LA-ICP-MS zircon U-Pb age and petrogeochemical characteristics of Late Triassic granite porphyry in Panshuihe area, West Kunlum Mountains, Xinjiang

In order to further enrich the data of intrusive rocks in Heshibeihu-Sandaohezi area of West Kunlun Mountains and provide a chronologic restriction for the formation age of the Panshuihe antimony deposit, the authors studied geology, petrology, geochemistry and chronology of the granodiorite porphyry in Panshuihe.The LA-ICP-MS zircon U-Pb dating yielded the age of Panshuihe granodiorite porphyry of 210.9±2.8 Ma, suggesting Late Triassic.Rock geochemistry shows that the content of SiO₂ in Panshuihe granodiorite porphyry is 66.1%~72.03%, the content of total alkali (Na₂O+K₂O) is 5.95%~8.29%, and the average value is 7.10%.The feature K₂O > Na₂O shows that the rock is rich in potassium and belongs to a high potassium (calc-alkaline) rock. The total REE is relatively low, and it shows strong enrichment of light rare earth elements, slight loss of europium (Eu=0.66~0.90), relative enrichment of Rb, Th, Ta, Ce and Hf, and relative dilution of Ba, K, P and Ti.The tectonic environment classification diagram shows that the Panshuihe granodiorite porphyry was formed in the tectonic environment of syn-collision, and that the syn-collision orogeny occurred on the northwestern margin of the Songpan-Garze landmass in this area from the Late Variscan to the Indosinian period, and the north lake of Heshibeihu-Sandaohezi magmatic belt in the area was formed by this orogenesis and the transition from ocean to land.