Crystallographic preferred orientation in albite samples deformed experimentally by dislocation and solution precipitation creep

Effect of surface orientation on dissolution rates and topography of CaF2

“…The fact that surfaces of different crystallographic orientation dissolve at different rates is consistent with results from experimentally deformed rocks (Heidelbach et al, 2000). In this case, a crystallographic preferred orientation of a polycrystalline material develops during extensive dissolution in a regime of differential stress.…”

Deformation of Granitic Rocks: Experimental Studies and Natural Examples

“…The fine-grained recrystallized zones undergo a dynamic steady state of work hardening and recovery by grain boundary bulging. Although a component of grain boundary sliding cannot be ruled out, TEM observations of recrystallized regions show a variable but high dislocation density and bulging rather than planar grain boundaries (Tullis et al 1990), and X-ray measurements show a moderately strong LPO (Heidelbach et al 2001). The optical microstructures characteristic of deformation in this low temperature dislocation creep regime are similar to those described for quartz; however, the two easy cleavage planes in feldspars allow microcracking and grain-scale fracturing to occur during the low strain, work-hardening phase of deformation.…”

“…Good results even for small volumes and fine grain sizes can be obtained with X-ray diffraction using a high intensity synchrotron source (e.g., Heidelbach et al 2001) or with EBSD (e.g., Prior and Wheeler 1999), and larger volumes can be analyzed using neutron diffraction (e.g., Wenk et al 1986), but most of the current data come from U-stage measurements. X-ray pole figures of albite samples experimentally deformed at 1.5 GPa and 900°C in general shear by regime 1 dislocation creep show maxima consistent with (001) [100] as the dominant slip system (Heidelbach et al 2001), whereas EBSD measurements on anorthite aggregates experimentally deformed at 300 MPa and 1100°C in axial compression by the same process indicate that (010)[100] was dominant (Ji et al 2000). It is not yet clear whether the difference is due to the different composition, or the difference in deformation conditions, or both.…”

Mechanical and microstructural characterization of calcium aluminosilicate (CAS) and SiO2/CAS composites deformed at high temperature and high pressure

“…Full crystallographic orientations of CAS cannot be determined using conventional X-ray due to the large number of overlapping diffraction peaks. The texture of triclinic albite (NaAlSi 3 O 8 ) has been measured by employing synchrotron X-ray goniometry, 17 but this technique is expensive and not widely available. Neutron diffraction goniometry has been applied to the measurements of plagioclase texture, 18,19 however, relatively large volumes of sample material (>1 cm 3 which is often larger than most of samples deformed experimentally [8][9][10][11] are needed for this type of measurements because neutron flux densities are generally low.…”