Characterising Complex Rock Samples using Symmetry

Introduction Geological samples can be extremely challenging to analyse using EBSD, not only are they non-conductive, but many rocks contain a large number of phases, typically with low symmetry and often producing relatively weak diffraction patterns. The challenge is twofold: firstly the EBSD detector needs to be sensitive enough to acquire good, high resolution EBSPs in a short time period, and secondly the software needs to be able to distinguish reliably between all the minerals present in the sample. In this application we demonstrate the power of the Symmetry® CMOS-based detector coupled with the AZtec® software for the successful analysis of a multiphase, deformed eclogite sample. The extreme sensitivity of Symmetry enables high quality diffraction patterns to be collected in just a few milliseconds, and the advanced indexing algorithms within AZtec, as well as the full integration of EDS data, ensure reliable and accurate measurement of all phases.