Experimentally induced deformation mechanisms in single crystal sodic plagioclase.

摘要

This dissertation is divided into four sections. The first section deals with the redesign of the small Griggs constant strain rate deformation apparatus used to perform the high temperature (T) and high pressure (P) deformation of the single crystal sodic plagioclases analyzed in this study. A numerical approach based on finite elements was used to determine which components contributed to the highest heat loss in the original design and to explore numerically new materials and geometries. New sample assemblies based on the numerical calculations were then machined and tested. The second section describes the micromechanisms of deformation observed in the deformed cores of the sodic plagioclase crystals. The third section discusses a mechanism for the enhanced rate of disordering observed during deformation experiments compared to the rate observed in hydrostatic experiments under the same P and T conditions. The last section discusses the possibility of deformation twinning in partially disordered sodic plagioclase, which is theoretically impossible, yet observed in unannealed samples favorably oriented to twinning deformed at 900(degree)C. 106 refs., 27 figs., 8 tabs. (ERA citation 15:035060)