铬铁矿矿物包裹体的聚焦离子束-透射电镜研究

铬铁矿矿物包裹体可以记录其成岩成矿时物理化学条件（温度、压力等）、化学成分演化、熔/流体富集活动规律等关键信息.然而传统的二维分析方法无法全面获取形态微小、成分复杂的包裹体信息.通过聚焦离子束-透射电镜（FIB-TEM）联用对华北克拉通遵化豆荚状铬铁矿中矿物包裹体进行观察测试，在三维空间上发现包裹体的矿物种类丰富（硅酸盐、铂族、碳酸盐等），矿物形态复杂多变，且包裹体矿物中发育位错、部分开放晶界/相界、熔流体痕迹等显微-超显微结构.因此综合矿物种类、形态、显微结构等信息推断遵化铬铁矿具有复杂的形成条件和演化过程. 

FIB-TEM Study of Mineral Inclusions in Chromite

Mineral inclusions in chromite can record key information of physicochemical conditions (pressure, temperature, etc.), evolution of chemical composition, mechanics of fluid enrichment activities when chromite and its host rock form. However, traditional two-dimensional analytical methods cannot fully reveal the information in tiny and complex inclusions. In this paper, mineral inclusions in the Zunhua podiform chromite from the North China craton were observed and tested by the focused ion beam combined with transmission electron microscopy (FIB-TEM). The mineral types of inclusions are various and mainly include silicate, platinum group mineral, carbonate, and so on. The morphology of these mineral inclusions is also various and complex. Many microstructures and ultra-microstructures are developed in these mineral inclusions such as dislocations, partially open grain/phase boundaries, fluid- or melt-present marks. Therefore, it can be inferred that the Zunhua chromite has complex formation conditions and evolution processes based on the information of mineral types, morphology, and microstructures.