Zircon U-Pb geochronology and geological implication of Early Jurassic ore-bearing porphyry from the Tangbai area on the southern margin of Gangdise, Tibet

The Tangbai ore district, located in the western segment of the Gangdise porphyry copper belt. Its south margin is Xigaze forearc basin. The surface exploration engineering of the mining area revealed that there are three orebodies (No.1, 2 and 3) in Early Jurassic hornblende quartz diorite porphyry. On the basis of field geological investigation, the authors carried out zircon LA-ICPMS U-Pb dating and whole-rock geochemical testing of Early Jurassic hornblende quartz diorite porphyry. The results of the study are as follows. The age of ore-bearing porphyry is 183.3±1.2Ma, suggesting Early Jurassic; geochemical characteristics of ore-bearing porphyry are similar to those of andesite from the oceanic island arc setting, indicating that ore-bearing porphyry in Tangbai area was formed in the oceanic island arc setting, and the Gangdise porphyry copper belt has huge potential in the search for porphyry deposits of subduction period. It is therefore held that in the future work emphasis should be placed on the subduction stage porphyry deposit exploration and evaluation, especially on the Early-Middle Jurassic porphyry metallogenic potential evaluation.