Neutron diffraction analysis of quartz in columnar gneiss of orthogneiss structure

The crystalline preferred orientations of quartz grains in columnar gneiss from the Erzgebirge (Southern GDR) are studied by means of neutron time-of-flight diffraction. A single component texture has been found where the trigonal axes are parallel to the tectonic a-direction. In the quartz c-axis pole figure strong maxima at ±a are connected by a girdle of intensity being not found in U-stage measurements. From the comparison with experimentally deformed quartzites and model calculations the approximate formation conditions of the given columnar gneiss could be deduced