中文摘要：

攀西地区的太和花岗质岩体和赋存超大型钒钛磁铁矿矿床的辉长岩体在空间上共生,成因上均与峨眉山地幔柱头的上升密切相关。太和花岗质岩体主要由超碱质花岗岩和石英正长岩及少量正长岩组成;富含高场强元素并具高Ga/Al值（3.74~5.63）,显示典型A型花岗岩的特征。花岗岩、正长岩和辉长岩的Nb/Ta和Zr/Hf值与洋岛玄武岩（OIB）的相应比值近似。花岗质岩石具较低的87Sr/86Sr初始值（0.7025~0.7049）和正的εNd（t）值（1.9~3.5）,与辉长岩的值相近[（87Sr/86Sr）i=0.7049~0.7052;εNd（t）=2.4~3.3]。太和花岗质岩体的εNd（t）为正值,显示地幔柱来源的底侵玄武质岩浆对其形成起主要作用。辉长质和花岗质岩石具相似的钕同位素组成,表明其母岩浆来自于同一源区。我们认为太和花岗质侵入体主要由底侵于下地壳的玄武质岩浆分异出的花岗质熔体侵位及随后经结晶分异而形成。因此,晚古生代时幔源岩浆底侵造成的地壳增生在峨眉山大火成岩省中表现极为显著。

英文摘要：

The late Permian Taihe granitic stock in the Pan-Xi area, SW China, showing spatial association with the giant Fe-Ti-V deposit-bearing gabbroic intrusion, is genetically related to the upwelling Emeishan plume head. This granitic intrusion consists mainly of peralkaline alkali-feldspar granite and quartz syenite with subordinate syenite. These granitic rocks have a distinctive A-type chemistry characterized by elevated high-field-strength elements （HFSE） contents and high Ga/Al ratios （3.74 to 5.63）. Nb/Ta and Zr/Hf ratios of the granitic rocks and gabbros are similar to those typical of oceanic island basalt （OIB）. The granitoids have relatively low initial 87 Sr/88Sr ratios （0. 7025--0. 7049）, positive εNd（t） values （＋1. 9 to ＋3. 5）, which are comparable to those of the gabbros [（87 Sr/86 Sr）i=0. 7049--0. 7052; εNd （t） = 2. 4--3. 3]. The positive εNd （t） values of the Taihe granitic intrusion indicate a significant contribution of plume-derived basaltic underplating to magma genesis. The similarity of the Nd isotopic compositions of the gabbroic and granitic rocks suggests that their parental magmas were derived from a common reservoir. We propose that the Taihe granitic intrusion was predominantly generated by the emplacement of granitic melts from differentiation of newly underplated, basaltic magmas ponded at depth and subsequent fractional crystallization. It is therefore demonstrated that the growth of juvenile crust through mantle-derived underplating during the late Permian was significant in the inner zone of the Emeishan large igneous province.