Marbles as building stones as well as in their natural environments show complex weathering phenomena. The most important damage scenario is based on the highly anisotropic thermal expansion coefficient a of calcite, i.e. extreme expansion parallel and contraction normal to the crystallographic c-axis. Therefore, the rock fabric and especially the latticepreferred orientation (texture) of calcite and/or dolomite as the predominant mineral phases in marbles have a significant influence on the mechanical weathering. The textures of marbles from five different locations vary from a more or less perfect prolate to moderate oblate shape of the [006] pole figure tensor. Accordingly, the texture-derived bulk thermal dilatation anisotropy covers a broad range from -0.048 to 0.680. The modelled thermal dilatations correlate with those obtained from experimental measurements. The difference in magnitude is basically explained by the microcrack fabrics which was not considered in the computations. All samples show a deterioration due to thermal treatment regardless of the strength of texture. The directional dependence of (a) the total magnitude of the thermal dilatation coefficient and (b) of the residual strain is highest in marbles with a strong texture, whereas the Carrara marble with a weak texture exhibits a uniform crack formation. The progressive loss of cohesion along grain boundaries due to dilatancy may serve as an example for the initial stage of physical weathering.

The application of Rietveld texture analysis (RTA) to time-of-flight (TOF) neutron diffraction data allows complex materials with many diffraction peaks to be investigated, for example, rocks composed of different minerals. At the recently upgraded SKAT texture diffractometer at the JINR in Dubna (Russia), which provides three alternative multidetector systems, resolution and accessible range of lattice d spacings can be adapted to sample requirements. In order to infer the optimum experimental setup and the reliability of texture estimates from complicated TOF patterns, the influence of counting statistics and various spectral resolutions on texture deconvolution was investigated. Comparing the results obtained at different resolutions and from different sections of the d patterns indicates that the textures of a four-phase sample can be determined, but using a section at small d spacings with a larger number of peak overlaps leads to smoother textures. A complex seven-phase sample shows orientation differences in addition to the smoothing effect. Weak textures and textures of the minor rock constituents are inaccurate owing to multiple peak overlaps. Consequently, good resolution is essential for RTA on such samples. Grid thinning tests confirmed that no more than 150 diffraction spectra are needed to characterize the texture of a monomineralic sample, and approximately 350 spectra are sufficient for a four-phase sample. The irregular grid point arrangement caused by the SKAT geometry has no negative consequences. research papers J. Appl. Cryst. (2014). 47, 1520-1534 Ruth Keppler et al. Potential of full pattern fit methods for texture analysis 1521 Figure 1Energy distribution of thermal neutrons at the IBR-2M reactor applying a water moderator at ambient conditions; the time of flight and wavelength range of the SKAT related to the accessible d ranges for various diffraction angles 2. research papers J. Appl. Cryst. (2014). 47, 1520-1534 Ruth Keppler et al. Potential of full pattern fit methods for texture analysis 1531

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