中文摘要：

本文对云南富民地区晚二叠世中—基性岩体、峨眉山玄武岩进行了同位素年代学、岩石学和地球化学的研究.富民基性岩体为辉绿岩,中性岩墙为碱性二长岩.两者均富集LREE、LILE和HFSE,具有OIB的特征,以及相似的Sr-Nd同位素特征,基性岩体的（87 Sr/86 Sr）i为0.70565～0.70626,εNd（t）为0.06～＋0.49,中性岩墙的（87Sr/86 Sr）i为0.70564～0.70567,εNd（t）为-0.32～＋0.41.基性岩LA-ICPMS锆石U-Pb测年结果为257.6±2Ma,表明富民中—基性岩体形成于峨眉山大火成岩省大规模岩浆作用的末期.地球化学证据表明富民中—基性岩体是高Ti型玄武质岩浆经连续演化形成的.富民中—基性岩的原始岩浆是地幔柱在石榴子石稳定区经小程度部分熔融的产物.同位素比值与抗蚀变不相容元素比值（如Nb/U）的相关性表明,基性岩在岩浆形成过程中未遭遇地壳混染,而二长岩遭受了少量地壳混染.富民地区晚二叠世中—基性岩体,尤其是螃蟹箐二长岩的发现,证实了ELIP地区“双峰式”火山岩组合中普遍缺失的中性岩体的存在,为长英质岩体的分离结晶成因模型提供了关键证据.

英文摘要：

Geochronology, petrology and geochemistry were performed systematically on the late Permian intermediary-marie intrusions in Fumin, Yunnan province. On the basis of petrography and major elements characteristics, mafic intrusions belong to diabase in lithology （high-Ti type）, while Pangxiejing dyke is alkaline monzonlite. Both display an enrichment of LREE, LILE, HFSE, and have Ocean island basalts （OIB） features. The Sr-Nd isotopic compositions are similar, with mafic intrusions：（87 Sr/86 Sr）i为0.70565～0.70626,εNd（t）为0.06～＋0.49and intermediary intrusions： （87Sr/86 Sr）i为0.70564～0.70567,εNd（t）为-0.32～＋0.41. The result of isotope geochronology of mafic intrusions is 256.7±4.3Ma by LA-ICP- MS, which indicates that the intermediary-marie intrusions were formed in the late stage of large-scale magmatism of Emeishan large igneous province. The intermediary-mafic intrusions appear to be related to the high-Ti basaltic lavas principally by continuous evolution. The primitive magma was derived from mantle plume confined within the garnet stability field and a relatively low degree of melting. Rough correlations of isotope ratios with ratios of alteration-resistant highly incompatible elements （e. g. , Nb/U） suggest no crust contamination in the formation of mafic intrusions, while minor amounts of contamination with monzonlite dyke. The discovery of the late Permian intermediary-mafic intrusions in Fumin would shed light on the debate of the ＂Daly gap＂ in the bimodal volcanic intrusions, and provide the key evidence for the origin model of silicic magma by the differentiation of mantle-derived basaltic intrusions.