Proterozoic Intrusive Magmatism in West Kunlun Area and Its Inspiration to Tectonic-Magmatic Evolution

According to rock types, ages and geochemical data of Proterozoic intrusive rocks, we studied the magmatic stages, petrogenesis and tectonic magmatic evolution of different structural units in West Kunlun area. Proterozoic intermediate-acid intrusive rocks in Tiekelike unit are characterized by A-type granitoids associated with partial melting of Tarim basement under low pressure and high temperature condition. While Paleoproterozoic and Early Mesoproterozoic intrusive rocks are I-type granites derived from partial melting of metabasalt in low temperature, late Mesoproterozoic and Neoproterozoic intermediate-acid rocks are dominated by A-type granitoid intrusions related to partial melting of Kunlun basement under high temperature condition. Meanwhile, Tianshuihai unit only developed Neoproterozoic S-type granites and originated from partial melting of Tianshuihai basement in low temperature and high pressure. According to magmatic evolution, Proterozoic West Kunlun area could be divided into four stages: ①2426-1567Ma: A-type granitoids in Tiekelike fault belt which formed Tarim intracontinental evolution, and calc-alkaline tholeiite I-type granitoids in Kunlun orogenic belt represent continental marginal arc; ②1 301-1 000 Ma: A-type granitoids in Tiekelike belt and Kunlun belt indicating intracontinental evolution; ③1 000-851 Ma: S-type granitoids in Tianshuihai belt indicating the collision and polymerization of Tianshuihai massif which may be a part of Rodinia supercontinent; ④815-644 Ma: bimodal magmatic rocks of alkali basic magmatite and A-type granitoids in Tiekelike belt and Kunlun belt, indicating the possibility of Tarim and West Kunlun block as components of the Rodinia and their breakup in this period. Consequently, according to the systematic analysis of Proterozoic intrusive rocks, it can be summarized that in West Kunlun area different structural units have undergone uneven crustal evolution processes.