地幔柱是起源于下地幔甚至核幔边界的柱状热物质流，在大火成岩省形成、全球地幔对流和超大陆裂解中扮演着极为重要的角色。地幔柱模型很好地解释了大火成岩省岩浆在短时间内巨量喷发的特点，然而在大火成岩省岩浆活动晚期，仍有小规模基性岩浆活动并能持续很长时间。前人对于这些晚期基性岩浆的成因研究相对比较薄弱，对于晚期基性岩浆与峰期岩浆的性质差异、岩石圈地幔是否参与熔融、地幔柱扮演何种角色等问题还没有得到很好的解决。申请者初步研究表明安益岩体是峨眉山地幔柱晚期基性岩浆活动的产物，并有岩石圈物质的参与。申请者试图在预研究的基础上，对云南牟定地区的安益、二台坡等基性-超基性岩体进行精细年代学和Sr-Nd-Hf-Os-O-B同位素研究，深入探讨峨眉山地幔柱晚期基性岩浆的持续时限、地球化学特征、岩石圈地幔参与程度和熔融机制等问题。从而全面揭示峨眉山地幔柱岩浆活动不同阶段的特征，进一步完善峨眉地幔柱岩浆作用模型。

Mantle plume is a columnar hot material flow which rises from the lower mantle or even core-mantle boundary. Mantle plume plays an important role in the formation of large igneous province (LIP), whole-scale mantle convection and break-up of super-continent. LIP is characterized by outpouring of huge amount of magma over a short period, which can be best explained by the mantle plume model. While during the late period of LIP magmatism, some small-scale mafic magmatism can last for a long time. The origin of this postdated mafic magma is poorly understood. Some problems are still not resolved, such as the difference between the postdated magmatism and the peak magmatism, the contribution of lithospheric mantle and the possible role of mantle plume in generation of the postdated magmatism. My preliminary study demonstrated that the Anyi intrusion is the product of postponed mafic magmatism associated with Emeishan mantle plume, with some contributions from lithospheric mantle. On the basis of our previous study, we will do further research of geochronology and Sr-Nd-Hf-Os-O-B isotope geochemistry on mafic-ultramafic intrusions, such as the Anyi and Ertaipo intrusions, in Mouding region, Yunnan Province. The purpose of our study is doing further research about the nature and duration of postdated plume mafic magmatism, the role of lithospheric mantle and possible mechanism of partial melting of mantle lithosphere. A better understanding of the characteristics of Emeishan Plume magmatism in different stage and further improvement of the model of Emeishan mantle plume magmatism can be achieved in our research.