The Papoose Flat Pluton: A Microstructural and Petrofabric-Based Analysis of Deformation Processes Associated with the Forceful Intrusion of a Granitic Pluton

本文将记录加利福尼亚东部帕波塞扁平岩体的应变路径和剪切感的时空变化。根据对该岩体边缘相及其周围岩石的早期岩石学研究，该岩体被认为是同轴应变场中强侵位的典型例子。然而，最近对已发表的岩体岩组构资料的重新评价表明，在岩体岩组构图中存在统一的不对称性，这与大规模非同轴剪切作用下的岩体侵位一致。显微结构和晶体结构标准将与来自旋转卟卟母细胞和收缩变质矿物组合的数据一起用于确定岩体就位期间的应变路径、温度和剪切感。运动和变形过程将因此被确定，这些数据将约束岩体就位的可能机制。本研究的结果将大大提高我们对岩体侵位机制的认识，并将在自然产生的变形微结构与实验和计算机模拟研究产生的变形微结构之间提供急需的联系。

Spatial and temporal variations in strain path and shear sense associated with emplacement will be documented for the Papoose flat pluton of eastern California. This pluton has been considered a classic example of forceful emplacement in a coaxial strain field on the basis of earlier petrographic studies of the pluton's marginal facies and its surrounding country rocks. Recent reevaluation of the published petrofabric data from the pluton shows, however, that a uniform sense of asymmetry exists in the fabric diagrams that is consistent with pluton emplacement during large scale non-coaxial shearing. Microstructural and crystallographic fabric criteria will be used with data from rotated porphyroblasts and contract metamorphic mineral assemblages to determine the strain path, temperature and shear sense during pluton emplacement. The kinematic and deformation processes operative will thus be determined and these data will constrain the possible mechanisms of pluton emplacement. The results of this study will greatly improve our understanding of pluton emplacement mechanisms in general, and will also provide a much needed link between naturally produced deformation microstructives and those produced experimentally and by computer simulation studies.