Backscatter Electron (BSE) Microscopy of Shale
BSE imaging of shale includes preparing a polished surface using an argon-ion mill that is subsequently imaged with
backscattered electrons. The analysis is done in a high-pressure chamber. The samples do not have to have a
conductive coating (typically gold, palladium, or carbon) that can obscure the fine details of the sample surface.
This provides the ability to investigate the small-scale textural features of the shale and to be able to characterize
the organic particles and distribution of microporosity.
Scanning electron microscopy provides visual documentation of pore geometry and distribution of clay and/or
other authigenic minerals associated with the pore system of a rock.
Energy Dispersive Analysis of X-Rays (EDX)
EDX analysis is a method to determine the elemental composition of individual particles or grains in a SEM sample. The
technique takes advantage of the generation of characteristic x-rays when the electron beam encounters a sample. The
characteristic x-rays are displayed on spectrum which provides the elemental composition of a particle. 'Dot maps' can
also be generated to map the distribution of specific elements. In the example below the concentration of phosphorus (red)
correlates to the fracture-fill material in the corresponding SEM image.
Environmental Scanning Electron Microscopy
The environmental SEM provides the ability to investigate 'fresh-state' samples without drying or coating the samples.