Three-dimensional Analyses of Geological Materials on Nanoscale by Electron Tomography

Electron tomography (ET), an electron-microscopy-based technique that provides three-dimensional (3D) structural information from a tilt series of two-dimensional (2D) projections, has promoted the in-depth investigation of biological molecules in structural biology and the analysis of material structures on the atomic scale in physical sciences. Although ET has developed rapidly as an effective technique wherein atomic-scale resolution has been achieved by using advanced transmission electron microscopy systems, it has not been widely used by the earth and planetary science community. Herein, we verify the applicability of ET in research related to earth and planetary science. The data demonstrate that ET can be used to observe the 3D morphology of mineral grains and 3D distributions of the chemical components of earth and planetary materials. Notably, ET coupled with spectroscopy, including electron energy loss spectroscopy and energy dispersive spectroscopy, is an effective technique for studying the 3D distribution of elements and their various oxidation states in geological materials. Atomic ET is also a promising technique for detecting trace elements in host minerals. The use of ET can advance the study of earth and planetary materials because it provides additional 3D information about geological objects.