• 责任者：Tong Laixi (State Key Laboratory of Isotope Geochemistry ; Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Chen Yibing
• 刊名：Acta Petrologica Sinica
• 出版年：2013
• 卷期：29(10)
• 关键词：麻粒岩 ; granulite ; 铀—铅计时 ; U-Pb dating ; 新疆 ; Xinjiang
• 页码：p.3435-3445
• 图表：6 illus., 3 tables, 55 refs.
• 分类号：0802
• issnNo：ISSN1000-0569
• isbnNo：CN11-1922/P

     Recently we have firstly recognized an ultrahigh-temperature （UHT） metapelitic granulite from the migmatitic parneiss near Kalasu in the Chinese Altai, NW China, with an assemblage of Gt-Opx-Sil-Cd-Sp-Bt-P1-Qtz. Orthopyroxene shows a high-A1 feature, with an AL2O3 content in excess of 8. 0% , indicating that its peak metamorphism reached UHT conditions （ 〉 900℃ ）. P-T estimate results show its peak metamorphic conditions as： P =～ 8kb, T = ～ 960℃. The preliminary P-T estimate results indicate an anticlockwise P-T path with a post-peak near isobaric cooling. Through LA-ICP-MS technique, the U-Pb age dating for zircons from the UHT metapelitic granulite has been undertaken, and the age data are mainly between 260 ～ 280Ma, with an intercept at 271 ± 5Ma, sparse ages of 380 ～390Ma, and detrital ages mainly between 450 ～ 500Ma. The age data support that the UHT metamorphic event in the Ahai orogen occurred during the Permian, highly consistent with the timing of the Permian Tarim mantle plume （ ～275Ma）, and also coeval with the extensive Permian （260 ～280Ma） post-orogenic or anorogenic mafic and granitic intrusions in the region. Thus, the Permian UHT metapelitic granulite in the Ahai orogen may be closely associated with a magmatic underplating and extensional heating in the lower crust, as a result of the Permian Tarim mantle plume event, and this is also compatible with its anticlockwise P-T path.