Petrofabric and Compositional Controls of Physical Properties Across the Granulite - Eclogite Transition

先前对挪威西南部Holsnoy岛暴露的石榴石麻粒岩-榴辉岩相过渡的研究表明，地震速度和密度在一个陡峭（1米厚）的过渡中增加。这种变化的幅度被认为与变质过程中的流体输送和变形过程中的织物发育引起的成分变化（二氧化硅耗损和Fe2O3、MgO和CaO的相对富集）有关。将使用古地磁钻在暴露的反应前沿进行详细采样，以验证这一想法。由此产生的矿物学和化学成分测定将与高围压下的地震速度测量结果进行比较，以便了解控制速度变化的因素。用标准u级法对榴辉岩和麻粒岩中的主要矿物相进行详细的岩组构分析。地震速度将根据首选定向数据计算，并根据实验室在高围压下确定的速度进行测试。

Previous investigation of the garnet granulite-eclogite facies transition exposed on Holsnoy Island, southwest Norway, suggests that seismic velocity and density increases across a sharp (1 m thick) transition. The magnitude of the changes are postulated to be related to compositional changes (silica depletion and relative enrichment of Fe2O3, MgO, and CaO) caused by fluid transport during metamorphism plus fabric development during deformation. Detailed sampling, using paleomag drills, across the exposed reaction fronts will be carried out to test this idea. Resultant mineralogical and chemical compositional determinations will be compared to seismic velocity measurements at high confining pressure in order to understand the factors controlling the variations in velocity. Detailed petrofabric analysis of major mineral phases in eclogites and granulites will be made with standard U-stage methods. Seismic velocity will be calculated from the preferred orientation data and tested against velocities determined in the laboratory at high confining pressure.