Using LA-ICP-MS U-Pb age dating reveal that the metarhyolite of Qingbaikouan System Beisainartag Formation in Quruqtagh Xishankou area formed at 841.0±1.4Ma（MSWD=0.42）.The discovery of metarhyolite indicate there are not only exist intrusive rock but also have volcanic activity in northern Tarim at MidNeoproterozoic. The trace element analyses indicate that the metarhyolite are characterized by enrichment of LILE（Rb，Ba and K）and strong depletion of HFSE（Nb，Ta，P and Ti）.In addition，the trace element of metarhyolite display adakitic affinity，which are characaterized by enrichment of Sr， strong depletion of Yb and Y， high ratio of Sr/Y（>40） and （La/Yb）N（>40）. The Hf isotope systematic of metarhyolite show thatεHf（t）is -29～-9， two—stage Hf model agesTDM2 is 3.43～2.24Ga， integrating with the whole rock characterized by high Mg#， positive Eu anomaly and strong depletion of HFSE suggest that the rock may have originated from the partial melted thickened lower crust. By using saturated zircon thermometer，the crystallization temperature for the metarhyolite can be constrained at 761℃～768℃， it is therefore inferred that these granitoids were probably produced at relatively low temperature by fluidpresent partial melting due to influx of external fluids.Integrating with regional geology，it can be concluded that the metarhyolite formed in a ocean—continent subduction collision tectonic setting during Early—Middle Neoproterozoic.
Lü Biao,Guo Ruiqing,Wang Haipei et al. Petrogenesis and geological implication of the Qingbaikouan System Beisainartag Formation metarhyolite in Quruqtagh，Xinjiang
[J]. Chinese Journal of Geology, 2016, 51(3): 806-823.