generation in a Middle Devonian fore-arc basin setting, whereas the diorite dyke was formed at 295.3±3.0 Ma, implying its generation in a post-collisional extensional setting. The emplacement of these two types of dykes that respectively represented a gold mineralization stage commonly inherited the previous tectonic position and later strong ductile shearing position.