Scanning Electron Microscopy

The scanning electron microscope (SEM) is one of the most versatile pieces of equipment currently available for geological analysis and offers a wide range of imaging and analytical modes, several of which are illustrated here. More recently the SEM has become synonymous with petrofabric analysis via the technique of electron backscattered diffraction (EBSD), which has largely superceded the earlier SEM-based approach using the electron channelling (EC) effect. Click on the appropriate thumb-nail sketch for the complete image and further details on that particular SEM technique.

Schematic SEM set up.	Secondary electron image
Atomic number (Z) contrast	Electron channelling (EC) orientation contrast (OC).
Electron channelling pattern (ECP).	Original ECP indexing.
Electron Backscattered Diffraction Pattern (EBSP).	Examples of EBSD OC (FSE) images.
EBSP indexing.	Example of automated EBSD analysis.
EBSP indexing problems I: pattern superposition.	EBSP indexing problems II: pseudosymmetry.
EBSP indexing problems III: similarities in crystal structures and/or mineral composition.	Cathodoluminescence