Zircon U-Pb ages and geochemical characteristics of the granite porphyry in Qingchaguan-Yuanbaoshan area, northern Dashitou Town, Jilin Province

The granite porphyry in Qingchaguan-Yuanbaoshan area, northern Dashitou Town, Jilin Province, is characterized by high SiO₂, rich aluminum, high rare earth elements (REE) and high large ion lithophile elements (LILE).The REE patterns are characterized by enrichment of LREEs relative to HREEs and distinct negative Eu anomalies in chondrite-normalized REE patterns, with right oblique and "V" shaped feature.The zircons from the granite porphyry show oscillatory growth zonation of typical magmatic origin and high Th/U ratios (0.47~1.07), indicating a magmatic origin for the zircons. The LA-ICP-MS dating of a zircon sample yielded U-Pb age of 116.8±1.5Ma (n=13, MSWD=1.13). These features suggest that the granite porphyry belongs to I-type granite of high potassium calc-alkaline and differentiation, being post-collisional granitoid, and its formation may be associated with the subduction of the ancient Pacific plate.