%A Ming Tianxue, Yang Qingbiao, Li Rong, Tang Zhong, Xue Ge, Luo Jianhong, Yu Haijun, Li Yongping %T Zircon U-Pb Age and Hf Isotope Characteristics of Caledonian Pinghe Composite Granite Pluton: Its Mineralization of Granite Weathering Crust Type REE Deposit %0 Journal Article %D 2020 %J Journal of Jilin University(Earth Science Edition) %R 10.13278/j.cnki.jjuese.20190026 %P 1685-1702 %V 50 %N 6 %U {http://xuebao.jlu.edu.cn/dxb/CN/abstract/article_11212.shtml} %8 2020-11-26 %X The Caledonian Pinghe composite granite pluton is located on the western edge of Baoshan block in western Yunnan, which consists mainly of monzonitic granite and porphyritic monzonitic granite. The major elements show that the total alkali (w(K2O+Na2O)) values are 6.89% and 7.44%, the K2O/Na2O values are 1.59 and 2.65, A/CNK values are 1.58 and 1.76, and the Rittmann indexes (σ) are 1.65 and 1.73; the trace and REE elements show that these rocks are rich in large-ion lithophile elements (Rb、Th) and depleted of high field-strength elements (Ta、Nb), enriched light rare-earth elements with LREE/HREE value of 1.40 and 6.43, and low-middle Eu anomalies (δEu=0.16 and 0.75). The zircon U-Pb ages of 478-476 Ma indicate that this pluton was emplaced during the Early Ordovician. 38 analyses from the two samples provide a wide range of zircon εHf(t) values, and the corresponding Hf-isotope crustal model ages are 2.2-1.7 Ga. The geochemical characteristics show that Pinghe composite granite pluton is calc-alkaline and per-aluminous S-type granite formed in a stress relaxation stage after the tectonic collision of pan-african movement, and closely related to the process of extrusion, collision, and dissociation during the period of original Tethys geological event in western Yunnan. In Datuanshan, ferromanganese cerium oxide, a rare earth mineral, is found in Caledonian Pinghe composite granite pluton for the first time, which contributes the most to REO in the entirely weathered rock mass. The REO is generally not high, ranging from 279.05×10-6 to 791.77×10-6, overall enrichment of Y, La, Ce elements, and partial enrichment of Nd. The heavy rare earth dysprosium oxide accounts for a high proportion in all of the fully weathered rock mass, were 2.30% to 4.62%. The discovery of Datuanshan rare earth mine shows that the Caledonian granite also has a potential for the granite weathering crust type REE deposit in western Yunnan.