地外样品研究中电子探针元素面扫描分析技术的应用

Applications of Electron Probe Elemental X-ray Mapping in the Study of Extraterrestrial Materials

由于月壤等地外样品十分珍贵,在实验室研究中优先使用原位、微区、无损的元素分析方法。电子探针元素面扫描是地外样品研究中常用的分析方法之一,它可获取样品整体或者感兴趣区域的多种元素分布数据,应用于矿物相识别与含量估算,锆石等定年矿物的快速定位,矿物环带、出溶、反应边结构等特殊岩相和矿物接触关系等分析和研究。以嫦娥五号月壤、月球陨石、火星陨石研究为例,介绍目前元素面扫描的应用方法,对比、分析了电子探针面扫描技术与其他面扫描技术的优缺点和适用范围。未来十年,我国将实施一系列月球、火星、小行星等天体采样返回任务。电子探针元素面扫描分析未来将在这些地外样品研究中广泛使用。同时,建议行星科学家围绕所关心的科学问题,合理搭配多种分析方法以实现各种技术优势互补和样品科学价值最大化,服务我国月球与深空探测任务科学产出和行星科学发展。

Lunar sample and other extraterrestrial materials are extremely precious.In laboratory studies,the in-situ,micro-area,high-resolution,and non-destructive elemental analysis methods are urgently needed for extraterrestrial materials.Electron probe elemental X-ray mapping is a commonly used analytical method in the study of extraterrestrial samples.X-ray mapping could acquire the spatial distribution of chemical elements within a sample.It is extremely useful for identifying the minerals and estimating their modal abundance,locating the phase such as zircon for dating,revealing special petrographic texture(chemical zoning,exsolution,and reaction rim structures) and contact relationships among mineral phases.Taking the study of Chang′e-5 lunar soil,lunar meteorites and Martian meteorites as examples,the present application methods of elemental surface scanning are introduced.In addition,electron probe X-ray mapping are compared with other mapping techniques,aiming to provide a technical reference for related scientific research and analysis work.In the coming decade,China will return samples from the Moon,Mars,and asteroids.Electron probe elemental mapping analysis will be widely used in the study of these extraterrestrial samples.Meanwhile,we suggest that planetary scientists could combine multiple mapping methods to achieve complementary advantages of different methods and maximize the scientific value of extraterrestrial samples,which eventually benefit the scientific return of China lunar and deep space missions and the develop of planetary science.