Introduction
In the last decade, micro-analytical facilities have increasingly come to include electron backscatter diffraction (EBSD) (Adams et al., 1993; Dingley, 1984; Venables and Harland, 1973). This application has been rapidly incorporated into the analytical geological toolbox (Prior et al., 1999). EBSD enables the systematic measurement of individual crystallographic orientations that can be used to study microstructures, internal textures, point-to-point orientation correlations, phase identification and distribution, to name but a few examples. EBSD is a scanning electron microscope (SEM) based technique and the necessary equipment can be easily added to most SEM’s. The technique can be performed either on a standard SEM with a vertical column and the specimen tilted to achieve the necessary geometry, or on a specialized SEM with an inclined column so the sample remains flat. EBSD is a surface technique, with the signal originating in the top 50nm of the sample (Lloyd, 1987a) and any damage to the crystal lattice in this surface layer will decrease the quality of the electron backscatter pattern (EBSP). Due to advances in computing capabilities and camera technology, data collection speed has increased significantly, allowing larger areas to be studied. From any sample, a single area can be studied using a variety of complementary techniques for instance, element/trace element distributions can be imaged using cathodoluminescence (CL) and measured using energy-dispersive spectroscopy (EDS), wavelength dispersive spectroscopy (WDS) or laser-ablation inductively-coupled-plasma mass-spectrometry (LA-ICP-MS) (Dingley and Randle, 1992; Martin et al., 2010). EBSD data can be used in conjunction with these other techniques to enhance our understanding of the evolution of the sample both structurally and geochemically. It also possible to perform 3D EBSD volumetric mapping by serial sectioning the sample (by repeatedly removing the sample from the SEM and grinding down a small distance) or using focused-ion-beam milling in the SEM to expose new sample surfaces for mapping. EBSD is limited to samples with a crystalline structure and grain sizes larger than several tens of nanometers. This paper presents a systematic methodology for application of EBSD to a sample, discussing how to orientate the sample for analysis, how to prepare the sample surface, guidelines on how to collect high quality EBSD data using Oxford Instruments HKL Channel 5 software and how to manipulate data and present it for interpretation.