球粒陨石的化学组成与太阳大气非常相似，代表了太阳系最原始的物质。铁陨石和其他无球粒陨石则是由球粒陨石在小行星内部经熔融分异后的产物。但是，铁陨石与球粒陨石之间的具体和详细的成因关系和演化历史却还不清晰。.铁陨石中有一组特殊的亚类，IIE群铁陨石，内部包含了大量毫米到厘米大小的硅酸盐包体。这些包体的矿物组合、化学组成、和氧同位素组成与H群普通球粒陨石相似，这两组陨石在成因上有着密切的关系，是研究行星体早期内部熔融分异演化的极佳窗口。由于金属相和硅酸盐相两者之间存在巨大的不相溶特性，如何合理解释IIE群铁陨石的成因是国际前沿性难题。本研究项目将在矿物岩石学工作的基础上，应用离子探针原位分析技术，对IIE群铁陨石硅酸盐包体中磷酸盐矿物开展U-Pb和Pb-Pb定年分析，获取硅酸盐包体的热变质年龄、熔融分异结晶年龄、以及硅酸盐相与金属相混合的时间，从时间角度来解密IIE群铁陨石硅酸盐包体的成因。

Chondrites are primitive condensates from the solar nebula, and achondrites are differentiated products of asteroids during the early stage of the solar system formation. But the genetic link between chondrites and achondrites remain enigmatic despite long and extensive debates.. There is one subgroup of iron meteorites, IIE irons, which commonly contain mm- to cm-sized silicate inclusions. The inclusions are either primitive in compositions or fractionated alkali-silica-rich, and share strong similarities with H chondrites in terms of petrographic texture, mineral chemistry and oxygen isotopic compositions. They provide important constraints on the evolution of planetesimals and asteroids, especially with regard to the nature of metal–silicate separation and mixing. This proposal aims at the petronegesis of silicate inclusions in IIE irons with the advance of SIMS phosphate U-Pb and Pb-Pb dating techniques.