Collaborative Research: Fabric and Seismic Anisotropy within the Lithospheric Mantle: Magnetic and Petrofabric Studies of Shear Zones in the New Caledonia Ophiolite

合作研究：岩石圈地幔内的组构和地震各向异性：新喀里多尼亚蛇绿岩剪切带的磁性和岩石组构研究

• 批准号: 0337458
• 负责人: Eric Ferre
• 金额: $ 6.19万
• 依托单位: Southern Illinois University at Carbondale
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-03-01 至 2006-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0337458&HistoricalAwards=false
• 关键词: Collaborative; Research; Fabric; Seismic; Anisotropy

The development of fabric and anisotropy in mantle peridotites in natural shear zones of the New Caledonia ophiolite is being studied using a combination of electron backscatter diffraction and high-field anisotropy of magnetic susceptibility techniques to determine lattice preferred orientation. Electron backscatter diffraction provides an accurate measurement of lattice preferred orientation and yields information on slip systems and deformation temperatures. High-field anisotropy of magnetic susceptibility is a new method that provides the orientation of the fabric main axes and the degree of anisotropy by isolating the magnetic contribution of silicates. The high-field anisotropy of magnetic susceptibility method is considerably faster than electron backscatter diffraction and, therefore, allows mapping of deformation gradients at a higher resolution. The project is quantitatively establishing the degree of correlation between high-field magnetic anisotropy and mineral fabric anisotropy determined using electron backscatter diffraction and other well-established methods such as the universal stage technique. If successful, the new method will permit more rapid study of mantle fabrics over a large area, thus aiding interpretation of seismic anisotropy data from the mantle.

正在研究新喀里多尼亚蛇绿岩自然剪切带地幔橄榄岩的组构和各向异性的发展，利用电子背散射衍射和磁化率高场各向异性技术的组合来确定晶格择优取向。电子背散射衍射提供了晶格择优取向的精确测量，并产生有关滑移系统和变形温度的信息。磁化率高场各向异性是一种新方法，通过隔离硅酸盐的磁性贡献来提供织物主轴的方向和各向异性程度。磁化率的高场各向异性方法比电子背散射衍射快得多，因此可以以更高分辨率绘制变形梯度。该项目正在定量确定高场磁各向异性和矿物织物各向异性之间的相关程度，使用电子背散射衍射和其他成熟的方法（例如通用阶段技术）确定。如果成功，新方法将能够更快速地研究大面积的地幔结构，从而有助于解释地幔地震各向异性数据。