Report on a joint meeting of the Metamorphic Studies Group and Tectonic Studies Group at Burlington House on 24 November 1982.
The meeting was opened by two introductory talks on the techniques of electron microscopy and microanalysis. Knipe outlined the basic principles involved in various formsof electron microscopy(scanning, transmission and high resolution) and the range of applicability of such methods for tackling geological problems. The combination of microstructural, crystal-lographic and geochemical information which can be obtained simultaneously from samples makes these techniques ideal for application to metamorphic rocks. Champness introduced the method of thin film analysis, contrasting this with conventional electron probe microanalysis and noting some of the problems involved and how they could be minimized. As an example of the applications of this technique she described work to examine the cause of brown staining in an olivine. TEM and microanalysis showed that particulate phases of diopside, chlorite and Fe oxide were all included in the olivine.
Lloyd described the method of backscattered SEM, both for atomic number contrast and electron channelling. He outlined the optimum sample preparation methods and illustrated someof the applications of both methods. Atomic number differences in the order of 0.1 can be imaged, enabling complex chemical zoning and inclusions to be studied, and indexing of electron channelling patterns allow variations in crystallographic orientations to be investigated between, for example, subgrains. between, for example, subgrains.
Two talks illustrated the usefulness of electron microscopy in studying experimental charges, where very small amounts of material are involved and