Texture Development in Limestones Deformed at Low Symmetry: Experiment and Theory

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The proposal, "Texture Development in limestones Deformed at Low Symmetry: Experiment and Theory," submittedfor renewal of EAR-8406070, addresses geophysical and geological applications of preferred orientation in deformed rocks and resulting anisotropy. Textures are measured in experimentally and naturally deformed samples y U-stage, X-ray and neutron diffraction and derive quantitative orientation distributions. These measured patterns are then be compared with theoretical predictions based on the Taylor theory but incorporating new developments such as relaxed constraints, rate sensitivity anc cluster model, which provide physically more realistic assumptions than rigorous homogeneous strain. From the comparison of texture patterns we obtain information about the strain path (e.g. simple versus pure shear which wer would like to investigate in the belt of core complexes in the Western United States) but the Taylor calculations can also be used to evaluate plastic anisotropy and the most economic strain path. New anisotropic flow laws in rocks with preferred orientatin take account of anisotropy which ranges between 10 and 20% in calcite, quartz or olivine rocks. Finally, we use orientation distributions to calculate elastic anisotropy which is known to exist in the crust and the mantle and of importance in evaluating seismic data. The study concentrates on monomineralic rocks but also is extended to polymineralic rocks.