APLIKACE TEXTURNÍ RTG-DIFRAKČNÍ ANALÝZY V TEKTONICE – KVANTIFIKACE PŘEDNOSTNÍ ORIENTACE KALCITU V KARBONÁTOVÝCH HORNINÁCH
The goal of this work was to apply texture x-ray diffraction analysis to study naturally strained rocks, in which the quantification of main preferred orientation cannot be conducted by the optical methods. This method has mainly been developed for metallography and its application in geology has been very limited so far. Samples of the fine-grained limestone have been collected from an outcrop, in which the direction of tectonic movement has been known. Thus, the tectonic situation could be correlated with the data obtained by XRD texture analysis. Analyses have been done by two devices with different geometry of experiment. The first experiment (Schulz reflection geometry) needed correction for the gain data, because of tilting of the sample, which led to the misalignment of the sample from the x-ray beam direction. The second one (in-plane geometry) has been measured, when the sample has been fixed and rotated, thus the correction was not needed. The results in a form of pole figures reflect the mechanism of deformation. The orientation of cleavage planes of calcite parallel to foliation indicates a cataclastic flow. Thus, the method could be used to study deformation mechanisms. The asymmetry of the results can show sense of shear, but it could also reflect inhomogenities of the samples.
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