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

提交EAR-8406070更新的提案“低对称性变形石灰岩的结构发育：实验和理论”，讨论了变形岩石中首选定向的地球物理和地质应用以及由此产生的各向异性。通过u级衍射、x射线衍射和中子衍射对实验和自然变形样品的织构进行了测量，并得出了定量的取向分布。然后将这些测量模式与基于泰勒理论的理论预测进行比较，但结合了新的发展，如放松约束，速率灵敏度和簇模型，这些模型提供了比严格的均匀应变更现实的物理假设。从织构图的比较中，我们获得了有关应变路径的信息（例如，我们想在美国西部的核心复合体带中研究的简单剪切与纯剪切），但泰勒计算也可用于评估塑性各向异性和最经济的应变路径。新的各向异性流动规律考虑了方解石、石英或橄榄岩的各向异性，各向异性在10 - 20%之间。最后，我们利用方向分布来计算弹性各向异性，这是已知存在于地壳和地幔中的，在评价地震资料中具有重要意义。研究的重点是单矿物岩石，但也扩展到多矿物岩石。

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.