青茶馆-元宝山花岗斑岩具有高硅、富铝、稀土元素含量较高、相对富集轻稀土元素、亏损重稀土元素的特征,负Eu异常明显,稀土元素配分图解具有右倾"V"字形的特征,并相对富集大离子亲石元素.锆石具有典型的岩浆振荡生长环带和较高的Th/U值(0.49~1.07),反映了岩浆成因特征.测得LA-ICP-MS锆石U-Pb年龄为116.8±1.5Ma(n=13,MSWD=1.13).以上特征表明,青茶馆-元宝山花岗斑岩为高钾钙碱性高分异I型花岗岩,为后造山花岗岩,其形成可能与古太平洋板块俯冲作用有关.%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 char?acterized 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 mag?matic 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.
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