Age and Geological Implications of Shasongwula Rapakivi Granite in East Kunlun Mountains

Shasongwula rapakivi granite, located in the South Kunlun suture belt, belongs to a part of Qinling-Kunlun orogenic belt. This rapakivi granite consists of porphyritic granodiorite, granodiorite, rapakivi granite, with special rapakivi texture. The U-Pb isotopic dating of porphyritic granodiorite and rapakivi granite has been carried out, the obtained zircon U-Pb ages are (440.6±1.1)Ma and (437±1.2)Ma respectively, which belong to the Early Silurian. Based on its geological characteristics and geochemical data, the Shasongwula rapakivi granite has been considered as a product of the collision orogenic stage and was formed by the partial melting of thickened orogenic crust through combining with the data regional tectonic environment. The dating of Shasongwula rapakivi granite has confirmed the existence of Caledonian granitic magma activity in South Kunlun suture belt, and has revealed the existence of Caledonian orogenic type rapakivi granite in this studying area. Thus, this study has a great significance to recognize the tectonic evolution haracteristics and composition of South Kunlun suture belt.