1:45 PM - 2:15 PM
[HRE16-06] Development of nano-fabrication and high-resolution electron microscopy techniques: their possible applications to resource geology
Keywords:microanalysis, Transmission electron microscopy, Focused ion beam
One of uniqueness of the FIB/TEM laboratory at KOCHI is a combined FIB-FESEM instrument equipped with an energy dispersive spectrometer (EDS) and a cryo-holder system . We are currently developing a FIB-fabrication scheme of fluid inclusions in minerals such as olivine and halite, so that those fluids are exposed in frozen state for their in-situ chemical analysis including X-ray elemental mapping using EDS . 3D tomography by micro X-ray CT is effective to visualize distribution of fluid inclusions especially in nontransparent minerals prior to nanofabrication and analysis by the FIB-FESEM system.
The nanoscale occurrence of fluid (as voids) and mineral inclusions can be further characterized by high-resolution TEM. This technique would be useful for mineralogical analysis of fine-grained resource materials such as deep-sea mud containing abundant rare-earth elements  and manganese deposits. As a typical example, we have mineralogically characterized several-micron-sized Mn-rich microparticles recently discovered in seafloor sediments, and found vernadite-like mineral therein based on their electron diffraction patterns and elemental mappings . We are further developing the linkage fabrication/analysis scheme to extend toward more comprehensive sample analysis including trace elemental and isotopic analyses using NanoSIMS . These microanalysis techniques would play a key role for our better understanding of environments for the formation of resource materials.
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