• 责任者：Cao Jun (State Key Laboratory of Isotope Geochemistry ; Guangzhou Institute of Geochemistry ; Chinese Academy of Sciences ; Guangzhou 510640 ; China) ; Xu Yigang
• 刊名：Acta Petrologica Sinica
• 出版年：2013
• 卷期：29(10)
• 关键词：大火成岩省 ; large igneous provinces ; A型花岗岩 ; A-type granite ; 塔里木盆地 ; Tarim Basin
• 页码：p.3336-3352
• 图表：11 illus., 3 tables, 49 refs.
• 分类号：0801
• issnNo：ISSN1000-0569
• isbnNo：CN11-1922/P

     The Early Permian dioritic and granitic dikes and Halajun granitic plutons I and II from the Piqiang region in the northem Tarim Block are spatially associated with the giant Piqiang Fe-Ti-V oxide-bearing gabbroic intrusion. They are considered to be genetically related to the magma upwelling of the Tarim mantle plume. Dioritic-granitic dikes occur in the eastern, northern and southern margin of the Piqiang gabbroic intrusion, and the Halajun granitic plutons I and II mainly outcrop to the west of the intrusion. The granitic dikes have typical A-type granitic affinity. They have 64% to 74% SiO2 and 8% to 10% Na2O ＋ K2O. They are enriched in large ion lithophile elements （Rb, Th and U） and high field strength elements （Nb, Ta, Zr and Hf） , but have very negative Eu, Ba and Sr anomalies. The rocks have high （Ga/A1） x 104ratios of 2. 85 to 3.85. The dioritic dikes have 53% to 59% SiO2 and 5% to 8% Na2O ＋ K2O. They have trace element patterns similar to the granitic dikes. The Halajun granitic plntons I and II have compositions similar to the granitic dikes. They both have εNd （t） values ranging from - 2. 9 to - 0. 2, comparable to those of the Piqiang gabbroic intrusion （ εNd （t） = - 1. 1 ～ 2. 1 ）, indicating that they have been derived from the same mantle reservoir. We propose that the dioritic-granitic dikes, Halajun granitic plutons I and II were predominantly generated by the emplacement of intermediate-felsic melts from differentiation of the newly underplated mafic magma ponding at the bottom of the lower crust, and subsequent fractional crystallization and assimilation to variable extent, whereas the Piqiang gabbroic intrusion are likely the product of emplacement of mafic magma at a shallow level. Hence large volume of underplating mafic magmas is the prerequisite for the formation of the coeval mafic-uhramafic intrusion and A-type granitic plutons of the Tarim large igneous province.