Authors: Michael Stipp, Bernd Leiss and Klaus Ullemeyer

Abstract
A methodical combination of Computer Integrated Polarization microscopy (CIP), X-ray goniometry and neutron diffraction analysis provides information about local texture heterogenities and their significance for the interpretation of a bulk texture. Generally, the type of the (001)-pole figure from CIP and neutron diffraction is consistent displaying a maximum parallel to Y and weaker maxima subparallel to X and Z. The related X-ray pole figure differs significantly showing effects of single crystal orientations because of the large recrystallized grain size of the sample. Despite the small amount of plagioclase, the intensity of the (20-1)-peak was strong enough to extract the (20-1)-pole figure from the neutron diffraction spectra. Both, the quartz and the plagioclase textures indicate a high temperature crystal plastic deformation.

Authors Description
A methodical combination of Computer Integrated Polarization microscopy (CIP), X-ray goniometry using the MENTEX-software for ODF calculation and neutron diffraction analysis in Dubna (Russia) provides information about local texture heterogenities and their significance for the interpretation of a bulk texture of a sample volume even in cases where the sample consists of rather large grains or polyphase aggregates. A quartz mylonite from the Tonale fault zone containing approximately 10% of plagioclase clasts has been sampled. The Tonale fault cuts the contact aureole of the Adamello pluton, it is contemporaneous with the thermal event. Consequently, the microstructure and the mineral textures of the samples can be correlated with metamorphic temperatures. The investigated sample was deformed at approximately 650°C. Generally, the type of the (001)-pole figure from CIP and neutron diffraction is consistent. There is evidence for weaker maxima subparallel to X and Z apart from the main maximum parallel to Y, which may be indicative of dominant {m} slip and subordinate {m} and (c) slip. The related X-ray pole figure differs significantly showing effects of single crystal orientations because of the large recrystallized grain size of the sample (approximately 1 to 5 mm in diameter). As the measurements of the three methods cannot be carried out over the same sample volume the intensities of the pole figures are not quantitatively comparable. The intensity of the maximum subparallel to X determined by neutron diffraction goniometry returns a value (normalized against the stronger Y-maximum) that is lower than expected by CIP and X-ray goniometry. This indicates local texture heterogenities within the samples, which can be overerstimated by CIP and X-ray goniometry. Despite the small amount of plagioclase, the intensity of the (20-1)-peak was strong enough to extract the (20-1)-pole figure from the neutron diffraction spectra. A weak but distinct maximum parallel to the lineation indicates a texture with an (010)-maximum oriented normal to the foliation. This also indicates a high temperature deformation and requires conditions in which the plagioclase was weak enough for crystal plasticity.