Seismic Properties of Shear Zones in the Lower Continental Crust

麻粒岩相地体中出露的糜棱岩带 位于北方意大利和卑尔根弧的伊夫雷亚-韦尔巴诺带， 挪威西部，提供了低断层带的例子 伸展和挤压体制的大陆地壳， 分别 在Ivrea带内，剪切带出现在 Pogallo断裂带的糜棱岩和高温剪切 瓦莱d 'Ossola麻粒岩域的区域。 变形 超镁铁质岩也是深部岩石的重要组成部分 Ivrea区的结构水平。 卑尔根弧中的糜棱岩 叠加在斜长复合体上， 榴辉岩相矿物学特征。 该研究调查了 这些地区岩石的地震特性， 评价糜棱岩带导致地壳深部 反思 工作的主要阶段是1）抽样 两个地区的计划; 2）优选矿物的调查 糜棱岩中的方向; 3）薄片和 样品组成的地球化学研究; 4）测定 弹性常数张量的纵横波测量 在围压高达600 MPa的速度; 4）施工 通过变形和未变形的假想速度剖面 序列的

Mylonite zones exposed within the granulite facies terrains of the Ivrea-Verbano zone, northern Italy, and the Bergen Arc, western Norway, provide examples of fault zones in the lower continental crust of extensional and compressional regimes, respectively. Within the Ivrea zone, the shear zones occur as mylonites of the Pogallo fault zone and as high temperature shear zones in the granulite domain of Valle d'Ossola. Deformed ultramafic rocks are also important constituents of deep structural levels of the Ivrea zone. Mylonites in the Bergen Arc are superimposed on an anorthositic complex and are characterized by an eclogite facies mineralogy. The research investigated the seismic properties of rocks from the these zones in order to evaluate the hypothesis that mylonite zones cause deep crustal reflections. The main phases of the work are 1) a sampling program in both regions; 2) investigation of preferred mineral orientations in the mylonitic rocks; 3) thin section and geochemical study of the composition of samples; 4) determination of the elastic constant tensor by measurement of P- and S-wave velocities at confining pressures up to 600 MPa; 4) construction of hypothetical velocity profiles through deformed and undeformed sequences.