Texture analysis of a muscovite-bearing quartzite: a comparison of some currently used techniques

Four well-established techniques were applied to determine the mineral text ures of a muscovite-bearing quartzite: (1) directional measurements on an o ptical U-stage; (2) X-ray; (3) neutron; and (4) electron diffraction (EBSD) . Techniques (1) and (4) are of the 'single grain' type and techniques (2) and (3) of the 'statistical' or 'volume' type. Experimental pole density di agrams were compared by means of the construction of pole figure difference s ('difference pole figures'), which led to the observation that EBSD- and U-stage derived pole figures agree well, even in detail. In contrast, pole figures derived from X-ray and neutron diffraction are clearly different fr om pole figures derived from the single grain techniques, visible as pronou nced preferred orientation in the difference pole figures. Specific propert ies of the applied techniques may be responsible for the observed differenc es, such as (1) missing proportionality to the grain volume in the single g rain methods, (2) the accessible sample volume, (3) erroneous data correcti on, or (4) statistical errors. Also the method of data treatment, which is basically different for the single grain and statistical methods, should be considered when pole figures are evaluated. Apart from purely economical c onstraints and availibility of equipment, the decision on the most suitable method for a texture determination should be based on the scientific goals and specific properties of particular techniques. Texture measurements of the statistical type are well suited for determination of bulk textures of rocks (e.g, as required for the calculation of anisotropic physical propert ies of rocks), whereas single grain measurements are advantageous for the i nvestigation of local textures and texture forming mechanisms. (C) 2000 Els evier Science Ltd. All rights reserved.