华北克拉通北缘三叠纪下覆岩石圈地幔的性质及成因是正确理解古生代古亚洲洋板片俯冲与克拉通早中生代岩浆作用关系的关键。本项目在已有研究的基础上，选择最能够揭示源区地幔信息的大同地区三叠纪煌斑岩岩墙群作为研究对象，拟通过：（1）对斑晶（金云母）和基质进行激光Ar-Ar定年，精确限定煌斑岩的侵位时代和演化历史；（2）Re-Os同位素研究，鉴别煌斑岩在侵位过程中是否以及多大程度上受到了地壳物质混染，以选择未受混染或混染微弱的样品来反演源区地幔性质；（3）岩石学、矿物学及全岩主量、微量和Pb-Nd-Sr同位素地球化学精细研究，查明煌斑岩岩浆体系性质及成因，进而反演其源区地幔的温度、流体组成、元素和同位素组成等特征，追踪地幔富集过程，识别是否有来自古亚洲洋俯冲物质对克拉通北缘岩石圈地幔的改造。该研究将有助于进一步理解华北克拉通北缘中生代的岩浆-构造体系和克拉通破坏作用。

The subduction of Paleo-Asian Ocean beneath the North China Craton (NCC) might be related to the magmatism in early Mesozoic in this area. The nature and origin of the Triassic sub-continental lithospheric mantle (SCLM) beneath the northern margin of NCC is the key to understand their relationships. In this project, Triassic lamprophyres dike swarms in Datong area will be studied to constrain the mantle conditions. We will (1), date the phenocryst (phlogopite) and the matrix of the lamprophyres to reveal their emplacement ages and evolution processes; (2), analyze the Os isotopes of the lamprophyres to distinguish the uncontaminated and contaminated samples by crustal materials and choose the uncontaminated ones to reveal their mantle source characteristics; (3), measure the geochemical data (major and trace elements, Pb, Nd and Sr isotopes) of the lamprophyres to investigate their nature and origin, indicating the temperatures, pressures, compositions of their mantle source. All these information can verify whether the SCLM beneath the NCC was metasomatized by the subduction of Paleo-Asian Oceanic slabs, which is of great significance in understanding the Mesozoic magmatic-tectonic affinities and the destruction process of the NCC.