• 责任者：Xie Hongjing (Beijing Institute of Geology for Mineral Resources ; Beijing 100012 ; China) ; Wu Guang
• 刊名：Chinese Journal of Geology
• 出版年：2013
• 卷期：48(3)
• 关键词：花岗闪长斑岩 ; granodiorite porphyry ; 花岗斑岩 ; granite porphyry ; 天山 ; Tianshan Mountains
• 页码：p.827-846
• 图表：11 illus., 4 tables, 50 refs.
• 分类号：0801
• issnNo：ISSN0563-5020
• isbnNo：CN11-1937/P

     The Lailisigaoer intrusion, located in northwestern Tien Shan, mainly consists of granodiorite porphyry and monzogranite porphyry which share the similar geochemistry characteristics and may be derived from the same source. The zircon Sensitive High-Resolution Ion Microprobe （SHRIMP）U-Pb analyses of the granodiorite porphyry yielded a weighted mean age of 374 ＋ 4 Ma, indicating that the intrusion emplaced during the Late Devonian. The Lailisigaoer intrusion has high SiO2 contents （67.75 % - 74.71% ） and K20/Na20 ratios （ 1.24 -2.20 ）and all the rocks show a high-K ealc-alkaline trend. Chondrite-normalized REE patterns are moderately fraetionated （ La/Yb ） N ： （ 5.25 - 10.57 ）. They display moderate to weak negative Eu anomalies 8Eu ： （ 0.55 - 0.92 ） , with enrichment of LILE and depletion of HFSE. The rocks show low Sr（ 122×10-6-356×10-6） contents and high Y（ 17.19×10-6 - 21.82×10-6 ） and Yb（ 1.78×10-6 - 2.57×10-6） contents. Initial Nd-Sr isotopic compositions for the rocks are /St=0. 707 867 ～0. 709 654 and 8Nd（t）= --2. 79  ～-1. 46. The Pb isotopic ratios for the intrusion are 206Pb/204pb = 18.423 ～ 19.915,207Pb/204Pb = 15. 576 - 15.685 and 208Pb/204Pb = 38. 344 ～ 39.305. All the geochemical data, in conjunction with the geodynamie evidence, suggest that the Lailisigaoer intrusion was most likely generated by partial melting of the Mesoproterozoic crust and the involvement of some mantle components. We propose that the Lailisigaoer intrusion was emplaeed in a continental are setting with southward steep subduction of the Junggar ocean to the Yili-central Tien Shan microplate during the Late Devonian.