组构对糜棱岩流变影响的实验研究

项目名称： 组构对糜棱岩流变影响的实验研究

项目编号： No.41402189

项目类型： 青年科学基金项目

立项/批准年度： 2015

项目学科： 天文学、地球科学

项目作者： 刘贵

作者单位： 中国科学院大学

项目金额： 12万元

中文摘要： 地壳深部岩石普遍存在变形组构，组构对岩石流变影响的相关实验非常有限，尤其缺少与地壳伸展和拆离断层形成相关的各向异性岩石流变实验。本申请拟采用具有先存变形组构的花岗质糜棱岩样品，在熔融盐固体介质三轴流变仪上开展高温高压流变实验，获得压缩方向与岩石面理呈0°、30°、45°、60°和90°角度的糜棱岩流变参数；利用扫描电镜研究实验样品主要矿物的变形微观结构与变形机制，利用电子探针分析样品的成分特征；利用电子背散射（EBSD）分析样品中石英C轴定向特征在实验前后的变化，研究实验变形对样品组构的改造和置换作用，探讨拆离断层形成和演化过程中后期变形对前期变形的改造作用。把实验结果与近年来取得的均匀结构的花岗质岩石的流变实验对比，综合分析组构对糜棱岩流变的影响，并利用实验结果研究华北克拉通地区中地壳流变结构。本研究能够为深入认识拆离断层形成和演化规律及完善地壳伸展减薄模型提供必要的实验数据。

中文关键词： 组构；各向异性；压缩轴与岩石面理夹角；高温高压流变；糜棱岩

英文摘要： Rock deformation has been widespread observed from middle to lower crust. However, experimental data are scarce for performing to investigate the effect of fabric to rheology of rocks, especially, the creep experiments of anistropic rocks are still an untouched area which is related to crustal extension and the detachment faults development. This project plans to perform creep tests in Griggs-type molten salt medium triaxial machine under high temperature and pressure condition using natural fine-grained felsic mylonite samples, and get the flow laws of anistropic rocks and effect of pre-exist fabric to rheology of narural deformed rocks. To do that, the experimental samples should be drilled and polished as the angle between the compression direction of experiments and the original foliation of samples are 0°, 30°, 45°, 60°and 90° respectively. To study the fabric evolution and deformation mechanisms of major minerals, microstructures, and chemical composition both in starting samples and experimental deformed samples should be analyzed under SEM and microprobe, particularly to analyze the c-aixial changing of quartz during experimental deformation using electron backscattered diffraction (EBSD), which could reveal the information of alteration and replacement to fabric of samples after experimental deformation

英文关键词： fabric；anistropic；the angle of compression direction with foliation；high temperature and high pressure；mylonite