Mechanics of Faults and Duplexes in Layered Sedimentary Rocks: Applications of Anisotropic Plastic Rheology

断层和复式构造是造成薄皮褶皱冲断楔内部构造和层状沉积岩块体变形的两种主要构造。从阿巴拉契亚山脉中部暴露良好的露头对这些结构的详细观察为理论研究提供了基础。重点介绍了基于各向异性粘性库仑材料变形理论的力学分析。将为以下三个主题开发理论结果。(1)相交的楔形断层与层状平行断层之间的相互作用，控制了层状岩石中逆冲断层的萌生和扩展。这就需要解决楔形区域内的汇流问题。(2)通过对受限层内流动不稳定性的分析，研究了双层结构的形成。(3)确定了各向异性塑性固体中速度特征的性质和方向，并用其解释了逆冲断层、扭结带和断层弯曲褶皱的铰链的力学性质。还将研究这些结构在层平行延伸中的类似情况，并将结果应用于对现有野外观测的解释。

Faults and duplexes are two major structures which contribute to the internal structure of thin-skinned fold-and-thrust wedges and the deformation of masses of layered sedimentary rock. Detailed observations of these structures from well-exposed outcrops in the central Appalachians provide the basis for a theoretical study. Emphasis is placed on mechanical analysis based on the theory for the deformation of an anisotropic cohesive Coulomb material. Theoretical results will be developed for the following three topics. (1) The interaction between intersecting wedge faults and bed-parallel faults, which controls the initiation and propagation of thrust faults in layered rock. This requires solutions for converget flow in wedge-shaped regions. (2) The initiation of duplex structures by analysis of flow instability in a confined layer. (3) The nature and orientation of velocity characteristics in an anisotropic plastic solid is determined and used to interpret the mechanical natures of thrust faults, kink bands, and the hinges of fault- bend folds. The analogs of these structutes in layer-parallel extension will also be studied, and the results applied to the interpretation of available field observations.