• 责任者：Li Hongyan (State Key Laboratory of Isotope Geochemistry ; Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Huang Xiaolong
• 刊名：Acta Petrologica Sinica
• 出版年：2013
• 卷期：29(10)
• 关键词：玄武岩 ; basalts ; 岩石地球化学 ; lithogeochemistry ; 塔里木盆地 ; Tarim Basin
• 页码：p.3353-3368
• 图表：10 illus., 3 tables, 51 refs.
• 分类号：0801
• issnNo：ISSN1000-0569
• isbnNo：CN11-1922/P

     The Early Permian basahs of the Qipan Formation in the Qimugan section are important magmatism belonging to the southwestern part of Tarim Large Igneous Province. Based on the detrital zircon U-Pb dating on the underlying and overlying sandstones, it is suggested that the Qimugan basalts erupted at ca. 284Ma, which is contemporary with the basahs of the Kaipaizileke Formation in the Keping area. The Qimugan basahs have wide range of major and compatible trace element concentration, indicating extensive fractional crystallization of olivine, clinopyroxne and feldspar. The Qimugan basahs are enriched in Th, U and LREE, with weak to moderate negative Eu anomaly （ Eu/Eu= 0. 82 ～ 0. 99） on the chondrite-normalized REE patterns and negative Nb and Ta anomalies on the primitive mantle-normalized trace elements diagram. They have negative εNd （t） （ -4. 8 ～ -3.9） and εhf （t） values （ -2. 4 ～ - 1.6） and high initial s7 Sr/SS Sr ratios （0. 7078 ～0. 7086） with decoupled Hf-Nd isotopes, suggesting an enriched mantle source containing pelagic sediments which were probably introduced during assembly of the Rodinia supercontinent. Overall, the Qimugan basahs are geochemically identical with the basahs of the Kaipaizileke Formation in the Keping area, but have more enriched Sr-Nd-Hf isotopic compositions. Thus there is a stronger mantle metasomatism by pelagic sediments beneath the marginal area than the interior of the Tarim Block.