• 责任者：Wang Juli (State Key Laboratory of Continental Dynamics ; Department of Geology ; Northwest University ; Xi’an 710069 ; China) ; Yang Meng
• 刊名：Acta Geoscientica Sinica
• 出版年：2013
• 卷期：34(6)
• 关键词：花岗闪长斑岩 ; granodiorite porphyry ; 岩石地球化学 ; lithogeochemistry ; 铀—铅计时 ; U-Pb dating ; 新疆 ; Xinjiang
• 页码：p.680-690
• 图表：6 illus., 3 tables, 32 refs.
• 分类号：0801
• issnNo：ISSN1006-3021
• isbnNo：CN11-3474/P

     The East Gurenggesala granitic intrusion in Gulungou area on the northern margin of Middle Tianshan Mountains consist of granodiorite-porphyry with porphyry copper mineralization. The intrusion is characterized by enrichment of alkali, with Na20/KeO ratio changing from 1.95 to 19.00, and depletion of Fe and Mg, accompanied by sub-alkaline （mainly tholeiitic and calc-alkaline series） and weakly peraluminous features （A/CNK=0.98-1.11）. REE concentrations are low （∑REE=61.28×106-99.50× 10-6） and show obvious differentiation between LREE and HREE （LaN/YbN=7.82--22.80）, with weak Eu negative anomalies （δEu=0.72-0.97）. In addition, the rock mass is relatively rich in such elements as Rb, Ba, Th, U and K, and poor in Nb, Ta, P, Ti etc., suggesting characteristics of volcanic-arc granite （VAG）. Zircon LA-ICP-MS U-Pb dating results show that the crystallization of the intrusion took place from （488.9±1.7） Ma to （470.5±3,1） Ma, i.e., in Early Ordovician. Sr-Nd isotopic compositions of East Gurenggesala granitic intrusion are fairly uniform： （87Sr/86Sr）i=0.70677-0.70685, esr（t）=40.10-41.21, （143Nd/X44Nd）i=0.51190-0.51191, eNd（t）=-2.62 - -2.30, tDM=l.31-1.38 Ga, implying that magma originated from partial melting of Meso-Proterozoic mantle-derived basic lower crust. Based on both previous and present research results, the authors have reached the conslusion that East Gurenggesala graniticintrusion was formed Yili-Central Tianshan in the epicontinental arc relevant to the subduction of the paleo-Junggar ocean towards plate in Early Ordovician together with porphyry copper mineralization. In general, the emplacement of East Gurenggesala granitic intrusion marked the epoch when the northern margin of Middle Tianshan entered into the stage of active epieontinental arc in connection with subduction in Early Ordovician.