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

点击翻译按钮获取中文摘要

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.