• 责任者：Li Weikai (State Key Laboratory of Geological Processes and Mineral Resources ; China University of Geosciences ; Beijing 100083 ; China) ; Xie Jincheng
• 刊名：Acta Petrologica Sinica
• 出版年：2013
• 卷期：29(11)
• 关键词：花岗岩 ; granite ; 岩石地球化学 ; lithogeochemistry ; 西藏 ; Tibet
• 页码：p.3745-3754
• 图表：6 illus., 3 tables, 33 refs.
• 分类号：0801
• issnNo：ISSN1000-0569
• isbnNo：CN11-1922/P

     Bomi granitoids in the southeast of Tibet located between Bangong Co-Nujiang suture zone and Yaluzangbujiang suture zone. Bomi granitoids are distributed in the north-west direction, with area of 29km2. Based on the petrological, geochemical and isotopic studies, Bomi granitoids are lithologically dominated by biotite granodiorite and biotite quartz diorite, LA-ICP-MS zircon U-Pb data for two samples of granodiorite give the ages of 113.1 ±2. 3Ma and 113.4 ±2. 1Ma respectively. The chemical analyses show that SiO2 varies from 64. 11% - 66. 63% for the granitoids. The total alkali contents are high in the granitoids （K20 ＋ Na20 = 6. 36% - 7.54% ）. The REE pattern is flat and slightly declining without clearly Eu anomaly with the total content of 114. 9 × 10 -6 - 182. 8 × 10-6 in the granitoids. In addition, A/CNK varies from 0. 80 -0. 95. The rocks are enriched in silica and alkali, but the content of phosphorus is low. Bomi granitoids are petrochemically rich in large-ion incompatible elements （Rb, K） and depleted in high field strength elements （Nb, Ta, P, Ti）, and show essential characteristics of arc magmatism. The rocks belong to medium-high K calc- alkaline I-type granite. 37 analyses from 2 samples give a wide range zircon 8,f （t） values （ - 13.72 - -0. 08） and Hf-isotope crustal model ages （891 - 2047Ma）. It shows that the Bomi granitoids are probably being derived from ancient anomaly crustal materials. The characteristics of petrological, geochemical and isotopic data are similar to middle Gangdese and Gangdese Retroarc Uplift Belt （GRUB）. Therefore, it was concerned that Bomi granitoids are related to the zonal magmatic flare-up of middle Gangdese at Early Cretaceous.