Advances in EBSD and EBSD/EDS integration for the characterization of mineralogical samples
Abstract
Electron BackScatter Diffraction (EBSD) is a well-known powerful technique for petrofabric studies using Scanning Electron Microscope. By assessing the quantitative microstructural information, i.e. crystallographic orientation data, it allows a large variety of applications: understanding the deformation mechanisms, seismic properties, metamorphic processes; and more recently, performing phase identification and discrimination when combined with Energy Dispersive X-Ray Spectroscopy (EDS). However, it is known that for multiphase mineralogical samples, the information delivered either by EBSD or by EDS alone is not enough to successfully distinguish the present phases. Typical examples for EBSD related indexing issues are phases creating similar patterns; and for EDS technique alone, phases with similar chemical composition like calcite and aragonite, quartz and cristobalite. Recent software and hardware developments have significantly improved the data quality as well as the efficiency/productivity. This presentation aims to reveal the latest development in data processing that has transformed the combination of the two complementary techniques into a powerful tool for characterizing multiphase materials. Through geosciences application examples, we will present the advantages brought by this new approach which uses the quantified EDS results and EBSP to identify the correct phase, reducing the need of data cleaning, and without spending extra time at the SEM. We will also demonstrate how powerful EBSD indexing algorithm can overcome the limitation from sample preparation, with some examples of high hit rate achieved on polyphase mineralogical specimen and even on shock-metamorphosed minerals. Last but not least, recent developments also enable the investigation of nanostructured materials in the scanning electron microscope (SEM) by Transmission Kikuchi Diffraction (TKD). Through some mineralogical applications, we will demonstrate the high spatial resolution (<10 nm) of this technique compared to conventional EBSD. EBSD phase map of an oxide gabbro collected by the Integrated Ocean Drilling Program Expedition 304/305, U1309D. phases: clinopyroxene, clinohypersthene, magnetite, ilmenite, tremolite, plagioclase, quartz, pyrrhotite, apatite, clinochlore. Sample courtesy: Dr. Angela Halfpenny, CSIRO Perth, Australia.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.V44B..04P
- Keywords:
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- 8494 VOLCANOLOGY Instruments and techniques;
- 3625 MINERALOGY AND PETROLOGY Petrography;
- microstructures;
- and textures;
- 8194 TECTONOPHYSICS Instruments and techniques;
- 6297 PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS Instruments and techniques